High-resolution fiber-coupled interferometric point sensor for micro- and nano-metrology

The determination of surface roughness is a common challenge in industrial quality assurance. Because tactile techniques like the stylus method or atomic force microscopy run the risk of damaging the measurement object there is a high demand for contact-free optical measurements. In this contribution we demonstrate the feasibility of a high resolution fiber-coupled interferometric point sensor with periodical path length modulation to determine the surface profile of rough surfaces. Measurements on two specimens characterized by different roughness parameters are presented and corrections for common measurement errors, due to phase ambiguity are discussed.