Enhanced second-harmonic generation is observed from silver and gold island films, and from regular arrays of Ag particles produced by microlithographic techniques. Enhancements are interpreted in terms of an electromagnetic model involving localized surface-plasma oscillations. The regular arrays allow the separation of fundamental and second-harmonic beams by a novel grating effect.

• Received 20 January 1981

DOI:https://doi.org/10.1103/PhysRevB.24.849