激光斑点漂移的研究

Analysis on the drifting phenomenon of laser speckles

用激光照射粗糙表面时,可以观测到颗粒状的细小斑点,当人眼或相机移动时,观测到斑点也发生移动.分析了激光散斑产生和漂移的原因,将散斑漂移简化为几何光学和波动光学问题,得到一致的散斑漂移速度计算公式.利用Mathematica计算光强关联函数,证实圆斑越大散斑越小.实验测量了散斑漂移速度与相机移动速度的关系,结果符合理论公式.

The grainy spots could be observed when the laser shined on the rough surface.The observed spots could move with the movement of the eye or camera.The causes of laser speckle and the drifting were analyzed.By the means of geometric optics and wave optics,the calculating formula of laser speckle drifting vilocity was analyzed quantitatively.The light intensity correlation function was calculated by Mathematica.It was proved that the larger the circular spot was,the smaller the speckle was.The relation between the drifting velocity of speckle and the moving velocity of camera was discussed experimentally,and the results were in accordance with the theoretical formula.