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Kouwenhoven K, Elwakil I, Wingerden JV, Murugesan V, Thoen DJ, Baselmans JJA, Visser PJD. Model and Measurements of an Optical Stack for Broadband Visible to Near-Infrared Absorption in TiN MKIDs. J Low Temp Phys 2022; 209:1249-1257. [PMID: 36467123 PMCID: PMC9712414 DOI: 10.1007/s10909-022-02774-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 06/17/2022] [Indexed: 06/17/2023]
Abstract
Typical materials for optical Microwave Kinetic Inductance Detetectors (MKIDs) are metals with a natural absorption of ∼ 30-50% in the visible and near-infrared. To reach high absorption efficiencies (90-100%) the KID must be embedded in an optical stack. We show an optical stack design for a 60 nm TiN film. The optical stack is modeled as sections of transmission lines, where the parameters for each section are related to the optical properties of each layer. We derive the complex permittivity of the TiN film from a spectral ellipsometry measurement. The designed optical stack is optimised for broadband absorption and consists of, from top (illumination side) to bottom: 85 nm SiO2, 60 nm TiN, 23 nm of SiO2, and a 100 nm thick Al mirror. We show the modeled absorption and reflection of this stack, which has >80% absorption from 400 to 1550 nm and near-unity absorption for 500-800 nm. We measure transmission and reflection of this stack with a commercial spectrophotometer. The results are in good agreement with the model.
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Affiliation(s)
- K. Kouwenhoven
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
- Department of Microelectronics, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
| | - I. Elwakil
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
| | - J. van Wingerden
- Else Kooi Laboratory, Delft University of Technology, Feldmannweg 17, 2628 CT Delft, The Netherlands
| | - V. Murugesan
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
| | - D. J. Thoen
- Department of Microelectronics, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - J. J. A. Baselmans
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
- Department of Microelectronics, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
| | - P. J. de Visser
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
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Hähnle S, Bueno J, Huiting R, Yates SJC, Baselmans JJA. Large Angle Optical Access in a Sub-Kelvin Cryostat. J Low Temp Phys 2018; 193:833-840. [PMID: 30930476 PMCID: PMC6404799 DOI: 10.1007/s10909-018-1940-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 04/30/2018] [Indexed: 06/09/2023]
Abstract
The development of lens-antenna-coupled aluminum-based microwave kinetic inductance detectors (MKIDs) and on-chip spectrometers needs a dedicated cryogenic setup to measure the beam patterns of the lens-antenna system over a large angular throughput and broad frequency range. This requires a careful design since the MKID has to be cooled to temperatures below 300 mK to operate effectively. We developed such a cryostat with a large opening angle θ = ± 37 . 8 ∘ and an optical access with a low-pass edge at 950 GHz . The system is based upon a commercial pulse tube cooled 3 K system with a 4 He - 3 He sorption cooler to allow base temperatures below 300 mK . A careful study of the spectral and geometric throughput was performed to minimize thermal loading on the cold stage, allowing a base temperature of 265 mK . Radio-transparent multi-layer-insulation was employed as a recent development in filter technology to efficiently block near-infrared radiation.
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Affiliation(s)
- S. Hähnle
- SRON Netherlands Institute for Space Research, 3584 CA Utrecht, Netherlands
| | - J. Bueno
- SRON Netherlands Institute for Space Research, 3584 CA Utrecht, Netherlands
| | - R. Huiting
- SRON Netherlands Institute for Space Research, 3584 CA Utrecht, Netherlands
| | - S. J. C. Yates
- SRON Netherlands Institute for Space Research, 3584 CA Utrecht, Netherlands
| | - J. J. A. Baselmans
- SRON Netherlands Institute for Space Research, 3584 CA Utrecht, Netherlands
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Endo A, Yates SJC, Bueno J, Thoen DJ, Murugesan V, Baryshev AM, Klapwijk TM, van der Werf PP, Baselmans JJA. Superconducting Coplanar Waveguide Filters for Submillimeter Wave On-Chip Filterbank Spectrometers. J Low Temp Phys 2016; 184:412-417. [PMID: 27340291 PMCID: PMC4880640 DOI: 10.1007/s10909-016-1579-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 03/02/2016] [Indexed: 06/06/2023]
Abstract
We show the first experimental results which prove that superconducting NbTiN coplanar-waveguide resonators can achieve a loaded Q factor in excess of 800 in the 350 GHz band. These resonators can be used as narrow band pass filters for on-chip filter bank spectrometers for astronomy. Moreover, the low-loss coplanar waveguide technology provides an interesting alternative to microstrip lines for constructing large scale submillimeter wave electronics in general.
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Affiliation(s)
- A. Endo
- />Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
- />Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - S. J. C. Yates
- />SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands
| | - J. Bueno
- />SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
| | - D. J. Thoen
- />Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
| | - V. Murugesan
- />SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
| | - A. M. Baryshev
- />SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands
- />Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands
| | - T. M. Klapwijk
- />Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
- />Physics Department, Moscow State Pedagogical University, 119991 Moscow, Russia
| | - P. P. van der Werf
- />Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
| | - J. J. A. Baselmans
- />Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
- />SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
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de Visser PJ, Baselmans JJA, Bueno J, Llombart N, Klapwijk TM. Fluctuations in the electron system of a superconductor exposed to a photon flux. Nat Commun 2014; 5:3130. [PMID: 24496036 PMCID: PMC3925999 DOI: 10.1038/ncomms4130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 12/17/2013] [Indexed: 11/09/2022] Open
Abstract
In a superconductor, in which electrons are paired, the density of unpaired electrons should become zero when approaching zero temperature. Therefore, radiation detectors based on breaking of pairs promise supreme sensitivity, which we demonstrate using an aluminium superconducting microwave resonator. Here we show that the resonator also enables the study of the response of the electron system of the superconductor to pair-breaking photons, microwave photons and varying temperatures. A large range in radiation power (at 1.54 THz) can be chosen by carefully filtering the radiation from a blackbody source. We identify two regimes. At high radiation power, fluctuations in the electron system caused by the random arrival rate of the photons are resolved, giving a straightforward measure of the optical efficiency (48±8%) and showing an unprecedented detector sensitivity. At low radiation power, fluctuations are dominated by excess quasiparticles, the number of which is measured through their recombination lifetime. Electromagnetic radiation detectors based on superconducting resonators have a range of potential uses from astronomy to quantum computing. De Visser et al. demonstrate a superconductor detector with unprecedented sensitivity limited only by fluctuations in the electron system of the superconductor.
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Affiliation(s)
- P J de Visser
- 1] SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA, Utrecht, The Netherlands [2] Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
| | - J J A Baselmans
- SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA, Utrecht, The Netherlands
| | - J Bueno
- SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA, Utrecht, The Netherlands
| | - N Llombart
- Terahertz Sensing Group, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD, Delft, The Netherlands
| | - T M Klapwijk
- Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
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de Visser PJ, Goldie DJ, Diener P, Withington S, Baselmans JJA, Klapwijk TM. Evidence of a nonequilibrium distribution of quasiparticles in the microwave response of a superconducting aluminum resonator. Phys Rev Lett 2014; 112:047004. [PMID: 24580483 DOI: 10.1103/physrevlett.112.047004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Indexed: 06/03/2023]
Abstract
In a superconductor, absorption of photons with an energy below the superconducting gap leads to redistribution of quasiparticles over energy and thus induces a strong nonequilibrium quasiparticle energy distribution. We have measured the electrodynamic response, quality factor, and resonant frequency of a superconducting aluminium microwave resonator as a function of microwave power and temperature. Below 200 mK, both the quality factor and resonant frequency decrease with increasing microwave power, consistent with the creation of excess quasiparticles due to microwave absorption. Counterintuitively, above 200 mK, the quality factor and resonant frequency increase with increasing power. We demonstrate that the effect can only be understood by a nonthermal quasiparticle distribution.
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Affiliation(s)
- P J de Visser
- SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands and Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - D J Goldie
- Cavendish Laboratory, Cambridge University, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - P Diener
- SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
| | - S Withington
- Cavendish Laboratory, Cambridge University, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - J J A Baselmans
- SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
| | - T M Klapwijk
- Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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de Visser PJ, Baselmans JJA, Diener P, Yates SJC, Endo A, Klapwijk TM. Number fluctuations of sparse quasiparticles in a superconductor. Phys Rev Lett 2011; 106:167004. [PMID: 21599404 DOI: 10.1103/physrevlett.106.167004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 03/25/2011] [Indexed: 05/30/2023]
Abstract
We have directly measured quasiparticle number fluctuations in a thin film superconducting Al resonator in thermal equilibrium. The spectrum of these fluctuations provides a measure of both the density and the lifetime of the quasiparticles. We observe that the quasiparticle density decreases exponentially with decreasing temperature, as theoretically predicted, but saturates below 160 mK to 25-55/μm(3). We show that this saturation is consistent with the measured saturation in the quasiparticle lifetime, which also explains similar observations in qubit decoherence times.
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Affiliation(s)
- P J de Visser
- SRON National Institute for Space Research, Utrecht, The Netherlands.
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Barends R, Baselmans JJA, Yates SJC, Gao JR, Hovenier JN, Klapwijk TM. Quasiparticle relaxation in optically excited high-Q superconducting resonators. Phys Rev Lett 2008; 100:257002. [PMID: 18643694 DOI: 10.1103/physrevlett.100.257002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Indexed: 05/26/2023]
Abstract
The quasiparticle relaxation time in superconducting films has been measured as a function of temperature using the response of the complex conductivity to photon flux. For tantalum and aluminum, chosen for their difference in electron-phonon coupling strength, we find that at high temperatures the relaxation time increases with decreasing temperature, as expected for electron-phonon interaction. At low temperatures we find in both superconducting materials a saturation of the relaxation time, suggesting the presence of a second relaxation channel not due to electron-phonon interaction.
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Affiliation(s)
- R Barends
- Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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Baselmans JJA, Heikkilä TT, van Wees BJ, Klapwijk TM. Direct observation of the transition from the conventional superconducting state to the pi state in a controllable Josephson junction. Phys Rev Lett 2002; 89:207002. [PMID: 12443501 DOI: 10.1103/physrevlett.89.207002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2002] [Indexed: 05/24/2023]
Abstract
We measure the full supercurrent-phase relation of a controllable pi junction around the transition from the conventional 0 state to the pi state. We show that around the transition the Josephson supercurrent-phase relation changes from I(sc) approximately I(c)sin((phi) to I(sc) approximately I(c)sin((2phi). This implies that, around the transition, two minima in the junction free energy exist, one at phi=0 and one at phi=pi, whereas only one minimum exists at the 0 state (at phi=0) and at the pi state (at phi=pi). Theoretical calculations based on the quasiclassical theory are in good agreement with the observed behavior.
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Affiliation(s)
- J J A Baselmans
- Department of Applied Physics and Materials Science Center, University of Groningen, Nijenborg 4, 9747 AG Groningen, The Netherlands
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Jedema FJ, Heersche HB, Filip AT, Baselmans JJA, van Wees BJ. Electrical detection of spin precession in a metallic mesoscopic spin valve. Nature 2002; 416:713-6. [PMID: 11961548 DOI: 10.1038/416713a] [Citation(s) in RCA: 588] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To study and control the behaviour of the spins of electrons that are moving through a metal or semiconductor is an outstanding challenge in the field of 'spintronics', where possibilities for new electronic applications based on the spin degree of freedom are currently being explored. Recently, electrical control of spin coherence and coherent spin precession during transport was studied by optical techniques in semiconductors. Here we report controlled spin precession of electrically injected and detected electrons in a diffusive metallic conductor, using tunnel barriers in combination with metallic ferromagnetic electrodes as spin injector and detector. The output voltage of our device is sensitive to the spin degree of freedom only, and its sign can be switched from positive to negative, depending on the relative magnetization of the ferromagnetic electrodes. We show that the spin direction can be controlled by inducing a coherent spin precession caused by an applied perpendicular magnetic field. By inducing an average precession angle of 180 degrees, we are able to reverse the sign of the output voltage.
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Affiliation(s)
- F J Jedema
- Department of Applied Physics and Materials Science Center, University of Groningen, The Netherlands.
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