title: Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam.
abstract: Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 10(5) W/cm(2). The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime.
authors.affiliation: Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.|Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.|Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.
authors.forename: Sen
authors.initials: S
authors.lastname: Gong
authors.affiliation: Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.|Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.
authors.forename: Min
authors.initials: M
authors.lastname: Hu
authors.affiliation: Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.|Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.
authors.forename: Renbin
authors.initials: R
authors.lastname: Zhong
authors.affiliation: Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.|Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.
authors.forename: Diwei
authors.initials: D
authors.lastname: Liu
authors.affiliation: Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.|Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.
authors.forename: Xiaoxing
authors.initials: X
authors.lastname: Chen
authors.affiliation: Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.|Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.|School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu, 210000, China.
authors.forename: Xinran
authors.initials: X
authors.lastname: Wang
authors.affiliation: Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.|School of Physics and Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2522, Australia.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.|School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu, 210000, China.
authors.forename: Peiheng
authors.initials: P
authors.lastname: Wu
authors.affiliation: Terahertz Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.|Cooperative Innovation Centre of Terahertz Science, Chengdu, Sichuan, 610054, China.
authors.forename: Shenggang
authors.initials: S
authors.lastname: Liu