Heterodyne linear polarization modulation ellipsometer

In this study, a novel heterodyne linear polarization modulation ellipsometer (LPME) is developed. It is based on a linear polarization rotator and is integrated with a common path heterodyne interferometer for ellipsometric parameter measurement. LPME is an amplitude-sensitive interferometric ellipsometer that can not only provide a wider range for its polarization modulation frequency than that of a conventional photometric ellipsometer but also be used for measurement in real time. LPME is also insensitive to laser intensity fluctuations. The independence of the elliptical polarization to the incident laser beam induced by imperfections in the quarter-wave plate in LPME is analyzed.