Optical Second-Harmonic Generation with Long-Range Surface Plasmons

Abstract

The first observation of enhanced optical second-harmonic generation due to excitation of the long-range surface plasmon is reported. When the fundamental mode of this plasmon is excited on both surfaces of a thin silver film bounded by a nonlinear quartz crystal and an index-matched liquid, the harmonic generation is over 2 orders of magnitude larger than that due to a single-boundary surface plasmon. Nonlinear excitation of the harmonic long-range surface-plasmon mode is also observed.