Near-field imaging of surface plasmon-polariton guiding in band gap structures at telecom wavelengths.

Using a collection near-field microscope, we image interaction of surface plasmon-polaritons (SPPs) excited locally at telecom wavelengths with periodic triangular arrays of gold bumps placed on gold film surfaces. We observe the inhibition of SPP propagation into the arrays within a certain wavelength range depending on their period and orientation, i.e., the band gap (BG) effect, as well as the SPP propagation along bent channels cut through these arrays. Prospects and challenges in realization of compact and efficient SPPBG waveguiding structures are discussed.