Experimental study of a phase-sensitive heterodyne detector
H. Fan（凡恒）, D. He（何德超） and S. Feng（冯胜）,
J. Opt. Soc. Am. B 32, 2172 (2015)
Although the quantum behaviors of optical detectors have been considered to be fully understood, a fundamental dilemma inevitably arises regarding a phase-sensitive heterodyne detector: On one hand, the detector should suffer 3 dB noise penalty caused by imageband vacuum, on the other hand, it, as a phase-sensitive device, should be noise free at the quantum level. We report on an experiment on a phase-sensitive heterodyne detector, where the quantum noise of the imageband vacuum is absent in the observation. The underlying mechanism behind the observation should be closely related to the origin of the quantum noise in optical detection.
