Dr Timothy S. Woodworth - Oak Ridge National Lab

Optomechanical force sensors can be used as gravimeters or accelerometers for applications in geodesy and inertial navigation

In my project, I explored how quadrature quantum correlations in two-mode squeezed states can be exploited to improve the force sensitivity of a dual cavity setup with a membrane acting as a common movable mirror. We have shown that, when working on-resonance for the optical cavities, the frequency at which the highest sensitivity is achieved can be effectively shifted via the squeezing angle of the probing quantum state. We also explore frequency domains with a quantum enhancement to force sensitivity when working away from the most sensitive frequency.

When working off-resonance from the optical cavities, our preliminary results show that a quantum enhancement is still possible and, more importantly, that it can be achieved via intensity measurements of the output optical fields instead of the typical homodyne phase measurements with minimal loss in sensitivity. The possibility of using intensity measurements results from the frequency dependent phase rotation between the carrier and sideband of the light reflected from an optical cavity.

The simplicity and stability of intensity measurements, with respect to homodyne measurements, allows for a more robust system, which will enable a deployable device capable of implementing longer integration times to further improve the sensitivity. In future work, we will expand our two-mode state into multiple quantum correlated modes to measure multiple force sensors. The use of entangled states will allow for an improved scaling with the number of sensors beyond what can be achieved with uncorrelated measurements of the same sensors.