Direct photolithographic deforming of organomodified siloxane films for micro-optics fabrication

Direct photolithographic deforming of hybrid glass films is used to fabricate optical structures. The structure is fabricated in polyethylene-oxide-acrylate modified hybrid glass films with (1) binary and gray-scale photomasks using a mercury UV-lamp exposure and (2) maskless UV-laser patterning. Fabrication of isolated lenslets, lens arrays, and gratings is presented, including the associated exposure patterns. The hybrid glass material yields light-induced deformation peak-to-valley (p.v.) heights up to 12.8 µm with mercury UV-lamp exposure and p.v. deformation heights up to 6.8 µm with 365-nm UV-laser exposure. The fabricated lenslets’ surface data are presented as Zernike-polynomial fit coefficients. Material synthesis and processing-related aspects are examined to understand and control the material’s deformation under exposure. The hybrid glass material exhibits a maximum spectral extinction coefficient of 1.6 × 10-3 µm-1 at wavelengths ranging from 450 to 2200 nm and has a refractive index of 1.52 at 632.8 nm. The fabricated structures exhibit rms surface roughness between 1 and 5 nm.