The use of specific symmetry properties of optical second-harmonic generati
on (the s, s-exclusion rule) has allowed us to observe high-contrast hyper-
Rayleigh interference patterns in completely diffuse light, an effect that
has no analog in the case of linear (Rayleigh) scattering. (C) 1999 Optical
Society of America. OCIS codes: 290.5870, 120.3180, 310.6860, 260.3160.