表面等离激元增强自由电子激励全息超材料的渡越辐射机理研究

The near infrared radiation investigation with free-electron driven subwavelength nanostructures is the key issue of free-electron based infrared source. However, how to enhance the infrared transition radiation with surface plasmon is one of the most difficult problems. In this project, we will investigate how the surface plasmon will enhance the transition radiation with free-electron impacting noble metals. The phase gradient dipoles array model is developed to simulate the free electron impacting effect and demonstrate the mechanism how the generated surface plasmon will interfere with the transition radiation in the near field. Besides, the infrared radiation efficiency dependence on different surface plasmon initial phase and amplitude attenuation generated holographic metamaterial is also taken into consideration. With experimental study, the surface plasmon enhancement of infrared radiation is observed and at least two radiation beam will be realized. The fulfillment of this project will significantly guide free-electron driven surface plasmon enhanced radiation application and push the development of integrated micro- and nanoscale infrared sources.

自由电子激励亚波长微纳结构产生的近红外辐射是基于自由电子微纳尺度红外光源的核心研究问题，然而近场表面等离激元如何增强红外渡越辐射是目前的一大难点。本项目拟开展自由电子垂直激发贵金属产生的表面等离激元的增强红外辐射机理研究，通过建立相位梯度偶极子阵列模拟自由电子束激发贵金属等离激元，阐明红外辐射中表面等离激元与渡越辐射的耦合机理，探寻不同近场初始相位和表面等离激元衰减振幅对全息超材料结构中红外辐射效率的影响。通过实验研究，观测表面等离激元对红外辐射的增强效果，实现两个近红外波长(800nm和700nm)的波束辐射。本项目的完成对利用自由电子激发表面等离激元超材料产生的近红外辐射作为可集成微纳光源有重要的指导意义。

纳米尺度光源是实现片上集成系统的核心元件。本项目基于人工微结构具有强大的光场调控能力，研究了亚波长尺度微纳结构与光子相互作用机制，阐明自由电子激励超表面的光子辐射规律，通过微结构的相位单元将可以实现辐射光子波长、偏振、方向、波前形式等参量的选择性控制。本项目全面完成研究内容，实现左旋或右旋圆极化光的完全独立出射，获得1个或2个分立光束，通过单元个数控制实现了不同拓扑荷数光束的强度增强，达成预定目标。在该项目的支持下，累计发表SCI 期刊论文13 篇。部分成果发表在Science Advances、Nanoscale、Optics Express、Optics Letters 等国际知名期刊上面。申请发明专利2项；项目负责人获得所在单位2018-2019年度优秀青年标兵称号，入选2020年上海青年科技启明星计划，担任国际期刊Journal of Physics D: Applied Phyiscs顾问委员会委员。