Who: Yuliy Bludov (Center for Physics, University of Minho, Portugal)
Place: Donostia International Physics Center (DIPC). Paseo Manuel de Lardizabal, 4, Donostia
Date: Thursday, 26 March 2015, 12:00
Linear and nonlinear surface polaritons in graphene-based structures
Center for Physics, University of Minho, Portugal
It is shown, that unique property of graphene ? an ability to control its doping (and conductivity) through the external electrostatic gating ? opens a possibility to tune dynamically the dispersion properties of surface
plasmon-polaritons in graphene and control their excitation both in the attenuated total reflection (ATR) and in periodical diffraction grating schemes. In particular, graphene layer deposited on substrate with periodically modulated thickness or dielectric constant demonstrates band-gap structure of the spectrum, where positions of gap and band edges can be effectively tuned by external gate voltage. Also by adjusting the external gate voltage of ATR structure with graphene layer, it is possible to tune the reflectance of the incident electromagnetic wave from total absorption to total reflection, as well as the polarization of reflected wave.
We also demonstrate that nonlinear dielectric, covered with graphene, can support and stabilize nonlinear transverse electric (TE) plasmon polaritons. We demonstrate that these nonlinear TE modes have a
subwavelength localization in the direction perpendicular to the surface, with the intensity much higher than that of an incident wave which excites the polariton. We also demonstrate that nonlinear graphene multilayer stack is described by discrete nonlinear Schrödinger equation, and they can support stable discrete TM- polarized plasmon solitons.