title: Reflected fourth-harmonic radiation from a centrosymmetric crystal.
abstract: We present measurements of fourth-harmonic generation in reflection from the interface between two centrosymmetric media [Si(001)- SiO(2)] , using femtosecond pulses well below damage threshold. Analyses of signal amplitudes, rotational anisotropy, and sensitivity to surface roughening reveal that the surface dipole fourth-harmonic contribution dominates the bulk quadrupole contribution much more strongly than for second-harmonic generation.
authors: Y S
authors: YS
authors: Lee
authors: M C
authors: MC
authors: Downer