We present a novel interferometric technique for performing ellipsometric
measurements. This technique relies on the use of a non-classical optical
source, namely, polarization-entangled twin photons generated by spontaneous
parametric down-conversion from a nonlinear crystal, in conjunction with a
coincidence-detection scheme. Ellipsometric measurements acquired with this
scheme are absolute; i.e., they do not require source and detector calibration.Comment: 10 pages, accepted for publication in Optics Letter