石墨烯双曲超材料中的太赫兹渡越辐射

Terahertz Transition Radiation in Graphene Hyperbolic Meta-Materials

本文理论预期了一种中心频率可调、高功率密度的宽频太赫兹辐射。研究表明,该辐射来源于自由电子垂直穿过多层石墨烯-介质复合结构时激发的表面等离子体激元的相互耦合。数值计算结果表明,该辐射所需自由电子能量极低;辐射频率几乎覆盖了整个太赫兹频段,其中心频率可通过调节石墨烯化学势进行调谐;且由于表面激元的场增强作用,该辐射场强较普通渡越辐射大两个数量级以上。因此,本文所提出的机理有利于开发小型化的宽频可调片上太赫兹辐射源。

A high-power density broadband terahertz radiation with adjustable center frequency is theoretically predicted.The research reveals that the radiation comes from the coupling of surface plasmonpolaritons excited by free electrons passing vertically through the multilayer composite structure of graphene and dielectric.The numerical simulation results show that the free electron energy required for the radiation is very low;the radiation frequency covers almost the entire terahertz band,and its central frequency can be tuned by adjusting the chemical potential of graphene;and due to the field enhancement effect of surface plasmonpolaritons,the radiation field intensity is more than two orders of magnitude higher than that of ordinary transition radiation.Therefore,the mechanism proposed is conducive to the development of miniaturized broadband on-chip terahertz radiation sources with tunable frequency.