为解决石墨烯（甚）长波红外探测器应用中衍射受限、低光谱响应率等关键问题，项目提出利用超材料金属表面等离子体（SP）共振局域场的增强收集能力实现性能增强的（甚）长波红外探测。主要研究内容：i）偏振转换局域SP（LSP）谐振结构、近场增强特性；ii）光栅耦合LSP、SP波（SPP）微F-P腔结构与性能；iii）SP增强吸收结构应用于石墨烯（甚）长波红外探测器、器件物理、性能及调控。其意义：a）LSP、SPP技术把红外辐射汇聚到电极间距远小于辐射波长的探测器光敏元上，突破了衍射极限、提高了器件的光电增益；b）TE与TM间的偏振转换可以实现偏振无关探测；c）光栅衍射或谐振耦合把沿纵向传输的TM辐射转换为沿石墨烯表面的LSP、SPP，产生的光场限制效应、微F-P腔中驻波效应增大了石墨烯的红外吸收率（~50%）；d）超材料结构同时作为器件的电极，易于光电信号采集、更提高了器件的集成度和可靠性。

To figure out key issues including the diffraction limit and low responsibility for graphene (extra) long-wave infrared detector, we propose a utilization of enhanced absorption structure based on the metal surface plasmons (SP) technology to realize graphene photodetector with the performances improved significantly. The investigation mainly includes: i) Resonance structure of polarization-transformed metamaterial and near-field enhancement based on localized SP (LSP); ii) Metal F-P micro resonator structure and characteristic of grating-coupling metamaterial based on LSP & surface-plasmonic polaritons (SPP); and iii) their applications for polarization-sensitive or insensitive graphene photodetector, device physics, and performance and its controlling. This arrangement has merits of: a) as the incident irradiation is highly concentrated within the metal gap of metamaterial by LSP or SPP technology, the photo-sensitive pixel can be designed in a smaller size beyond the diffraction limited, and shorter space from two electrodes will lead to an increased photo-electron gain; b) polarization-insensitive photodetector can be realized by transformation between TE and TM polarizations; c) as transmitting photo-energy of TM-polarized radiation flow in longitudinal direction is turned to that of LSP & SPP in transverse direction and along the graphene surface, an introduced confinement to the optical field and standing-wave effect in the micro resonator increases the infrared absorption (~50%); d) the metamaterial also worked as the electrodes. This arrangement is easy for electrical signal readout, and increases integration and reliability for the devices.