Fabrication of refractive microlens in hybrid SiO2/TiO2 sol-gel glass by electron beam lithography

We present the fabrication of a refractive microlens in hybrid SiO2/TiO2 sol-gel glass by electron beam lithography. The hybrid sol-gel material has high transmittance (greater than 95%) in the wavelength range from 362nm to 2000nm. Under the electron beam exposure, the polymerized film thickness was as large as 4 mum. A 3D microlens profile can be formed by exposure of the sol-gel film under different electron dosages that leads to different polymerized film thickness after development. As an example, a microlens with a 250 mum diameter and a 2.05 mum sag height was fabricated. (C) 2003 Optical Society of America.