Second harmonic generation in Ga nanoparticle monolayers

Ga nanoparticle monolayers formed by evaporation-condensation in ultrahigh vacuum and embedded in a transparent SiOx matrix generate second harmonic ( SH) signals in transmission and reflection when illuminated by a 150 fs, 80 0 nm laser pulses. The observed SH light exhibits a critical dependence on input and output polarizations, angle of incidence and azimuthal orientatio n of the samples. The results lead to a consistent picture of shape and ori entation of the nanoparticles. Linear transmittance spectra in the visible range support these findings and the observed size dependence of the SH sig nal.