高均匀性小孔径激光照明系统

激光照明应用当中激光的高斯分布和散斑现象极大地影响了照明质量,为了将激光器出射的高斯分布的激光整形成类似平顶分布,同时对散斑进行抑制,实现均匀的激光照明,对随机漫射体抑制散斑的可行性进行了探讨。设计了一套基于"随机微透镜阵列"的激光照明系统,可实现出光孔径2mm,半发散角18°的平顶均匀激光照明。并对比了在此种结构下采用石英玻璃棒和自聚焦透镜作为光导元件时光斑质量的区别,对光斑的分布及散斑进行了测量,验证了此种方法能够将散斑对比度降低到4.84%,极大地提升了激光照明质量。

High uniformity laser illumination system with small aperture

The speckle phenomenon and the Gaussian distribution affects image quality greatly in laser illumination. In order to change Gaussian distribution to flat-top distribution and reduce the speckle phenomenon to get uniform light spots, this paper discusses the feasibility of speckle reduction using random diffuser. We designed a laser illumination system using "random micro-lens array" as the random diffuser. It can achieve a flat-top light illumination with divergence angle 36° and aperture 2 mm. A comparison of the quality of the light spot is made using fused silica stick and G-lens as the light transmitting component. We measured the distribution of the light spot and the speckle. This method can be verified to reduce speckle contrast to 4.84%, which reflects the excellent ability to enhance the quality of laser illumination.