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Schoenlein R, Elsaesser T, Holldack K, Huang Z, Kapteyn H, Murnane M, Woerner M. Recent advances in ultrafast X-ray sources. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20180384. [PMID: 30929633 DOI: 10.1098/rsta.2018.0384] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Over more than a century, X-rays have transformed our understanding of the fundamental structure of matter and have been an indispensable tool for chemistry, physics, biology, materials science and related fields. Recent advances in ultrafast X-ray sources operating in the femtosecond to attosecond regimes have opened an important new frontier in X-ray science. These advances now enable: (i) sensitive probing of structural dynamics in matter on the fundamental timescales of atomic motion, (ii) element-specific probing of electronic structure and charge dynamics on fundamental timescales of electronic motion, and (iii) powerful new approaches for unravelling the coupling between electronic and atomic structural dynamics that underpin the properties and function of matter. Most notable is the recent realization of X-ray free-electron lasers (XFELs) with numerous new XFEL facilities in operation or under development worldwide. Advances in XFELs are complemented by advances in synchrotron-based and table-top laser-plasma X-ray sources now operating in the femtosecond regime, and laser-based high-order harmonic XUV sources operating in the attosecond regime. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.
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Affiliation(s)
- Robert Schoenlein
- 1 SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, CA 94025 , USA
| | - Thomas Elsaesser
- 2 Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie , 12489 Berlin , Germany
| | - Karsten Holldack
- 3 Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Albert-Einstein-Strasse 15, 12489 Berlin , Germany
| | - Zhirong Huang
- 1 SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, CA 94025 , USA
| | - Henry Kapteyn
- 4 Department of Physics and JILA, University of Colorado , Boulder, CO 80309-0440 , USA
| | - Margaret Murnane
- 4 Department of Physics and JILA, University of Colorado , Boulder, CO 80309-0440 , USA
| | - Michael Woerner
- 2 Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie , 12489 Berlin , Germany
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2
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Wahlstrand JK, Jhajj N, Milchberg HM. Controlling femtosecond filament propagation using externally driven gas motion. OPTICS LETTERS 2019; 44:199-202. [PMID: 30644860 PMCID: PMC6547820 DOI: 10.1364/ol.44.000199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
The thermal density depression (or "density hole") produced by a high-repetition-rate femtosecond filament in air acts as a negative lens, altering the propagation of the filament. We demonstrate the effects of externally driven gas motion on these density holes and the resulting filament steering, and we derive an expression for the gas velocity that maximizes the effect. At gas velocities more than ∼3 times this value, the density hole is displaced from the filament, and it no longer affects filament propagation. We demonstrate density hole displacement using an audio speaker-driven sound wave, leading to a controllable, repeatable deflection of the filament. Applications are discussed, including quasi-phase matching in gas-based nonlinear optics. To the best of our knowledge, this is the first demonstration of femtosecond filament propagation control through controlled motion of the nonlinear medium.
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Affiliation(s)
- J. K. Wahlstrand
- lnstitutefor Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA
- Currently with Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - N. Jhajj
- lnstitutefor Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA
| | - H. M. Milchberg
- lnstitutefor Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA
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Jin C, Hong KH, Lin CD. Optimal generation of spatially coherent soft X-ray isolated attosecond pulses in a gas-filled waveguide using two-color synthesized laser pulses. Sci Rep 2016; 6:38165. [PMID: 27929036 PMCID: PMC5144061 DOI: 10.1038/srep38165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/04/2016] [Indexed: 11/08/2022] Open
Abstract
We numerically demonstrate the generation of intense, low-divergence soft X-ray isolated attosecond pulses in a gas-filled hollow waveguide using synthesized few-cycle two-color laser waveforms. The waveform is a superposition of a fundamental and its second harmonic optimized such that highest harmonic yields are emitted from each atom. We then optimize the gas pressure and the length and radius of the waveguide such that bright coherent high-order harmonics with angular divergence smaller than 1 mrad are generated, for photon energy from the extreme ultraviolet to soft X-rays. By selecting a proper spectral range enhanced isolated attosecond pulses are generated. We study how dynamic phase matching caused by the interplay among waveguide mode, neutral atomic dispersion, and plasma effect is achieved at the optimal macroscopic conditions, by performing time-frequency analysis and by analyzing the evolution of the driving laser's electric field during the propagation. Our results, when combined with the on-going push of high-repetition-rate lasers (sub- to few MHz's) may eventually lead to the generation of high-flux, low-divergence soft X-ray tabletop isolated attosecond pulses for applications.
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Affiliation(s)
- Cheng Jin
- Department of Applied Physics, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, P. R. China
| | - Kyung-Han Hong
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
| | - C. D. Lin
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
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Jin C, Stein GJ, Hong KH, Lin CD. Generation of Bright, Spatially Coherent Soft X-Ray High Harmonics in a Hollow Waveguide Using Two-Color Synthesized Laser Pulses. PHYSICAL REVIEW LETTERS 2015; 115:043901. [PMID: 26252685 DOI: 10.1103/physrevlett.115.043901] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Indexed: 06/04/2023]
Abstract
We investigate the efficient generation of low-divergence high-order harmonics driven by waveform-optimized laser pulses in a gas-filled hollow waveguide. The drive waveform is obtained by synthesizing two-color laser pulses, optimized such that highest harmonic yields are emitted from each atom. Optimization of the gas pressure and waveguide configuration has enabled us to produce bright and spatially coherent harmonics extending from the extreme ultraviolet to soft x rays. Our study on the interplay among waveguide mode, atomic dispersion, and plasma effect uncovers how dynamic phase matching is accomplished and how an optimized waveform is maintained when optimal waveguide parameters (radius and length) and gas pressure are identified. Our analysis should help laboratory development in the generation of high-flux bright coherent soft x rays as tabletop light sources for applications.
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Affiliation(s)
- Cheng Jin
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Gregory J Stein
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
| | - Kyung-Han Hong
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
| | - C D Lin
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
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Liu LZ, O’Keeffe K, Hooker SM. Polarization-controlled quasi-phase-matching of high harmonic generation. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20134101008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Veysman M, Andreev NE, Maynard G, Cros B. Nonsymmetric laser-pulse propagation in capillary tubes with variable radius. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:066411. [PMID: 23368063 DOI: 10.1103/physreve.86.066411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Indexed: 06/01/2023]
Abstract
A model describing the nonsymmetrical laser-pulse propagation in capillary tubes with inner radius smoothly varying with the capillary length is proposed. Using this model, the use of capillaries with specially profiled entrance sections (particularly cone matching elements) for improving the coupling of the laser energy into a capillary and avoiding capillary ablation is analyzed. It is shown that cone entrances with a sufficiently small angle (α_{cone}≲10 mrad) help decrease the longitudinal energy flux and ablation of the entrance face of a capillary, but do not remove the requirements on the precision of laser-pulse focusing necessary to obtain regular laser fields, characterized by a symmetrical intensity distribution, centered on the capillary axis. To achieve regular laser fields without strong transverse gradients, the angle between the laser and capillary axes has to be smaller than 1 mrad for capillaries with an inner radius of the order of tens of microns.
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Affiliation(s)
- M Veysman
- Institute for High Energy Densities, Moscow, Russia
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Liu LZ, O'Keeffe K, Hooker SM. Optical rotation quasi-phase-matching for circularly polarized high harmonic generation. OPTICS LETTERS 2012; 37:2415-2417. [PMID: 22739926 DOI: 10.1364/ol.37.002415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A scheme for quasi-phase-matching high harmonic generation of circularly polarized radiation is proposed: optical rotation quasi-phase-matching (ORQPM). In ORQPM, propagation of the driving radiation in a system exhibiting circular birefringence causes its plane of polarization to rotate; by appropriately matching the period of rotation to the coherence length, it is possible to avoid destructive interference of the generated radiation. It is shown that ORQPM is approximately five times more efficient than conventional QPM, and half as efficient as true phase-matching.
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Affiliation(s)
- Lewis Z Liu
- Clarendon Laboratory, University of Oxford Physics Department, Parks Road, Oxford OX1 3PU, UK.
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Kohler MC, Keitel CH, Hatsagortsyan KZ. Attochirp-free high-order harmonic generation. OPTICS EXPRESS 2011; 19:4411-4420. [PMID: 21369272 DOI: 10.1364/oe.19.004411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A method is proposed for arbitrarily engineering the high-order harmonic generation phase achieved by shaping a laser pulse and employing xuv light or x rays for ionization. This renders the production of bandwidth-limited attosecond pulses possible while avoiding the use of filters for chirp compensation. By adding the first 8 Fourier components to a sinusoidal field of 1016 W/cm2, the bandwidth-limited emission of 8 as is shown to be possible from a Li2+ gas. The scheme is extendable to the zs-scale.
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Chapman RT, Butcher TJ, Horak P, Poletti F, Frey JG, Brocklesby WS. Modal effects on pump-pulse propagation in an Ar-filled capillary. OPTICS EXPRESS 2010; 18:13279-13284. [PMID: 20588457 DOI: 10.1364/oe.18.013279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Accurate three-dimensional modelling of nonlinear pulse propagation within a gas-filled capillary is essential for understanding and improving the XUV yield in high harmonic generation. We introduce both a new model based on a multimode generalized nonlinear Schrödinger equation and a novel spatio-spectral measurement technique to which the model can be compared. The theory shows excellent agreement with the measured output spectrum and the spatio-spectral measurement reveals that the model correctly predicts higher order mode contributions to spectral broadening of the pulse. Fluorescence from the excited argon is used to verify the predicted ion distribution along the capillary.
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Affiliation(s)
- Richard T Chapman
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
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Serrat C, Biegert J. All-regions tunable high harmonic enhancement by a periodic static electric field. PHYSICAL REVIEW LETTERS 2010; 104:073901. [PMID: 20366884 DOI: 10.1103/physrevlett.104.073901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Indexed: 05/23/2023]
Abstract
Simulations show that a static electric field periodically distributed in space can be used to control the production of coherent light by high-order harmonic generation in a wide spectral range covering extreme-ultraviolet and soft x-ray radiation. The radiation yield is selectively enhanced due to symmetry breaking induced by a static electric field on the interaction between the driving laser and the medium. The spectral position of the enhancement is tuned by varying the periodicity of the static electric field which matches twice the coherence length of the harmonics in the desired region. We find that the static electric field strength inducing enhancement decreases for shorter wavelengths and predict an increase of more than two orders of magnitude for harmonics in the water window spectral range with a static electric field as weak as 1.12 MV/cm.
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Affiliation(s)
- Carles Serrat
- ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain.
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Thomann I, Bahabad A, Liu X, Trebino R, Murnane MM, Kapteyn HC. Characterizing isolated attosecond pulses from hollow-core waveguides using multi-cycle driving pulses. OPTICS EXPRESS 2009; 17:4611-4633. [PMID: 19293890 DOI: 10.1364/oe.17.004611] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The generation of attosecond-duration light pulses using the high-order harmonic generation process is a rapidly evolving area of research. In this work, we combine experimental measurements with careful numerical analysis, to demonstrate that even relatively long-duration, 15 fs, carrier-envelope-phase (CEP) unstabilized near-infrared (NIR) pulses can generate isolated attosecond extreme-ultraviolet (EUV) pulses by the dynamically-changing phase matching conditions in a hollow-core waveguide geometry. The measurements are made using the laser-assisted photoelectric effect to cross-correlate the EUV pulse with the NIR pulse. A FROG CRAB analysis of the resulting traces (photoelectron signal versus photoelectron energy and EUV-NIR delay) is performed using a generalized projections (GP) algorithm, adapted for a wide-angle photoelectron detection geometry and non-CEP stabilized driving laser pulses. In addition, we performed direct FROG CRAB simulations under the same conditions. Such direct simulations allow more freedom to explore the effect of specific pulse parameters on FROG CRAB traces than is possible using the automated GP retrieval algorithm. Our analysis shows that an isolated pulse with duration of approximately 200 attoseconds can result from CEP unstabilized, high intensity approximately 15 fs multi-cycle driving pulses coupled into a hollow-core waveguide filled with low-pressure Argon gas. These are significantly longer driving pulses than used in other experimental implementations of isolated attosecond pulses.
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Affiliation(s)
- I Thomann
- JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA.
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12
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Bahabad A, Cohen O, Murnane MM, Kapteyn HC. Quasi-periodic and random quasi-phase matching of high harmonic generation. OPTICS LETTERS 2008; 33:1936-1938. [PMID: 18758570 DOI: 10.1364/ol.33.001936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Quasi-phase matching schemes employing quasi-periodic or random spatial modulations, previously applied to perturbative nonlinear optics, are demonstrated theoretically for the extreme nonlinear optical process of high harmonic generation. We show that quasi-periodic quasi-phase matching of high harmonic generation can be used for simultaneous enhancement of arbitrarily chosen spectral regions. We also demonstrate enhancement of a single extremely wide bandwidth using random quasi-phase matching.
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Affiliation(s)
- Alon Bahabad
- Department of Physics and JILA, University of Colorado at Boulder and NIST, Boulder, CO 80309, USA.
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13
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Cohen O, Zhang X, Lytle AL, Popmintchev T, Murnane MM, Kapteyn HC. Grating-assisted phase matching in extreme nonlinear optics. PHYSICAL REVIEW LETTERS 2007; 99:053902. [PMID: 17930753 DOI: 10.1103/physrevlett.99.053902] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Indexed: 05/25/2023]
Abstract
We propose a new technique for phase matching high harmonic generation that can be used for generating bright, tabletop, tunable, and coherent x-ray sources at keV photon energies. A weak quasi-cw counterpropagating field induces a sinusoidal modulation in the phase of the emitted harmonics that can be used for correcting the large plasma-induced phase mismatch. We develop an analytical model that describes this grating-assisted x-ray phase matching and predicts that very modest intensities (<10(10) W/cm2) of quasi-cw counterpropagating fields are required for implementation.
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Affiliation(s)
- Oren Cohen
- Department of Physics and JILA, University of Colorado at Boulder and NIST, Boulder, Colorado 80309, USA.
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Lytle AL, Zhang X, Peatross J, Murnane MM, Kapteyn HC, Cohen O. Probe of high-order harmonic generation in a hollow waveguide geometry using counterpropagating light. PHYSICAL REVIEW LETTERS 2007; 98:123904. [PMID: 17501126 DOI: 10.1103/physrevlett.98.123904] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Indexed: 05/15/2023]
Abstract
We use counterpropagating light to directly observe the coherent buildup of high harmonic generation in a hollow waveguide geometry. We measure, for the first time, coherence lengths for high photon energies that cannot be phase matched using conventional approaches. We also probe the transition through phase matching, the ionization level at which different harmonic orders are generated, and the change in the coherence length as the driving laser is depleted. These results directly prescribe the optimal structures or pulse trains required for implementing quasiphase matching.
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Affiliation(s)
- A L Lytle
- JILA and Department of Physics University of Colorado at Boulder, Boulder, Colorado 80309, USA.
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15
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Seres E, Seres J, Krausz F, Spielmann C. Generation of coherent soft-X-ray radiation extending far beyond the titanium L edge. PHYSICAL REVIEW LETTERS 2004; 92:163002. [PMID: 15169224 DOI: 10.1103/physrevlett.92.163002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2003] [Indexed: 05/24/2023]
Abstract
Coherent soft-x-ray radiation up to photon energies of 700 eV is obtained by focusing several-mJ, 10-fs near infrared laser pulses into a He gas jet. The observed nearly constant photon yield over several hundred eVs may be attributed to nonadiabatic self-phase matching, originating from a substantial ionization within a fraction of the optical cycle of the driving laser pulse.
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Affiliation(s)
- Enikö Seres
- Institut für Photonik, Technische Universität Wien, Gusshausstrasse 27/387, 1040 Wien, Austria
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Gibson EA, Paul A, Wagner N, Tobey R, Gaudiosi D, Backus S, Christov IP, Aquila A, Gullikson EM, Attwood DT, Murnane MM, Kapteyn HC. Coherent Soft X-ray Generation in the Water Window with Quasi-Phase Matching. Science 2003; 302:95-8. [PMID: 14526077 DOI: 10.1126/science.1088654] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We demonstrate enhanced generation of coherent light in the "water window" region of the soft x-ray spectrum at 4.4 nanometers, using quasi-phase-matched frequency conversion of ultrafast laser pulses. By periodically modulating the diameter of a gas-filled hollow waveguide, the phase mismatch normally present between the laser light and the generated soft x-ray light can be partially compensated. This makes it possible to use neon gas as the nonlinear medium to coherently convert light up to the water window, illustrating that techniques of nonlinear optics can be applied effectively in the soft x-ray region of the spectrum. These results advance the prospects for compact coherent soft x-ray sources for applications in biomicroscopy and in chemical spectroscopy.
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Affiliation(s)
- Emily A Gibson
- Department of Physics and JILA, University of Colorado, Boulder, CO 80309-0440, USA
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Paul A, Bartels RA, Tobey R, Green H, Weiman S, Christov IP, Murnane MM, Kapteyn HC, Backus S. Quasi-phase-matched generation of coherent extreme-ultraviolet light. Nature 2003; 421:51-4. [PMID: 12511950 DOI: 10.1038/nature01222] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2002] [Accepted: 10/15/2002] [Indexed: 11/09/2022]
Abstract
High-harmonic generation is a well-known method of producing coherent extreme-ultraviolet (EUV) light, with photon energies up to about 0.5 keV (refs 1, 2). This is achieved by focusing a femtosecond laser into a gas, and high harmonics of the fundamental laser frequency are radiated in the forward direction. However, although this process can generate high-energy photons, efficient high-harmonic generation has been demonstrated only for photon energies of the order 50-100 eV (ref. 5). Ionization of the gas prevents the laser and the EUV light from propagating at the same speed, which severely limits the conversion efficiency. Here we report a technique to overcome this problem, and demonstrate quasi-phase-matched frequency conversion of laser light into EUV. Using a modulated hollow-core waveguide to periodically vary the intensity of the laser light driving the conversion, we efficiently generate EUV light even in the presence of substantial ionization. The use of a modulated fibre shifts the energy spectrum of the high-harmonic light to significantly higher photon energies than would otherwise be possible. We expect that this technique could form the basis of coherent EUV sources for advanced lithography and high-resolution imaging applications. In future work, it might also be possible to generate isolated attosecond pulses.
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Affiliation(s)
- A Paul
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology, Boulder, Colorado 80309-0440, USA
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