Volume growth initiated by point-to-point ultraviolet-laser direct writing in hybrid solgel glass for three-dimensional microfabrication

Volume-growth solgel glass acting as self-developing material is used for three-dimensional (3D) fabrication of micro-optical elements. The solgel glass is exposed to a focused laser beam (lambda = 325 nm), and surface corrugation is created as a result of surface expansion in the exposed area. The profile depth is related to the laser beam intensity, which is controlled by an acousto-optic modulator, which makes it possible to fabricate 3D structures in the material. Preliminary results show that the controllable volume-growth effect will be of considerable use for production of 3D micro-optical elements with excellent surface smoothness in solgel materials.