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) Frequency at the Brillouin center of the second dispersion band and band gap versus the grating profile factor b for the symmetrical trapezoidal grating. (b) Radiation intensity with frequency at the Brillouin center of the second dispersion band in vacuum and substrate sides versus the grating profile factor b , other parameters are the same as that used in Fig. 2 .