Research On The Theory And Method Of Terahertz Radiation Based On Graphene

THZ wave,of which the wavelength is between 0.03 mm ~ 3 mm and the corresponding frequency is between 0.1 ~ 10 THZ electromagnetic wave,is the key to connect electronics and photonics band with outstanding application value in science and technology.Graphene,a new type of two-dimensional single crystal material,is currently the focus of the study of physical science and material science.Its excellent optical coupling,the nature of the electron transport,electromagnetism and other novel properties make it heavily favored today.Graphene has many novel physical phenomena and potential applications,including the THz science and application prospect.Because of the linear energy level structures and negative conductivity in THz spectrum,grapheme can be used as THz source materials and magnified.The main content of this paper include:The physical mechanism of graphene terahertz radiation has been expounded.Necessarily,we make a discussion on surface plasma of graphene,Cherenkov radiation,and the transmission properties of photonic crystals,this three related parts.The numerical simulation method has been detailed introducted,including the selection of direct solution of Maxwell's equations of Cherenkov radiation method.We also compare the finite difference time domain method,the plane wave expansion method and the transfer matrix method.The transfer matrix method is preferred to calculate photonic crystal band structure.Analyses of electromagnetic characteristics of graphene,the movement speed of electron beam,and the space of a photonic crystal structure on the influence of radiation frequency has been made.The Fermi level of graphene is found to be proportional to the frequency of graphene surfaceplasma.By adjusting photonic crystals filling rate,we can get 7 ~ 18 THz frequency modulation range and 8.8 ~ 9.4 THz frequency modulation range by adjusting the movement speed of electron beam.From the viewpoint of energy conservation,this paper expounds the mechanism of radiant energy.By a numerical simulation,we found that when ?/c = 0.0432,the radiation energy is maximum.If the valueof charge density of electron beam is fixed ? = 100 PCS/cm,the radiant energy can reach 10-3?J/cm2 order of magnitude.