基于PPMgOLN绿光微片激光器的散斑抑制

Speckle suppression based on PPMgOLN microchip green laser

提出了一种将激光耦合入多模光纤后,利用改变多模光纤长度并结合振动光纤的方法来抑制散斑的方法。介绍了抑制散斑的相关理论及实验验证方法。实验中采用自主研发的基于PPMg OLN晶体的高效紧凑型微片绿光激光器作为激光光源,经过CCD相机采集屏幕上的散斑图像,通过图像处理,得到了相同型号的多模光纤在不同长度下,光纤在振动与不振动时,图像散斑对比度的变化趋势及在屏幕上的强度分布,从理论上分析了产生该变化趋势及强度分布情况的原因。实验所得的图像散斑对比度在4.7%左右,满足视觉观察的要求。

A speckle suppression method by vibrating multimode fibers and changing fiber lengths is proposed after the laser couples into multimode fibers. The speckle suppression was theoretically analyzed and verified by experi- ments. The high efficient and compact microchip green laser based on PPMgOLN that is made by our group is used as the light sources. The speckle images in the screen were collected through CCD camera, and then the images were pro- cessed. The variations of the speckle contrast and the intensity distribution in the screen were obtained for different length of muhimode fibers both in vibrating and static modes, and the reasons were theoretically analyzed. This method can effectively reduce the speckle contrast to 4. 7% ,which meets the need of human eyes observation.