Completely Automatic Synthesis of Optical Thin Film Systems

Abstract

The various methods for the synthesis of optical thin film systems with prescribed properties are reviewed. One general approach is to refine numerically the properties of an initial system. In many problems, however, the choice of a suitable starting design for refinement is not at all obvious. The present paper describes a computer program for the completely automatic design of optical thin film systems by evolution which does not require a starting design. Apart from the specification of the desired optical properties of the system, the only input data necessary are the refractive indexes of the substrate, the medium, and the thin film materials that may be employed for the construction of the coating. Optical properties that may be specified at present include transmittance, reflectance, phase changes on transmission and reflection, and the first and second derivatives of these quantities, with respect to wavenumber and angle of incidence. Several examples are given to illustrate the performance of this program. Ways are indicated in which this automatic design program can be improved further in the future.