面向磁场传感的瓶状微腔奇异点增强机理及器件研究

As a rising star in the microcavity family, the bottle-like microcavity combined with magnetic fluid and novel mechanism can achieve high sensitivity for the magnetic field sensing, due to its advantages of ultra-high Q factor, smaller mode volume, and the hollow core to integrate the functional materials. We propose a bottle-like microcavity device filled with the magnetic fluid, and study the sensing enhancement mechanism of exceptional point and high sensitive magnetic field sensing characteristics. The main contents includes: 1) Theoretical research: The coupling between micro-nano fiber tapers and bottle-like microcavity, the modes of bottle-like microcavity filled with the magnetic fluid under the magnetic field, the characteristics under exceptional points, and the exceptional point enhancement mechanism will be studied based on the mode theory, coupled mode theory and exceptional point theory; 2) Device fabrication: To explore and optimize the process to improve device performance, we will use many technologies, including the bottle-like microcavity prepared by the combination of electric discharge and pumping air, micro/nano fiber probes fabricated by the heating and pulling, the nanoprobe etched by the hydrofluoric acid, magnetic fluid filling and so on; 3) Sensing experiment: We will study the enhanced magnetic field sensing characteristics of exceptional points and the realization of higher sensitivity by multi-dimensional micro-nano manipulation tuning the bottle-like microcavity working at the exceptional point. The magnetic fluid-filled bottle-like microcavity and its magnetic field sensing properties of exceptional point mode studied in this project have important developments in the study of microcavity optics and the enhanced sensitivity of exceptional point, and will have an important application potentials for magnetic field sensing.

作为微腔家族中的后起之秀，瓶状微腔具有超高Q值、较小模式体积、中空微流通道能集成功能材料等优点，结合磁流体和新机理有望实现高灵敏磁场传感。本课题提出一种磁流体填充的瓶状微腔器件，并研究奇异点传感增强机理及高灵敏磁场传感特性。主要工作包括：1）理论研究：基于模式理论、耦合模理论和奇异点理论，研究微纳光纤与瓶状微腔耦合、磁场作用下磁流体填充的瓶状微腔模式及奇异点特性、奇异点增强机理；2）器件研制：通过放电与鼓气结合制备瓶状微腔、火焰拉锥制备微纳光纤融锥、氢氟酸腐蚀制备纳米探针、磁流体填充等工艺技术，探索优化制备方案以改进器件性能；3）传感实验：通过多维微纳操控纳米探针，调谐瓶状微腔使其工作在奇异点，实验研究奇异点增强的磁场传感特性，及更高灵敏度实现方案。本项目所研究的磁流体填充瓶状微腔及其处于奇异点下的磁场传感特性，是对微腔光学及奇异点增强灵敏研究的重要拓展，将在磁场传感领域有着重要应用前景。

作为微腔家族中的后起之秀，瓶状微腔具有超高Q值、较小模式体积、中空微流通道能集成功能材料等优点，结合磁流体和新机理有望实现高灵敏磁场传感。在磁流体辅助下，微瓶谐振腔可将磁场信号转换为回音壁模式谐振波长、强度及线宽等参量的变化。本项目采用磁流体填充的回音壁模式微瓶谐振腔器件，分析其模式分布及耦合传输特性，研究其磁场传感特性并探索基于奇异点的传感灵敏度增强机理。本项目主要开展四个方面的研究：1）空芯光纤传输机理及结构设计研究，包括单模光纤—毛细管—单模光纤三段式结构传输机理研究、三段式级联结构多传输机理共存研究、具有椭圆管道的低损耗负曲率空芯光纤结构设计研究；2）基于空芯光纤内嵌微球谐振腔的回音壁模式耦合器及应用研究，包括双悬芯空芯光纤回音壁模式耦合器、大内径毛细管zigzag 回音壁模式耦合器、基于毛细管内嵌空心玻璃微球的半圆干涉仪及液压传感应用研究；3）回音壁模式微瓶谐振腔器件及传感特性研究，包括微柱谐振腔模式劈裂观测及光谱简化研究、空心微瓶谐振腔曲率模型及传输特性研究、空心微瓶谐振腔流速及液滴质量监测研究、空心微瓶谐振腔矢量磁场传感特性研究；4）微腔奇异点灵敏度增强机理及传感应用研究，包括耦合微腔奇异点调控及纳米颗粒探测理论研究、基于微腔奇异点的磁场传感理论研究。本项目是对微腔光学及奇异点增强灵敏研究的重要拓展，将在磁场传感领域有着重要应用前景。