This paper proposes a common-path optical-heterodyne interferometer for developing a very stable force microscope. The deflections of the force-sensing cantilever are detected by the optical ...heterodyne method which reduces low-frequency noise. The optical system is a common-path interferometer using a Wollaston prism, which reduces the effects of mechanical vibrations and perturbation of the optical path length. In this paper, we proposed the optical system, constructed a system and measured the surface profile of optical disk grooves.
