高斯光束照射下联合变换相关器特性研究

Characteristics of joint transform correlators under the illumination of Gaussian beam

为了研究联合变换相关器中照明光束对输出相关点的影响,针对特定目标图像,采用数值模拟的方法,定量分析了联合变换相关器中照明光束为高斯光束时,输出相关峰值随高斯光束特性参量和输入图像在输入平面上位置的变化情况。得到了输出相关峰值随高斯光束腰斑半径减小和输入平面上目标图像位置偏离高斯光束中心距离的增加而减小的结果。模拟结果显示,如果腰斑半径1mm的高斯光束,扩束为腰斑半径32mm的高斯光束时,刚好满足输入图像在光斑边缘处输出相关峰值为输入图像在光斑中心处输出相关峰值的90%,则要求扩束前后高斯光束腰斑中心振幅比值为5.7。结果表明,为使输入图像在整个输入平面上任何位置都输出高的相关峰值,扩束后的高斯光束腰斑半径应满足一定要求。

In order to study the effect of illuminating beam on output correlation spots ,for a given target image, the relation among the output correlation peak value, the parameters of Gaussian beam and the location of the image on the input plane was simulated with the joint transform correlator illuminated by Gaussian beam. It was found that the output correlation peak value decreased with the decrease of the waist radius of Gaussian beam and the increase of the interval between target image on input plane and the center of Gaussian beam. Simulation results show that the ratio of amplitude of the center of Gaussian beam before and after beam expansion should be 5.7 if the waist radius of lmm is expanded to 32mm,where the output correlation peak value at the edge of the faeula is 90% of that at the center, and that in order to output high correlation peak value when images locate any place on the input plane, the waist radius of Gaussian beam must be expanded big enough.