Analytical initial approximation for multiorder binary grating design

Abstract

An analytical approximation, based on the properties of diffracting focusing elements into a line, as the initial starting point in a gradient search process for binary grating profile optimization is proposed. Quick and stable convergence is achieved for asymmetrical gratings with orders up to 281. Designs of binary gratings with equal order intensities and linear distributions are reported with efficiencies in the range 78-84% and RMS error 1-5%.