生物医学光声成像是基于光声效应、以超声信号检测为物理手段的新型成像方法，同时结合了光学成像的高对比度优势和超声成像的高穿透深度特性。超声信号检测是光声成像技术中的关键技术环节，如何实现具有高探测精度、高对比度、高空间分辨率的光声成像手段成为研究人员的共同目标。传统采用压电式传感器进行超声信号探测，其灵敏度相对较低，响应带宽窄，不利于实现高分辨率成像。本项目提出一种新型的传感基元—“微纳光纤光栅Fabry-Perot高阶干涉型超声传感器”，通过其高阶模式干涉可以更为有效的实现对外部环境折射率变化的感测能力，全面阐释超声传感中高阶模式的作用机制，明确影响传感灵敏度的决定性因素，更好的实现超声检测的高灵敏度要求。同时，影响光声成像空间分辨率的一个重要参数就是传感器的截面直径尺寸，较小直径的微纳光纤能更好地实现光声成像的高空间分辨率要求，最终达到高探测精度、高空间分辨率的光声成像方法。

Biomedical Optoacoustic imaging technology, one of the newest imaging approaches, has received great interests since it presents the advantages of high contrast and high penetration depth. This approach, based on the optoacoustic effect and the detection of ultrasonic signals, has developed as a highly effective non destructive means for biomedical imaging. Ultrasonic signal detection is the key technology of photoacoustic imaging technology, the main challenge for this imaging technique lies in how to simultaneously realize high sensitivity, high contrast, and high spatial resolution. Conventiona methods relying piezo electrical sensors present relatively low sensitivities and narrow response bandwidth., which is not conducive to the realization of high resolution imaging. The project put forward a kind of new sensing element, microfiber Bragg grating Fabry Perot interference higher-order type ultrasonic sensor, through the high order mode interference can be more effective implementation of external environment refraction rate of change of the sensing capability, higher order modes of a comprehensive interpretation of the ultrasonic sensing mechanism, clearly affect the decisive factor of the sensor sensitivity, the better to achieve high sensitivity of ultrasonic testing requirements. At the same time, the effects on photoacoustic imaging spatial resolution of an important parameter is the sensor's section diameter, the smaller diameter of microfiber can better realize photoacoustic imaging with high spatial resolution requirements, eventually reaching the photoacoustic imaging method with high spatial resolution and high detection precision.