Broadening the high sensitivity range of squeezing-assisted interferometers by means of two-channel detection

TL;DR

This paper proposes a method to extend the phase range of high-sensitivity squeezing-assisted interferometers by using two-channel detection and phase-sensitive amplification, achieving loss-tolerant, phase-independent sub-shot-noise sensitivity.

Contribution

It introduces a novel detection scheme with two-channel detection and phase-sensitive amplification to broaden the phase sensitivity range of squeezing-enhanced interferometers.

Findings

Phase sensitivity becomes independent of the operation point.

Detection loss tolerance is improved with phase-sensitive amplification.

The method enhances the practical robustness of quantum interferometry.

Abstract

For a squeezing-enhanced SU(2) interferometer, we theoretically investigate the possibility to broaden the phase range of sub-shot-noise sensitivity. We show that this goal can be achieved by implementing detection in both output ports, with the optimal combination of the detectors outputs, leading to a phase sensitivity independent of the interferometer operation point. Provided that each detector is preceded by a phase-sensitive amplifier, this sensitivity could be also tolerant to the detection loss.