Multi-order combined diffractive optical elements for identification of different-magnitude wave aberrations

In this article, multi-order combined diffractive optical elements (DOEs) matched with a set of wave aberrations and Zernike polynomials are proposed and developed. The combination of two different types of matched functions present in one DOE allows using it as a wave aberration detector with sensitivity ranging from 0.05λ to 0.5λ. Based on numerical modeling, it is shown that using multi-order DOEs, a set of aberration-transformed patterns can be generated in one plane. Criteria for detecting ultra-small aberrations (up to 0.1λ) and larger aberrations (up to 0.5λ) are introduced. Based on these criteria, an algorithm for automated selection of target areas of interest in the focal intensity patterns is developed. A 49-channel optical element matched with wave aberrations of up to the 4th order (in terms of Zernike functions) and Zernike functions is designed. Using test aberrated wave fronts we demonstrate that the proposed optical elements can be utilized to detect aberrations of different ranges, as well as to identify their type and weight.