电子注激发石墨烯表面等离子体波产生相干太赫兹辐射的研究

在太赫兹科学技术迅速发展过程中，太赫兹辐射源仍是一个亟待解决的问题。石墨烯表面等离子体波作为近年来科学技术研究的热点，其频率正好在太赫兹波段，而电子注能够有效的激发表面等离子体波，因此结合电子注与石墨烯表面等离子体波极有可能成为发展太赫兹辐射源的一个新突破口。然而石墨烯表面等离子体波与自由空间传输波之间存在巨大的波矢不匹配，这成为制约其应用于太赫兹辐射源的主要瓶颈。本项目从理论和实验两方面研究石墨烯表面等离子体波波矢匹配问题及其在电子注激励下产生太赫兹辐射的物理机制。具体内容包括：通过研究石墨烯表面等离子体波色散特性，探索调控其波矢的机制从而实现波矢匹配；采用电磁理论分析电子注激发表面等离子体波产生太赫兹辐射的物理机制和辐射特性；实验研究基于电磁仿真优化的石墨烯结构色散特性，验证理论分析。本项目旨在探索基于电子注激发石墨烯表面等离子体波的太赫兹辐射新机理，为发展新型太赫兹辐射源奠定基础。

Terahertz (THz) scicence and technology has developed rapidly, but lacking of the required THz radiation sources is still an urgent problem.Graphene surface plasmon polaritons (SPPs) are the most attracting hotspot in the recent research of science and technology. Their frequecies lie in the THz regime, and can be efficiently excited by moving electron beam, therefore, combinating the electron beam and SPPs is very likely to be a new breakthrough for the development of THz radiation sources. However, the large dismatch of the wavevector between SPPs and the electromagnetic waves in the free-space restricts the application of SPPs on the THz radiation sources. This project studies the problem of wavevector match of graphene SPPs and the physical mechanism of THz radiation from SPPs excited by an electron beam by the theoretical and experimental methods. The research contents include the study of the dispersion characteristics of graphene SPPs, the exploration of the method of wavevector match, the analysis of the underlying physics of THz generation by the electromagnetic theory, the optimization of the simulation results, and the experimental research of dispersion features of SPPs. This project aims at exploring a THz radiation source based on the electron beam excited graphene SPPs, and paving a way to develop novel THz radiation sources.