For the controlled production of thin films it is very important to determine the deposition rate of the used device. The simplest way is to produce a set of films with different deposition times, find out their thickness and determine the slope of the - hopefully linear - thickness vs. time relation. In many cases the thickness of the produced films can be obtained with the help of optical spectroscopy.

Here we show a simple example, namely the determination of the deposition rate for sputtering silver on glass. The thickness is obtained analyzing measured reflectance spectra in the spectral range from 200 to 1100 nm. We will work with fixed optical constants for silver and glass that we take from the database. The only fit parameter will be the silver thickness. After the determination of the thickness for several spectra the sputtering rate can be computed.