部分时空相干光束匀滑研究  

Analysis of Partially Coherent Beam Smoothing

作　　者：陈子昂 张笑琪 张艳丽[1] 唐健豪 王瑞峰 朱健强[1] Chen Ziang;Zhang Xiaoqi;Zhang Yanli;Tang Jianhao;Wang Ruifeng;Zhu Jianqiang(National Laboratory on High Power Laser and Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China)

机构地区：[1]中国科学院上海光学精密机械研究所高功率激光物理联合实验室,上海201800 [2]中国科学院大学材料与光电研究中心,北京100049 [3]上海科技大学物质科学与技术学院,上海201210

出　　处：《中国激光》2024年第22期103-109,共7页Chinese Journal of Lasers

基　　金：中国科学院战略先导科技专项A类(XDA25020203,XDA25020301)。

摘　　要：对多横模平顶高斯部分时空相干光(MPCB)通过连续相位板(CPP)后的焦斑特性进行研究,用厄米-高斯模式叠加的方式构建MPCB,不改变已有相干光CPP设计和目标光场,对比不同空间相干度的MPCB和相干光结合CPP后焦斑的差异。结果表明,CPP可对MPCB焦斑进行整形,MPCB焦斑轮廓略大于相干光焦斑;同一滤波水平下,MPCB焦斑均匀性始终优于相干光焦斑;MPCB空间相干度越低,焦斑调制度越低,焦斑越均匀。Objective In recent years,a variety of coherent beam smoothing technologies,including temporal and spatial smoothing,have been developed to control the spatiotemporal characteristics of focal spots,which have helped reduce the Rayleigh-Taylor instability generated by laser plasma in the process of inertial confinement fusion.Spatial smoothing technologies,such as continuous phase plates(CPP)and lens arrays(LA),along with temporal smoothing technologies,such as induced spatial incoherence(ISI)technology and smoothing by spectral dispersion(SSD)have been widely used in large scientific devices.Considering coherent beam-smoothing technologies,we explored the feasibility of partially coherent beam smoothing.The high fill factor of a multi-transverse mode-flattened Gaussian partially coherent beam(MPCB)is conducive to energy storage extraction from the laser medium and often used in high-power laser systems.Thus,the technical route of MPCB smoothing is of great significance,as discussed in this paper,in analyzing the relationship between the integration time and focal spot of MPCB passing through a CPP designed for coherent beam smoothing.The relationship between the spatial coherence of MPCB and the smoothing effect and profile of the focal spot are also reported.Methods In this study,a one-dimensional MPCB is constructed through an incoherent superposition of Hermite‒Gaussian(HG)modes.This is easily extendable to a two-dimensional MPCB,using an analytical algorithm that recovers the modal weights(Fig.1).The spatial coherence of the MPCB at any position in space can be evaluated by the modal weights and is determined by the light field order N,representing the number of HG modes involved in the superposition.The larger the N,the lower the spatial coherence of MPCB.Two different spatial coherences of MPCBs are established,with N values of 22 and 46.The CPP designed for coherent beam smoothing is calculated using the Gerchberg-Saxton algorithm.The differences in the focal spots of the coherent beam and MPCBs passing

关 键 词：部分相干光 多横模 连续相位板 相干度 

分 类 号：TN241[电子电信—物理电子学]