Investigation Of Dielectric Laser Mirrors Using Transmission Electron Microscopy

Cross-sections of dielectrical laser mirrors are examined by Transmission Electron Microscopy (TEM). The TEM picture shows the whole layer structure which offers the possibility to observe the development of interface roughness from the substrate up to the top layer. The TEM pictures reveal the great difference between the interface roughness of evaporated and ion beam sputtered layers. Using computer image processing techniques the increasing roughness within the evaporated layer system has been measured. Furthermore the correlation lengths of the roughness has been determined in this way. The knowledge of these two parameters over the entire system enables the calculation of scatter losses for the system.