Cavity optomechanical mass sensor in water with sub-femtogram resolution

TL;DR

This paper demonstrates a cavity optomechanical mass sensor in water with sub-femtogram resolution, significantly surpassing previous setups and enabling highly sensitive in-liquid chemical and biological measurements.

Contribution

The study introduces a twin-microbottle glass resonator sensor achieving unprecedented mass resolution in water, advancing in-liquid optomechanical sensing technology.

Findings

Achieved mass resolution of (7.0×2.0)×10^{-16} g in water

Sensor resolution is four orders of magnitude better than previous setup

Provides a versatile probe for in-situ chemical and biological applications

Abstract

Sub-femtogram resolution of an in-liquid cavity optomechanical mass sensor based on the twin-microbottle glass resonator is demonstrated. An evaluation of the frequency stability using an optomechanical phase-locked loop reveals that this cavity optomechanical sensor has the highest mass resolution of $(7.0\times2.0)\times 10^{-16}$ g in water, which is four orders of magnitude better than that in our first-generation setup [Sci. Adv. 8, eabq2502 (2022)]. This highly sensitive mass sensor provides a free-access optomechanical probe in liquid and could thus be extended to a wide variety of in-situ chemical and biological metrology applications.