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。

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.