红外聚焦光探测系统中光限制效应的优化分析

计算和分析了红外聚焦光探测系统中光限制材料的几何排布对光限制效应的影响，给出了优化的几何分布。结果显示，近场条件下的光限制效应与远场条件下的完全不同，在某些情况下，具有正光学非线性系数的材料不能被用作光限制之用，这与远场情况不同，分析也表明，聚焦几何排布可用于非线性折射系数的测量，并具有比常规Ｚ扫描方法更高的灵敏度。

ANALYSIS ON OPTIMIZING OPTICAL LIMITING IN INFRARED FOCUSED OPTICAL-DETECTING SYSTEMS

The effect of geometry arrangements of optical-limiting media with cubic nonlinearities in infrared focused optical-detecting systems on the optical limiting was calculated and analyzed by using beam propagaton and Gaussian decomposition (GD) methods, and optimum geometry arrangements were given in the analysis. The results show that the optical limiting for the near-field geometry arrangement is very different from that for the far-field geometry arrangements, and in some geometry arrangements nonlinear media with positive nonlinear index can not be employed as optical-limiting media, which is different from previous suggestions for the far-field geometry arrangements. It is also shown that focused geometry arrangements can be employed for measurements of nonlinear refractive index with a higher sensitivity than that of common Z-scan techniques.