Optical whispering-gallery mode (WGM) microresonators, confining resonant photons in a microscale volume for long periods of time, strongly enhance light-matter interactions, making them an ideal platform for photonic sensors. One of the features of WGM sensors is their capability to respond to environmental perturbations that influence the optical mode distribution. The exceptional sensitivity of WGM devices, coupled with the diversity in their structures and the ease of integration with existing infrastructures, such as conventional chip-based technologies, has catalyzed the development of WGM sensors for a broad range of analytes. WGM sensors have been developed for multiplexed detection of clinically relevant biomolecules while also being adapted for the analysis of single-protein interactions. They have been used for the detection of materials in different phases and forms, including gases, liquids, and chemicals. Furthermore, WGM sensors have been used for a wide variety of field-based sensing applications, including electric field, magnetic field, force, pressure, and temperature. WGM sensors hold great potential for applications in life and environmental sciences. They are expected to meet the ever-increasing demand in sensor networks, the Internet of Things, and real-time health monitoring. Here we review the mechanisms, structures, parameters, and recent advances of WGM microsensors and discuss the future of this exciting research field.

光学回音壁模式（WGM）微谐振器可将谐振光子长时间限制在微尺度体积内，大大增强了光与物质的相互作用，使其成为光子传感器的理想平台。WGM 传感器的特点之一是能够响应影响光学模式分布的环境扰动。WGM 设备卓越的灵敏度，加上其结构的多样性以及与现有基础设施（例如传统的基于芯片的技术）集成的便利性，促进了针对各种分析物的 WGM 传感器的开发。WGM 传感器已开发用于临床相关生物分子的多重检测，同时也适用于分析单一蛋白质相互作用。它们已用于检测不同相和形式的材料，包括气体、液体和化学品。此外，WGM 传感器已广泛用于各种基于场的传感应用，包括电场、磁场、力、压力和温度。WGM 传感器在生命和环境科学领域具有巨大的应用潜力。它们有望满足传感器网络、物联网和实时健康监测不断增长的需求。在这里，我们回顾了 WGM 微传感器的机制、结构、参数和最新进展，并讨论了这个令人兴奋的研究领域的未来。