High-performance laser beam homogenizer based on double-sided concave microlens

Microlens array (MLA) has attracted increasing interest as its application in micro-optical device and system. In this letter, we proposed a new approach that applies rotational displacement MLA to the laser homogenization system. These are nonregular arrays consisting of close-packed concave MLAs on two sides with specific rotation angle. And, the double-sided MLAs diffusers with new design parameter were successfully fabricated using single pulse femtosecond laser assisted chemical wet etching. Simulation and experimental results reveal the good homogenization performance of the double-sided MLAs. In addition, we fabricated diffusers with different rotation angles θ, and when θ = 60 °, the diffuser obtains the best optical performance.