报告题目：Surface Plasmon Polaritons and Optical Bistability in Graphene in Far-infrared and Terahertz Regime (太赫兹波段表面等离激元及石墨烯中的光学双稳态)
报 告 人：张潮 教授(卧龙岗大学（澳大利亚）)
报告时间：2017年11月28日（周二）10:00
报告地点：校本部G309
邀请人：金钻明
邀请单位：8455新葡萄场网站物理系
报告摘要：Due to the nature of graphene’s conductivity, both TE (transverse electric) and TM (transverse magnetic) modes of surface plasmon polaritons are supported on a graphene sheet. We show that both the intraband optical and interband conductivity in graphene becomes nonlinear under a moderate electrical field and in the far-infrared regime. The energy of surface plasmon polaritons is enhanced and enters the radiation zone of dielectrics. As a result, the surface plasmon polariton can be directly transformed to ration without the need of structural modification. The radiation intensity of an electron beam exited surface plasmon polarition can be two orders of magnitude high than that without a graphene layer. The mechanism opens a possibility of generating high powered and tunable radiation sources in FIR and terahertz regime for imaging and sensing applications. we show that for an opaque incident light on the graphene between two dielectrics, reflectivity exhibits bistability due to the nonlinear coupling of the incident light and the surface plasmon polariton. The transmitted light can be two orders of magnitude stronger than the incident light. Finally we discuss some recent work in charge dynamics in three dimensional Dirac semi-metals.
