A Global Optimisation Technique for Optical Thin Film Design
Wuhan University of Technology Press
Faculty of Computing, Health and Science
School of Computer and Information Science
Many advanced local and global optimisation techniques, such as Gradient, Simplex, Flip-flop, Needle, Genetic and Simulated annealing, have been successfully applied to optical thin-film design. Any optimisation algorithm applied to a particular design problem should firstly address the issue of choosing a reasonable starting design, which is always a big obstacle to an inexperienced designer. To find the true global optimised solution for a thin film design problem, we need to solve an array of interlinked multi-dimensional simultaneous equations. For more than just a few layers, until recently this has been a very difficult task, requiring the use of a supercomputer and highly skilled programming. By using the orthogonal Latin Square theory and an experimental design methodology in a search space reduction process, a Windows based program has been written that can operate on even a desktop personal computer. It can find the global optimum design for a 23 layers design using any dispersive and lossy material within a period of several hours. Additionally, this methodology (DGL-Optimisation, DGL is the short for D.G. Li) allows the usc of target spectra such as s & p polarisation, with reflection and transmission simultaneously.