Propagation of intense short laser pulses in the atmosphere.

The propagation of short, intense laser pulses in the atmosphere is investigated theoretically and numerically. A set of three-dimensional (3D), nonlinear propagation equations is derived, which includes the effects of dispersion, nonlinear self-focusing, stimulated molecular Raman scattering, multiphoton and tunneling ionization, energy depletion due to ionization, relativistic focusing, and ponderomotively excited plasma wakefields. The instantaneous frequency spread along a laser pulse in air, which develops due to various nonlinear effects, is analyzed and discussed. Coupled equations for the power, spot size, and electron density are derived for an intense ionizing laser pulse. From these equations we obtain an equilibrium for a single optical-plasma filament, which involves a balancing between diffraction, nonlinear self-focusing, and plasma defocusing. The equilibrium is shown to require a specific distribution of power along the filament. It is found that in the presence of ionization a self-guided optical filament is not realizable. A method for generating a remote spark in the atmosphere is proposed, which utilizes the dispersive and nonlinear properties of air to cause a low-intensity chirped laser pulse to compress both longitudinally and transversely. For optimally chosen parameters, we find that the transverse and longitudinal focal lengths can be made to coincide, resulting in rapid intensity increase, ionization, and white light generation in a localized region far from the source. Coupled equations for the laser spot size and pulse duration are derived, which can describe the focusing and compression process in the low-intensity regime. More general examples involving beam focusing, compression, ionization, and white light generation near the focal region are studied by numerically solving the full set of 3D, nonlinear propagation equations.

[1]  Roland Sauerbrey,et al.  Electrical conductivity of long plasma channels in air generated by self-guided femtosecond laser pulses , 1999 .

[2]  Raymond M. Measures,et al.  Laser remote chemical analysis , 1988 .

[3]  Guillaume Petite,et al.  Free-Free Transitions Following Six-Photon Ionization of Xenon Atoms , 1979 .

[4]  J. Ripoche,et al.  Anomalous long-range propagation of femtosecond laser pulses through air: moving focus or pulse self-guiding? , 1998, Optics letters.

[5]  V. S. Averbakh,et al.  Stimulated Raman scattering on rotational and vibrational transitions in nitrogen gas , 1978 .

[6]  G. S. McDonald,et al.  Ultrabroad-bandwidth multifrequency Raman generation. , 1994, Optics letters.

[7]  S. Chin,et al.  Conical emission from laser plasma interactions in the filamentation of powerful ultrashort laser pulses in air. , 1997, Optics letters.

[8]  Govind P. Agrawal,et al.  Nonlinear Fiber Optics , 1989 .

[9]  Pierre Couture,et al.  Triggering and guiding leader discharges using a plasma channel created by an ultrashort laser pulse , 2000 .

[10]  D. M. Wolkow.  Über eine Klasse von Lösungen der Diracschen Gleichung , 1935 .

[11]  Paul A. Bernhardt,et al.  Direct reconstruction methods for hyperspectral imaging with rotational spectrotomography , 1995 .

[12]  See Leang Chin,et al.  Ultrafast white-light continuum generation and self-focusing in transparent condensed media , 1999 .

[13]  P. Corkum,et al.  Femtosecond continua produced in gases , 1989 .

[14]  Bernard Prade,et al.  Determination of the inertial contribution to the nonlinear refractive index of air, N 2 , and O 2 by use of unfocused high-intensity femtosecond laser pulses , 1997 .

[15]  See Leang Chin,et al.  Fast pulsed electric field created from the self-generated filament of a femtosecond Ti:Sapphire laser pulse in air , 2000 .

[16]  Howard R. Reiss,et al.  Effect of an intense electromagnetic field on a weakly bound system , 1980 .

[17]  J. Diels,et al.  Femtosecond ultraviolet laser pulse induced lightning discharges in gases , 1995 .

[18]  K. Nakajima,et al.  Structure of the wake field in plasma channels , 1997 .

[19]  Leon J. Radziemski,et al.  Lasers-Induced Plasmas and Applications , 1989 .

[20]  J. Ripoche,et al.  Determination of the time dependence of n2 in air , 1997 .

[21]  N. H. Burnett,et al.  Above-threshold ionization in the long-wavelength limit , 1989 .

[22]  A. Couairon,et al.  Breakup and fusion of self-guided femtosecond light pulses in air. , 2001, Physical review letters.

[23]  Michael G. Raymer,et al.  Theory of stimulated Raman scattering with broad-band lasers , 1979 .

[24]  Esarey,et al.  Nonlinear interaction of intense laser pulses in plasmas. , 1989, Physical review. A, Atomic, molecular, and optical physics.

[25]  Corkum,et al.  Supercontinuum generation in gases. , 1986, Physical review letters.

[26]  Bohn,et al.  Sustained kilowatt lasing in a free-electron laser with same-cell energy recovery , 2000, Physical review letters.

[27]  M. Levenson.  The principles of nonlinear optics , 1985, IEEE Journal of Quantum Electronics.

[28]  Bahman Hafizi,et al.  Generation of high-average-power ultrabroad-band infrared pulses , 1999 .

[29]  Esarey,et al.  Self-guiding and stability of intense optical beams in gases undergoing ionization. , 1996, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[30]  B. Stein,et al.  Remote sensing of the atmosphere using ultrashort laser pulses , 2000 .

[31]  M. Rokni,et al.  Stimulated rotational Raman scattering in the atmosphere , 1986 .

[32]  Hickman,et al.  Theory of multiwave propagation and frequency conversion in a Raman medium. , 1986, Physical review. A, General physics.

[33]  E. Wright,et al.  Power dependence of dynamic spatial replenishment of femtosecond pulses propagating in air , 1999 .

[34]  A. Couairon,et al.  Modeling the filamentation of ultra-short pulses in ionizing media , 2000 .

[35]  Remo Guidieri.  Res , 1995, RES: Anthropology and Aesthetics.

[36]  E. Wright,et al.  Power dependence of dynamic spatial replenishment of femtosecond pulses propagating in air. , 1998, Optics express.

[37]  P. Milonni,et al.  Solitons and four-wave mixing. , 1986, Physical review. A, General physics.

[38]  C. McKinstrie,et al.  Stimulated Raman forward scattering and the relativistic modulational instability of light waves in rarefied plasma , 1992 .

[39]  Tang,et al.  Analysis of radiation focusing and steering in the free-electron laser by use of a source-dependent expansion technique. , 1987, Physical review. A, General physics.

[40]  H. Pépin,et al.  Single-shot chirped-pulse spectral interferometry used to measure the femtosecond ionization dynamics of air. , 2000, Optics letters.

[41]  Generation of electromagnetic pulses from plasma channels induced by femtosecond light strings. , 2000, Physical review letters.

[42]  Eric Esarey,et al.  Propagation and stability of intense laser pulses in partially stripped plasmas , 1997 .

[43]  P. W. Grounds,et al.  Electrical conductivity of a femtosecond laser generated plasma channel in air , 2001 .

[44]  Sprangle,et al.  Laser pulse modulation instabilities in plasma channels , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[45]  Fujio Shimizu,et al.  Frequency Broadening in Liquids by a Short Light Pulse , 1967 .

[46]  J. C. Wyant,et al.  Report to The American Physical Society of the study group on science and technology of directed energy weapons , 1987 .

[47]  Andrew G. Glen,et al.  APPL , 2001 .

[48]  C. Bowden,et al.  White-light continuum generation and filamentation during the propagation of ultra-short laser pulses in air , 2001 .

[49]  Jean-Claude Kieffer,et al.  Filamentation of ultrashort pulse laser beams resulting from their propagation over long distances in air , 1999 .

[50]  K. S. Syed,et al.  Transverse effects in ultrabroadband multifrequency Raman generation , 2000 .

[51]  Bowden,et al.  Femtosecond pulse propagation in air: variational analysis , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[52]  K. O'Donnell,et al.  Scattering by plasmon polaritons on a metal surface with a detuned roughness spectrum. , 1996, Optics letters.

[53]  Roland Sauerbrey,et al.  Modifications to the lidar equation due to nonlinear propagation in air , 2001 .

[54]  P. Lucas,et al.  PROCEEDINGS 2001 PARTICLE ACCELERATOR CONFERENCE , 2001 .

[55]  J. Kupersztych.  Inverse Half-Bremsstrahlung in Multiphoton Ionization of Atoms in Intense Light Beams , 1987 .

[56]  P. Sprangle,et al.  Guiding and stability of short laser pulses in partially stripped ionizing plasmas , 1999 .

[57]  Hermann A. Haus,et al.  Raman response function of silica-core fibers , 1989, Annual Meeting Optical Society of America.

[58]  R. Fernsler,et al.  Models of lightning-produced sprites and elves , 1996 .

[59]  Henesian,et al.  Nonlinear index of air at 1.053 microm. , 1989, Physical review. A, General physics.

[60]  E. Wright,et al.  Femtosecond pulse propagation in argon: A pressure dependence study , 1998 .

[61]  R Sauerbrey,et al.  Backward supercontinuum emission from a filament generated by ultrashort laser pulses in air. , 2001, Optics letters.

[62]  Farhard Faisal,et al.  Multiple absorption of laser photons by atoms , 1973 .

[63]  Keith J. Blow,et al.  Theoretical description of transient stimulated Raman scattering in optical fibers , 1989 .

[64]  P. Sprangle,et al.  Interaction of ultrahigh laser fields with beams and plasmas , 1992 .

[65]  A. Mysyrowicz,et al.  Formation of a conducting channel in air by self-guided femtosecond laser pulses. , 1999, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[66]  Joyce,et al.  Frequency up-shifting of laser pulses by copropagating ionization fronts. , 1991, Physical review. A, Atomic, molecular, and optical physics.

[67]  A. Ali,et al.  High‐energy electron beam deposition and plasma velocity distribution in partially ionized N2 , 1990 .

[68]  C. G. Morgan.  Laser-induced breakdown of gases , 1975 .

[69]  R Sauerbrey,et al.  Infrared extension of the super continuum generated by femtosecond terawatt laser pulses propagating in the atmosphere. , 2000, Optics letters.

[70]  Eric Esarey,et al.  INTENSE LASER PULSE PROPAGATION AND STABILITY IN PARTIALLY STRIPPED PLASMAS , 1997 .

[71]  S. Chin,et al.  Moving focus in the propagation of ultrashort laser pulses in air. , 1997, Optics letters.

[72]  See Leang Chin,et al.  Semi-empirical model for the rate of tunnel ionization of N2 and O2 molecule in an intense Ti:sapphire laser pulse , 1999 .

[73]  F. Salin,et al.  Conical emission from self-guided femtosecond pulses in air. , 1996, Optics letters.

[74]  G. Mourou,et al.  Self-channeling of high-peak-power femtosecond laser pulses in air. , 1995, Optics letters.

[75]  M. Feit,et al.  Effect of refraction on spot-size dependence of laser-induced breakdown , 1974 .

[76]  M. Henesian,et al.  Stimulated rotational Raman scattering in nitrogen in long air paths. , 1985, Optics letters.

[77]  Bahman Hafizi,et al.  Progress in the development of a high average power ultra-broadband infrared radiation source , 2001 .

[78]  Hickman,et al.  Theory of Stokes and anti-Stokes generation by Raman frequency conversion in the transient limit. , 1988, Physical review. A, General physics.

[79]  See Leang Chin,et al.  The critical laser intensity of self-guided light filaments in air , 2000 .

[80]  Miroslav Kolesik,et al.  OPTICALLY TURBULENT FEMTOSECOND LIGHT GUIDE IN AIR , 1999 .

[81]  N Menyuk,et al.  Laser Remote Sensing of the Atmosphere , 1987, Science.