错位双层金属光栅的光学特性、物理原理和应用研究

Metal nanoparticales and nanostructures have attracted lots of attention, because they can focus light into a nanoscale region, which have important applications in integrated optics and biosensors. In this application, we will study the optical properties and physical mechanism of the dislocated double-layer metal gratings. Especially, we will study and disclose the interaction of the localized surface plasmon resonances of the double-layer metal gratings with their spacing larger than the near-field interaction region, but shorter than the far-field interaction region. We will also study the application of the dislocated double-layer metal gratings in the field of optoelectronics, such as unidirectional coupling, refractive index sensing, and gas sensing. We will experimentally test the optical properties of the dislocated double-layer metal gratings. Based on the above researches, we will design and fabricate the prototypes of omnidirection coupler, refractive index and gas sensors. At present, most of the researches are focused on the interaction of the localized surface plasmon resonances in the near field region, the interaction of the localized surface plasmon resonances when the distance of the resonances is larger than the near-field interaction spacing but shorter than the far field interaction spacing will be studied in this proposal, which could have a contribution to the understood of the interaction of the localized surface plasmon resonances. Meanwhile, the dislocated double-layer metal gratings can also be found application in various fields, such as unidirectional coupler, refractive index and gas sensors, which indicates that our proposal will also have a important contribution to the optoelectronics devices.

金属纳米颗粒和微纳结构引起的表面等离子体谐振可以将光场聚焦于纳米尺度，在集成光子学、生物探测器等领域具有非常重要的应用，是当前的一个研究热点。本申请项目中，我们将研究错位双层金属光栅的光学特征和相关的物理原理，尤其是双层金属光栅的间距在既非近场又非远场范围内时的局域表面等离子体谐振的相互作用，探索这种相互作用产生的光学新现象和物理原理；探索错位双层金属光栅在光电子器件中的应用机理，比如在单向耦合、折射率传感，气体探测等方面的应用；实验上验证错位双层金属光栅的光学特性，同时研制相关的原型器件。当前局域表面等离子体谐振之间的相互作用研究主要集中在近场区，本项目对局域表面等离子体谐振之间在既非近场又非远场相互作用的探索，具有科学意义。同时对这种相互作用的应用研究，将丰富光电子器件的种类和范围，比如单向耦合器、折射率探测器、氢气探测器等，所以也具有较好应用价值。

通过对双层错位/非错位金属光栅的深入研究，我们得到如下结果。1）阐明了双层金属光栅的耦合机制，上下层光栅之间可以通过局域表面等离激元进行耦合，也可以通过上下层光栅构成的有效层之间法布里-珀罗腔进行耦合，也可以通过光栅的衍射效应进行耦合，不同的耦合模式之间也可以相互作用，也可以通过错位效应引起的上下层光栅之间的耦合光的相位差，调控光在光栅间隔层形成的波导中的传播方向等，从而形成非常复杂的机制。2）通过对这些机制的调控，我们实现了高FOM的折射率传感器；3）设计并实验演示了表面等离激元单向传感器，以及偏振可控的表面等离激元单向/多向耦合器；4）通过金纳米草和上下层光栅之间的耦合，实现了高均匀性和高增强因子的Raman散射衬底。同时发现量子点的发光增强的偏振依赖性和金颗粒阵列的偏振散射依赖性一致，但是量子点发光的寿命减少（发射几率的增大）和偏振无关的现象，并解释了其物理机理。5）通过对钯膜包覆金颗粒表面，形成了高效率的氢气传感器，同时设计了和演示了高灵敏度的光子晶体微腔气体传感器；6）进一步，我们发展了纳米制备工艺，提出并演示基于导模调控的全聚合物微流控反射率波器。所得成果发表了14篇SCI论文，其中影响因子大于10的论文2篇，影响因子大于7的论文3篇，科学院一区研究论文5篇，其中一篇论文发表在新刊物Nanoscale Horizons, 被引为封面论文。并作了6次国际会议的邀请报告。在此过程中，博士生沈杨的博士论文获得国家光学工程学会的优秀博士论文奖（首届）。同时该项目执行过程中的多篇论文也被用于申报2017年广东省科学技术奖（自然科学奖），获二等奖。