石墨烯微纳结构中的等离激元诱导透明效应及其动态调控研究

Recent studies have shown that graphene is a type of excellent plasmonic materials, which possesses many advantage characteristics, such as low losses, a wide range of tunable conductivity, very large third-order nonlinear optical response and so on. Graphene has attracted intensive investigation in the field of optoelectronics nowadays. The project will study the plasmon induced transparency (PIT) and its dynamic manipulation which are caused by the coupling effect between resonance structures (that is the bright mode/dark mode excited directly/indirectly by the electromagnetic waves) in the micro-nano structures constituted by graphene. The research aspects of this project are shown as follows. First, we will study the physical mechanism of resonance induced interference and the realization of PIT in graphene micro-nano structures. Second, we will study the dynamical behavior of PIT manipulation comes from the variation of conductivity or nonlinear characteristics of graphene. At the same time, we will also study the transport properties of wave which are caused by the dynamical manipulation of PIT, such as wave dispersion and velocity. The last, based on the above work, we will study the new electromagnetic characteristics and functionalities which come from the resonance induced quantum-like coherent effect in more complex micro-nano structures composed of more mode units (bright modes/dark modes/bright modes and dark modes), e.g., multiple dynamic controllable PIT. This study not only realizes the low loss and fast dynamic response of PIT, analogy reproduces lots of quantum coherence effects, but also is instructive for development of ultra micro optical devices, such as ultra micro sensor, slow wave device and so on.

近期研究表明石墨烯是一种优秀的等离激元材料，具有损耗低、电导率大范围可调、非常大的三阶非线性光学响应等特点，是当前光电子学领域前沿研究方向之一。本项目围绕石墨烯构建的微纳结构，研究其中共振结构(指可被电磁波直接激发和不能直接激发的亮模和暗模)之间耦合引起的等离激元诱导透明(简称PIT)及其动态调控。拟开展的研究工作包括：1）石墨烯微纳结构中共振诱导干涉的物理机理及其中PIT的实现；2）石墨烯电导率的变化、非线性特性对PIT动态调控的动力学行为，并深入研究由此引起的对波的色散、波速等输运特性的调控；3）在上述工作基础之上，研究多模式单元（亮模/暗模/亮模和暗模）级联的更复杂石墨烯微纳结构中共振诱导的类量子相干效应带来的电磁新特性和功能，如，多重动态可调的PIT。此研究不仅可实现低损耗、动态响应速度快的PIT、类比再现许多量子相干效应，而且对超微型传感器、慢波器等相关器件的研制具有指导意义。

众所周知，等离激元诱导透明（简称PIT）是当今量子光学及其交叉学科的研究热点，具有重要的应用价值。近年来，科研工作者主要利用具有表面等离激元特性的金属构建人工微纳结构来实现PIT现象。但金属具有损耗大，不能动态可调等缺点在一定程度上限制了PIT效应在光学领域的应用。近期研究发现石墨烯在可见光和红外波段可激发表面等离激元，并且具有损耗低、动态可调、高局域性、易制备等优异特性。因此，本项目围绕石墨烯微纳结构中的等离激元诱导透明效应及其动态调控展开研究。取得的主要研究成果主要包括：1）设计研究了一可产生非常强健，不敏感于入射波频率及背景费米能改变的深亚波长聚焦的石墨烯微纳结构。2）研究设计了一可产生单向PIT行为的石墨烯微纳结构。3）研究设计一种由多个等离激元诱导透明单元构建的动态可调的多通道阻带石墨烯等离激元滤波器。4）研究设计了一种可产生PIT现象但产生机制不同于传统机制的石墨烯微纳结构。该结构中PIT现象的产生来源于具有失谐频率的石墨烯带之间的杂交共振。5）研究设计了可产生双PIT的石墨烯微纳结构。6）在本项目的资助下我们还在相关领域进行了拓展研究：通过研究设计在由超导体组成的微纳结构中实现了布洛赫震荡、研究设计了一种具有多种功能的光剑电磁超表面透镜等。上述研究成果不仅可实现低损耗、动态响应速度快的PIT、类比再现许多量子相干效应，而且对超微型传感器、慢波器等相关器件的研制具有指导意义。