Plasmonic and magnetic effects accompanying optical second-harmonic generation in Au/Co/Au nanodisks

Optical second-harmonic (SH) generation in Au/Co/Au sandwich-like nanodisks is studied, using several experimental techniques, at SH frequency being close to that of the plasmon resonance in the system. The dependences of the relative amplitude and phase of the magnetization-induced SH component on the angle of incidence are found to significantly differ from those measured for a continuous Au/Co/Au trilayer film. A phenomenological description of the observed effects is proposed, with special emphasis on resonant excitation of the local plasmon modes by the nonlinear sources induced in the nanodisks.