Single layers of quasi-spherical metal nanoparticles of uniform and control
led size were fabricated by evaporation-condensation in ultrahigh vacuum, e
xploiting the partial wetting of Ga with respect to the underlying SiOx mat
rix. The net linear and nonlinear optical response of such self-assembled l
iquid Ga nanoparticles was determined using CW optical methods as well as p
ulsed laser excitation. Second, harmonic generation was observed in transmi
ssion using femtosecond laser pulses. The fluence, polarization and azimuth
angle dependence as well as the second-harmonic (SH) signal dependence on
particle size are presented and discussed. (C) 2001 Elsevier Science B.V. A
ll rights reserved.