1kHz飞秒激光脉冲在空气中传输成丝的演化过程

利用高重复频率(１kHz)、低能量的飞秒激光脉冲研究激光脉冲在空气中传输成丝的演化过程.采用成像的方法观测飞秒激光脉冲在大气传输过程中光束截面上光强分布变化，以及大气等离子体通道对光强分布的反作用.实验结果表明，激光脉冲在传输过程中先形成双丝结构，再逐渐合并成单丝结构.实验结果与利用非线性薛定谔方程耦合多光子电离的数值模拟结果基本一致. 关键词： 飞秒激光脉冲 等离子体通道 成像

Evolvement of filamentation of femtosecond laser pulses of a kHz repetition rate propagating in Air

In this paper the evolvement of the filamentation of femtosecond laser pulses propagating in air is studied experimentally.We observed the variation of light intensity in the beam profile and the interaction of the filament with the distribution of light intensity in the forming of the plasma filament by using imaging.The experimental results show that the laser pulse propagating in air first forms two filaments and then merges into a single filament.The numerical simulation using the nonlinear Schrdinger equation coupled to a multiphoton ionization law appears to describe several experimental results quite well.