NIR femtosecond laser induced hyper-Rayleigh scattering and luminescence from silver nanoprisms

The nonlinear response of silver nanoprisms (edge length 40 +/- 5 nm and thickness 4.5 +/- 0.5 nm) was studied by exciting with NIR femtosecond pulses (780-880 nm). These nanostructures were observed to generate hyper-Rayleigh scattering (HRS) and broadband luminescence. While HRS showed the expected second order power dependence, the luminescence was observed to follow a third order excitation power dependence. Both HRS and luminescence were observed to be dipolar in nature. The first hyperpolarizability of the nanoprisms was found to be an order of magnitude higher than approximately 15 nm sized nanospheres.