在利用电荷耦合器件CCD对激光光束质量测量的过程中, 通过对比不同的激光波长, 分析了CCD的光电响应非线性特性对光束质量M2因子评价的影响。由于对未进行线性标定的CCD所测得的四种不同波长的激光器的光束束宽值相对比较大, 这会对激光光束质量的测量精度带来影响, 因此提出了一种新的基于面阵型光电探测器的光电响应标定方法。搭建基于CCD测量法的激光光束质量测量系统, 建立高斯型激光光束的近远场传输模型, 对激光束在传输方向上不同位置处的焦散廓形进行多次采样, 利用统计学方法得到CCD的光电响应线性区间。仿真和实验结果表明: 利用CCD光电响应特性的标定结果对图像进行非线性灰度修正, 对比国际标准激光光束质量分析仪, 所测得的激光光束质量M2因子更加准确且相对误差降低了2.36%。提出的方法可有效提高激光光束质量M2因子的测量精度, 对于评价激光光束质量具有重要的应用价值。

In the process of measuring laser beam quality by using the CCD, the influence of nonlinear optoelectronic response of the CCD on the beam propagation ratios M2 was analyzed in the paper through comparing the wavelength of different lasers. As the beam width values from four different wavelength lasers measured by non-linear calibrated CCD were relatively large, the measuring accuracy of laser beam quality will be affected to a certain extent. Therefore, a new calibration method of optoelectronic response based on the CCD will be put forward. By setting up a laser beam quality measurement system based on CCD measurement and building the near-field and far-field transmission model of Gaussian laser beam as well as multiple sampling from laser beams′ caustic profile in different positions of a certain transmission direction, the photoelectric response linear range can be obtained with statistical methods. The result of simulation and experiment shows that by using the optoelectronic response character′s calibration result of the CCD to make nonlinear gray level restoration on images, the laser beam quality factor M2 can be measured more accurately and the relative error can be decreased by 2.36% compared with the measuring result by the international standard laser beam profiler. The method mentioned in the paper can effectively increase the measuring accuracy of the laser beam quality factor M2 and it has great application values on evaluating the laser beam quality.