Flat plate optical element and method for preparing the same

摘要

A flat plate optical element and a method for preparing the same are disclosed, which flat plate optical element comprises an optical element with a predetermined pattern formed by ion diffusion from a restricted region within a flat substrate, wherein an ion diffusion layer having a uniform thickness is formed with the same ions as those used for forming the optical element on the whole surface of the substrate opposite to the surface on which the optical element is formed, and the total volume of the optical element is substantially equal to the total volume of the ion diffusion layer.