Thickness optimization algorithm to improve multilayer diffractive optical elements performance

Abstract

The diffractive zone thicknesses of conventional diffractive optical elements (DOEs) are generally obtained using the thin element approximation (TEA). However, the TEA yields inaccurate results in the case of thick multilayer DOEs (MLDOEs). The extended scalar theory (EST) is an alternative thickness optimization method that depends on the diffractive order and the optimization wavelength. We developed an algorithm to research suitable EST input parameters. It combines ray-tracing and Fourier optics to provide a performance estimate for each EST parameter pair. The resulting “best” MLDOE designs for three different material combinations are analyzed using rigorous finite-difference time-domain. Compared to the TEA, the proposed algorithm can provide performing zone thicknesses.

An improved algorithm for diffractive optical element with high imaging quality

“…Research on design methods of DOE has academic and application value. Scholars have conducted extensive studies and achieved some research findings, such as Gerchberg-Saxton (GS) algorithm, inputoutput algorithm, simulated annealing algorithm, Yang-Gu algorithm, genetic algorithm, and other design methods [6][7][8][9][10][11]. The GS algorithm plays a significant role in DOE design because of its features of fast optimization speed and high diffraction efficiency.…”