Realization of an Ultrasensitive Heisenberg-Limited Interferometer
Olivier Pfister · 2006
The goal of the project "Realization of an Ultrasensitive Heisenberg-Limited Interferometer," supported by ARO grant DAAD19-01-1-0721 from August 1, 2001 to July 31, 2006, was the investigation of quantum interferometry with bright nonclassical light beams emitted by an ultrastable optical parametric oscillator (OPO). Theoretical studies of the Holland-Burnett Bayesian detection scheme were conducted for realistic experimental implementation in photonic quantum optics. The main result, applicable to any boson wave (eg. matter waves), is that the ultimate Heisenberg limit 1/N (N being the average number of photons detected in the measurement) can still be reached in the presence of losses for Bayesian detection, if the losses do not exceed 1/N. The main experimental results were the first demonstration of macroscopic Hong-Ou-Mandel quantum interference at a beam splitter and the demonstration of heterodyne polarimetry with a noise floor 4.8 dB below the interferometric shot noise limit (1/sqrt{N}). The latter can be applied to enhancing the sensitivity of chiral molecule detection. Realistic extensions of this study are larger amounts of squeezing (-10 dB and beyond) as well as RF broadband phase measurements, which are a direct consequence of the stability performance of our OPO and for which we also present preliminary results.