Nonlinear analysis of relativistic harmonic generation by intense lasers in plasmas

A linearly polarized, ultraintense laser field induces transverse plasma currents which are highly relativistic and nonlinear, resulting in the generation of coherent harmonic radiation in the forward direction (i.e., copropagating with the incident laser field). A nonlinear cold fluid model, valid for ultrahigh intensities, is formulated and used to analyze relativistic harmonic generation. The plasma density response is included self-consistently and is shown to significantly reduce the current driving the harmonic radiation. Phase detuning severely limits the growth of the harmonic radiation. The effects of diffraction are considered in the mildly relativistic limit. No third-harmonic signal emerges from a uniform plasma of near-infinite extent. A finite third-harmonic signal requires the use of a semi-infinite or finite slab plasma. For an initially uniform plasma, no second-harmonic radiation is generated. Generation of even harmonics requires transverse gradients in the initial plasma density profile. >

[1]  Edward Ott,et al.  Self‐focusing of short intense pulses in plasmas , 1987 .

[2]  Eric H. Esarey,et al.  Laser wakefield acceleration and relativistic optical guiding , 1988 .

[3]  P. Sprangle,et al.  Relativistic focusing and beat wave phase velocity control in the plasma beat wave accelerator , 1988 .

[4]  W. M. Wood,et al.  Tight focusing and blue shifting of millijoule femtosecond pulses from a conical axicon amplifier. , 1988, Optics letters.

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

[6]  D. Umstadter,et al.  Harmonic Generation by an Intense Picosecond Laser in an Underdense Plasma , 1992 .

[7]  Mori,et al.  Generation of tunable radiation using an underdense ionization front. , 1991, Physical review. A, Atomic, molecular, and optical physics.

[8]  E. Esarey,et al.  Relativistic Self-Focusing of Short-Pulse Radiation Beams in Plasmas , 1987, IEEE Transactions on Plasma Science.

[9]  E. Esarey,et al.  Laser wakefield acceleration , 1989, IEEE 1989 International Conference on Plasma Science.

[10]  J. Ward,et al.  Optical Third Harmonic Generation in Gases by a Focused Laser Beam , 1969 .

[11]  P. Sprangle,et al.  Nonlinear wake‐field generation and relativistic focusing of intense laser pulses in plasmas , 1990 .

[12]  E. Sarachik,et al.  Classical theory of the scattering of intense laser radiation by free electrons , 1970 .

[13]  L. A. Lompré,et al.  Multiple-harmonic conversion of 1064 nm radiation in rare gases , 1988 .

[14]  V. I. Kirsanov,et al.  The excitation of plasma waves by an electromagnetic wave packet , 1987 .

[15]  F. Brunel.  Harmonic generation due to plasma effects in a gas undergoing multiphoton ionization in the high-intensity limit , 1990 .

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

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

[18]  Dyson,et al.  Experiments and simulations of tunnel-ionized plasmas. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[19]  Clayton,et al.  Strongly coupled stimulated Raman backscatter from subpicosecond laser-plasma interactions. , 1992, Physical review letters.

[20]  The laser wakefield accelerator , 1989 .

[21]  P. Sprangle,et al.  Frequency shifts induced in laser pulses by plasma waves. , 1990, Physical review. A, Atomic, molecular, and optical physics.

[22]  Esarey,et al.  Stimulated backscattered harmonic generation from intense laser interactions with beams and plasmas. , 1991, Physical review letters.

[23]  Gerard Mourou,et al.  Compression of amplified chirped optical pulses , 1985 .

[24]  P. Sprangle,et al.  Nonlinear theory of intense laser-plasma interactions. , 1990, Physical review letters.

[25]  M. Perry,et al.  Spectral shaping in chirped-pulse amplification. , 1990, Optics letters.

[26]  Dyson,et al.  Plasma physics aspects of tunnel-ionized gases. , 1992, Physical review letters.

[27]  A. Bruce Langdon,et al.  Self-Modulation and Self-Focusing of Electromagnetic Waves in Plasmas , 1974 .

[28]  N. Isenor,et al.  Three Photon Ionization of Alkali Atoms at the Ruby Laser Wavelength , 1975 .

[29]  Y. Zhu,et al.  Second harmonic emission from an underdense laser‐produced plasma and filamentation , 1987 .

[30]  Fisch,et al.  Third-harmonic generation with ultrahigh-intensity laser pulses. , 1992, Physical review letters.

[31]  Michael D. Perry,et al.  Design and performance of a multiterawatt, subpicosecond neodymium:glass laser , 1990 .

[32]  Gerard Mourou,et al.  Development and applications of compact high‐intensity lasers , 1992 .

[33]  T. Tajima,et al.  Laser Electron Accelerator , 1979 .

[34]  Dawson,et al.  Evolution of self-focusing of intense electromagnetic waves in plasma. , 1988, Physical review letters.

[35]  Generation of stimulated backscattered harmonic radiation from intense-laser interactions with beams and plasmas. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[36]  Gerard Mourou,et al.  Generation of ultrahigh peak power pulses by chirped pulse amplification , 1988 .

[37]  Dawson,et al.  Photon accelerator. , 1989, Physical review letters.

[38]  Henry C. Kapteyn,et al.  Relativistic pulse compression , 1991 .

[39]  Charles K. Rhodes,et al.  Studies of multiphoton production of vacuum-ultraviolet radiation in the rare gases , 1987 .

[40]  Joyce,et al.  Propagation and guiding of intense laser pulses in plasmas. , 1992, Physical review letters.