Characterization of long-range surface plasmon-polariton in stripe waveguides using scanning near-field optical microscopy

Abstract

Propagation characteristics of long-range surface plasmon-polariton (LRSPP) guiding along thin gold stripes embedded in polymer cover layers are investigated by scanning near-field optical microscopy (SNOM). It is shown that the characterization of samples with cover layers up to 10 μm is feasible in the optical communication wavelength range. We found that the spatial dimension of the optical signal is directly related to the geometrical dimension of the guiding layer, and the light collected by the SNOM is scattered light from the surface and not the evanescent field. We also discuss the limitations of the SNOM technique for the characterization of LRSPP modes. © 2007 American Institute of Physics.