Plasmonic modes of extreme subwavelength nanocavities.
We study the physics of a new type of subwavelength nanocavities. They are based on U-shaped metal-insulator-metal waveguides supporting the excitation of surface plasmon polaritons. The nanocavity arrays are excited by plane waves at either a normal or oblique incidence. Because of their finite length, discrete modes emerge within the nanocavity. We show that the excitation symmetry with respect to the cavity ends permits the observation of even and odd modes. Our investigations include near- and far-field simulations and predict a strong spectral far-field response of the comparably small nanoresonators. The strong near-field enhancement observed in the cavity at resonance might be suitable to increase the efficiency of nonlinear optical effects and quantum analogies and might facilitate the development of optical elements, such as active plasmonic devices.
Petschulat
Jörg
J
Institute of Applied Physics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743, Jena, Germany. joerg.petschulat@uni-jena.de
Helgert
Christian
C
Steinert
Michael
M
Bergner
Norbert
N
Rockstuhl
Carsten
C
Lederer
Falk
F
Pertsch
Thomas
T
Tünnermann
Andreas
A
Kley
Ernst-Bernhard
EB