Optical Calculation Of TiO₂/Ag/TiO₂ Multilayer Film Based On Optimization Method

The transmittance of thin films is determined by the optical parameters of thin films. It is important to accurately calculate the optical parameters of thin films for optimizing the design of the films and improving the transmittance of the films. In this paper on the basis of the experimental measurement of the transmission spectrum,Optical parameters of single TiO₂ films and TiO₂/Ag/TiO₂ multilayers are calculated by an optimization method, and the mechanism of argon plasma irradiation increasing TiO₂/Ag/TiO₂ multilayer film transmittance is discussed.Firstly, In order to accurately calculate the optical parameters of thin films, based on experiments, the effective optical parameters and transmittance spectra of TiO₂ film and Ag film after irradiation are calculated by MATLAB calculation program and the optimization method.Then, based on the calculation of optical parameters of single layer film,TiO₂/Ag/TiO₂composite film transmittance is obtained by using the characteristic matrix method. The impact of TiO₂ thickness d,the refractive index n and middle silver layer thickness d,refractive index n,extinction coefficient k on Ti02/Ag/TiO₂ composite film transmittance is explored.Mechanism of the argon plasma irradiation improving composite film transmittance is explored by adjusting the silver film optical parameters, eventually the optimal value of silver film optical parameters is solved by composite membrane transmission spectra and TiO₂/Ag/TiO₂ composite membrane transmission spectra is fitted. the fitting result is consistent with the experimental results.The results show that the refractive index and extinction coefficient can be reduced by argon plasma irradiation, and the transmittance of the composite film in the visible light can be improved.