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Author(s): |
Liwen Zhang, College of Electronics and Information Engineering, Henan University of Science and Technology, Luoyang, China, 471003
Ming Shao, Unit 63891 PLA, Luoyang, China, 471003
Wei Tian, College of Electronics and Information Engineering, Henan University of Science and Technology, Luoyang, China, 471003 |
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Abstract: |
The influence of laser parameters on long range propagation of femtosecond laser pulses in air is studied theoretically and numerically, basing on the propagation model of ultra-short femtosecond laser pulses in air, which utilizes the dispersive and nonlinear properties of air to cause a low intensity chirped laser pulse to compress both longitudinally and transversely. Coupled equations for the laser beam size and pulse duration are derived, which can describe the focusing and compression process. The results show that the propagation distances for both longitudinal and transverse compression change obviously with the laser parameters of the initial chirp and initial beam size, increasing laser initial chirp and initial beam size is favorable to the long range propagation in air. Also, for optimally chosen parameters, the transverse and longitudinal focal lengths can be made to coincide, resulting in a filament generation in a localized region far from the source to control the filament distance.
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