On the Lamellar Reflectivity and Phase Shift for Multiple Reflections

Abstract

An expression for calculating the lamellar reflectivity of a single layer on a surface of metal is given by extending Nathanson and Bartberger’s equation. Then, interpreting this expression as reflectivity for a surface of hypothetical medium with an “effective refractive index”, we calculated the reflectivity and the phase shift due to the reflection of two or more thin films on a surface of metal and the results were compared with the experiments of A. F. Turner and G. Hass. It was ascertained that the results of calculation show a good coincidence with the experimental data, except in case of very thin aluminium film, in which the optical constants different from those of bulk aluminium must be used. This method of calculation is useful for producing the interference filter, and reflection increasing or reducing by multilayer films, etc. Finally, from the result of the calculation, a method of obtaining a reflection-type interference filter using ZnS was induced.