In fabricating optical thin films by evaporating dielectrics onto a glass substrate there are various unwanted errors for the structure of dielectric multilayers, for example, thickness errors, lack of thickness uniformity, anisotropic refractive indices of growing dielectric films in a certain direction, etc. In particular, it is of interest to take thermal diffusion into account in the process of alternate deposition of one low-index material and one high-index material. It is not possible to avoid the diffusion of thin films in vacuum deposition technology as long as the dielectric components of different refractive indices are to be thermally heated. It is the aim of this presentation to numerically determine the influence on the performance of the thin films from the thermal diffusion during the vacuum deposition inside a chamber system. It is required to solve the accurate equation[1,2] [see Eq.(2) below] for the reflection coefficients to find the performance of the thin films. In this presentation we confine ourselves to the thermal diffusion effects on the quarter-wave stacks of alternating two (high- and low-index) dielectric materials for high reflectance in a broad region and the filters which transmit only selected regions of spectrum. Here the dispersion has not been included in the calculations for simplicity.
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