Film Optical Constants And Thickness, Determined By The Full Spectrum Fitting

With the widely use of optical thin films and thin film instruments in both study and application, how to measure the optical parameters and thickness quickly and exactly becomes an important problem of today. This paper introduces a method about measuring the optical parameters of thin films using whole optical spectrum fitting and describes several kinds of Overall Optimization Algorithms. It emphasizes the design difficulties and principle outlines. And it tells the testing results and improvement of this measuring method.The experiment system includes Lamp-house, Spectrograph, Optical Probe and Computer. Using the Overall Optimization Algorithms in programming, the whole transmission curve or reflection curve captured by Spectrograph can be fitted. Then the solutions of these thin film parameters can be computed.In this project, we try to use different Optimization Algorithms and to make improvement. By doing this, we try to find out the suitable algorithm for the measuring method of whole spectrum fitting. By measuring and computing several kinds of different optical thin films, we get their fitting results in the whole spectrum and the solutions of all optical parameters. Compare the precision and efficiency of these algorithms, we expatiate the applicability the method of whole optical spectrum fitting.Through this project, we finish the program design of using the Adaptive Simulating Annealing (ASA) algorithm, the Adaptive Genetic Algorithm (AGA) and the combination of both these two (ASAGA), compare and analyze them and obtain a certain research results.