Quantum-Noise-Limited Sensitivity-Enhancement of a Passive Optical Cavity by a Fast-Light Medium

TL;DR

This paper demonstrates that a passive optical cavity with a dispersive medium can significantly enhance quantum-noise-limited sensitivity, achieving over two orders of magnitude improvement through temperature tuning near critical anomalous dispersion.

Contribution

It introduces a method to enhance sensitivity in optical cavities using a dispersive atomic medium, validated by experiments and simulations.

Findings

Over two orders of magnitude increase in scale factor.

More than tenfold enhancement in measurement precision.

Confirmation of predictions through Monte-Carlo simulations.

Abstract

We demonstrate for a passive optical cavity containing a dispersive atomic medium, the increase in scale factor near the critical anomalous dispersion is not cancelled by mode broadening or attenuation, resulting in an overall increase in the predicted quantum-noise-limited sensitivity. Enhancements of over two orders of magnitude are measured in the scale factor, which translates to greater than an order-of-magnitude enhancement in the predicted quantum-noise-limited measurement precision, by temperature tuning a low-pressure vapor of non-interacting atoms in a low-finesse cavity close to the critical anomalous dispersion condition. The predicted enhancement in sensitivity is confirmed through Monte-Carlo numerical simulations.