Method for the design of diffractive optical elements through low-dimensional optimization

A method for the simulation and design of diffractive optical structures is presented. In this paper, we present a design of a finite diffractive-optic structure that has been generated by solving for the electromagnetic fields inside an optimization loop. The scalar electromagnetic fields are computed in the region of a two-dimensional diffractive-optic structure by solving the scalar Helmholtz equation, using the finite-difference method. This analysis process is inserted into a simulated annealing algorithm that designs the optimal structure by maximizing a predetermined figure of merit. Computationally efficient methods that allow for reasonable computational requirements are described, including the defining of structure parameters as relatively simple polynomial functions. This allows for changes in the structure to be made by the program while maintaining a small number of dimensions for the search by the simulated annealing algorithm.