Resonant second-harmonic generation in metal–insulator–metal structure

Abstract

Optical second-harmonic generation (SHG) in a metal–insulator–metal (MIM) structure is investigated. The experimental results of the second-harmonic (SH) intensity profile as a function of the angle of incidence indicate that the SH light observed from the MIM structure is mainly from bulk nonlinear polarization (quadrupoles or magnetic dipoles) in the metallic layer rather than from the nonlinear electric dipoles at the metallic surface (surface SHG). This is because the SH fields from the metallic surfaces in contact with the insulator layer are canceled and the SH light from the bulk nonlinear polarization (bulk SHG) is dominantly observed. A comparison with the SH intensity from a quartz crystal used as a standard reveals that the susceptibility for the bulk nonlinear polarization is found be in the order of 102 pm/V.