基于布拉格声光衍射场的光强非均匀空间分布研究

Inhomogeneous spatial distribution of scattering light intensity based on Bragg acousto-optic diffraction field

为了保证合成孔径激光雷达测试中信号光的光束质量,从波动方程出发,推导出传统的衍射光源布拉格声光作用的耦合波方程。根据测试对光束质量的不同要求,借助有限差分方法分析衍射场光强的空间三维分布,发现声场振幅的不均匀分布会影响声光衍射场的光强分布,光强分布不均造成实验中信息光源的探测难度。通过光强空间分布研究增大有效通光孔径到3 mm,解决了声光调制器光束衍射质量问题,改进后的光束质量达到实验要求。该研究方法适用于改进声光器件工作参数。

Proceeding from the wave equation,the coupled wave equations for Bragg acousto-optic interaction of the traditional diffraction sources were deduced to ensure the quality of the signal light beam in the synthetic aperture lidar testing,.According to the different requirements of each testing on the beam quality,the spatial three-dimensional distribution of the light intensity in the diffraction field is analyzed by the aid of the finite difference method.It is found that uneven distribution of the acoustic amplitude affects the intensity distribution in the acousto-optic diffraction field and the inhomogeneous intensity distribution results in the difficulty of information source detection in the experiment.By means of the research of the intensity spatial distribution,the effective clear aperture was increased to 3 mm and the problem of the beam diffraction quality of the acousto-optic modulator was solved.The improved beam quality meets the requirement of the experiment.This method is applied to improving the working parameters of acousto-optic devices.