Imaging-based Quantum Optomechanics

TL;DR

This paper extends quantum imaging analysis to compliant surfaces, revealing how multimode backaction and spatiotemporal photon shot noise influence imaging and enable entanglement of spatial modes, opening new avenues in quantum sensing and networks.

Contribution

It introduces a framework for understanding multimode backaction in compliant surfaces and demonstrates the generation of spatial mode entanglement via spatiotemporal backaction effects.

Findings

Backaction arises from spatiotemporal photon shot noise.

Imprecision-backaction product matches the standard quantum limit.

Spatiotemporal backaction can generate entangled spatial modes.

Abstract

In active imaging protocols, information about an object is encoded into the spatial mode of a scattered photon. Recently the quantum limits of active imaging have been explored with levitated nanoparticles, which experience a multimode radiation pressure backaction (the photon recoil force) due to radiative scattering of the probe field. Here we extend the analysis of multimode backaction to compliant surfaces, accessing a broad class of mechanical resonators and fruitful analogies to quantum imaging. As an example, we consider imaging of the flexural modes of a membrane by sorting the spatial modes of a laser reflected from its surface. We show that backaction in this setting can be understood to arise from spatiotemporal photon shot noise, an effect that cannot be observed in single-mode optomechanics. We also derive the imprecision-backaction product in the limit of purely spatial (intermodal) coupling, revealing it to be equivalent to the standard quantum limit for single-mode optomechanical coupling. Finally, we show that optomechanical correlations due to spatiotemporal backaction can give rise to two-mode entangled light, providing a mechanism for entangling desired pairs of spatial modes. In conjunction with high-Q nanomechanics, our findings point to new opportunities at the interface of quantum imaging and optomechanics, including sensors and networks enhanced by spatial mode entanglement.