电子等离子体波对超短脉冲激光传播过程的作用

EFFECT OF ELECTRON PLASMA WAVE ON THE PROPA-GATION OF AN ULTRASHORT-PULSE LASER

提出等离子体波对光脉冲产生相位调制的观点,把光脉冲在背景等离子体波中传播时的频率移动与脉宽压缩效应统一起来。给出了脉宽演化的方程,它类似于在势阱中运动的经典粒子的能量守恒方程;估算了脉宽压缩对应的等离子体波振幅阈值。数值计算进一步证实这些结论。最后指出实验上用等离子体波压缩短脉冲激光脉宽的可能性。

Unification of the frequency shift and pulse compression of an ultrashort laser pulse propagating in a background plasma wave is realized by employing the concept of phase modulation of the laser pulse by the plasma wave. The equation for the evolution of the pulse width is obtained, which is analogues to the 'energy conservation equation' for a classical particle moving in a potential well. The threshold amplitude of plasma wave for the pulse compression is estimated. Numerical calculation is performed to confirm these results. The possibitity of laser pulse compression by plasma wave in practice is suggested finally.