The regulation of multiple filaments during an intense femtosecond laser propagation in a transparent optical medium is still challenging. In this study, by tracing the phase variation of the laser pulse during the propagation, the effect of the beam ellipticity on the generation of multiple filaments was investigated using the efficient π -phase plate. The spatial distribution of the generated multiple filaments did not follow the predesigned pattern of the phase plate when the laser beam was elliptic owing to the asymmetric change of the laser phase by the linear diffraction and nonlinear Kerr effect.

中文翻译：

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光束椭圆度对π相板调节飞秒激光复丝的影响

飞秒激光在透明光学介质中的强烈传播过程中对多根灯丝的调节仍然具有挑战性。在这项研究中，通过跟踪传播过程中激光脉冲的相位变化，使用高效的π相板研究了光束椭圆度对多根灯丝产生的影响。当激光束为椭圆形时，由于线性衍射和非线性Kerr效应引起的激光相的不对称变化，产生的多根灯丝的空间分布不遵循相位板的预先设计图案。