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Ellis JL, Dorney KM, Durfee CG, Hernández-García C, Dollar F, Mancuso CA, Fan T, Zusin D, Gentry C, Grychtol P, Kapteyn HC, Murnane MM, Hickstein DD. Phase matching of noncollinear sum and difference frequency high harmonic generation above and below the critical ionization level. OPTICS EXPRESS 2017; 25:10126-10144. [PMID: 28468388 DOI: 10.1364/oe.25.010126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We investigate the macroscopic physics of noncollinear high harmonic generation (HHG) at high pressures. We make the first experimental demonstration of phase matching of noncollinear high-order-difference-frequency generation at ionization fractions above the critical ionization level, which normally sets an upper limit on the achievable cutoff photon energies. Additionally, we show that noncollinear high-order-sum-frequency generation requires much higher pressures for phase matching than single-beam HHG does, which mitigates the short interaction region in this geometry. We also dramatically increase the experimentally realized cutoff energy of noncollinear circularly polarized HHG, reaching photon energies of 90 eV. Finally, we achieve complete angular separation of high harmonic orders without the use of a spectrometer.
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Walia K. Nonlinear Interaction of High Power Elliptical Laser Beam with Cold Collisionless Plasma. JOURNAL OF FUSION ENERGY 2016. [DOI: 10.1007/s10894-016-0059-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Palastro JP, Antonsen TM, Pearson A, Zhu W, Jain N. Raman scattering of intense, short laser pulses in modulated plasmas. Phys Rev E 2011; 83:046410. [PMID: 21599319 DOI: 10.1103/physreve.83.046410] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Indexed: 11/07/2022]
Abstract
We examine the exponentiation of the Raman forward scattering instability in modulated plasma channels computationally and analytically. An evolution equation for the complex phases of the Raman scattered waves treating the spatial localization and discrete nature of the channel modes is derived. Simulations with WAKE [P. Mora and T. M. Antonsen Jr., Phys. Plasmas 4, 217 (1997)] verify the theory in the linear growth regime and provide insight into the nonlinear stage of the instability when cascading and pump depletion play a role. We find that the exponentiation in modulated channels depends on two factors: the increase in coupling due to the increased plasma wavenumber in the high-density regions of the channel and a decreased coupling due to the reduced longitudinal spatial coherence. For the parameters considered, simulations show that the finite extent of the pump pulse is more significant in determining the exponentiation than phase mixing due to the transverse variation of the channel. Both the theory and simulations confirm that modulated channels allow for the stable guiding of longer pulses than nonmodulated channels.
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Affiliation(s)
- J P Palastro
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20740, USA
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Palastro JP, Antonsen TM, Morshed S, York AG, Milchberg HM. Pulse propagation and electron acceleration in a corrugated plasma channel. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:036405. [PMID: 18517531 DOI: 10.1103/physreve.77.036405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Indexed: 05/26/2023]
Abstract
A preformed plasma channel provides a guiding structure for laser pulses unbound by the intensity thresholds of standard waveguides. The recently realized corrugated plasma channel [Layer, Phys. Rev. Lett. 99, 035001 (2007)] allows for the guiding of laser pulses with subluminal spatial harmonics. These spatial harmonics can be phase matched to high energy electrons, making the corrugated plasma channel ideal for the acceleration of electrons. We present a simple analytic model of pulse propagation in a corrugated plasma channel and examine the laser-electron beam interaction. Simulations show accelerating gradients of several hundred MeV/cm for laser powers much lower than required by standard laser wakefield schemes.
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Affiliation(s)
- J P Palastro
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA
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Layer BD, York A, Antonsen TM, Varma S, Chen YH, Leng Y, Milchberg HM. Ultrahigh-intensity optical slow-wave structure. PHYSICAL REVIEW LETTERS 2007; 99:035001. [PMID: 17678290 DOI: 10.1103/physrevlett.99.035001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Indexed: 05/16/2023]
Abstract
We report the development of corrugated "slow-wave" plasma guiding structures with application to quasiphase-matched direct laser acceleration of charged particles and generation of a wide spectrum of electromagnetic radiation. These structures support guided propagation at intensities up to 2 x 10(17) W/cm(2), limited by our current laser energy and side leakage. Hydrogen and argon plasma waveguides up to 1.5 cm in length with corrugation period as short as 35 microm are generated in a cryogenic cluster jet. Experimental data are consistent with simulations showing periodic modulations of the laser pulse intensity.
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Affiliation(s)
- B D Layer
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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7
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Cohen O, Popmintchev T, Gaudiosi DM, Murnane MM, Kapteyn HC. Unified microscopic-macroscopic formulation of high-order difference-frequency mixing in plasmas. PHYSICAL REVIEW LETTERS 2007; 98:043903. [PMID: 17358769 DOI: 10.1103/physrevlett.98.043903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Indexed: 05/14/2023]
Abstract
We investigate high-order difference-frequency mixing in plasmas, taking into account the microscopic rescattering physics and propagation effects for the first time. We show that phase matching can occur over a broad frequency range, up to very high photon energies, and that it is confined to specific temporal and spatial windows. This gated phase matching mechanism is driven by the continuous phase slip between two driving fields and can be employed for manipulating the temporal, spatial, and spectral properties of high harmonic emission.
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Affiliation(s)
- Oren Cohen
- JILA, University of Colorado, National Institute of Standards and Technology, Boulder, Colorado 80309, USA.
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Kim KY, Milchberg HM, Faenov AY, Magunov AI, Pikuz TA, Skobelev IY. X-ray spectroscopy of 1 cm plasma channels produced by self-guided pulse propagation in elongated cluster jets. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:066403. [PMID: 16906984 DOI: 10.1103/physreve.73.066403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Indexed: 05/11/2023]
Abstract
We diagnose the self-channeled propagation of intense femtosecond pulses over an extended distance in a N2O cluster gas target using high resolution kilovolt x-ray pinhole images of the channel and spatially resolved x-ray spectra. The x-ray images are consistent with femtosecond optical scattering, shadowgraphy, and interferometry images. We observe extended plasma channels (approximately 9 mm) limited either by the cluster jet length or by absorption, for injected laser intensities in the range of 10(16)-10(17) W/cm2. Spectral line shapes for the OVII 1s2-1s3p and OVIII 1s-2p transitions (at 1.8627 and 1.8969 nm, respectively) show significant broadening to the blue side and with truncated emission on the red side. We attribute this effect to Doppler blueshifted emission from fast ions from exploding clusters moving toward the spectrometer; redshifted emission from the opposite side of the cluster is absorbed.
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Affiliation(s)
- K Y Kim
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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Gaudiosi DM, Reagan B, Popmintchev T, Grisham M, Berrill M, Cohen O, Walker BC, Murnane MM, Kapteyn HC, Rocca JJ. High-order harmonic generation from ions in a capillary discharge. PHYSICAL REVIEW LETTERS 2006; 96:203001. [PMID: 16803170 DOI: 10.1103/physrevlett.96.203001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Indexed: 05/10/2023]
Abstract
We demonstrate a significant extension of the high-order harmonic cutoff by using a fully-ionized capillary discharge plasma as the generation medium. The preionized plasma dramatically reduces ionization-induced defocusing and energy loss of the driving laser due to ionization. This allows for significantly higher photon energies, up to 150 eV, to be generated from xenon ions, compared with the 70 eV observed previously. We also demonstrate enhancement of the harmonic flux of nearly 2 orders of magnitude at photon energies around 90 eV when the capillary discharge is used to ionize xenon, compared with harmonic generation in a hollow waveguide. The use of a plasma as a medium for high-order harmonic generation shows great promise for extending efficient harmonic generation to much shorter wavelengths using ions.
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Affiliation(s)
- David M Gaudiosi
- JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado, 80309-0440, USA
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Milchberg HM, Kim KY, Kumarappan V, Layer BD, Sheng H. Clustered gases as a medium for efficient plasma waveguide generation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2006; 364:647-61. [PMID: 16483955 DOI: 10.1098/rsta.2005.1729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Clustered gas jets are shown to be an efficient means for plasma waveguide generation, for both femtosecond and picosecond generation pulses. These waveguides enable significantly lower on-axis plasma density (less than 10(18) cm(-3)) than in conventional hydrodynamic plasma waveguides generated in unclustered gases. Using femtosecond pump pulses, self-guided propagation and strong absorption (more than 70%) are used to produce long centimetre scale channels in an argon cluster jet, and a subsequent intense pulse is coupled into the guide with 50% efficiency and guided at above 10(17)W cm(-2) intensity over 40 Rayleigh lengths. We also demonstrate efficient generation of waveguides using 100 ps axicon-generated Bessel-beam pump pulses. Despite the expected sub-picosecond cluster disassembly time, we observe long pulse absorption efficiencies up to a maximum of 35%. Simulations show that in the far leading edge of the long laser pulse, the volume of heated clusters evolves to a locally uniform and cool plasma already near ionization saturation, which is then efficiently heated by the remainder of the pulse.
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Affiliation(s)
- H M Milchberg
- University of Maryland Institute for Physical Science and Technology College Park, MD 20742, USA
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Cooley JH, Antonsen TM, Milchberg HM, Fan J, Margolin L, Pyatnitskii L. Parametric instability in the formation of plasma waveguides. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:036404. [PMID: 16605665 DOI: 10.1103/physreve.73.036404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Revised: 11/15/2005] [Indexed: 05/08/2023]
Abstract
Plasma waveguides generated by focusing a moderate intensity laser into neutral gas with an axicon lens can be unstable to the generation of axial modulations in the channel parameters. A model is proposed in which the modulations are due to the nonlinear coupling between the axicon field and a scattered mode in the evolving channel. Good agreement is found with experimental measurements of these modulations.
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Affiliation(s)
- J H Cooley
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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Sheng H, Kim KY, Kumarappan V, Layer BD, Milchberg HM. Plasma waveguides efficiently generated by Bessel beams in elongated cluster gas jets. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:036411. [PMID: 16241583 DOI: 10.1103/physreve.72.036411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Indexed: 05/05/2023]
Abstract
We demonstrate the efficient generation of plasma waveguides in elongated cluster gas jets using 100 ps axicon-generated Bessel beam pump pulses. The plasma waveguide space and time evolution is measured using picosecond interferometry. Small radius waveguides with central densities as low as approximately 10(18) cm(-3) can be generated with this technique. Despite the expected subpicosecond cluster disassembly time, we observe long pulse absorption efficiencies that can be more than a factor of 10 greater than in unclustered gas targets of the same volume average atomic density. The maximum long pulse absorption observed in cluster jets under our range of conditions was 35%. The explanation for the enhanced absorption is that in the far-leading edge of the laser pulse, the volume of heated clusters evolves to a locally uniform and cool plasma already near ionization saturation, which is then heated by the remainder of the pulse. From this perspective, the use of clustered gases is equivalent to a supercharged preionization scheme for long duration laser pulses.
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Affiliation(s)
- H Sheng
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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Kumarappan V, Kim KY, Milchberg HM. Guiding of intense laser pulses in plasma waveguides produced from efficient, femtosecond end-pumped heating of clustered gases. PHYSICAL REVIEW LETTERS 2005; 94:205004. [PMID: 16090259 DOI: 10.1103/physrevlett.94.205004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Indexed: 05/03/2023]
Abstract
We demonstrate intense pulse guiding in efficient femtosecond end-pumped waveguides generated in clustered gases. This novel scheme provides a route to significantly lower on-axis plasma density (< 10(18) cm(-3)) more than is feasible in conventional hydrodynamic plasma waveguides. Self-focused propagation and strong absorption of intense femtosecond laser pulses are used to produce long centimeter scale channels in an argon cluster jet, and a subsequent pulse is guided with 3 x 10(17) W cm(-2) intensity and approximately 50% coupling efficiency. Preliminary results with hydrogen clusters also show guiding.
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Affiliation(s)
- V Kumarappan
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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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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15
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Lopes NC, Figueira G, Silva LO, Dias JM, Fonseca R, Cardoso L, Russo C, Carias C, Mendes G, Vieira J, Mendonça JT. Plasma channels produced by a laser-triggered high-voltage discharge. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 68:035402. [PMID: 14524825 DOI: 10.1103/physreve.68.035402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2003] [Indexed: 05/24/2023]
Abstract
A plasma waveguide scheme for high-intensity laser guiding with densities and lengths suitable for laser-plasma particle accelerators is presented. This scheme uses a laser-triggered high-voltage discharge, presents negligible jitter, allows full access to the plasma, and can be scaled to large distances. Experimental results showing the feasibility of this scheme are presented.
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Affiliation(s)
- N C Lopes
- GoLP-Centro de Fisica dos Plasmas, Instituto Superior Tecnico-Universidade Tecnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal.
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Gordon DF, Hafizi B, Hubbard RF, Peñano JR, Sprangle P, Ting A. Asymmetric self-phase modulation and compression of short laser pulses in plasma channels. PHYSICAL REVIEW LETTERS 2003; 90:215001. [PMID: 12786561 DOI: 10.1103/physrevlett.90.215001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2002] [Indexed: 05/24/2023]
Abstract
A relativistically intense femtosecond laser pulse propagating in a plasma channel undergoes dramatic photon deceleration while propagating a distance on the order of a dephasing length. The deceleration of photons is localized to the back of the pulse and is accompanied by compression and explosive growth of the ponderomotive potential. Fully explicit particle-in-cell simulations are applied to the problem and are compared with ponderomotive guiding center simulations. A numerical Wigner transform is used to examine local frequency shifts within the pulse and to suggest an experimental diagnostic of plasma waves inside a capillary.
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Affiliation(s)
- D F Gordon
- Icarus Research, Inc, PO Box 30780, Bethesda, Maryland 20824-0780, USA
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Andreev NE, Nishida Y, Yugami N. Propagation of short intense laser pulses in gas-filled capillaries. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 65:056407. [PMID: 12059715 DOI: 10.1103/physreve.65.056407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2001] [Indexed: 05/23/2023]
Abstract
The guided laser pulse propagation and wake-field generation are studied in a wide (in comparison with the laser spot size) gas-filled capillary with an on-axis gas density depletion, which can be produced by a rapid spin of the capillary around its axis or by radially propagating shock waves generated in a piezoceramic tube. A single equation for the wake-field potential, which describes the fully relativistic plasma response in the presence of optical field ionization (OFI) of a gas, is derived and used to demonstrate a guided propagation of a short intense laser pulse over many Rayleigh lengths in a leaky plasma channel produced by the pulse due to OFI in the capillary filled with a radially inhomogeneous gas. The efficient generation of a regular wake field over long distances suitable for the laser wake-field accelerators is shown.
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Affiliation(s)
- N E Andreev
- Institute for High Energy Densities, Associated Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13/19, Moscow 127412, Russia.
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Fan J, Parra E, Kim KY, Alexeev I, Milchberg HM, Cooley J, Antonsen TM. Resonant self-trapping of high intensity Bessel beams in underdense plasmas. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 65:056408. [PMID: 12059716 DOI: 10.1103/physreve.65.056408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2001] [Indexed: 05/23/2023]
Abstract
We present a comprehensive report based on recent work [Phys. Rev. Lett. 84, 3085 (2000)] on resonant self-trapping and enhanced absorption of high power Bessel beams in underdense plasmas. The trapping resonance is strongly dependent on initial gas pressure, Bessel-beam geometry, and laser wavelength. Analytic estimates, and simulations using a one-dimensional Bessel-beam-plasma interaction code consistently explain the experimental observations. These results are for longer, moderate intensity pulses where the self-trapping channel is induced by laser-heated plasma thermal pressure. To explore the extension of this effect to ultrashort, intense pulsed Bessel beams, we perform propagation simulations using the code WAKE [Phys. Rev. E 53, R2068 (1996)]. We find that self-trapping can occur as a result of a plasma refractive index channel induced by the combined effects of relativistic motion of electrons and their ponderomotive expulsion.
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Affiliation(s)
- J Fan
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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Spence DJ, Hooker SM. Investigation of a hydrogen plasma waveguide. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:015401. [PMID: 11304307 DOI: 10.1103/physreve.63.015401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2000] [Indexed: 05/23/2023]
Abstract
A hydrogen plasma waveguide for high-intensity laser pulses is described. The guiding channel is formed by a small-scale discharge in a hydrogen-filled capillary. The measured lifetime of the capillary is inferred to be greater than 10(6) shots. The results of interferometric measurements of the electron density in the capillary are presented. The guiding channel is found to be highly ionized with an axial electron density of 2.7x10(18) cm(-3), and parabolic, the curvature corresponding to a matched spot-size of 37.5 microm.
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Affiliation(s)
- D J Spence
- Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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Fan J, Parra E, Alexeev I, Kim KY, Milchberg HM, Margolin LY, Pyatnitskii LN. Tubular plasma generation with a high-power hollow bessel beam. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 2000; 62:R7603-R7606. [PMID: 11138111 DOI: 10.1103/physreve.62.r7603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2000] [Revised: 09/25/2000] [Indexed: 05/23/2023]
Abstract
A high power, hollow Bessel beam (J5) is generated using an axicon and a phase plate in combination. The optical breakdown of a gas target and generation of a tubular plasma fiber with such a beam is realized. Hydrodynamic simulations of the hollow beam-plasma breakdown and heating are in reasonable agreement with interferometric measurements of the plasma time evolution.
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Affiliation(s)
- J Fan
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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21
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Tempea G, Geissler M, Schnurer M, Brabec T. Self-phase-matched high harmonic generation. PHYSICAL REVIEW LETTERS 2000; 84:4329-4332. [PMID: 10990678 DOI: 10.1103/physrevlett.84.4329] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/1999] [Indexed: 05/23/2023]
Abstract
Our theoretical analysis reveals that tunnel ionization significantly modifies the electric field of few-cycle laser pulses within a single oscillation period. This subcycle self-modulation is predicted to result in phase matching, making high harmonic generation in the x-ray regime possible for the first time. Such a radiation source opens novel possibilities in the investigation of matter with x-ray techniques, such as time resolved x-ray diffraction and absorption.
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Affiliation(s)
- G Tempea
- Institut fur Photonik, Technische Universitat Wien, Gusshausstrasse 27/387, A-1040 Wien, Austria
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22
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Esarey E, Schroeder CB, Shadwick BA, Wurtele JS, Leemans WP. Nonlinear theory of nonparaxial laser pulse propagation in plasma channels. PHYSICAL REVIEW LETTERS 2000; 84:3081-3084. [PMID: 11019017 DOI: 10.1103/physrevlett.84.3081] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/1999] [Indexed: 05/23/2023]
Abstract
Nonparaxial propagation of ultrashort, high-power laser pulses in plasma channels is examined. In the adiabatic limit, pulse energy conservation, nonlinear group velocity, damped betatron oscillations, self-steepening, self-phase modulation, and shock formation are analyzed. In the nonadiabatic limit, the coupling of forward Raman scattering (FRS) and the self-modulation instability (SMI) is analyzed and growth rates are derived, including regimes of reduced growth. The SMI is found to dominate FRS in most regimes of interest.
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Affiliation(s)
- E Esarey
- Center for Beam Physics, Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
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23
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Fan J, Parra E, Milchberg HM. Resonant self-trapping and absorption of intense bessel beams. PHYSICAL REVIEW LETTERS 2000; 84:3085-3088. [PMID: 11019018 DOI: 10.1103/physrevlett.84.3085] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/1999] [Indexed: 05/23/2023]
Abstract
We report the observation of resonant self-trapping and enhanced laser-plasma heating resulting from propagation of high intensity Bessel beams in neutral gas. The enhancement in absorption and plasma heating is directly correlated to the spatial trapping of laser radiation.
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Affiliation(s)
- J Fan
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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24
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Sprangle P, Hafizi B, Penano JR. Laser pulse modulation instabilities in plasma channels. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 2000; 61:4381-4393. [PMID: 11088236 DOI: 10.1103/physreve.61.4381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/1999] [Indexed: 05/23/2023]
Abstract
In this paper the modulational instability associated with propagation of intense laser pulses in a partially stripped, preformed plasma channel is analyzed. In general, modulation instabilities are caused by the interplay between (anomalous) group velocity dispersion and self-phase modulation. The analysis is based on a systematic approach that includes finite-perturbation-length effects, nonlinearities, group velocity dispersion, and transverse effects. To properly include the radial variation of both the laser field and plasma channel, the source-dependent expansion method for analyzing the wave equation is employed. Matched equilibria for a laser beam propagating in a plasma channel are obtained and analyzed. Modulation of a uniform (matched) laser beam equilibrium in a plasma channel leads to a coupled pair of differential equations for the perturbed spot size and laser field amplitude. A general dispersion relation is derived and solved. Surface plots of the spatial growth rate as a function of laser beam power and the modulation wave number are presented.
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Affiliation(s)
- P Sprangle
- Beam Physics Branch, Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA
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Clark TR, Milchberg HM. Optical mode structure of the plasma waveguide. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 2000; 61:1954-1965. [PMID: 11046482 DOI: 10.1103/physreve.61.1954] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/1999] [Indexed: 05/23/2023]
Abstract
The quasibound modes of an evolving plasma waveguide were investigated by using variably delayed end-injected and side-injected probe pulses. The use of these different coupling geometries allowed the probing of the waveguide's optical modes during two temporal regimes: early-time plasma channel development, characterized by leaky optical confinement, and later channel hydrodynamic expansion characterized by stronger confinement. The wave equation was solved to determine the available quasiguided optical modes and their confinement for experimentally measured electron density profiles. The guided intensity patterns and spectra measured at the waveguide exit were successfully explained in terms of these mode solutions. The spectrum of broadband end-coupled probe pulses was found to be unaffected by the guiding process, mainly because those modes which survived to the waveguide exit were well-bound, and for strongly bound fields, the transverse mode profiles are wavelength independent. By contrast, side coupling to the quasibound modes of the plasma waveguide was seen to be highly mode and frequency selective.
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Affiliation(s)
- TR Clark
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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Spence DJ, Burnett PD, Hooker SM. Measurement of the electron-density profile in a discharge-ablated capillary waveguide. OPTICS LETTERS 1999; 24:993-995. [PMID: 18073920 DOI: 10.1364/ol.24.000993] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present the results of time-resolved interferometric measurements of the electron-density profile in a discharge-ablated capillary waveguide. We observe the development of a pronounced axial minimum in the electron-density profile with a relative depth of as much as 60% of the axial electron density. Such a profile is suitable for channeling high-intensity laser pulses.
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Kaganovich D, Ting A, Moore CI, Zigler A, Burris HR, Ehrlich Y, Hubbard R, Sprangle P. High efficiency guiding of terawatt subpicosecond laser pulses in a capillary discharge plasma channel. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1999; 59:R4769-72. [PMID: 11969516 DOI: 10.1103/physreve.59.r4769] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/1999] [Indexed: 04/18/2023]
Abstract
Transmission efficiencies in excess of 75% were obtained in the optical guiding of subpicosecond, terawatt laser pulses in a 2-cm-long capillary discharge plasma channel at the Naval Research Laboratory. The guided laser beam size at the exit of the channel was measured using far field imaging and Thomson scattering techniques. The guided laser intensity was >1 x 10(17) W/cm(2) at a guided beam diameter of 35 microm for a propagation length of 22 Rayleigh ranges. There is evidence that the plasma channel extends beyond the ends of the capillary and affects the far field beam structure of the transmitted laser pulse.
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Affiliation(s)
- D Kaganovich
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
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Rundquist A, Durfee CG, Chang Z, Herne C, Backus S, Murnane MM, Kapteyn HC. Phase-matched generation of coherent soft X-rays. Science 1998; 280:1412-5. [PMID: 9603725 DOI: 10.1126/science.280.5368.1412] [Citation(s) in RCA: 240] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Phase-matched harmonic conversion of visible laser light into soft x-rays was demonstrated. The recently developed technique of guided-wave frequency conversion was used to upshift light from 800 nanometers to the range from 17 to 32 nanometers. This process increased the coherent x-ray output by factors of 10(2) to 10(3) compared to the non-phase-matched case. This source uses a small-scale (sub-millijoule) high repetition-rate laser and will enable a wide variety of new experimental investigations in linear and nonlinear x-ray science.
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Affiliation(s)
- A Rundquist
- Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI 48109-2099, USA
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Durfee Iii CG, Backus S, Murnane MM, Kapteyn HC. Ultrabroadband phase-matched optical parametric generation in the ultraviolet by use of guided waves. OPTICS LETTERS 1997; 22:1565-1567. [PMID: 18188300 DOI: 10.1364/ol.22.001565] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present what is believed to be the first experimental demonstration of guided-wave phase-matched frequency mixing and harmonic conversion in gases. Broad-bandwidth ultrafast pulses, tunable around 270 nm, were generated from an ultrafast Ti:sapphire amplifier system using 2? + 2? - ? parametric wave mixing in a capillary waveguide. We achieved nonresonant phase matching by coupling both the fundamental and the second-harmonic light into the lowest-order mode. The output 3? pulses have an energy of >4muJ at a 1-kHz repetition rate. Simple extensions of this method can generate higher-energy 10-20-fs pulses tunable throughout the vacuum ultraviolet.
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Kan C, Capjack CE, Rankin R, Brabec T, Burnett NH. Phase-matched frequency conversion in ionizing atomic gases. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1996; 54:R1026-R1029. [PMID: 9913663 DOI: 10.1103/physreva.54.r1026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Meyer S, Eichmann H, Menzel T, Nolte S, Wellegehausen B, Chichkov BN, Momma C. Phase-matched high-order difference-frequency mixing in plasmas. PHYSICAL REVIEW LETTERS 1996; 76:3336-3339. [PMID: 10060941 DOI: 10.1103/physrevlett.76.3336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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