SCL Seminar by Jorge Pedrós

Scientific Computing Laboratory seminar will be held on Friday, 21 October 2016 at 14:00 in “Dr. Dragan Popović” library reading room of the Institute of Physics Belgrade. The talk entitled

"Active plasmonics in graphene using surface acoustic waves"

will be given by Prof. Jorge Pedrós (Institute of Optoelectronic Systems and Microtechnology, Universidad Politécnica de Madrid, Spain).

Abstract of the talk:

In comparison to conventional plasmonics, the tunability of graphene plasmons offers unique possibilities for applications in metamaterials, quantum optics control, biosensing, and light harvesting. However, most of the techniques developed so far for coupling light into graphene plasmons do not offer active control of the coupling mechanism. We have recently demonstrated a method to couple far-field radiation into propagating graphene plasmons by periodically deforming a continuous graphene sheet with an electrically generated surface acoustic wave (SAW) [1]. This mechanism allows to create a tunable optical grating without the need of any patterning in either the graphene layer or the substrate, thus eliminating edge scattering and fragility issues. An interdigital transducer (IDT) on a piezoelectric film is used to launch the SAW across the graphene sheet. By diffraction at the grating, incident laser light can overcome the momentum mismatch and excite propagating plasmons in the graphene sheet. This approach permits to efficiently control the graphene plasmons both temporally and spatially. Thus, the propagating plasmons can be switched electrically via the high-frequency signal at the IDT and the generated plasmon wavefronts can be shaped by tailoring the IDT design.  Moreover, the IDT technology ensures the easy fabrication of graphene plasmonic devices by the microelectronics industry.

In this talk, we will briefly review the different methods used so far for the generation of graphene plasmons, before presenting the details of our novel SAW-assisted approach. We will present the hybridized graphene plasmon-phonon dispersion in the graphene/piezoelectric structures, as well as the design and fabrication technology of the plasmonic devices, including the transfer of graphene [2] to various piezoelectric materials. We will finally discuss different SAW-mediated plasmon functionalities based on several engineered device geometries.

Acknowledgements: Financial support from the EU Erasmus+ Programme, EU project SAWTrain (H2020-MSCA-ITN-2014-642688), and Spanish MINECO project GRAFAGEN (ENE2013-47904-C3-1-R).

[1] J. Schiefele, J. Pedrós, F. Sols, F. Calle, and F. Guinea, Phys. Rev. Lett. 111, 237405 (2013).
[2] A. Boscá, J. Pedrós, J. Martínez, T. Palacios, and F. Calle, Sci. Rep. 6, 21676 (2016).