摘要
非线性光场增强是导致高功率激光装置终端光学元件损伤的主要原因之一。系统地研究单缺陷的精细形貌以及双缺陷的三维空间分布对调制光束的非线性演变规律的影响,发现了多种非线性传输新现象并揭示了其产生机制。仿真结果表明:边缘陡峭的单一缺陷会产生双峰热像,这打破了传统认知中缺陷和热像在纵向的共轭关系;双缺陷间的相互作用导致双缺陷中轴位置上额外热像峰的出现,打破了缺陷和热像在横向的一一对应关系。系列研究结果表明了调制光束非线性传输的复杂性,上游缺陷的精细形貌差别和相互干涉均可能使得下游产生额外的光场强区,强度得到进一步增强,最终导致基于原有关于B积分和热像认知的驱动器非线性控制策略失效。本研究结果加深了对复杂非线性光场传输规律的认知,不仅有助于优化装置中终端元件的排布,而且对高功率激光装置中大口径光学元件缺陷的精密检测和评估提出了新的要求,为高功率激光装置的终端负载能力提高提供了重要技术参考。
Objective Currently,the development of high-power laser drivers is limited by the damage to terminal optical system components.Furthermore,self-focusing is an important nonlinear propagation effect that causes damage to components.As a special self-focusing phenomenon,a hot image,with extremely high intensity of light field,typically appears in the downstream conjugate position of the upstream defect relative to the nonlinear medium.Therefore,in the design of system,the nonlinear propagation effect is usually controlled by regulating the B integral and arranging the optical elements to avoid the conjugate plane of the hot image.This in turn reduces the damage threat to the components.However,in the operation experiment of the laser drivers,it is determined that the position and intensity of certain light field strength areas deviate from the existing theory.Hence,unexpected damage often occurs in the components.Therefore,laws and mechanisms relating to nonlinear propagation effects of high-power lasers should be further examined.Methods The formation of hot image can be divided into three processes.First,the beam modulated by defects reaches the nonlinear medium via linear propagation.Second,when the beam propagates in the nonlinear medium,the third-order nonlinear polarization of the medium is induced,and the beam gradually converges.Third,the beam propagates linearly after ejecting from the medium,and it finally converges to form hot images.Based on the thin slice approximation,the analytical expressions of the position and intensity of the hot image can be obtained by solving the nonlinear Schrödinger equation.However,in practical high-power laser systems,nonlinear media usually do not satisfy the condition of slice approximation.In this study,the angular spectrum method for the linear diffraction propagation and the split-step Fourier algorithm for the nonlinear propagation were used to explore the evolution of the hot image characteristics.Results and Discussions For the single defect,when considering the e
作者
刘雨欣
焦兆阳
王宏昌
孙明营
朱健强
Liu Yuxin;Jiao Zhaoyang;Wang Hongchang;Sun Mingying;Zhu Jianqiang(Key Laboratory of High Power Laser and Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronic Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2024年第11期131-142,共12页
Chinese Journal of Lasers
基金
国家自然科学基金(62105343)。
关键词
高功率激光驱动器
非线性传输效应
缺陷
光场调制
自聚焦
high power laser driver
nonlinear propagation effect
defect
optical field modulation
self-focusing
