Optical coating synthesis by simultaneous refractive-index and thickness refinement of inhomogeneous films

A fast, efficient thin-film synthesis technique is described. Dielectric films are subdivided into thin layers whose refractive indices and thicknesses are varied simultaneously. Because of the large number of optimized parameters, speed and accuracy are given special attention. The efficiency of the method is demonstrated by the successful reproduction of several complex nonpolarizing filters synthesized in the past with the needle method, one of the best approaches currently available.