Coherent-Light Boosted, Super-Sensitive, Quantum Interferometry

TL;DR

This paper proposes a quantum interferometry scheme that combines coherent light and squeezed states to achieve phase sensitivity below the shot noise limit, using simple detection and current technology.

Contribution

It introduces a hybrid interferometry scheme utilizing coherent-beam-stimulated two-mode squeezed light with no complex detection, enhancing sensitivity with existing technology.

Findings

Potential to reach below shot noise limit in phase sensitivity

Scheme is simple, practical, and avoids complex detection protocols

Sensitivity scales with a sub-Heisenberg contribution

Abstract

We present in this letter a scheme for optical interferometry. We utilize coherent-beam-stimulated two-mode squeezed light, which interacts with a phase shifter and is then squeezed again before detection. Our theoretical device has the potential to reach far below the shot noise limit (SNL) in phase sensitivity. This new proposal avoids the pitfalls of other setups, such as difficulty in creating the required resource. Furthermore, our scheme requires no complicated detection protocol, relying instead only on simple intensity measurement. Also, bright, coherent sources "boost" squeezed light, creating a very sensitive device. This hybrid scheme relies on no unknown components and can be constructed with current technology. In the following we present our analysis of this relatively straightforward device, using the operator propagation method. We derive the phase sensitivity and provide a simple numerical example of the power of our new proposal. Sensitivity scales as a shot noise limited Mach-Zehnder Interferometer, multiplied by a sub-Heisenberg contribution from the squeezed light.