Exact surface-relief profile of a kinoform lens from its phase function

Abstract

Modeling of kinoforms in optical design software packages can be done in terms of the phase function ϕ(r). The required surface-relief profile t(r) is determined approximately from the relation t(r) = [λ/2π(μ − 1)][ϕ(r)]2π, where λ is the operating wavelength, μ is the refractive index of the optical material of the surface relief, and [ϕ(r)]2π is the phase function ϕ(r) modulo 2π. We present a semianalytical approach that enables one to determine the exact surface-relief profile from a given phase function. It is seen that there is a small but significant difference between the exact and the approximate surface-relief profiles. Some computational results are presented.