Long-Range Surface Plasmon Polaritons in Metal Films Bounded by Similar-Refractive-Index Materials

Abstract

We have numerically and experimentally investigated the propagation characteristics of surface plasmon polaritons (SP’s) in metal films bounded by materials with very similar refractive indices. The calculation indicates that the SP’s can propagate over macroscopic distances in the visible region. ATR experiments for angle scans (glass prism-index matching oil-Ag film-Pyrex glass) have shown that a propagation length of ∼200 μm can be readily gotten at 632.8 nm wavelength under an appropriate condition.