Properties of filamentation of intense femtosecond laser pulses propagation in air

Abstract

Abstract:

Based on the variational principle of nonlinear shrödinger(NLS) equation describing laser pulses propagation in air, the properties of femtosecond filaments have been studied by using numerical simulation method. Numerical results were derived on the developing process of filamentation under the situations of whether or not taking account of multiphoton absorption dissipation (MPA). It shows that a dynamic equilibrium between optical self-focusing and plasma defocusing will be broken due to the MPA, which will induce instability of femtosecond filamentation. The first foci of the filaments are displaced for different incidence laser power. Further investigate reveals that stably filamentation propagation described by defocusing-refocusing cycles can only arise for power in laboratory. With the incidence power gradually increasing, the beam will undergo optical collapse due to intense focusing, and then the formation of femtosecond multiple filamentation(MF) can be obtained.

Key words: laser techniques, self-focusing, plasmas defocusing, femtosecond laser filamentation, multiphoton absorption

CLC Number:

O437

WANG Hai-Tao, Fan Cheng-Yu, QIAO Chun-Hong, ZHANG Jing-Hui, ZHANG Peng-Fei, MA Hui-Min. Properties of filamentation of intense femtosecond laser pulses propagation in air[J]. J4, 2011, 28(5): 544-550.

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