Plasmonic slot waveguides

Document Type

Article

Publication Date

10-1-2008

Abstract

We investigate the properties of the modes supported by three-dimensional subwavelength plasmonic slot waveguides. We show that the fundamental mode supported by a symmetric plasmonic slot waveguide, composed of a subwavelength slot in a thin metallic film embedded in an infinite homogeneous dielectric, is always a bound mode. Its modal fields are highly confined over a wavelength range extending from zero frequency to the ultraviolet. We then show that for an asymmetric plasmonic slot waveguide, in which the surrounding dielectric media above and below the metal film are different, there always exists a cutoff wavelength above which the mode becomes leaky. In addition, we investigate the properties of compact couplers between high-index contrast dielectric slab waveguides and two-dimensional metal-insulator-metal sub-wavelength plasmonic waveguides. We show that a coupler created by simply placing a dielectric waveguide terminated fl{ligature}at at the exit end of a plasmonic waveguide can be designed to have a transmission efficiency of ~70% at the optical communication wavelength. We also show that the transmission efficiency of the couplers can be further increased by using optimized multisection tapers. In both cases the transmission response is broadband. In addition, we investigate the properties of a Fabry-Perot structure in which light is coupled in and out of a plasmonic waveguide sandwiched between dielectric waveguides. © 2009 by Pan Stanford Publishing Pte. Ltd. All rights reserved.

Publication Source (Journal or Book title)

Plasmonic Nanoguides and Circuits

First Page

159

Last Page

187

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