二元振幅调制的单次曝光光束质量分析技术研究  

Single Exposure Beam Quality Analysis Technique with Binary Amplitude Modulation

作　　者：何思源 潘兴臣[1,2] 刘诚[1,2] 朱健强[1,2] He Siyuan;Pan Xingchen;Liu Cheng;Zhu Jianqiang(Key Laboratory of High Power Laser and Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;National Laboratory on High Power Laser and Physics,China Academy of Engineering Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,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]中国科学院中国工程物理研究院高功率激光物理联合实验室,上海201800 [3]中国科学院大学,北京100049

出　　处：《中国激光》2021年第17期80-88,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(61827816,11875308,61675215);中国科学院科研仪器设备研制项目(YJKYYQ20180024);中国科学院战略性先导科技专项(A类)(XDA25020306,XDA25020105);上海市“科技创新行动计划”(19142202600);国家青年科学基金(61905259)。

摘　　要：激光光束质量因子(M^(2))是全面表征激光光束质量的一个技术评价指标。提出了一种基于振幅调制的M2测量方法,该方法通过记录单幅激光光斑就可以利用迭代计算重建光束的复振幅;进而根据标量衍射理论,可以得到沿光束传输方向任意截面位置的光束强度分布;最后由二阶矩和双曲线拟合方法计算M^(2)因子。模拟和实验验证了所提方法的有效性,且该实验技术简单、快速,不需要复杂的机械扫描结构,适用于脉冲激光光束质量的测量。Objective In laser applications,the propagation characteristics of the beam directly affect its application quality.Accordingly,various standards for measuring the laser beam quality have been proposed to better evaluate the laser beam quality.The laser beam quality factor M^(2) is the product of the beam waist diameter and the far-field divergence angle,which does not change with the optical system.Therefore,using M^(2) for the beam quality measurement is stricter and more comprehensive.The representative measurement methods of the M^(2) factor are knife-edge and array detection,among others.However,the measurement process of these methods is slow and requires multiple captures,exhibiting high requirements on the beam stability.A pulsed beam(e.g.,laser output from a high-power driver)shows a certain degree of instability;hence,a simple pulsed beam quality measurement method is required.Methods The algorithm of coherent modulation imaging based on amplitude coding(CAMI),which uses a binary random amplitude plate to modulate the incident beam.A single-shot method based on coherent modulation imaging is presented for the measuring of the beam quality.The laser beam to be measured first illuminates a highly random phase plate with a known structure and subsequently the intensity of the resulting diffraction pattern is recorded by a charge-coupled device positioned behind the phase plate.Intensity distribution of the laser beam is accurately reconstructed with the coherent modulation imaging method,then the scalar diffraction theory is used to perform numerical inversion,the beam intensity distribution of any plane can be obtained by calculation.According to the standard beam quality analysis algorithm,the quality of the laser beam is calculated.In addition,since the CAMI method adopts an amplitude modulation structure and does not require calibration,in theory,this method is applicable to any wavelength.Therefore,compared with the existing method,the structure is simpler,suitable for single exposure measurement,and

关 键 词：激光技术 相干振幅调制成像 图像重建 二阶矩拟合 M^(2)因子 

分 类 号：O436[机械工程—光学工程]