基于点衍射干涉与微偏振相移的光束瞬态波前检测方法研究

It is of great importance to develop transient optical wavefront sensing method in some applications, such as in the high power laser systems. In this project a novel method applicable to the transient optical wavefront sensing is proposed, by combination of the point-diffraction interferomtry and the micropolarizer-array based phase shift technology. The principal theories as well as the key techniques of this method will be thoroughly studied. The technique routes for the design of point-diffraction plate, the fabrication and packaging of the mircropolarizer array, as well as the design of the wavefront construction algorithms have been determined. A novel computer-aided pinhole alignment approach based on the two dimensional power spectrum density analysis is put forward, meanwhile, the importance of correlation analysis between the wavefront sensing problem and the wavefront correction problem is emphasized. A wavefront sensing protype system will be built up, and the measurement performance of this method will be evaluated, by comparing with some other typical wavefront sensing methods. It can be expected that this project will establish the theoretical and the technical foundations for the implementation of the proposed compact and precise transient wavefont sensing system, and it will make contributions to enhance the performance of the high power laser systems.

光束的瞬态波前检测，在高功率激光等应用领域具有重要的研究价值。提出一种将点衍射干涉与微偏振相移相结合的新型瞬态波前检测方法，以充分发挥二者的优势，实现高精度的光束瞬态波前检测。针对其中的一些基本理论和关键技术进行研究，确定了点衍射板设计、微偏振阵列单元的设计、制作与封装集成，以及波前重建算法设计需遵循的技术发展路线，提出了基于二维功率谱密度分析的计算机辅助针孔对准方法，并强调了将波前检测问题与波前校正问题进行关联分析的重要性。构建波前检测光路并完成检测实验，通过与其它典型的波前检测方法进行比对，考核验证检测方法的总体性能水平。通过本项目研究，为研制高效、高精度、结构紧凑的光束瞬态波前检测系统提供理论和技术依据，为提升高功率激光装置性能做出积极贡献。

本项目针对高功率激光等应用领域中的光束瞬态波前检测问题，开展了基于点衍射干涉与微偏振相移技术的波前检测方法研究。对波前检测系统进行理论建模，分析了点衍射孔、波片、微偏振片阵列等关键元件所对应设计参数及其装调（装配）、加工误差对波前检测精度的影响。开展了点衍射孔的精确对准方法研究，面内对准误差可小于0.5倍衍射极限；引入Lissajous图椭圆拟合相位解调方法，实现对微偏振片阵列与CCD之间的装配误差相对不敏感的高精度相位解调；针对复杂相位的解包裹问题，采用按行（或列）高阶相位多项式拟合展开、虚拟Hartmann-Shack法进行重构，以增强解包裹过程的鲁棒性。搭建测试光路，实验验证了基于点衍射孔与微偏振相移的瞬态波前检测方法的有效性，目前实测检测精度约0.1个波长；做为拓展应用，开展了基于偏振相机进行波片元件标定测试的实验研究；针对整形光学元件在线情形下光束瞬态低频波前畸变信息的获取问题，提出了一种基于改进Hartmann-Shack法的检测方法，并实验验证了该方法的有效性。开展了提升波前校正性能方面的研究。针对高功率装置中通常采用的多程放大光路结构特点，研究了一种渐进式多程波前校正方法，提高了波前控制精度，降低了对波前检测系统测量动态范围的要求；提出了一种基于光束掠入射及光束反转模块相结合的波前校正方案，可提高单块变形镜情形下波前校正的空间分辨率。