Tunable terahertz radiation from arbitrary profile dielectric grating coated with graphene excited by an electron beam

Zhao Tao^a),^b), Zhong Ren-Bin†^a),^b), Hu Min^a),^b), Chen Xiao-Xing^a),^b), Zhang Ping^a),^b), Gong Sen^a),^b), Liu Sheng-Gang^a),^b)

(a) Schematic of graphene situated on a one-dimensional dielectric grating with arbitrary profile. (b) Multi-layer model of trapezoidal grating, the grating region is divided into M layers with equal thickness, and each layer approximates to be with rectangular profile.