Cavity optomechanical mass sensor in water with sub-femtogram resolution

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 +/- 2.0) x 10(- 16)g in water, which is four orders of magnitude better than that in our first-generation setup [Sci. Adv. 8,X 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. (c) 2023 The Japan Society of Applied Physics

Automated summary

In this study, a sub-femtogram resolution in-liquid cavity optomechanical mass sensor based on the twin-microbottle glass resonator is demonstrated. Evaluation of the frequency stability using an optomechanical phase-locked loop shows that this sensor provides the highest mass resolution of (7.0 +/- 2.0) x 10(- 16)g in water, which is four orders of magnitude better than the first-generation setup. The highly sensitive mass sensor can be utilized as a free-access optomechanical probe in liquid for various in situ chemical and biological metrology applications.