Interference of surface plasmon polaritons from a “point” source

Abstract

The interference patterns of the surface plasmon polaritons (SPPs) on the metal surface from a “point” source are observed. Innovation to the previous works, a point SPPs source with diameter of 100 nm is generated at the freely chosen positions on Au/air interface using near field excitation method. Such a point source provides good enough coherence to generate obvious interference phenomenon. This point SPPs source may be useful in the investigation of plasmonics for its high coherence, deterministic position, and minimum requirement for the initial light source.