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Hao Y, Hu R, Zhang B, Zeng M, Zhang H, Ma Z, Huang Y, Chen Q, Gao K, Guan H. Stability improvement of 40Ca + optical clock by using a transportable ultra-stable cavity. OPTICS EXPRESS 2024; 32:4081-4092. [PMID: 38297616 DOI: 10.1364/oe.509502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/27/2023] [Indexed: 02/02/2024]
Abstract
The instability of the clock laser is one of the primary factors limiting the instability of the optical clocks. We present an ultra-stable clock laser based on a 30-cm-long transportable cavity with an instability of ∼3 × 10-16 at 1 s-100 s. The cavity is fixed by invar poles in three orthogonal directions to restrict the displacement, meeting the requirements of transportability and low vibration sensitivity. By applying the ultra-stable laser to a transportable 40Ca+ optical clock with a systematic uncertainty of 4.8 × 10-18 and using the real-time feedback algorithm to compensate the linear shift of the clock laser, the short-term stability of the transportable 40Ca+ optical clock has been greatly improved from 4.0×10-15/τ/s to 1.16×10-15/τ/s, measured at ∼100 s-1000 s of averaging time, enriching its applications in metrology, optical frequency comparison, and time keeping.
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2
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Lin X, Hartman MT, Zhang S, Seidelin S, Fang B, Le Coq Y. Multi-mode heterodyne laser interferometry realized via software defined radio. OPTICS EXPRESS 2023; 31:38475-38493. [PMID: 38017953 DOI: 10.1364/oe.500077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/12/2023] [Indexed: 11/30/2023]
Abstract
The agile generation and control of multiple optical frequency modes combined with the realtime processing of multi-mode data provides access to experimentation in domains such as optomechanical systems, optical information processing, and multi-mode spectroscopy. The latter, specifically spectroscopy of spectral-hole burning (SHB), has motivated our development of a multi-mode heterodyne laser interferometric scheme centered around a software-defined radio platform for signal generation and processing, with development in an entirely open-source environment. A challenge to SHB is the high level of shot noise due to the laser power constraint imposed by the spectroscopic sample. Here, we have demonstrated the production, detection, and separation of multiple optical frequency modes to the benefit of optical environment sensing for realtime phase noise subtraction as well as shot noise reduction through multi-mode averaging. This has allowed us to achieve improved noise performance in low-optical-power interferometry. Although our target application is laser stabilization via SHB in cryogenic temperature rare-earth doped crystals, these techniques may be employed in a variety of different contexts.
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3
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Kim K, Aeppli A, Bothwell T, Ye J. Evaluation of Lattice Light Shift at Low 10^{-19} Uncertainty for a Shallow Lattice Sr Optical Clock. PHYSICAL REVIEW LETTERS 2023; 130:113203. [PMID: 37001111 DOI: 10.1103/physrevlett.130.113203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 02/23/2023] [Indexed: 06/19/2023]
Abstract
A Wannier-Stark optical lattice clock has demonstrated unprecedented measurement precision for optical atomic clocks. We present a systematic evaluation of the lattice light shift, a necessary next step for establishing this system as an accurate atomic clock. With precise control of the atomic motional states in the lattice, we report accurate measurements of the multipolar and the hyperpolar contributions and the operational lattice light shift with a fractional frequency uncertainty of 3.5×10^{-19}.
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Affiliation(s)
- Kyungtae Kim
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Alexander Aeppli
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Tobias Bothwell
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
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4
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Gillot J, Falzon Tetsing-Talla S, Denis S, Goavec-Merou G, Millo J, Lacroûte C, Kersalé Y. Digital control of residual amplitude modulation at the 10 -7 level for ultra-stable lasers. OPTICS EXPRESS 2022; 30:35179-35188. [PMID: 36258475 DOI: 10.1364/oe.465597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/05/2022] [Indexed: 06/16/2023]
Abstract
The stabilization of lasers on ultra-stable optical cavities by the Pound-Drever-Hall (PDH) technique is a widely used method. The PDH method relies on the phase-modulation of the laser, which is usually performed by an electro-optic modulator (EOM). When approaching the 10-16 fractional frequency stability level, this technology requires an active control of the residual amplitude modulation (RAM) generated by the EOM in order to bring the frequency stability of the laser down to the thermal noise limit of the ultra-stable cavity. In this article, we report on the development of an active system of RAM reduction based on a free space EOM, which is used to perform PDH-stabilization of a laser on a cryogenic silicon cavity. A minimum RAM instability of 1.4 × 10-7 is obtained by employing a digital servo that stabilizes the EOM DC electric field, the crystal temperature and the laser power. Considering an ultra-stable cavity with a finesse of 2.5 × 105, this RAM level would contribute to the fractional frequency instability at the level of about 5 × 10-19, well below the state of the art thermal noise limit of a few 10-17.
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5
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Orenes DB, Sewell RJ, Lodewyck J, Mitchell MW. Improving Short-Term Stability in Optical Lattice Clocks by Quantum Nondemolition Measurement. PHYSICAL REVIEW LETTERS 2022; 128:153201. [PMID: 35499904 DOI: 10.1103/physrevlett.128.153201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/20/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
We propose a multimeasurement estimation protocol for quantum nondemolition (QND) measurements in a Rabi clock interferometer. The method is well suited for current state-of-the-art optical lattice clocks with QND measurement capabilities. The protocol exploits the correlations between multiple nondestructive measurements of the initially prepared coherent spin state. A suitable Gaussian estimator for the clock laser detuning is presented, and an analytic expression for the sensitivity of the protocol is derived. We use this analytic expression to optimize the protocol using available experimental parameters, achieving an improvement of 7.9 dB with respect to the standard quantum limit in terms of clock stability. We also discuss the measurement back-action effects of our protocol into the atomic state.
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Affiliation(s)
- Daniel Benedicto Orenes
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Robert J Sewell
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Jérôme Lodewyck
- LNE-SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, 61 avenue de l'Observatoire, F-75014 Paris, France
| | - Morgan W Mitchell
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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6
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Differential clock comparisons with a multiplexed optical lattice clock. Nature 2022; 602:425-430. [PMID: 35173344 DOI: 10.1038/s41586-021-04344-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/14/2021] [Indexed: 11/08/2022]
Abstract
Rapid progress in optical atomic clock performance has advanced the frontiers of timekeeping, metrology and quantum science1-3. Despite considerable efforts, the instabilities of most optical clocks remain limited by the local oscillator rather than the atoms themselves4,5. Here we implement a 'multiplexed' one-dimensional optical lattice clock, in which spatially resolved strontium atom ensembles are trapped in the same optical lattice, interrogated simultaneously by a shared clock laser and read-out in parallel. In synchronous Ramsey interrogations of ensemble pairs we observe atom-atom coherence times of 26 s, a 270-fold improvement over the measured atom-laser coherence time, demonstrate a relative instability of [Formula: see text] (where τ is the averaging time) and reach a relative statistical uncertainty of 8.9 × 10-20 after 3.3 h of averaging. These results demonstrate that applications involving optical clock comparisons need not be limited by the instability of the local oscillator. We further realize a miniaturized clock network consisting of 6 atomic ensembles and 15 simultaneous pairwise comparisons with relative instabilities below [Formula: see text], and prepare spatially resolved, heterogeneous ensemble pairs of all four stable strontium isotopes. These results pave the way for multiplexed precision isotope shift measurements, spatially resolved characterization of limiting clock systematics, the development of clock-based gravitational wave and dark matter detectors6-12 and new tests of relativity in the lab13-16.
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7
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Jin L. Performance manipulation of the squeezed coherent light source based on four-wave mixing. OPTICS EXPRESS 2021; 29:30198-30207. [PMID: 34614747 DOI: 10.1364/oe.435735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
We present performance manipulation of the squeezed coherent light source based on four-wave mixing (FWM) in alkaline-earth atoms. We investigate the dynamic response of the system and the spectroscopic feature of lasing generated by resonantly enhanced wave-mixing in coherently prepared system. In this method, the spectral purity and stability of the wave-mixing lasing can be manipulated at will by choosing optimal laser parameters. We also analyze the effect of Langevin noise fluctuations on the system and the relative-intensity noise spectrum of the wave-mixing lasing is well below the standard quantum limit (down to -4.7 dB). This work opens new possibilities for alternative routes to laser stabilization and provides a promising path to realize precision metrology.
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Li L, Wang J, Bi J, Zhang T, Peng J, Zhi Y, Chen L. Ultra-stable 1064-nm neodymium-doped yttrium aluminum garnet lasers with 2.5 × 10 -16 frequency instability. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:043001. [PMID: 34243418 DOI: 10.1063/5.0025498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 04/05/2021] [Indexed: 06/13/2023]
Abstract
Cavity-stabilized ultra-stable optical oscillators are one of the core ingredients in the ground-based or spaceborne precision measurements such as optical frequency metrology, test of special relativity, and gravitational wave observation. We report in detail the development of two ultra-stable systems based on 1064-nm neodymium-doped yttrium aluminum garnet lasers and 20-cm optical cavities. The optical cavities adopt ultra-low-loss silica mirrors with compensating rings. An electro-optic crystal with a wedged angle is used to reduce the residual amplitude modulation. Using two-stage thermal control, long-term stabilities of 100 µK are achieved for the outer wall of the vacuum chamber housing the optical cavity. Two additional thermal shields increased the time constant of the optical cavities to 70 h. By operating the optical cavity at the temperature of zero coefficient of thermal expansion, the frequency stability reaches 2.5 × 10-16 at 10 s averaging time and remains below 5 × 10-16 with an extended time of 1000 s after removing the first- and second-order drifts. The dependence of the laser linewidth on the measurement time is tested against a simplified theoretical model.
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Affiliation(s)
- Liufeng Li
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jia Wang
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jin Bi
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Tao Zhang
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jiankang Peng
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Yunlin Zhi
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Lisheng Chen
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
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9
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Pedrozo-Peñafiel E, Colombo S, Shu C, Adiyatullin AF, Li Z, Mendez E, Braverman B, Kawasaki A, Akamatsu D, Xiao Y, Vuletić V. Entanglement on an optical atomic-clock transition. Nature 2020; 588:414-418. [PMID: 33328668 DOI: 10.1038/s41586-020-3006-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/21/2020] [Indexed: 11/09/2022]
Abstract
State-of-the-art atomic clocks are based on the precise detection of the energy difference between two atomic levels, which is measured in terms of the quantum phase accumulated over a given time interval1-4. The stability of optical-lattice clocks (OLCs) is limited both by the interrupted interrogation of the atomic system by the local-oscillator laser (Dick noise5) and by the standard quantum limit (SQL) that arises from the quantum noise associated with discrete measurement outcomes. Although schemes for removing the Dick noise have been recently proposed and implemented4,6-8, performance beyond the SQL by engineering quantum correlations (entanglement) between atoms9-20 has been demonstrated only in proof-of-principle experiments with microwave clocks of limited stability. The generation of entanglement on an optical-clock transition and operation of an OLC beyond the SQL represent important goals in quantum metrology, but have not yet been demonstrated experimentally16. Here we report the creation of a many-atom entangled state on an OLC transition, and use it to demonstrate a Ramsey sequence with an Allan deviation below the SQL after subtraction of the local-oscillator noise. We achieve a metrological gain of [Formula: see text] decibels over the SQL by using an ensemble consisting of a few hundred ytterbium-171 atoms, corresponding to a reduction of the averaging time by a factor of 2.8 ± 0.3. Our results are currently limited by the phase noise of the local oscillator and Dick noise, but demonstrate the possible performance improvement in state-of-the-art OLCs1-4 through the use of entanglement. This will enable further advances in timekeeping precision and accuracy, with many scientific and technological applications, including precision tests of the fundamental laws of physics21-23, geodesy24-26 and gravitational-wave detection27.
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Affiliation(s)
- Edwin Pedrozo-Peñafiel
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Simone Colombo
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Chi Shu
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA
| | - Albert F Adiyatullin
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Zeyang Li
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Enrique Mendez
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Boris Braverman
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Physics and Max Planck Centre for Extreme and Quantum Photonics, University of Ottawa, Ottawa, Ontario, Canada
| | - Akio Kawasaki
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.,W. W. Hansen Experimental Physics Laboratory and Department of Physics, Stanford University, Stanford, CA, USA
| | - Daisuke Akamatsu
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.,National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Yanhong Xiao
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.,State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, and Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, China
| | - Vladan Vuletić
- Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
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10
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Loh W, Stuart J, Reens D, Bruzewicz CD, Braje D, Chiaverini J, Juodawlkis PW, Sage JM, McConnell R. Operation of an optical atomic clock with a Brillouin laser subsystem. Nature 2020; 588:244-249. [PMID: 33299197 DOI: 10.1038/s41586-020-2981-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 10/01/2020] [Indexed: 11/09/2022]
Abstract
Microwave atomic clocks have traditionally served as the 'gold standard' for precision measurements of time and frequency. However, over the past decade, optical atomic clocks1-6 have surpassed the precision of their microwave counterparts by two orders of magnitude or more. Extant optical clocks occupy volumes of more than one cubic metre, and it is a substantial challenge to enable these clocks to operate in field environments, which requires the ruggedization and miniaturization of the atomic reference and clock laser along with their supporting lasers and electronics4,7,8,9. In terms of the clock laser, prior laboratory demonstrations of optical clocks have relied on the exceptional performance gained through stabilization using bulk cavities, which unfortunately necessitates the use of vacuum and also renders the laser susceptible to vibration-induced noise. Here, using a stimulated Brillouin scattering laser subsystem that has a reduced cavity volume and operates without vacuum, we demonstrate a promising component of a portable optical atomic clock architecture. We interrogate a 88Sr+ ion with our stimulated Brillouin scattering laser and achieve a clock exhibiting short-term stability of 3.9 × 10-14 over one second-an improvement of an order of magnitude over state-of-the-art microwave clocks. This performance increase within a potentially portable system presents a compelling avenue for substantially improving existing technology, such as the global positioning system, and also for enabling the exploration of topics such as geodetic measurements of the Earth, searches for dark matter and investigations into possible long-term variations of fundamental physics constants10-12.
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Affiliation(s)
- William Loh
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA.
| | - Jules Stuart
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA.,Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David Reens
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Colin D Bruzewicz
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Danielle Braje
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - John Chiaverini
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Paul W Juodawlkis
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Jeremy M Sage
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA.,Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Robert McConnell
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
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11
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Hu C, Luo B, Pan W, Yan L, Zou X. Multipoint stable radio frequency long distance transmission over fiber based on tree topology, with user fairness and deployment flexibility. OPTICS EXPRESS 2020; 28:23874-23880. [PMID: 32752377 DOI: 10.1364/oe.394741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
In this paper, we propose a multipoint stable radio frequency (RF) optical transmission system with tree structure. Based on the principle of phase conjugation, the phase jitter induced by environment variation can be compensated by frequency mixing. Different from other schemes, the RF signal is modulated on a optical comb at local and each tooth is grouped with a near subcarrier for a user. By using wavelength division multiplexer, these groups are separated and transmitted to the multiple points over fiber. Therefore, the degradation of compensation performance caused by the wavelength difference between the common main carrier and farther subcarrier can be avoided, and the accumulated power loss induced by the branch points will be significantly reduced. In addition, an acousto-optic modulator is used at the local station to depress the impact of Rayleigh scattering. Experimentally, we demonstrate 2.4 GHz RF signal transmission to the two users over 25 and 100 km fiber during 1 × 104 seconds, and the phase jitter mean square errors are 2.50 × 10-2 and 4.27 × 10-2 rad, respectively.
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12
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Lai W, Ma YQ, Zhuang L, Liu WM. Photovoltaic Effect of Atomtronics Induced by an Artificial Gauge Field. PHYSICAL REVIEW LETTERS 2019; 122:223202. [PMID: 31283295 DOI: 10.1103/physrevlett.122.223202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/18/2019] [Indexed: 06/09/2023]
Abstract
We investigate the photovoltaic effect of atomtronics induced by an artificial gauge field in four optical potentials. Under an effective magnetic flux, the atom occupation probability would be polarized in a double-dot system, which gives rise to an atomic current. The relation between the atomic current and magnetic flux behaves like the current-phase property in a Josephson junction. A neutral particle photovoltaic cell is well defined by the atomic opened system that has an effective voltage and two different poles corresponding to two internal states of atomtronics. The atom flow is controllable by tuning the direction of incident light and other parameters. The detection of the atomic current intensity is available through an optical emission spectrum in experiments.
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Affiliation(s)
- Wenxi Lai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Applied Science, Beijing Information Science and Technology University, Beijing 100192, China
| | - Yu-Quan Ma
- School of Applied Science, Beijing Information Science and Technology University, Beijing 100192, China
| | - Lin Zhuang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-Sen University, Guangzhou 510275, China
| | - W M Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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13
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Ma Y, Meng F, Liu Y, Zhao F, Zhao G, Wang A, Zhang Z. Visible astro-comb filtered by a passively stabilized Fabry-Perot cavity. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:013102. [PMID: 30709169 DOI: 10.1063/1.5053706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 12/15/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate a compact 29.3 GHz visible astro-comb covering the spectrum from 560 nm to 700 nm. A 837 MHz Yb:fiber laser frequency comb phase locked to a Rb clock served as the seed comb to ensure the frequency stability and high side mode suppression ratio. After the visible super-continuum generation, a Fabry-Perot cavity based on ultra-low expansion glass was utilized to filter the comb teeth. The mirrors were home-made complementary chirped mirrors pair with zero net-dispersion and high reflection to guarantee no mode skipping. Those filtered comb teeth were clearly resolved in an astronomical spectrograph of 49 000 resolution, exhibiting sharp line shape, zero noise floor, and uniform exposure amplitude.
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Affiliation(s)
- Yuxuan Ma
- State Key Laboratory of Advanced Optical Communication System and Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Fei Meng
- State Key Laboratory of Advanced Optical Communication System and Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Yizhou Liu
- State Key Laboratory of Advanced Optical Communication System and Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Fei Zhao
- National Astronomical Observatories of China, Chinese Academy of Science, Beijing 100012, China
| | - Gang Zhao
- National Astronomical Observatories of China, Chinese Academy of Science, Beijing 100012, China
| | - Aimin Wang
- State Key Laboratory of Advanced Optical Communication System and Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Zhigang Zhang
- State Key Laboratory of Advanced Optical Communication System and Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
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14
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Jin L, Jiang Y, Yao Y, Yu H, Bi Z, Ma L. Laser frequency instability of 2 × 10 -16 by stabilizing to 30-cm-long Fabry-Pérot cavities at 578 nm. OPTICS EXPRESS 2018; 26:18699-18707. [PMID: 30114043 DOI: 10.1364/oe.26.018699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
Laser light at 578 nm is frequency-stabilized to two independent 30-cm-long Fabry-Pérot cavities. To achieve a thermal-noise-limited cavity length stability, the geometry and support configuration of the Fabry-Pérot cavities are optimized. The fractional frequency instability of each cavity-stabilized laser system is 2 × 10-16 at 1 s averaging time, approaching to the thermal-noise-induced length instability of the reference cavity. The most probable linewidth of each laser system is about 0.2 Hz, and the laser frequency noise at Fourier frequency of 1 Hz is 0.1 Hz/√Hz.
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15
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Mehlstäubler TE, Grosche G, Lisdat C, Schmidt PO, Denker H. Atomic clocks for geodesy. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:064401. [PMID: 29667603 DOI: 10.1088/1361-6633/aab409] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We review experimental progress on optical atomic clocks and frequency transfer, and consider the prospects of using these technologies for geodetic measurements. Today, optical atomic frequency standards have reached relative frequency inaccuracies below 10-17, opening new fields of fundamental and applied research. The dependence of atomic frequencies on the gravitational potential makes atomic clocks ideal candidates for the search for deviations in the predictions of Einstein's general relativity, tests of modern unifying theories and the development of new gravity field sensors. In this review, we introduce the concepts of optical atomic clocks and present the status of international clock development and comparison. Besides further improvement in stability and accuracy of today's best clocks, a large effort is put into increasing the reliability and technological readiness for applications outside of specialized laboratories with compact, portable devices. With relative frequency uncertainties of 10-18, comparisons of optical frequency standards are foreseen to contribute together with satellite and terrestrial data to the precise determination of fundamental height reference systems in geodesy with a resolution at the cm-level. The long-term stability of atomic standards will deliver excellent long-term height references for geodetic measurements and for the modelling and understanding of our Earth.
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Affiliation(s)
- Tanja E Mehlstäubler
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
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16
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Campbell SL, Hutson RB, Marti GE, Goban A, Darkwah Oppong N, McNally RL, Sonderhouse L, Robinson JM, Zhang W, Bloom BJ, Ye J. A Fermi-degenerate three-dimensional optical lattice clock. Science 2018; 358:90-94. [PMID: 28983047 DOI: 10.1126/science.aam5538] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 06/04/2017] [Accepted: 08/24/2017] [Indexed: 11/02/2022]
Abstract
Strontium optical lattice clocks have the potential to simultaneously interrogate millions of atoms with a high spectroscopic quality factor of 4 × 1017 Previously, atomic interactions have forced a compromise between clock stability, which benefits from a large number of atoms, and accuracy, which suffers from density-dependent frequency shifts. Here we demonstrate a scalable solution that takes advantage of the high, correlated density of a degenerate Fermi gas in a three-dimensional (3D) optical lattice to guard against on-site interaction shifts. We show that contact interactions are resolved so that their contribution to clock shifts is orders of magnitude lower than in previous experiments. A synchronous clock comparison between two regions of the 3D lattice yields a measurement precision of 5 × 10-19 in 1 hour of averaging time.
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Affiliation(s)
- S L Campbell
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA.,Department of Physics, University of Colorado Boulder, 390 UCB, Boulder, CO 80309, USA
| | - R B Hutson
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA.,Department of Physics, University of Colorado Boulder, 390 UCB, Boulder, CO 80309, USA
| | - G E Marti
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - A Goban
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - N Darkwah Oppong
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - R L McNally
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA.,Department of Physics, University of Colorado Boulder, 390 UCB, Boulder, CO 80309, USA
| | - L Sonderhouse
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA.,Department of Physics, University of Colorado Boulder, 390 UCB, Boulder, CO 80309, USA
| | - J M Robinson
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA.,Department of Physics, University of Colorado Boulder, 390 UCB, Boulder, CO 80309, USA
| | - W Zhang
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - B J Bloom
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA.,Department of Physics, University of Colorado Boulder, 390 UCB, Boulder, CO 80309, USA
| | - J Ye
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA. .,Department of Physics, University of Colorado Boulder, 390 UCB, Boulder, CO 80309, USA
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17
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Shang H, Zhang X, Zhang S, Pan D, Chen H, Chen J. Miniaturized calcium beam optical frequency standard using fully-sealed vacuum tube with 10 -15 instability. OPTICS EXPRESS 2017; 25:30459-30467. [PMID: 29221074 DOI: 10.1364/oe.25.030459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
We implement a miniaturized calcium beam optical frequency standard using specially-designed fully-sealed vacuum tube, and realize the comparison with another calcium beam optical clock whose vacuum tube is sealed by flanges. The electron shelving detection method is adopted to improve the signal-to-noise ratio of the clock transition spectroscopy, and the readout laser is locked by modulation-free frequency locking technology based on Doppler effect. Injection locking is carried out to boost the power of the 657 nm master clock transition laser, thus ensuring the comparison. The fractional instability of the miniaturized calcium beam optical frequency standard using fully-sealed vacuum tube is 1.8×10-15 after 1600 s of averaging. Total volume of the system except for electronics is about 0.3 m3. To our knowledge, it's the first time to realize the optical frequency standard using fully-sealed vacuum tube. This work will promote the miniaturization and transportability of the optical clock based on atomic beam.
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18
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Zhang S, Zhang X, Cui J, Jiang Z, Shang H, Zhu C, Chang P, Zhang L, Tu J, Chen J. Compact Rb optical frequency standard with 10 -15 stability. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:103106. [PMID: 29092459 DOI: 10.1063/1.5006962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We achieved a low-cost and small-sized Rb optical frequency standard based on 85Rb 5S1/2 → 6P3/2 transition with 10-15 stability, which is comparable with that of the best 532 nm I2 optical frequency standards. In this system, we directly lock the 420 nm diode laser on the 5S1/2 F = 3 → 6P3/2 F' = 4 hyperfine transition line without an additional Pound-Drever-Hall pre-locking system. The signal-to-noise-ratio reaches as high as 350 000 when the averaging time is at 1 s. Eventually by the fluctuation of the residual error signal after locking, the preliminary stability of the optical frequency standard reaches 1.2×10-14/τ, decreasing to 2.1 × 10-15 at 80 s. It shows potential in stability performance, experimental cost, and system volume compared with the 532 nm I2 optical frequency standard as a wavelength standard. It also opens a door for the achievement of wavelength standards by using higher excited states of alkalies.
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Affiliation(s)
- Shengnan Zhang
- State Key Laboratory of Advanced Optical Communication Systems and Networks, and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Xiaogang Zhang
- State Key Laboratory of Advanced Optical Communication Systems and Networks, and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Jingzhong Cui
- National Key Laboratory of Science and Technology on Vacuum Technology and Physics, Lanzhou Institute of Physics, CAST, Lanzhou, Gansu 730000, China
| | - Zhaojie Jiang
- State Key Laboratory of Advanced Optical Communication Systems and Networks, and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Haosen Shang
- State Key Laboratory of Advanced Optical Communication Systems and Networks, and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Chuanwen Zhu
- State Key Laboratory of Advanced Optical Communication Systems and Networks, and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Pengyuan Chang
- State Key Laboratory of Advanced Optical Communication Systems and Networks, and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
| | - Ling Zhang
- National Key Laboratory of Science and Technology on Vacuum Technology and Physics, Lanzhou Institute of Physics, CAST, Lanzhou, Gansu 730000, China
| | - Jianhui Tu
- National Key Laboratory of Science and Technology on Vacuum Technology and Physics, Lanzhou Institute of Physics, CAST, Lanzhou, Gansu 730000, China
| | - Jingbiao Chen
- State Key Laboratory of Advanced Optical Communication Systems and Networks, and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China
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19
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Hollberg L, Cornell EH, Abdelrahmann A. Optical atomic phase reference and timing. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0241. [PMID: 28652494 PMCID: PMC5487717 DOI: 10.1098/rsta.2016.0241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/07/2016] [Indexed: 06/07/2023]
Abstract
Atomic clocks based on laser-cooled atoms have made tremendous advances in both accuracy and stability. However, advanced clocks have not found their way into widespread use because there has been little need for such high performance in real-world/commercial applications. The drive in the commercial world favours smaller, lower-power, more robust compact atomic clocks that function well in real-world non-laboratory environments. Although the high-performance atomic frequency references are useful to test Einstein's special relativity more precisely, there are not compelling scientific arguments to expect a breakdown in special relativity. On the other hand, the dynamics of gravity, evidenced by the recent spectacular results in experimental detection of gravity waves by the LIGO Scientific Collaboration, shows dramatically that there is new physics to be seen and understood in space-time science. Those systems require strain measurements at less than or equal to 10-20 As we discuss here, cold atom optical frequency references are still many orders of magnitude away from the frequency stability that should be achievable with narrow-linewidth quantum transitions and large numbers of very cold atoms, and they may be able to achieve levels of phase stability, ΔΦ/Φtotal ≤ 10-20, that could make an important impact in gravity wave science.This article is part of the themed issue 'Quantum technology for the 21st century'.
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Affiliation(s)
- L Hollberg
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - E H Cornell
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - A Abdelrahmann
- Department of Physics, Stanford University, Stanford, CA 94305, USA
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20
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Chasing the thermodynamical noise limit in whispering-gallery-mode resonators for ultrastable laser frequency stabilization. Nat Commun 2017; 8:8. [PMID: 28364116 PMCID: PMC5431900 DOI: 10.1038/s41467-017-00021-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 02/20/2017] [Indexed: 11/11/2022] Open
Abstract
Ultrastable high-spectral-purity lasers have served as the cornerstone behind optical atomic clocks, quantum measurements, precision optical microwave generation, high-resolution optical spectroscopy, and sensing. Hertz-level lasers stabilized to high-finesse Fabry-Pérot cavities are typically used for these studies, which are large and fragile and remain laboratory instruments. There is a clear demand for rugged miniaturized lasers with stabilities comparable to those of bulk lasers. Over the past decade, ultrahigh-Q optical whispering-gallery-mode resonators have served as a platform for low-noise microlasers but have not yet reached the stabilities defined by their fundamental noise. Here, we show the noise characteristics of whispering-gallery-mode resonators and demonstrate a resonator-stabilized laser at this limit by compensating the intrinsic thermal expansion, allowing a sub-25 Hz linewidth and a 32 Hz Allan deviation. We also reveal the environmental sensitivities of the resonator at the thermodynamical noise limit and long-term frequency drifts governed by random-walk-noise statistics. High-quality optical resonators have the potential to provide a miniaturized frequency reference for metrology and sensing but they often lack stability. Here, Lim et al. experimentally characterize the stability of whispering-gallery resonators at their fundamental noise limits.
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21
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Wiens E, Nevsky AY, Schiller S. Resonator with Ultrahigh Length Stability as a Probe for Equivalence-Principle-Violating Physics. PHYSICAL REVIEW LETTERS 2016; 117:271102. [PMID: 28084778 DOI: 10.1103/physrevlett.117.271102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Indexed: 06/06/2023]
Abstract
In order to investigate the long-term dimensional stability of matter, we have operated an optical resonator fabricated from crystalline silicon at 1.5 K continuously for over one year and repeatedly compared its resonance frequency f_{res} with the frequency of a GPS-monitored hydrogen maser. After allowing for an initial settling time, over a 163-day interval we found a mean fractional drift magnitude |f_{res}^{-1}df_{res}/dt|<1.4×10^{-20}/s. The resonator frequency is determined by the physical length and the speed of light and we measure it with respect to the atomic unit of time. Thus the bound rules out, to first order, a hypothetical differential effect of the Universe's expansion on rulers and atomic clocks. We also constrain a hypothetical violation of the principle of local position invariance for resonator-based clocks and derive bounds for the strength of space-time fluctuations.
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Affiliation(s)
- E Wiens
- Institut für Experimentalphysik, Heinrich-Heine-Universtität Düsseldorf, 40225 Düsseldorf, Germany
| | - A Yu Nevsky
- Institut für Experimentalphysik, Heinrich-Heine-Universtität Düsseldorf, 40225 Düsseldorf, Germany
| | - S Schiller
- Institut für Experimentalphysik, Heinrich-Heine-Universtität Düsseldorf, 40225 Düsseldorf, Germany
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22
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Yao Y, Jiang Y, Yu H, Bi Z, Ma L. Optical frequency divider with division uncertainty at the 10−21 level. Natl Sci Rev 2016. [DOI: 10.1093/nsr/nww063] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Optical clocks with unprecedented accuracy of 10−18 promise innovations in many research areas. Their applications rely to a large extent on the ability of precisely converting the frequency from one optical clock to another, or particularly to the frequencies in the fiber telecom band for long-distance transmission. This report demonstrates a low-noise, high-precision optical frequency divider, which realizes accurate optical frequency conversion and enables precise measurement of optical frequency ratios. By measuring against the frequency ratio between the fundamental and the second harmonic of a 1064-nm laser instead of a second copy of the same system, we demonstrate that the optical frequency divider has a fractional frequency division instability of 6 × 10−19 at 1 s and a fractional frequency division uncertainty of 1.4 × 10−21. The remarkable numbers can support frequency division of the best optical clocks in the world without frequency-conversion-caused degradation of their performance.
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Affiliation(s)
- Yuan Yao
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Yanyi Jiang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
| | - Hongfu Yu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Zhiyi Bi
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
| | - Longsheng Ma
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
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23
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Abstract
Abstract
Precision measurement and frequency metrology have pushed many scientific and technological frontiers in the field of atomic, molecular and optical physics. In this article, we provide a brief review on the recent development of optical atomic clocks, with an emphasis placed on the important inter-dependence between measurement precision and systematic effects. After presenting a general discussion on the motivation and techniques behind the development of optical lattice clocks, where the use of many atoms greatly enhances the measurement precision, we present the JILA strontium optical lattice clock as the leading system of frequency metrology with the lowest total uncertainty, and we describe other related research activities. We discuss key ingredients that have enabled the optical lattice clocks with ultracold atoms to reach the 18th digit in both precision and accuracy. Furthermore, we discuss extending the power of precision clock spectroscopy to study quantum many-body physics and to provide control for atomic quantum materials. In addition, we explore future research directions that have the potential to achieve even greater precision.
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Affiliation(s)
- Xibo Zhang
- JILA, NIST and University of Colorado, 440 UCB, Boulder, CO 80309, USA
| | - Jun Ye
- JILA, NIST and University of Colorado, 440 UCB, Boulder, CO 80309, USA
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24
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Ultralow noise miniature external cavity semiconductor laser. Nat Commun 2015; 6:7371. [PMID: 26104321 PMCID: PMC4491184 DOI: 10.1038/ncomms8371] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/30/2015] [Indexed: 11/08/2022] Open
Abstract
Advanced applications in optical metrology demand improved lasers with high spectral purity, in form factors that are small and insensitive to environmental perturbations. While laboratory-scale lasers with extraordinarily high stability and low noise have been reported, all-integrated chip-scale devices with sub-100 Hz linewidth have not been previously demonstrated. Lasers integrated with optical microresonators as external cavities have the potential for substantial reduction of noise. However, stability and spectral purity improvements of these lasers have only been validated with rack-mounted support equipment, assembled with fibre lasers to marginally improve their noise performance. In this work we report on a realization of a heterogeneously integrated, chip-scale semiconductor laser featuring 30-Hz integral linewidth as well as sub-Hz instantaneous linewidth.
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25
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Lindkvist J, Sabín C, Johansson G, Fuentes I. Motion and gravity effects in the precision of quantum clocks. Sci Rep 2015; 5:10070. [PMID: 25988238 PMCID: PMC4437316 DOI: 10.1038/srep10070] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 03/27/2015] [Indexed: 11/09/2022] Open
Abstract
We show that motion and gravity affect the precision of quantum clocks. We consider a localised quantum field as a fundamental model of a quantum clock moving in spacetime and show that its state is modified due to changes in acceleration. By computing the quantum Fisher information we determine how relativistic motion modifies the ultimate bound in the precision of the measurement of time. While in the absence of motion the squeezed vacuum is the ideal state for time estimation, we find that it is highly sensitive to the motion-induced degradation of the quantum Fisher information. We show that coherent states are generally more resilient to this degradation and that in the case of very low initial number of photons, the optimal precision can be even increased by motion. These results can be tested with current technology by using superconducting resonators with tunable boundary conditions.
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Affiliation(s)
- Joel Lindkvist
- Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Göteborg, Sweden
| | - Carlos Sabín
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingam NG7 2RD, United Kingdom
| | - Göran Johansson
- Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Göteborg, Sweden
| | - Ivette Fuentes
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
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26
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Häfner S, Falke S, Grebing C, Vogt S, Legero T, Merimaa M, Lisdat C, Sterr U. 8 × 10⁻¹⁷ fractional laser frequency instability with a long room-temperature cavity. OPTICS LETTERS 2015; 40:2112-2115. [PMID: 25927798 DOI: 10.1364/ol.40.002112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a laser system based on a 48 cm long optical glass resonator. The large size requires a sophisticated thermal control and optimized mounting design. A self-balancing mounting was essential to reliably reach sensitivities to acceleration of below Δν/ν<2×10(-10)/g in all directions. Furthermore, fiber noise cancellations from a common reference point near the laser diode to the cavity mirror and to additional user points (Sr clock and frequency comb) are implemented. Through comparison with other cavity-stabilized lasers and with a strontium lattice clock, instability of below 1×10(-16) at averaging times from 1 to 1000 s is revealed.
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27
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Nicholson T, Campbell S, Hutson R, Marti G, Bloom B, McNally R, Zhang W, Barrett M, Safronova M, Strouse G, Tew W, Ye J. Systematic evaluation of an atomic clock at 2 × 10(-18) total uncertainty. Nat Commun 2015; 6:6896. [PMID: 25898253 PMCID: PMC4411304 DOI: 10.1038/ncomms7896] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 03/11/2015] [Indexed: 11/24/2022] Open
Abstract
The pursuit of better atomic clocks has advanced many research areas, providing better quantum state control, new insights in quantum science, tighter limits on fundamental constant variation and improved tests of relativity. The record for the best stability and accuracy is currently held by optical lattice clocks. Here we take an important step towards realizing the full potential of a many-particle clock with a state-of-the-art stable laser. Our (87)Sr optical lattice clock now achieves fractional stability of 2.2 × 10(-16) at 1 s. With this improved stability, we perform a new accuracy evaluation of our clock, reducing many systematic uncertainties that limited our previous measurements, such as those in the lattice ac Stark shift, the atoms' thermal environment and the atomic response to room-temperature blackbody radiation. Our combined measurements have reduced the total uncertainty of the JILA Sr clock to 2.1 × 10(-18) in fractional frequency units.
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Affiliation(s)
- T.L. Nicholson
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - S.L. Campbell
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - R.B. Hutson
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - G.E. Marti
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - B.J. Bloom
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - R.L. McNally
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - W. Zhang
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - M.D. Barrett
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Centre for Quantum Technologies, 3 Science Drive 2, Singapore 117543, Singapore
| | - M.S. Safronova
- University of Delaware, Newark, Delaware 19716, USA
- Joint Quantum Institute, NIST and the University of Maryland, College Park, Maryland 20899, USA
| | - G.F. Strouse
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - W.L. Tew
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - J. Ye
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
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28
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Westergaard PG, Christensen BTR, Tieri D, Matin R, Cooper J, Holland M, Ye J, Thomsen JW. Observation of motion-dependent nonlinear dispersion with narrow-linewidth atoms in an optical cavity. PHYSICAL REVIEW LETTERS 2015; 114:093002. [PMID: 25793810 DOI: 10.1103/physrevlett.114.093002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Indexed: 06/04/2023]
Abstract
As an alternative to state-of-the-art laser frequency stabilization using ultrastable cavities, it has been proposed to exploit the nonlinear effects from coupling of atoms with a narrow transition to an optical cavity. Here, we have constructed such a system and observed nonlinear phase shifts of a narrow optical line by a strong coupling of a sample of strontium-88 atoms to an optical cavity. The sample temperature of a few mK provides a domain where the Doppler energy scale is several orders of magnitude larger than the narrow linewidth of the optical transition. This makes the system sensitive to velocity dependent multiphoton scattering events (Dopplerons) that affect the cavity field transmission and phase. By varying the number of atoms and the intracavity power, we systematically study this nonlinear phase signature which displays roughly the same features as for much lower temperature samples. This demonstration in a relatively simple system opens new possibilities for alternative routes to laser stabilization at the sub-100 mHz level and superradiant laser sources involving narrow-line atoms. The understanding of relevant motional effects obtained here has direct implications for other atomic clocks when used in relation to ultranarrow clock transitions.
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Affiliation(s)
- Philip G Westergaard
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
- Danish Fundamental Metrology, Matematiktorvet 307, 1 sal, 2800 Kongens Lyngby, Denmark
| | - Bjarke T R Christensen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - David Tieri
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Rastin Matin
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - John Cooper
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Murray Holland
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Jan W Thomsen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
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29
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Dai X, Jiang Y, Hang C, Bi Z, Ma L. Thermal analysis of optical reference cavities for low sensitivity to environmental temperature fluctuations. OPTICS EXPRESS 2015; 23:5134-5146. [PMID: 25836547 DOI: 10.1364/oe.23.005134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The temperature stability of optical reference cavities is significant in state-of-the-art ultra-stable narrow-linewidth laser systems. In this paper, the thermal time constant and thermal sensitivity of reference cavities are analyzed when reference cavities respond to environmental perturbations via heat transfer of thermal conduction and thermal radiation separately. The analysis as well as simulation results indicate that a reference cavity enclosed in multiple layers of thermal shields with larger mass, higher thermal capacity and lower emissivity is found to have a larger thermal time constant and thus a smaller sensitivity to environmental temperature perturbations. The design of thermal shields for reference cavities may vary according to experimentally achievable temperature stability and the coefficient of thermal expansion of reference cavities. A temperature fluctuation-induced length instability of reference cavities as low as 6 × 10(-16) on a day timescale can be achieved if a two-layer thermal shield is inserted between a cavity with the coefficient of thermal expansion of 1 × 10(-10) /K and an outer vacuum chamber with temperature fluctuation amplitude of 1 mK and period of 24 hours.
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30
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Cazalilla MA, Rey AM. Ultracold Fermi gases with emergent SU(N) symmetry. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:124401. [PMID: 25429615 DOI: 10.1088/0034-4885/77/12/124401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We review recent experimental and theoretical progress on ultracold alkaline-earth Fermi gases with emergent SU(N) symmetry. Emphasis is placed on describing the ground-breaking experimental achievements of recent years. The latter include (1) the cooling to below quantum degeneracy of various isotopes of ytterbium and strontium, (2) the demonstration of optical Feshbach resonances and the optical Stern-Gerlach effect, (3) the realization of a Mott insulator of (173)Yb atoms, (4) the creation of various kinds of Fermi-Bose mixtures and (5) the observation of many-body physics in optical lattice clocks. On the theory side, we survey the zoo of phases that have been predicted for both gases in a trap and loaded into an optical lattice, focusing on two and three dimensional systems. We also discuss some of the challenges that lie ahead for the realization of such phases such as reaching the temperature scale required to observe magnetic and more exotic quantum orders. The challenge of dealing with collisional relaxation of excited electronic levels is also discussed.
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Affiliation(s)
- Miguel A Cazalilla
- Department of Physics, National Tsing Hua University and National Center for Theoretical Sciences, Hsinchu City, Taiwan. Donostia International Physics Center (DIPC), Manuel de Lardizabal, 4. 20018 San Sebastian, Spain
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31
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Hagemann C, Grebing C, Lisdat C, Falke S, Legero T, Sterr U, Riehle F, Martin MJ, Ye J. Ultrastable laser with average fractional frequency drift rate below 5 × 10⁻¹⁹/s. OPTICS LETTERS 2014; 39:5102-5105. [PMID: 25166084 DOI: 10.1364/ol.39.005102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Cryogenic single-crystal optical cavities have the potential to provide high dimensional stability. We have investigated the long-term performance of an ultrastable laser system that is stabilized to a single-crystal silicon cavity operated at 124 K. Utilizing a frequency comb, the laser is compared to a hydrogen maser that is referenced to a primary caesium fountain standard and to the 87Sr optical lattice clock at Physikalisch-Technische Bundesanstalt (PTB). With fractional frequency instabilities of σ(y)(τ)≤2×10(-16) for averaging times of τ=60 s to 1000 s and σ(y)(1 d)≤2×10(-15) the stability of this laser, without any aid from an atomic reference, surpasses the best known microwave standards for short averaging times and is competitive with the best known hydrogen masers for longer times of 1 day. The comparison of modeled thermal response of the cavity with measured data indicates an average fractional frequency drift below 5×10(-19)/s, which we do not expect to be a fundamental limit.
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32
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Zhang X, Bishof M, Bromley SL, Kraus CV, Safronova MS, Zoller P, Rey AM, Ye J. Spectroscopic observation of SU(N)-symmetric interactions in Sr orbital magnetism. Science 2014; 345:1467-73. [DOI: 10.1126/science.1254978] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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33
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Wiens E, Chen QF, Ernsting I, Luckmann H, Rosowski U, Nevsky A, Schiller S. Silicon single-crystal cryogenic optical resonator. OPTICS LETTERS 2014; 39:3242-3245. [PMID: 24876023 DOI: 10.1364/ol.39.003242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report on the demonstration and characterization of a silicon optical resonator for laser frequency stabilization, operating in the deep cryogenic regime at temperatures as low as 1.5 K. Robust operation was achieved, with absolute frequency drift less than 20 Hz over 1 h. This stability allowed sensitive measurements of the resonator thermal expansion coefficient (α). We found that α=4.6×10(-13) K(-1) at 1.6 K. At 16.8 K α vanishes, with a derivative equal to -6×10(-10) K(-2). The temperature of the resonator was stabilized to a level below 10 μK for averaging times longer than 20 s. The sensitivity of the resonator frequency to a variation of the laser power was also studied. The corresponding sensitivities and the expected Brownian noise indicate that this system should enable frequency stabilization of lasers at the low-10(-17) level.
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34
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Kessler EM, Kómár P, Bishof M, Jiang L, Sørensen AS, Ye J, Lukin MD. Heisenberg-limited atom clocks based on entangled qubits. PHYSICAL REVIEW LETTERS 2014; 112:190403. [PMID: 24877919 DOI: 10.1103/physrevlett.112.190403] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Indexed: 06/03/2023]
Abstract
We present a quantum-enhanced atomic clock protocol based on groups of sequentially larger Greenberger-Horne-Zeilinger (GHZ) states that achieves the best clock stability allowed by quantum theory up to a logarithmic correction. Importantly the protocol is designed to work under realistic conditions where the drift of the phase of the laser interrogating the atoms is the main source of decoherence. The simultaneous interrogation of the laser phase with a cascade of GHZ states realizes an incoherent version of the phase estimation algorithm that enables Heisenberg-limited operation while extending the coherent interrogation time beyond the laser noise limit. We compare and merge the new protocol with existing state of the art interrogation schemes, and identify the precise conditions under which entanglement provides an advantage for clock stabilization: it allows a significant gain in the stability for short averaging time.
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Affiliation(s)
- E M Kessler
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA and ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
| | - P Kómár
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA
| | - M Bishof
- JILA, National Institute of Standards and Technology, Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - L Jiang
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - A S Sørensen
- QUANTOP, Danish National Research Foundation Centre of Quantum Optics, Niels Bohr Institute, DK-2100 Copenhagen, Denmark
| | - J Ye
- JILA, National Institute of Standards and Technology, Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - M D Lukin
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA
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35
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Dubé P, Madej AA, Tibbo M, Bernard JE. High-accuracy measurement of the differential scalar polarizability of a 88Sr+ clock using the time-dilation effect. PHYSICAL REVIEW LETTERS 2014; 112:173002. [PMID: 24836242 DOI: 10.1103/physrevlett.112.173002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Indexed: 06/03/2023]
Abstract
We report a high-accuracy measurement of the differential static scalar polarizability Δα(0) of the 5s(2)S(1/2)-4d(2)D(5/2) transition of the (88)Sr(+) ion. The high accuracy is obtained by comparing the micromotion-induced positive scalar Stark shift to the negative time-dilation shift. Measurement of the trap drive frequency where these shifts cancel is used to determine Δα(0) without the need to determine the electric field. Δα(0) is a critical parameter for the operation of frequency standards as it determines the blackbody radiation frequency shift coefficient, the largest source of uncertainty in the (88)Sr(+) ion clock. The measured value of Δα(0) is -4.7938(71) × 10(-40) J m(2)/V(2). Taking into account the dynamic correction, the blackbody shift at 300 K is 0.247,99(37) Hz. The contribution of the blackbody shift coefficient to the uncertainty of the ion standard has been reduced by a factor of 24, from 2 × 10(-17) to 8.3 × 10(-19). The revised total uncertainty of our reference standard is 1.2 × 10(-17), limited by the blackbody field evaluation. An additional benefit of the low uncertainty of Δα(0) is the ability to suppress, by a factor of about 200, the net micromotion frequency shifts.
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Affiliation(s)
- Pierre Dubé
- Frequency and Time Group, Measurement Science and Standards Portfolio, National Research Council of Canada, Ottawa, Canada K1A 0R6
| | - Alan A Madej
- Frequency and Time Group, Measurement Science and Standards Portfolio, National Research Council of Canada, Ottawa, Canada K1A 0R6
| | - Maria Tibbo
- Frequency and Time Group, Measurement Science and Standards Portfolio, National Research Council of Canada, Ottawa, Canada K1A 0R6
| | - John E Bernard
- Frequency and Time Group, Measurement Science and Standards Portfolio, National Research Council of Canada, Ottawa, Canada K1A 0R6
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36
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Zhang W, Martin MJ, Benko C, Hall JL, Ye J, Hagemann C, Legero T, Sterr U, Riehle F, Cole GD, Aspelmeyer M. Reduction of residual amplitude modulation to 1 × 10⁻⁶ for frequency modulation and laser stabilization. OPTICS LETTERS 2014; 39:1980-1983. [PMID: 24686654 DOI: 10.1364/ol.39.001980] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Active control and cancellation of residual amplitude modulation (RAM) in phase modulation of an optical carrier is one of the key technologies for achieving the ultimate stability of a laser locked to an ultrastable optical cavity. Furthermore, such techniques are versatile tools in various frequency modulation-based spectroscopy applications. In this Letter we report a simple and robust approach to actively stabilize RAM in an optical phase modulation process. We employ a waveguide-based electro-optic modulator (EOM) to provide phase modulation and implement an active servo with both DC electric field and temperature feedback onto the EOM to cancel both the in-phase and quadrature components of the RAM. This technique allows RAM control on the parts-per-million level where RAM-induced frequency instability is comparable to or lower than the fundamental thermal noise limit of the best available optical cavities.
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37
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Koller AP, Beverland M, Gorshkov AV, Rey AM. Beyond the spin model approximation for Ramsey spectroscopy. PHYSICAL REVIEW LETTERS 2014; 112:123001. [PMID: 24724647 DOI: 10.1103/physrevlett.112.123001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Indexed: 06/03/2023]
Abstract
Ramsey spectroscopy has become a powerful technique for probing nonequilibrium dynamics of internal (pseudospin) degrees of freedom of interacting systems. In many theoretical treatments, the key to understanding the dynamics has been to assume the external (motional) degrees of freedom are decoupled from the pseudospin degrees of freedom. Determining the validity of this approximation-known as the spin model approximation-has not been addressed in detail. Here we shed light in this direction by calculating Ramsey dynamics exactly for two interacting spin-1/2 particles in a harmonic trap. We focus on s-wave-interacting fermions in quasi one- and two-dimensional geometries. We find that in one dimension the spin model assumption works well over a wide range of experimentally relevant conditions, but can fail at time scales longer than those set by the mean interaction energy. Surprisingly, in two dimensions a modified version of the spin model is exact to first order in the interaction strength. This analysis is important for a correct interpretation of Ramsey spectroscopy and has broad applications ranging from precision measurements to quantum information and to fundamental probes of many-body systems.
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Affiliation(s)
- A P Koller
- JILA, NIST, and Department of Physics, University of Colorado Boulder, Colorado 80309, USA
| | - M Beverland
- Institute for Quantum Information and Matter, California Institute of Technology, MC 305-16, Pasadena, California 91125, USA
| | - A V Gorshkov
- Joint Quantum Institute, NIST, and University of Maryland, College Park, Maryland 20742, USA
| | - A M Rey
- JILA, NIST, and Department of Physics, University of Colorado Boulder, Colorado 80309, USA
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38
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Gil LIR, Mukherjee R, Bridge EM, Jones MPA, Pohl T. Spin squeezing in a Rydberg lattice clock. PHYSICAL REVIEW LETTERS 2014; 112:103601. [PMID: 24679291 DOI: 10.1103/physrevlett.112.103601] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Indexed: 06/03/2023]
Abstract
We theoretically demonstrate a viable approach to spin squeezing in optical lattice clocks via optical dressing of one clock state to a highly excited Rydberg state, generating switchable atomic interactions. For realistic experimental parameters, these interactions are shown to generate over 10 dB of squeezing in large ensembles within a few microseconds and without degrading the subsequent clock interrogation.
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Affiliation(s)
- L I R Gil
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - R Mukherjee
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - E M Bridge
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - M P A Jones
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - T Pohl
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
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39
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Experimental realization of an optical second with strontium lattice clocks. Nat Commun 2014; 4:2109. [PMID: 23839206 DOI: 10.1038/ncomms3109] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 06/04/2013] [Indexed: 11/08/2022] Open
Abstract
Progress in realizing the SI second had multiple technological impacts and enabled further constraint of theoretical models in fundamental physics. Caesium microwave fountains, realizing best the second according to its current definition with a relative uncertainty of 2-4 × 10(-16), have already been overtaken by atomic clocks referenced to an optical transition, which are both more stable and more accurate. Here we present an important step in the direction of a possible new definition of the second. Our system of five clocks connects with an unprecedented consistency the optical and the microwave worlds. For the first time, two state-of-the-art strontium optical lattice clocks are proven to agree within their accuracy budget, with a total uncertainty of 1.5 × 10(-16). Their comparison with three independent caesium fountains shows a degree of accuracy now only limited by the best realizations of the microwave-defined second, at the level of 3.1 × 10(-16).
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40
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Ong A, Berengut JC, Flambaum VV. Optical Transitions in Highly Charged Ions for Detection of Variations in the Fine-Structure Constant. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/978-3-642-45201-7_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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41
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Bloom BJ, Nicholson TL, Williams JR, Campbell SL, Bishof M, Zhang X, Zhang W, Bromley SL, Ye J. An optical lattice clock with accuracy and stability at the 10(-18) level. Nature 2014; 506:71-5. [PMID: 24463513 DOI: 10.1038/nature12941] [Citation(s) in RCA: 726] [Impact Index Per Article: 72.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 12/04/2013] [Indexed: 11/09/2022]
Abstract
Progress in atomic, optical and quantum science has led to rapid improvements in atomic clocks. At the same time, atomic clock research has helped to advance the frontiers of science, affecting both fundamental and applied research. The ability to control quantum states of individual atoms and photons is central to quantum information science and precision measurement, and optical clocks based on single ions have achieved the lowest systematic uncertainty of any frequency standard. Although many-atom lattice clocks have shown advantages in measurement precision over trapped-ion clocks, their accuracy has remained 16 times worse. Here we demonstrate a many-atom system that achieves an accuracy of 6.4 × 10(-18), which is not only better than a single-ion-based clock, but also reduces the required measurement time by two orders of magnitude. By systematically evaluating all known sources of uncertainty, including in situ monitoring of the blackbody radiation environment, we improve the accuracy of optical lattice clocks by a factor of 22. This single clock has simultaneously achieved the best known performance in the key characteristics necessary for consideration as a primary standard-stability and accuracy. More stable and accurate atomic clocks will benefit a wide range of fields, such as the realization and distribution of SI units, the search for time variation of fundamental constants, clock-based geodesy and other precision tests of the fundamental laws of nature. This work also connects to the development of quantum sensors and many-body quantum state engineering (such as spin squeezing) to advance measurement precision beyond the standard quantum limit.
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Affiliation(s)
- B J Bloom
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA [3]
| | - T L Nicholson
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA [3]
| | - J R Williams
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA [3] Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - S L Campbell
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - M Bishof
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - X Zhang
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - W Zhang
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - S L Bromley
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - J Ye
- 1] JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA [2] Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
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42
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Aikawa K, Frisch A, Mark M, Baier S, Grimm R, Ferlaino F. Reaching Fermi degeneracy via universal dipolar scattering. PHYSICAL REVIEW LETTERS 2014; 112:010404. [PMID: 24483874 DOI: 10.1103/physrevlett.112.010404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Indexed: 06/03/2023]
Abstract
We report on the creation of a degenerate dipolar Fermi gas of erbium atoms. We force evaporative cooling in a fully spin-polarized sample down to temperatures as low as 0.2 times the Fermi temperature. The strong magnetic dipole-dipole interaction enables elastic collisions between identical fermions even in the zero-energy limit. The measured elastic scattering cross section agrees well with the predictions from the dipolar scattering theory, which follow a universal scaling law depending only on the dipole moment and on the atomic mass. Our approach to quantum degeneracy proceeds with very high cooling efficiency and provides large atomic densities, and it may be extended to various dipolar systems.
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Affiliation(s)
- K Aikawa
- Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - A Frisch
- Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - M Mark
- Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - S Baier
- Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - R Grimm
- Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria and Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
| | - F Ferlaino
- Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
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43
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Jansen P, Bethlem HL, Ubachs W. Perspective: Tipping the scales: Search for drifting constants from molecular spectra. J Chem Phys 2014; 140:010901. [DOI: 10.1063/1.4853735] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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44
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Leibrandt DR, Thorpe MJ, Chou CW, Fortier TM, Diddams SA, Rosenband T. Absolute and relative stability of an optical frequency reference based on spectral hole burning in Eu3+:Y2SiO5. PHYSICAL REVIEW LETTERS 2013; 111:237402. [PMID: 24476301 DOI: 10.1103/physrevlett.111.237402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Indexed: 06/03/2023]
Abstract
We present and analyze four frequency measurements designed to characterize the performance of an optical frequency reference based on spectral hole burning in Eu3+:Y2SiO5. The first frequency comparison, between a single unperturbed spectral hole and a hydrogen maser, demonstrates a fractional frequency drift rate of 5×10(-18) s(-1). Optical frequency comparisons between a pattern of spectral holes, a Fabry-Pérot cavity, and an Al(+) optical atomic clock show a short-term fractional frequency stability of 1×10(-15)τ(-1/2) that averages down to 2.5(-0.5)(+1.1)×10(-16) at τ=540 s (with linear frequency drift removed). Finally, spectral-hole patterns in two different Eu(3+):Y2SiO(5) crystals located in the same cryogenic vessel are compared, yielding a short-term stability of 7×10(-16)τ(-1/2) that averages down to 5.5(-0.9)(+1.8)×10(-17) at τ=204 s (with quadratic frequency drift removed).
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Affiliation(s)
- David R Leibrandt
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305, USA
| | - Michael J Thorpe
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305, USA
| | - Chin-Wen Chou
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305, USA
| | - Tara M Fortier
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305, USA
| | - Scott A Diddams
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305, USA
| | - Till Rosenband
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305, USA
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45
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Biedermann GW, Takase K, Wu X, Deslauriers L, Roy S, Kasevich MA. Zero-dead-time operation of interleaved atomic clocks. PHYSICAL REVIEW LETTERS 2013; 111:170802. [PMID: 24206471 DOI: 10.1103/physrevlett.111.170802] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Indexed: 06/02/2023]
Abstract
We demonstrate a zero-dead-time operation of atomic clocks. This clock reduces sensitivity to local oscillator noise, integrating as nearly 1/τ whereas a clock with dead time integrates as 1/τ(1/2) under identical conditions. We contend that a similar scheme may be applied to improve the stability of optical clocks.
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Affiliation(s)
- G W Biedermann
- Physics Department, Stanford University, Stanford, California 94305, USA
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46
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Hinkley N, Sherman JA, Phillips NB, Schioppo M, Lemke ND, Beloy K, Pizzocaro M, Oates CW, Ludlow AD. An Atomic Clock with 10
–18
Instability. Science 2013; 341:1215-8. [DOI: 10.1126/science.1240420] [Citation(s) in RCA: 569] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- N. Hinkley
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - J. A. Sherman
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
| | - N. B. Phillips
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
| | - M. Schioppo
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
| | - N. D. Lemke
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
| | - K. Beloy
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
| | - M. Pizzocaro
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
- Instituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
- Politecnico di Torino, Corso duca degli Abruzzi 24, 10125 Torino, Italy
| | - C. W. Oates
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
| | - A. D. Ludlow
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
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47
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Bishof M, Zhang X, Martin MJ, Ye J. Optical spectrum analyzer with quantum-limited noise floor. PHYSICAL REVIEW LETTERS 2013; 111:093604. [PMID: 24033036 DOI: 10.1103/physrevlett.111.093604] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Indexed: 06/02/2023]
Abstract
Interactions between atoms and lasers provide the potential for unprecedented control of quantum states. Fulfilling this potential requires detailed knowledge of frequency noise in optical oscillators with state-of-the-art stability. We demonstrate a technique that precisely measures the noise spectrum of an ultrastable laser using optical lattice-trapped 87Sr atoms as a quantum projection noise-limited reference. We determine the laser noise spectrum from near dc to 100 Hz via the measured fluctuations in atomic excitation, guided by a simple and robust theory model. The noise spectrum yields a 26(4) mHz linewidth at a central frequency of 429 THz, corresponding to an optical quality factor of 1.6×10(16). This approach improves upon optical heterodyne beats between two similar laser systems by providing information unique to a single laser and complements the traditionally used Allan deviation which evaluates laser performance at relatively long time scales. We use this technique to verify the reduction of resonant noise in our ultrastable laser via feedback from an optical heterodyne beat. Finally, we show that knowledge of our laser's spectrum allows us to accurately predict the laser-limited stability for optical atomic clocks.
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Affiliation(s)
- M Bishof
- JILA, National Institute of Standards and Technology and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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48
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Borregaard J, Sørensen AS. Near-Heisenberg-limited atomic clocks in the presence of decoherence. PHYSICAL REVIEW LETTERS 2013; 111:090801. [PMID: 24033016 DOI: 10.1103/physrevlett.111.090801] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Indexed: 06/02/2023]
Abstract
The ultimate stability of atomic clocks is limited by the quantum noise of the atoms. To reduce this noise it has been suggested to use entangled atomic ensembles with reduced atomic noise. Potentially this can push the stability all the way to the limit allowed by the Heisenberg uncertainty relation, which is denoted the Heisenberg limit. In practice, however, entangled states are often more prone to decoherence, which may prevent reaching this performance. Here we present an adaptive measurement protocol that in the presence of a realistic source of decoherence enables us to get near-Heisenberg-limited stability of atomic clocks using entangled atoms. The protocol may thus realize the full potential of entanglement for quantum metrology despite the detrimental influence of decoherence.
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Affiliation(s)
- J Borregaard
- QUANTOP, The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
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49
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Martin MJ, Bishof M, Swallows MD, Zhang X, Benko C, von-Stecher J, Gorshkov AV, Rey AM, Ye J. A Quantum Many-Body Spin System in an Optical Lattice Clock. Science 2013; 341:632-6. [DOI: 10.1126/science.1236929] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Strongly interacting quantum many-body systems arise in many areas of physics, but their complexity generally precludes exact solutions to their dynamics. We explored a strongly interacting two-level system formed by the clock states in 87Sr as a laboratory for the study of quantum many-body effects. Our collective spin measurements reveal signatures of the development of many-body correlations during the dynamical evolution. We derived a many-body Hamiltonian that describes the experimental observation of atomic spin coherence decay, density-dependent frequency shifts, severely distorted lineshapes, and correlated spin noise. These investigations open the door to further explorations of quantum many-body effects and entanglement through use of highly coherent and precisely controlled optical lattice clocks.
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Affiliation(s)
- M. J. Martin
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - M. Bishof
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - M. D. Swallows
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - X. Zhang
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - C. Benko
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - J. von-Stecher
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - A. V. Gorshkov
- Institute for Quantum Information and Matter (IQIM), California Institute of Technology, Pasadena, CA 91125, USA
| | - A. M. Rey
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
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