利用表面等离激元Fano共振调制磁光效应的关键技术研究

Recently, great efforts have been devoted to surface plasmon polaritons (SPPs) because they allow electromagnetic energy to be concentrated in nanoscale volumes near metal/dielectric interfaces, which leads to the enhancement of many optical effects. As the applications of SPPs have gradually penetrated into other research fields, great prospects for modern magneto-optical technology have been brought. However, people usually focus on the improvement of magneto-optical intensity but ignore its sensitivity. This may limit the further development of magneto-optical technology. Aiming at such problem, SPPs are proposed to be applied to modulate magneto-optical effect in this project. Specially, Fano resonances are also used since they have highly responsive characteristics. This project will include several main contents that given as follows. We propose a new kind of periodic structure in which the elements are composed by noble metal Au and magnetic material Co. In this structure, how to use the strongly localized field to enhance the magneto-optical effect with the most effective pattern is studied. And we also explore how to use Fano resonances to modulate the magneto-optical effect by using asymmetry designs in structure. In addition, the device will be fabricated and its characteristics will be examined based on numerical simulation results. This project provides the technical supports for the realization of magneto-optical devices with strong intensity and high sensitivity, and also sets as an important theoretical reference for the magneto-optical effect in the applications of detection and sensing technology.

近年来，随着表面等离激元这个热门研究领域逐渐渗透到磁光研究中，它毫无疑问地为现代磁光技术带来了巨大的发展动力和应用前景。然而，目前大家关注的重点主要集中在提高磁光强度方面，而对磁光效应的变化敏感度问题甚为忽视，这将在一定程度上限制其应用范围和技术发展。本项目正是针对此问题，在利用金属表面等离激元的基础上，将具有变化强烈、反应灵敏特性的Fano共振应用于调控磁光效应，探索兼具高强度、高变化敏感性质的磁光器件，并进行实验制备和测试分析工作。项目的主要研究包括：提出贵金属-磁材料的复合单元并将其构建周期阵列，探讨如何利用表面等离激元的局域效应对磁光响应进行直接、高效作用的调制模式；对上述周期阵列的局部和整体引入双重非对称模式，探讨如何将表面等离激元Fano共振应用在磁光调控技术上。本项目为有效调制磁光效应提供技术支持，也为磁光器件在探测、传感方面的应用提供重要的参考价值。

本项目将谱线特性具有变化强烈、反应灵敏的Fano共振应用于金属表面等离激元效应、磁光效应等方面，探讨如何实现探测具有高灵敏度的金属微纳器件、高传输非互易性的磁光器件。具体研究内容分为以下三个方面：①研究金属表面等离激元Fano共振传感器件，一是在圆形金属圆腔中对腔芯引入对称破缺，实现对Fano共振的波长和线形进行灵活调节；二种是研究利用金属圆腔和矩形腔之间耦合效应形成的Fano共振，通过调节腔耦合效应实现Fano共振的独立调控、线性调节问题；三是研究一种新型扇形耦合腔纳米结构，在较宽光谱范围内获得平均间隔约为30nm的十个共振模式，为超密集多重滤波器件提供参考。②研究基于磁光效应的光子晶体器件，一是利用铁氧体材料和等离子体材料耦合，实现具有TM和TE双偏振的环行器，两种偏振情况的插损均小于0.15 dB，隔离度均大于20 dB；二是在二维正方晶格光子晶体中提出星形铁氧体柱的具有低损耗宽带环行器，研究中心磁光微腔与相应波导的耦合调制。③研究利用金属表面等离激元Fano共振获得可调型反射滤波器、高传输的磁光效应。本项目基本按照项目预期计划和目标实施，研究成果给金属表面等离激元效应、磁光效应、Fano共振技术等方面交叉应用带来新思路和新前景，在传感、探测技术领域具有重要的应用价值。