Hybrid method for calculating diffractive optical elements (DOEs) focusing into radial focal domain

The problem of focusing into an off-axis radial domain is reduced to the 1-D task of focusing into a segment. A new iterative method is proposed assuming the calculation of two 1-D Fourier transforms per each iteration and enabling us to generate diffractive optical elements (DOEs) intended for focusing into a radial off-axis focal domain. A phase calculated within ray-tracing approach was used as a starting point for iterative procedure.