Determination of thin metal film's thickness and optical constants based on SPR phase detection by simulated annealing particle swarm optimization

Simulated annealing particle swarm optimization (SAPSO) method for inverse model of optical properties of multilayer thin films based on surface plasmon resonance (SPR) experimental results is introduced in this paper. The purpose is to extract unknown parameters from the phase difference between P- and S- polarizations of the reflected light occurred at the metal/dielectric interface. The results of both the metallic and bimetallic layer derived from our method are in better agreement with the experiment data than particle swarm optimization (PSO) method. Therefore, the approach reveals the possibility of retrieving the thickness and optical constants from the measurement results of the phase difference for multilayers, and makes it be a much better option to be employed for further film's parameter analysis applications.