Fabrication of Reflective Non-Imaging Homogeniser Based on Microlens Arrays on Heteroepitaxially Grown Diamond for High-Fluence Laser Beam Shaping

Abstract

In this study, a robust reflective non-imaging homogeniser based on diamond microlens arrays (MLAs) is proposed and fabricated via heteroepitaxial diamond growth and using thermal reflow techniques; this homogeniser is expected to be used for high-fluence laser beam shaping. The MLAs in the obtained optical elements had a compact arrangement and an area of 20 mm2. The sublenses had a surface roughness of 2 nm, a radius of curvature of 1.116 mm, and a focal length of 0.7644 mm. The diamond MLAs demonstrated good uniformity and strong imaging performance in projection experiments. A homogenisation experiment revealed that the optical element showed a homogenising performance.

Keywords: microstructure, microlens arrays, high-fluence laser homogenisation, crystal growth, Diamond