SOL-GEL REPLICATION OF MICROOPTICAL ELEMENTS AND ARRAYS

Facile replication of microoptical elements and arrays was performed i n sol-gel matrixes prepared by the fast sol-gel method. These sol-gel resins, made from mixtures of alkylalkoxysilane monomers, undergo hydr olysis and polymerization within 10-20 min and curing within a few day s. Single-step reproducible fabrication of large crack-free elements o f 1 cm thickness and up to 10 cm in diameter was demonstrated. High ac curacy of replication was facilitated by maintaining a very small shri nkage of only a few percent during the curing stage. This was attained by removing most of the volatile products from the sol, without gelli ng, prior to casting it onto the template. Accurate replication depend s on adequate control of two key parameters: the replica-template adhe sion-separation timing, by manipulating the template surface via oxida tive etching, and the drying-cross-linking relative pace, by accuratel y tailoring the silanes mixture, the water-to-silane ratio, and their hydrolysis and polymerization.