Computer Aided Design and Manufacture of Optical Multilayer Filters
Y K Lim
PhD Thesis - The University of Reading, Department of Cybernetics (1985)
Abstract
An introduction discusses microcomputers and the impact on filter design. An initial survey of multilayer theory in Chapter 2 includes a complete treatment of the 'Characteristic Matrix' representation of multilayer thin-film systems with absorbing media. Expressions for reflectance, transmittance, and absorptance of such systems are derived for light incident at non - normal angles and reflection from the back - face of the substrate is also considered.
Chapter 3 contains detailed studies of Periodic and Herpin systems. In the latter, the equivalent layer parameters are analysed and their importance in periodic system computations are shown. In Chapter 4, an initial discussion of synthesis is followed by a review of formulation for the Tshebyshev extraction technique. A study of the Tshebyshev prototype function is presented and expressions relating ripple and offset intensities to media ratio are derived. The design data extraction procedure is presented and an analysis of the extraction parameters and the various cases produced expressions for exact ripple and ripple plus offset intensities for specified media. An algorithm for the complete synthesis process is also presented.
Chapter 5 discusses the problems encountered during the process of layer deposition. A simulation of the monitoring technique extended to the proposal of a suitable monitoring scheme for on - line aid to the plant operator during manufacture. The algorithm for the proposed scheme was implemented and the results presented.
Chapter 6 begins with a brief discussion of the computer hardware and software tools used during the research period. A complete software system specification is outlined for a proposed comprehensive thin-film software package and is followed by details of the design and organisation of the proposed system. The programs' flowcharts for each individual module are presented and the BASIC listings for an IBM personal computer are also included in the appendices.