Abstract

A cavity optomechanical sensor of liquid level is demonstrated using a twin-microbottle resonator, which is a glass fiber optomechanical prober. The minimum resolution estimated from the frequency stability reaches (9.6±0.3) × 10^-12 m as a result of using an optomechanical phase locked loop with a bandwidth of 5 Hz. This small optomechanical liquid level sensor with a high level of resolution could be used to resolve tiny fluctuations in an air-liquid or liquid-liquid interface for chemical and biological sensing.

© 2023 The Author(s)