Interferometer-less surface profilerometer

We demonstrate experimentally an optical scanning technique for measuring the step heights of surface features without using conventional optical interferometers. This technique involves the deployment of the so-called photo-EMF sensors that are capable of sensing the presence of step-like features on an otherwise optically flat surface. Scanning of the target surface is achieved by rotating the object being investigated while keeping the laser beam stationary. Theoretical modeling and experimental data will be presented indicating the resolution of step-like features with merely 15 nm in height.