Application of optical squeezing to microresonator based optical sensors

TL;DR

This paper investigates how optical squeezing can enhance the sensitivity of microresonator-based sensors beyond the shot-noise limit by utilizing quantum states of light and addressing optical losses.

Contribution

It demonstrates the potential of using squeezed light in microresonators to surpass classical sensitivity limits, incorporating strategies to mitigate optical losses.

Findings

Squeezed light improves sensor sensitivity beyond shot-noise limit

Optical losses constrain the maximum achievable sensitivity

Additional in-resonator squeezing can reduce loss effects

Abstract

High-Q optical microresonators combine low losses and high optical energy concentration in a small effective mode volume, making them an attractive platform for optical sensors. While light is confined in the microresonator by total internal reflection, a portion of the optical field, known as the evanescent field, extends outside. This makes the mode's resonant frequency sensitive to changes in the surrounding environment. In this work, we explore the quantum sensitivity limits of this type of sensors. We demonstrate that by preparing the probe light in a squeezed quantum state, it is possible to surpass the shot-noise limit. The resulting sensitivity is constrained only by optical losses and the available degree of squeezing. The influence of the losses can be reduced using additional squeezing of the light inside the microresonator.