Abstract

The results of experimental and theoretical studies of the evolution of the small-scale transverse structure of high-power femtosecond laser radiation propagating in air in the multiple filamentation mode are presented. It has been found that the presence of intensity inhomogeneities in the initial transverse profile of the laser beam leads to the formation of spatially isolated light channels due to the Kerr self-focusing effect. When the power in these channels exceeds a certain threshold value (the critical power), radiation filamentation occurs in them. The parameters of these light channels are theoretically estimated on the basis of the diffraction-ray model of single filamentation. It is shown that for a laser beam with a centimeter radius and subterawatt power, the initial radius of intensity inhomogeneities in the transverse profile has a characteristic value of several millimeters.

中文翻译：

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空气中成丝过程中飞秒激光辐射的空间结构

摘要

介绍了以多丝模式在空气中传播的高功率飞秒激光辐射的小尺度横向结构演化的实验和理论研究结果。已经发现，由于克尔自聚焦效应，激光束初始横向轮廓中强度不均匀性的存在导致空间隔离光通道的形成。当这些通道中的功率超过某个阈值（临界功率）时，就会在其中发生辐射丝状。这些光通道的参数是基于单丝的衍射射线模型在理论上估计的。结果表明，对于半径为厘米、功率为亚瓦的激光束，