Abstract

The propagation of an ultrashort terahertz (THz) pulse in a nonequilibrium plasma channel produced by a UV femtosecond laser pulse in air is investigated theoretically. The analysis is carried out based on joint solution of the second-order wave equation and the Boltzmann kinetic equation in the binomial approximation for the electron velocity distribution function in the channel plasma. We assume that a THz pulse is quite weak and does not produce a reverse action on the electron energy spectrum in the channel plasma. It is shown that the plasma channel in air under a pressure of several atmospheres is a medium for effective amplification of ultrashort THz pulses in the frequency range up to several terahertz.

中文翻译：

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飞秒紫外线在多量子电离过程中在空气中产生的强非平衡等离子体通道中超短太赫兹脉冲的传播和放大的特殊性

摘要

从理论上研究了紫外线飞秒激光脉冲在空气中产生的非平衡等离子体通道中超短太赫兹（THz）脉冲的传播。基于二阶波动方程和玻尔兹曼动力学方程的二项式近似，对通道等离子体中的电子速度分布函数进行联合求解，进行了分析。我们假设太赫兹脉冲非常微弱，并且不会对通道等离子体中的电子能谱产生反向作用。结果表明，在数个大气压下的空气中的等离子通道是有效放大频率高达几太赫兹的超短THz脉冲的介质。