Multibeam laser writing of diffractive optical elements

A new version of the method of direct multibeam laser writing of diffractive optical elements (DOE) is proposed and investigated. A writing area in the form of an array of focused light spots is formed by splitting the writing laser beam into multiple beams by using a Dammann grating and focusing of these beams in the plane of a moving carrier with a photosensitive material. Adjustment of the radial pitch of writing and correction of the uniformity of the beam intensity is carried out by tilting the Dammann grating and displacing it in the dispersion direction. In writing DOEs, the radial pitch of discrete displacement of the writing area with respect to the plane of the DOE is set equal to or multiple of the average radial distance between the radial projections of the centers of the focused light spots. This version provides improved performance and accuracy due to high-quality paralleling of the writing beam and the averaging effect in superimposed writing. © 2012 Allerton Press, Inc.