超快激光成丝现象的多丝控制

Control of multiple filamentation induced by ultrafast laser pulses

研究了强场超快激光脉冲在光学介质中传输引起的成丝现象。考虑无序的多丝降低了激光光束的光斑质量,影响了光丝的能量分布,限制了超快激光脉冲成丝在实际中的应用,本文介绍了目前对高功率超快激光脉冲在介质中传输时产生的多丝进行控制的方法,并对各种方法进行了分析和比较。研究表明,目前对于多丝的控制主要采用振幅调制或相位调制等方法,已实现了减弱或消除强度微扰与传输介质折射率扰动,可避免多丝间相互联系及能量的竞争,使多丝按照预想的空间图样排布,达到多丝控制的目的。文章指出,目前多丝控制存在的主要问题是还不能准确完成对多丝长度及间距位置的精确控制。

The filamentation phenomena come from the propagation of intense ultrafast laser pulses in transparent optical media is explored. It shows that the irregular distribution of filaments will reduce the quality of laser beams, effect on its energy distribution and constitute a serious drawback in practi- cal applications. Therefore, this paper studies how to control the multiple filaments come from higher power laser propagation in optical media and analyzes and compares these control methods. It points out that the amplitude modulation and phase modulation are the main methods to control the multiple filamentation currently, which can decrease or eliminate the intensity perturbance and refractive index perturbance of transmission media, and avoids the interrelation between the multiple filamentations and their energy competition so that the multiple filamentations can be arranged in a preconceived form. It summarized that the existing problems for multiple filamentation control are how to control the length and spacing of the filamentation precisely.