Thermally induced changes in thin gold films detected by polaritonic ellipsometry

The effect of vacuum heat treatment in the range between 100 and 360 °°C on the structure and optical properties of thermally evaporated thin gold films was studied. The structure of films was revealed by atomic force microscopy (AFM). optical characterization was performed using multiple-angle-of-incidence (MAI) reflectance ellipsometry at fixed wavelength (632.8 nm) in attenuated total reflection mode in contact with water. The observed temperature dependent non-monotonic modifications of optical constants of Au films were correlated with the evolution of both the film microstructure and film microrelief. This effect might be crucial in polaritonic optoelectronics and optochemical sensors.