title: Spectrally wide-band terahertz wave modulator based on optically tuned graphene.
abstract: New applications in the realms of terahertz (THz) technology require versatile adaptive optics and powerful modulation techniques. Semiconductors have proven to provide fast all-optical terahertz wave modulation over a wide frequency band. We show that the attenuation and modulation depth in optically driven silicon modulators can be significantly enhanced by deposition of graphene on silicon (GOS). We observed a wide-band tunability of the THz transmission in a frequency range from 0.2 to 2 THz and a maximum modulation depth of 99%. The maximum difference between the transmission through silicon and GOS is Δt = 0.18 at a low photodoping power of 40 mW. At higher modulation power, the enhancement decreased due to charge carrier saturation. We developed a semianalytical band structure model of the graphene-silicon interface to describe the observed attenuation and modulation depth in GOS.
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger-Strasse, 67663 Kaiserslautern, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Weis
authors.forename: Juan L
authors.initials: JL
authors.lastname: Garcia-Pomar
authors.forename: Michael
authors.initials: M
authors.lastname: Höh
authors.forename: Benjamin
authors.initials: B
authors.lastname: Reinhard
authors.forename: Alexander
authors.initials: A
authors.lastname: Brodyanski
authors.forename: Marco
authors.initials: M
authors.lastname: Rahm
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012031:Refractometry / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*; D055053:Terahertz Radiation
chemical_list: D006108:Graphite