Masanobu HARAGUCHI¹, David F. P. PILE^1,2, Toshihiro OKAMOTO¹, Masuo FUKUI¹ and Dmitri K. GRAMOTNEV²

¹Department of Optical Science and Technology, The University of Tokushima, 2-1 Minami-josanjima, Tokushima 770-8506, Japan
²School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia

(Received November 15, 2005; Accepted March 3, 2006)

We have numerically shown the existence of coupled wedge plasmons (CWPs) which propagates along a nano gap of a twin metal wedge. The CWPs are formed by wedge plasmons which can interact with each other. The dispersion relations of the wavenumber, propagation distance, and beam area of CWPs, are described and show that the characteristics of CWPs are similar to those of wedge plasmons and of gap plasmons. We also propose a new plasmon waveguide composed of twin metal wedges with a nano gap.

Key words: plasmon, plasmon waveguide, coupled wedge plasmon, metal wedge, nano gap, silver, finite difference time domain