Geometry-controllable micro-optics with laser catapulting

Abstract

Individual or arrayed microlenses offer remarkable opportunities in optics and photonics. However, their usage is currently limited by the lack of manufacturing technologies capable of tailoring the lens geometry to target devices. Here, we demonstrate how laser catapulting (LCP), a recent laser-based additive manufacturing technique, enables the preparation of microlenses with controlled geometry and curvature. LCP exploits single laser pulses to catapult polymeric microdisks into user-selectable positions on a substrate, which are converted into microlenses following a thermal reflow treatment. By shaping the irradiance distribution of the incident laser beam, we obtained arrays of circular, triangular, and cylindrical microlenses with a radius between 50-250 µm and 100% fill-factor. The good quantitative agreement between beam shape and microlens geometry, combined with the in-situ fabrication capabilities and high-throughput of LCP, can help the consolidation of laser additive methods for micro-optics in scientific and industrial applications.