OPTICAL GRATING STRUCTURES AND METHOD FOR THEIR MANUFACTURE

摘要

A method is disclosed for the fabrication of an optical grating structure. An intermediate layer (3) of a relatively low refractive index material is deposited on a planar substrate (1) of relatively low refractive index or upon a base layer (2) of relatively high-refractive index material applied to the substrate (1). The intermediate layer (3) is of a material capable of being formed precisely into a pattern corresponding to a desired grating pattern. Material is selectively removed from the intermediate layer (3) so as to create a corrugation in the intermediate layer (3) corresponding to the desired grating pattern. A surface layer (5) of relatively high refractive index material of uniform thickness is deposited on the intermediate layer (3), whereby the surface layer (5) is formed with a corrugation corresponding to the corrugation formed in the intermediate layer (3).