Excitation gratings in cross-beam filament wake channels in a dense argon gas: Formation, control, and Rabi sideband manifestation
Excitation gratings in cross-beam filament wake channels in a dense argon gas: Formation, control, and Rabi sideband manifestation
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稠密氩气中交叉束灯丝尾流通道中的激发光栅：形成、控制和拉比边带表现
DOI：
10.1103/physreve.107.065202
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发表时间：
2023
影响因子：
2.4
通讯作者：
Romanov, Dmitri A.
中科院分区：
文献类型：
--
作者：
Bajpai, Suyash;Romanov, Dmitri A.
当两束强激光束以小角度交叉时，交叉区域的干涉会产生有限强度的光栅。我们考虑在这种光栅中形成飞秒激光成丝，在这种情况下，该过程很大程度上局限于光栅最大值并导致形成结构化的灯丝尾流通道。在稠密气体中，激光脉冲期间的电子撞击过程会引起中性原子的大量激发，从而形成激发原子密度的有限光栅。通过数值求解激光驱动动力学方程，我们获得了该光栅的特性，该特性取决于干涉光束的特性，尤其是光束间相位延迟。当皮秒 800 nm 激光脉冲探测时，由此形成的激发光栅会产生拉比边带发射的标志效应，该脉冲与激发态流形中的跃迁耦合。发射辐射的光谱和空间干涉形成四维空间光谱条纹图案，可在远程屏幕上观察。这些图案表示激发光栅结构；它们对交叉泵浦脉冲之间的相位延迟的敏感性值得实验验证。
When two intense laser beams cross at a small angle, the interference in the crossing area results in a finite intensity grating. We consider femtosecond laser filamentation in such a grating, in a situation when the process is largely confined to the grating maxima and leads to formation of a structured filament wake channel. In a dense gas, electron impact processes during the laser pulse cause a copious excitation of neutral atoms, resulting in formation of a finite grating of the density of excited atoms. Numerically solving the equations of laser-driven kinetics, we obtain the properties of this grating, as depending on the characteristics of the interfering beams and especially on the interbeam phase delay. The excitation gratings thus formed give rise to a hallmark effect of Rabi sideband emission when probed by a picosecond 800 nm laser pulse, which couples with transitions in the excited states manifold. Spectral and spatial interference of the emitted radiation forms four-dimensional spatial-spectral fringe patterns accessible for observation on a remote screen. The patterns are indicative of the excitation grating structure; their sensitivity to the phase delay between the crossing pump pulses warrants experimental verification.