Metrology with $\mathcal{PT}$-symmetric cavities: Enhanced sensitivity near the $\mathcal{PT}$-phase transition

TL;DR

This paper introduces a novel metrology method using $ ext{PT}$-symmetric microcavities with balanced gain and loss, achieving enhanced sensitivity near the phase transition point, with potential applications in ultra-high precision sensing.

Contribution

It demonstrates how $ ext{PT}$-symmetric microcavities can surpass traditional loss-only systems in sensitivity, especially near the phase transition, opening new avenues in precision metrology.

Findings

Sensitivity is significantly enhanced near the $ ext{PT}$ phase transition.

$ ext{PT}$-symmetric cavities outperform loss-only systems in detection sensitivity.

Potential applications in ultra-high precision sensing and metrology.

Abstract

We propose and analyze a new approach based on parity-time ($\mathcal{PT}$) symmetric microcavities with balanced gain and loss to enhance the performance of cavity-assisted metrology. We identify the conditions under which $\mathcal{PT}$-symmetric microcavities allow to improve sensitivity beyond what is achievable in loss-only systems. We discuss its application to the detection of mechanical motion, and show that the sensitivity is significantly enhanced in the vicinity of the transition point from unbroken- to broken-$\mathcal{PT}$ regimes. We believe that our results open a new direction for $\mathcal{PT}$-symmetric physical systems and it may find use in ultra-high precision metrology and sensing.