Patent ID: 8715516

Claim:
A method of manufacturing an optical element comprising a substrate, and a first layer and a second layer formed on the substrate, the method comprising the steps of: forming the first layer on the substrate; processing in the first layer a repetition structure comprised of spaces and structural parts, having a pitch equal to or less than a wavelength of visible light; filling the spaces with a filling material; etching the filling material to expose an upper portion of the repetition structure from the filling material, so that side surfaces of the repetition structure are exposed in a range of 3 nm or more and 20 nm or less from an upper surface of the repetition structure; forming the second layer on the filling material and the upper portion of the repetition structure, so that the upper portion of the repetition structure of the first layer and a lower portion of the second layer engage each other in a range of 3 nm or more and 20 nm or less; processing in the second layer a repetition structure comprised of spaces and structural parts, having a pitch equal to or less than a wavelength of visible light; and removing the filling material.