Experimental observation of percolation-enhanced nonlinear light scattering from semicontinuous metal films - art. no. 125106

Strongly enhanced second-harmonic generation (SHG), which is characterized by a nearly isotropic intensity distribution, is observed for gold-glass fi lms near the percolation threshold. The diffuselike SHG scattering, which c an be thought of as nonlinear critical opalescence, is in sharp contrast wi th highly collimated linear reflection and transmission from these nanostru ctured semicontinuous metal films. Our observations, which can be explained by giant fluctuations of local nonlinear sources for SHG due to plasmon lo calization, verify recent predictions of percolation-enhanced nonlinear sca ttering.