Second harmonic generation by crossed surface plasma waves over a metallic surface

Abstract

Excitation of second harmonic radiation by nonlinear mixing of two surface plasma waves (SPWs), propagating at an angle to each other over an air–metal interface, is investigated. The SPWs exert a ponderomotive force on electrons, driving a nonlinear surface current and producing the second harmonic. Depending upon the angle between the SPWs and the electron density of metals, the excited radiation could be a radiation mode or a surface mode. The latter requires a surface ripple for phase matching. The efficiency of radiative second harmonic increases with the free electron density of the metal. It is sensitive to the angle between the interacting SPWs. The surface mode second harmonic is relatively more efficient.