Active Plasmonics with Surface Acoustic Waves in LiNbO3-Metal Hybrid Structures

Neben Licht, das sich frei in der Umgebung ausbreitet, existieren auch optische Moden, die an Metalloberflächen gebunden sind. Die starke räumliche Lokalisierung der Moden macht diese zu interessanten Kandidaten für optische Anwendungen. Das Projekt zielt auf die Konversion von Licht in oberflächengebundene optische Moden mittels hochfrequenter Schallwellen.

Collective electronic excitations at a metal-dielectric interface and, in particular, surface plasmon polaritons (SPPs) play a key role in nanophotonics. Gratings represent a straightforward tool to overcome the wavevector mismatch between light and SPPs and to achieve efficient coupling into surface-bound modes. Active control of the coupling is difficult because it is dictated by the geometry of the grating and the incident radiation. Here, we study semiconductor-metal microstructures that utilize gratings induced by surface acoustic waves (SAWs) to achieve active plasmonic functionalities. The prototypical device is a SAW driven SPP launcher. A radio-frequency voltage is applied to an interdigital transducer on a piezoelectric LiNbO3 chip and induces a propagating SAW. This excitation causes a periodic deformation of the surface of an adjacent gold film. This electronically induced transient structure enables to convert near-infrared light into propagating SPP modes. More specifically, we want to (i) optimize the above concept in terms of efficiency and usable wavelengths and (ii) use SAWs to modulate existing passive plasmonic devices. It also serves as preparatory work for the study of the time-reverse effect: the excitation of SPP modes on a piezoelectric substrate should come along with the generation of hypersound waves.

Antragsteller

Technische Universität Dortmund: Prof. Dr. Markus Betz (Experimentelle Physik II)

Förderlinie: Anschubförderung
Fördersumme: 48.800 Euro
Laufzeit: 01.10.2010 – 30.09.2011

Ansprechpartner

Prof. Dr. Markus Betz
TU Dortmund
Fakultät für Physik
Experimentelle Physik II
Otto-Hahn-Str. 4
44221 Dortmund

Telefon: 0231-7553670
markus.betz (at) tu-dortmund(dot)de