skip to main content

SciTech ConnectSciTech Connect

Title: Graphene-based terahertz tunable plasmonic directional coupler

We propose and numerically analyze a terahertz tunable plasmonic directional coupler which is composed of a thin metal film with a nanoscale slit, dielectric grating, a graphene sheet, and a dielectric substrate. The slit is employed to generate surface plasmon polaritons (SPPs), and the metal-dielectric grating-graphene-dielectric constructs a Bragg reflector, whose bandgap can be tuned over a wide frequency range by a small change in the Fermi energy level of graphene. As a graphene-based Bragg reflector is formed on one side of the slit, the structure enables SPP waves to be unidirectionally excited on the other side of the slit due to SPP interference, and the SPP waves in the Bragg reflector can be efficiently switched on and off by tuning the graphene's Fermi energy level. By introducing two optimized graphene-based Bragg reflectors into opposite sides of the slit, SPP waves can be guided to different Bragg reflectors at different Fermi energy levels, thus achieving a tunable bidirectional coupler.
Authors:
; ; ;  [1] ;  [2] ; ;  [3] ; ; ;  [4]
  1. Institute of Mathematics and Physics, Central South University of Forestry and Technology, Changsha 410004 (China)
  2. College of Science, Jiujiang University, Jiujiang 332005 (China)
  3. Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, Hunan University, Changsha 410082 (China)
  4. National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China)
Publication Date:
OSTI Identifier:
22311349
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BRAGG REFLECTION; DIELECTRIC MATERIALS; ENERGY LEVELS; FERMI LEVEL; FILMS; FREQUENCY RANGE; GRAPHENE; INTERFERENCE; METALS; NANOSTRUCTURES; PLASMONS; POLARONS; SUBSTRATES; SURFACES; SWITCHES