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Raman laser amplification in preformed and ionizing plasmas

Published online by Cambridge University Press:  02 June 2005

D.S. CLARK
Affiliation:
Lawrence Livermore National Laboratory, Livermore, CA
N.J. FISCH
Affiliation:
Princeton Plasma Physics Laboratory, Princeton, NJ

Abstract

The recently proposed backward Raman laser amplification scheme utilizes the stimulated Raman backscattering in plasma of a long pumping laser pulse to amplify a short, and frequency downshifted seed pulse. The output intensity for this scheme is limited by the development of forward Raman scattering (FRS) or modulational instabilities of the highly amplified seed. Theoretically, focused output intensities as high as 1025 W/cm2, and pulse lengths of less than 100 fs, could be accessible by this technique for 1 μm lasers—an improvement of 104–105 in focused intensity over current techniques. Simulations with the particle-in-cell (PIC) code Zohar are presented, which investigate the effects of FRS and modulational instabilities, and of Langmuir wave breaking on the output intensity for Raman amplification. Using the intense seed pulse to photoionize the plasma simultaneous with its amplification (and hence avoid plasmas-based instabilities of the pump) is also investigated by PIC simulations. It is shown that both approaches can access focused intensities in the 1025 W/cm2 range.

Type
Research Article
Copyright
2005 Cambridge University Press

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References

REFERENCES

Antonsen, T.M. & Mora, P. (1992). Self-focusing and Raman scattering of laser pulses in tenuous plasmas. Phys. Rev. Lett. 69, 2204.CrossRefGoogle Scholar
Clark, D.S. & Fisch, N.J. (2002). Regime for a self-ionizing Raman laser amplifier. Phys. Plasmas 9, 2772.CrossRefGoogle Scholar
Clark, D.S. & Fisch, N.J. (2003). Operating regime for a backward Raman laser amplifier in preformed plasma. Phys. Plasmas 10, 3363.Google Scholar
Coffey, T.P. (1971). Breaking of large amplitude plasma oscillations. Phys. Fluids 14, 1402.CrossRefGoogle Scholar
Dawson, J.N. (1959). Nonlinear electron oscillations in a cold plasma. Phys. Rev. 113, 383.CrossRefGoogle Scholar
Esarey, E., Joyce, G. & Sprangle, P. (1991). Frequency up-shifting of laser pulses by copropagating ionization fronts. Phys. Rev. A 44, 3908.Google Scholar
Langdon, A.B. & Lasinski, B.F. (1976). Electromagnetic and relativistic plasma simulation models. In Methods in Computational Physics (Killeen, J., Alder, R., Fernbach, S. & Rotenberg, M., Eds.), pp. 327266, New York: Academic Press.Google Scholar
Litvak, A.G. (1970). Finite-amplitude wave beams in a magnetoactive plasma. Sov. Phys. JETP 30, 344.Google Scholar
Malkin, V.M., Shvets, G. & Fisch, N.J. (1999). Fast compression of laser beams to highly overcritical powers. Phys. Rev. Lett. 82, 4448.CrossRefGoogle Scholar
Malkin, V.M. & Fisch, N.J. (2001). Backward Raman amplification of ionizing laser pulses. Phys. Plasmas 8, 4698.CrossRefGoogle Scholar
Max, C., Arons, J. & Langdon, A.B. (1974). Self-modulation and self-focusing of electromagnetic waves in plasmas. Phys. Rev. Lett. 33, 209.CrossRefGoogle Scholar
Rae, S.C. & Burnett, K. (1992). Detailed simulations of plasma-induced spectral blueshifting. Phys. Rev. A 46, 2077.CrossRefGoogle Scholar