The influence of substrate temperature on the optical losses of ZnS film

Loss measurements in waveguide thin films are shown to exhibit a sensitive optical probe of surface and volume losses and thus of film quality. The high accuracy and sensitivity of this device was exploited for assessing the role of substrate temperature on the optical performance of ZnS films. In general, film losses tend to increase with substrate temperature. However, broad optima in losses are observed at 200 and 250 °C. A correlation between film structure and scatter losses as measured by the integrating sphere method with results of losses obtained from waveguide mode technique is discussed. This correlation leads to more reliable interpretation of the influence of substrate temperature on the losses of ZnS film.