用H-S波前传感器测量穿过超声速流场的激光像差特性

 用Hartmann-Shack(H-S)波前传感器可以准确测量穿过超声速流场的激光波面及其变化过程，进一步计算可以获得光束质心漂移、远场分布等数据。给出了H-S方法测量穿过超声速流场激光波面的原理，采用模式法进行了波前重构，计算了在几种流场条件下的激光波面像差特性PV值，RMS值和Zernike像差系数、Strehl比和环围能量曲线等。结果表明，H-S法可以很好地反映流场建立、稳定和结束过程中Zernike像差的变化。比较无流场和给定参数的超声速流场，激光穿越后产生的最明显的像差变化为离焦和低阶像散的增大。在相同流场参数下，无模型时光束质量好于有模型时光束质量。

Wavefront measurement of laser beam traversing a supersonic flow with H-S wavefront sensor

The wavefront distribution and the dynamic wavefront change of laser beam traversing a supersonic flow could be measured with Hartmann-Shack wavefront sensor. The centroid shift and the far-field distribution of laser beam could be obtained by further analyzing and calculating the experimental data. The experimental principle of laser beam traversing a supersonic flow was given. Wavefront aberration under different flow conditions was obtained by adopting Zernike mode-construction theory. The PV and RMS curve, Zernike aberration coefficient, Strehl ratio and circle energy were presented. Experimental results show that the establishing process, the stablizing process and the ending process of the supersonic flow can be measured and analyzed with H-S wavefront sensor. Comparing the data of no flow with that of a given supersonic flow, it is the defocus and astigmatism aber-ration that increase obviously with the supersonic flow. And beam quality without test-model is better than with test-model.