Abstract

The most common optical thin film design technique is certainly refinement. It is used successfully to generate conventional homogeneous multilayers as well as inhomogeneous, or graded index, systems [1]–[3]. The latter have been found to be useful not only for their unique optical properties, but also as an intermediate stage in the design of conventional multilayers [4]. Another successful approach in inhomogeneous thin film design is based on the use of Fourier transforms [4]. It is sometimes classified as a synthesis technique because, contrary to refinement, it requires little knowledge of a suitable starting point. Typically, it converges quickly and provides useful insight into the problem. However, its accuracy tends to be limited in regions of high reflectance, due to approximations made in the theory. The lack of the speed of standard refinement techniques and/or their reliance on a good starting design are limitations in design problems involving a large number of parameters. Inhomogeneous systems often fall in this category. Special implementations are needed to design such systems [5]. In this work, we describe an efficient algorithm for the design of inhomogeneous films. This algorithm is based on the exact theoretical formulas.

© 1995 Optical Society of America