Determination of optical properties and thickness of optical thin film using stochastic particle swarm optimization

•Modified Forouhi–Bloomer dispersion model.•Proposed points selection strategies when using Forouhi–Bloomer dispersion model.•Gave the application scope of Cauchy and Forouhi–Bloomer dispersion model. The wavelength-selective properties of optical thin films offer a sensible solution to the problems of effective wavelength-selective use of solar energy. However, the design of the optical constants of these optical thin films is crucial to the study of the film’s optical properties. To address this problem, we introduced stochastic particle swarm optimization (SPSO) to an inverse model of the optical constants and thicknesses of optical thin films in this paper. Initially, we discussed the anti-error capacity of the Cauchy dispersion model, and we then discussed the importance of the parameters used in the Forouhi–Bloomer dispersion model, before modifying the Forouhi–Bloomer dispersion model on this basis. We also discussed the influence of the measured error on the inversion effects of each parameter in the modified model. Finally, we inverted the measured transmittance data using the Cauchy dispersion model, the Forouhi–Bloomer dispersion model and a modified Forouhi–Bloomer dispersion model, and the effectiveness and the feasibility of SPSO when applied to the determination of optical constants is verified.