Distinguishing the nonlinear propagation regimes of vortex femtosecond pulses in fused silica by evaluating the broadened spectrum

作者：Dongwei Li, Wei Liang, Deming Li, Longfei Ji, Bingxin Yan, Junwei Chang, Tingting Xi, Lanzhi Zhang, Yangjian Cai, Zuoqiang Hao · 发表于：Optics Express · 年份：2023 · DOI：10.1364/oe.497418 · 被引用次数：7 · 研究领域：Laser-Matter Interactions and Applications、Advanced Fiber Laser Technologies、Laser Material Processing Techniques

The nonlinear propagation dynamics of vortex femtosecond laser pulses in optical media is a topic with significant importance in various fields, such as nonlinear optics, micromachining, light bullet generation, vortex air lasing, air waveguide and supercontinuum generation. However, how to distinguish the various regimes of nonlinear propagation of vortex femtosecond pulses remains challenging. This study presents a simple method for distinguishing the regimes of nonlinear propagation of femtosecond pulses in fused silica by evaluating the broadening of the laser spectrum as the input pulse power gradually increases. The linear, self-focusing and mature filamentation regimes for Gaussian and vortex femtosecond pulses in fused silica are distinguished. The critical powers for self-focusing and mature filamentation of both types of laser pulses are obtained. Our work provides a rapid and convenient method for distinguishing different regimes of nonlinear propagation and determining the critical powers for self-focusing and mature filamentation of Gaussian and structured laser pulses in optical media.