Abstract

The synthesis of thin-film systems with prescribed spectral characteristics has been the subject of many papers in the past three decades. A particularly powerful method, first described by Sossi, uses Fourier transforms to solve the inverse scattering problem for an inhomogeneous layer.¹ This layer can then be transformed into a multilayer consisting of homogeneous films of many refractive indices. Through the use of the Herpin equivalent index concept, this multilayer can be transformed into a system consisting of two materials only. More recently Southwell described a simple numerical method which directly yields solutions based on the use of two materials.² He applied it to the design of antireflection coatings. In this paper the two methods are applied to several different spectral filtering problems. The properties of the resulting numerical solutions are compared and contrasted.

© 1985 Optical Society of America