Method for estimating the surface roughness of relief-phase holographic optical elements and its effect on their imaging properties

摘要

This paper describes a method for determining the short-wavelength usage limit of relief-phase holographic optical elements (HOEs), caused by their surface roughness. It essentially consists of using data obtained from an atomic-force microscope to determine the shape of the relief profile of an HOE, averaged over the base area, i.e., the scanning area; using this as a basis for determining its rms surface roughness, averaged over the same base area; and then calculating the limiting wavelength in which the HOE can be used. A software module has been developed for implementing this method.