Atomic force microscopy with optical heterodyne detection method

We report on an atomic force microscope (AFM) based on a simple optical set-up using heterodyne detection. The deflection of the cantilever in the AFM was interferometrically measured using a Michelson interferometer. At a scanning speed of 2 mum/s and an integration time of 10 ms, the measured vertical resolution was 0.4 nm. The lateral resolution was 20 nm and is determined by the scanning speed and the integration time