One-step transfer of diffractive structure from a designed pattern to a replica by use of a hybrid solgel film

A one-step method for microfabrication of a diffractive lens mold with continuous relief, including a solgel process for replication, is presented. The mold is fabricated by focused ion beam milling (FIBM) on a substrate of bulk silicon and is then used directly for replication of the diffractive structure by means of a hybrid solgel glass stamping process. The surface roughness of the replica, Ra, is 4 nm over a 5 m x 5 m area. The measured diffraction efficiency is 86% and is influenced by accumulated mold geometry and solgel process errors. The demonstrated process of direct stamping by use of the master fabricated by FIBM offers the potential for mass production at very low cost.