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