Fabrication of the asymmetric double-sided concave microlens arrays by femtosecond laser

In the last decades, fabrication of microlens array in materials with high-damage threshold has attracted increasing interest, especially in the application of high-power laser. In this paper, we propose an advanced strategy to efficiently fabricate microlens array on the surface of glass using a single-pulsed femtosecond laser wet etch process, which is a combination of high-speed laser scanning and the subsequent chemical etch with HF solution. Based on this method, double-sided microlens array, non-regular arrays consisting of close-packed concave microlens array on one side and regular concave MLA on the other side, were fabricated on the 1cm^∗1cm glass. Especially over one million microlenses could be acquired within an hour, exhibiting great superiority in practical application. Moreover, the optical properties of the asymmetric double-sided MLA were experimentally characterized, and the experimental results reveal the good light homogenization performance.