Acoustic Sensing Based on Optical Microcavities: A Review

Currently, acoustic sensing technology is widely applied in military defense, non-destructive testing (NDT), and biomedical imaging, and it is increasingly penetrating various aspects of daily life. However, traditional piezoelectric acoustic sensors are highly susceptible to performance degradation when operated in harsh environments. In contrast, optical microcavities-a class of optical resonant cavities with characteristic dimensions on the micrometer scale—offer distinct advantages, including compact footprints, immunity to electromagnetic interference (EMI), and ultra-high sensitivity. Leveraging these exceptional properties, researchers have extensively explored acoustic sensing technologies based on optical microcavity platforms. This paper reviews recent research progress in optical microcavity-based acoustic sensing, categorized by the structural configurations of the microcavities. First, we introduce the key performance specifications of different optical microcavities in acoustic sensing, such as sensitivity and frequency response bandwidth. Second, we categorically discuss the structural designs of various optical microcavities alongside corresponding optimization methods to improve sensing performance. Finally, we summarize the current applications of optical microcavity-based acoustic sensing across multiple fields and outline future development trends in this research area.