Abstract

Several low-scatter optical surfaces and ion-etched gratings have been profiled by using a scanning tunneling microscope (STM) or atomic force microscope (AFM) and a conventional Talystep mechanical surface profiler with a diamond stylus. Lateral resolution was not a problem with the low-scatter optical surfaces; the polished fused silica surface had about the same roughness on an atomic lateral resolution scale as it did on the macroscopic scale of the diamond stylus profiler. The ion-etched gratings had a period of 0.7 μm and a groove depth of ~2500 Å. The groove shape and depth could not be measured with the diamond-stylus profiler because the grooves were only partially resolved with a "shovel-shaped" stylus having a short radius (~0.2 μm). However, once the true shape was measured with the STM, the approximate profile that would be recorded by a diamond stylus profiler could be calculated. This calculation showed that it is not possible to guess the shape of the part of the groove that is not contacted by the diamond stylus by means of a mechanical-profiler measurement alone. Representative profiles taken with both types of instruments will be shown and compared.

© 1990 Optical Society of America