近年来,空气激光因在大气传感和环境监测等领域具有重要的潜在应用价值而备受关注。空气激光通常是指强激光诱导大气组分粒子布居数反转,进而产生的远场无腔光放大的激射现象。氮气和氧气作为两种主要的大气组分,均可在强激光激发下产生激射行为。光增益介质可以是氧原子、氮原子、氮分子和氮分子离子。本文以飞秒光丝诱导氮分子和氮分子离子激光为例,讨论了空气激光的现象观测、机理探索和应用前景,并着重介绍了光场偏振效应对氮分子离子激射行为影响的研究进展。

Recently, air lasing has attracted significant attention owing to its promising applications in atmospheric sensing and environmental monitoring. Air lasing usually refers to strong-laser-induced population inversion of atmospheric constituents, resulting in no-cavity light amplification over a remote distance. It has been revealed that with the excitation of intense laser pulses, molecules of the two primary atmospheric constituents, i.e., nitrogen and oxygen, can exhibit lasing behaviors. The gain media can be atomic oxygen and nitrogen, as well as neutral nitrogen molecules and nitrogen molecular ions. Herein, we present the phenomena, underlying mechanisms, and potential applications of air lasing with a focus on the gain media of neutral and single-ionized nitrogen molecules. Moreover, the influence of the laser polarization state on the N2+ lasing is discussed in more detail.