We present an analytical study of surface plasmon polariton (SPP) propagation about a circular bend formed by the interface between a metal and a dielectric with the metal occupying the inner volume. It is shown that in the short wavelength limit, the problem is essentially analogous to scattering from a 1D finite potential well, with standard expressions for the transmittance and reflectance. In certain cases, we find that propagation on nonplanar interfaces may result in lower losses than on flat surfaces, contrary to expectation. We also show that the same approach is valid when the metal occupies the outer volume, such that in the 1D approximation SPPs propagating around such bends do not radiate. An upper bound for the transmittance, valid even when our approximation breaks down, is also derived. This is found to depend nonmonotonically on the bend radius, allowing increased transmission with decreasing radius. We further present a numerical study using the finite- difference time-domain method and show that it is consistent with theoretical predictions. We also show that the introduction of a microcavity plasmon resonator could significantly enhance the transmission.

Date Published: 31 March 2005
PDF: 8 pages
Proc. SPIE 5728, Integrated Optics: Devices, Materials, and Technologies IX, (31 March 2005); doi: 10.1117/12.589892

Published in SPIE Proceedings Vol. 5728:
Integrated Optics: Devices, Materials, and Technologies IX
Yakov Sidorin; Christoph A. Waechter, Editor(s)