Xue Li, Pang Yingfei, Liu Wenjing, Liu Liwei, Pang Hui, Cao Axiu, Shi Lifang, Fu Yongqi, Deng Qiling
University of Electronic Science and Technology of China, Chengdu 610054, China.
Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China.
Micromachines (Basel). 2020 Mar 24;11(3):338. doi: 10.3390/mi11030338.
The miniaturized and integrated microlens array (MLA) can effectively achieve the beam homogenization, compactness and miniaturization of laser systems. When the high-coherence laser beam is homogenized by means of using the MLA, interference fringes will occur in the homogenized light spot due to the periodicity of the MLA, which seriously affects the uniformity of the homogenized light spot. To solve this problem, a novel random microlens array (rMLA) structure was proposed for the purpose of achieving beam homogenization. The coherence in the homogenization process is suppressed by means of breaking the periodicity of the MLA. The homogenized light spot with a high energy utilization is then obtained accordingly. In the fabrication process, a clever method of combining chemical etching with lithography technology is performed to fabricate a honeycomb rMLA and a rectangular rMLA. The experimental results show that the energy utilization rate of the two types of the rMLAs is about 90%, and the uniformity of the homogenized light spots generated by the honeycomb rMLA and the rectangular rMLA are more than 80% and 85%, respectively. Meanwhile, fully cost-effective fabrication is possible to be realized.
小型化集成微透镜阵列（MLA）能够有效地实现激光系统的光束均匀化、紧凑性和小型化。当利用MLA对高相干激光束进行均匀化时，由于MLA的周期性，在均匀化光斑中会出现干涉条纹，这严重影响了均匀化光斑的均匀性。为了解决这个问题，提出了一种新型随机微透镜阵列（rMLA）结构以实现光束均匀化。通过打破MLA的周期性来抑制均匀化过程中的相干性。相应地，可获得具有高能量利用率的均匀化光斑。在制造过程中，采用了一种将化学蚀刻与光刻技术相结合的巧妙方法来制造蜂窝状rMLA和矩形rMLA。实验结果表明，两种类型的rMLA的能量利用率约为90%，蜂窝状rMLA和矩形rMLA产生的均匀化光斑的均匀性分别超过80%和85%。同时，有可能实现完全具有成本效益的制造。
