Microlens Array Fabricated by Gray-Scale Lithography Maskless System

Abstract

This work presents the fabrication of a high fill factor Fresnel microlens array (MLA) by employing a low-cost home-built maskless exposure lithographic system. A phase relief structure was generated on a photoresist-coated silicon wafer, replicated in Polydimethylsiloxane (PDMS) and electrostatically bonded to a glass substrate. Optical characterization was based on the evaluation of the maximum intensity of each spot generated at the MLA focal plane as well as its full width at half maximum (FWHM) intensity values. The resulting FWHM and maximum intensity spot mean values were 50 ± 8% µm and 0.71 ± 7% a.u , respectively. Such a MLA can be applied as Shack-Hartmann wavefront sensors, in optical interconnects and to enhance the efficiency of detector arrays.