A system for measuring optical properties of a sample is provided. A light source provides incident polarized light. A detector detects reflected light from the sample surface. A processor determines a first coefficient (R) of the reflected light detected by the detector, determines a second coefficient (n), extinction coefficient (k), and thickness of the film based on the measured first coefficient, and determines a first dielectric constant (.di-elect cons..sub.1) and a second dielectric constant (.di-elect cons..sub.2) of the film according to the second coefficient (n) and extinction coefficient (k).