Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
An experimental report on correlated-photon ellipsometry
Kimani C. Toussaint, Giovanni Di Giuseppe, Alexander V. Sergienko, Bahaa E. A. Saleh, Malvin Carl Teich
Abstract
Traditional ellipsometric measurements are limited in their accuracy because of the use of an external reference sample for calibration, and because of the noise inherent in the source at low light levels. We demonstrate that these limitations can be circumvented by using a non-classical source of light, namely, twin photons generated by the process of spontaneous parametric downconversion, in conjunction with a novel polarization interferometer and coincidence-counting detection scheme. The twin-photon nature of the source is a unique feature of our scheme. We are guaranteed, on the detection of a photon in one of the arms of the setup, that its twin will be in the other. We present experimental results showing how the technique operates.