Cost-effective fabrication of microlenses on hybrid sol-gel glass with a high-energy beam�sensitive gray-scale mask

A negative-tone inorganic-organic hybrid SiO(2):TiO(2) glass is investigated for fabrication of refractive microlenses. This sol-gel material enjoys an advantage over materials used in conventional photoresist-based fabrication techniques in that it lends itself to a single-step etching-free process. The application of a high-energy beam-sensitive (HEBS) mask provides a reliable and simple method for fabrication of three-dimensional micro-optical elements with a single UV exposure. The technique of using the sol-gel material with the HEBS gray-scale mask has considerable potential for low-cost mass production of continuous-phase-level diffractive optical elements and micro-optical structures.