基于磁流体光子晶体的全光高灵敏、宽线性响应磁场传感技术研究

Magnetic fluid is kind of novel magnetic-field-sensitive materials. The magnetically controllable optical properties of magnetic fluid make it has the potentials of sensing magnetic field based on optical techniques. The current proposed magnetic field sensors with magnetic fluid have the intrinsic deficiencies in terms of compactness, integration, temperature and magnetic field cross-sensitivity, sensing performance such as sensitivity and range of linear response, the magnetic fluid photonic crystal (waveguide, microcavity) is proposed to fabricated out with the silicon-based (SOI) materials in this project. The all-optical highly sensitive magnetic field sensing technique is realized based on the magnetic-field-dependent transmission and characteristic spectrum of the device. The SOI materials used in the silicon nanophotonics and integrated optics are utilized in this project, which means the as-fabricated devices are highly compatible with the integrated circuits or integrated photonic devices with respect to technique, fabrication and interconnect. It is favorable for realizing the integrated and miniature sensors. Different from the reported fiber-based magnetic field sensors, the proposed sensing structure in this project has less critical requirement on choosing the magnetic fluid (e.g. index matching is not necessary). This makes it possible to sense the magnetic field with high sensitivity and large range of linear response. The issue of temperature and magnetic field cross-sensitivity is easily solved by designing a photonic crytal microcavity beside the photonic crytal waveguide and using the developed two-parameter matrix method. Accomplishing this project will be significant to have an in-depth understanding of the magnetically controllable optical properties of magnetic fluid. It will lead to the technique of micro/nano magnetic field sensor based on magnetic fluid and promote the photonic integration and utilizable perspective of the corresponding sensors.

磁流体是一种新型的磁场敏感材料，其磁场可控光学特性使其在基于光学技术的磁场传感器中具有重要的潜在应用价值。针对当前磁流体磁场传感器在微型化、集成化、温度-磁场交叉敏感、灵敏度及线性响应范围等性能方面的不足，本项目通过构筑磁流体光子晶体(波导、微腔)，利用其独特的场控光传输及透射光谱特征实现磁场传感。项目采用纳米光子学/集成光学中的硅基材料(SOI)，使器件易与现有的集成光路(光器件)在技术、工艺和互联上兼容，实现传感器的微型化与集成化。区别于光纤结构的磁场传感器，本传感结构不需要满足磁流体折射率匹配等特殊限制性要求，为实现全光高灵敏、宽线性响应的磁场传感器提供了可能。通过磁流体光子晶体波导与微腔耦合，借助双参量矩阵法，简便地解决温度-磁场交叉敏感问题。项目的成功开展有望进一步深入认识磁流体磁控光学特性，形成基于磁流体的微纳磁场传感技术，促进磁场传感器的光子集成与实用化。

磁流体作为一种特殊的纳米功能材料，由于其磁场敏感性，其在磁场传感领用受到了极大的关注。本项目基于磁流体的场诱导团聚和折射率可调等新型光学特性，对其磁场诱导的光传输及光谱透射特性进行了理论分析和实验研究。通过利用磁流体构筑光子晶体及其耦合微腔结构，提出并研究了基于磁流体光子晶体的磁场传感技术。根据折射率匹配原理、泄漏模技术以及游标效应，提出利用磁流体实现超高灵敏的磁场传感。通过特殊结构设计，借助双参量矩阵法或温度自补偿技术，简便地解决了温度-磁场交叉敏感问题。同时，还适当增加了新型磁场传感结构、矢量磁场传感、磁性纳米颗粒的光镊效应等方面的初步探索研究。利用光子耦合结构及共振环型光子结构，研究了其在磁场传感上的应用，实现了灵敏度增强的磁场传感技术。本项目的研究已取得了一些创新性的成果，所提出的磁流体光子晶体及相关光子结构磁场传感器的优点是尺寸小、易于集成、不需要温度补偿结构，利于促进磁流体磁场传感器的微型化和实用化。项目的研究成果对深入掌握纳米磁流体的新型光学性质以及促进磁流体光学、磁场传感技术的发展具有重要的意义，对磁流体在新型光学磁场传感器上的应用将起到推动的作用。