Two-dimensional plasmonic eigenmode nanolocalization in an inhomogeneous metal-dielectric-metal slot waveguide
D. A. Smirnova+, A. I. Smirnov*, A. A. Zharov+×
+Institute for Physics of Microstructures RAS, 603950 N.Novgorod, Russia
*Institute of Applied Physics RAS, 603950 N.Novgorod, Russia
×National Research University of Information Technologies, Mechanics and Optics, 197101 St.-Petersburg, Russia
Abstract
We show that transverse, with respect to the propagation
direction, local narrowing of a metal-dielectric-metal plasmonic slot
waveguide leads to a two-dimensional surface plasmon nanolocalization and can
squeeze the plasmon eigenmode into a spot with a characteristic size of about
several tens of nanometers. We demonstrate that the simultaneous waveguide
tapering and decreasing transverse narrowing scale make possible an
enhancement of the plasmon propagation distance in comparison with the
homogeneous waveguide. We also find the fundamental limit of 2D plasmon
nanolocalization, which is of the same order as the depth of penetration of the
electromagnetic field into a metal which is actually independent of the field frequency in
the near infrared domain.