Nonlinearity management of photonic composites and observation of spatial-modulation instability due to quintic nonlinearity

摘要

We present a procedure for nonlinearity management of metal-dielectric nanocomposites (MDNCs). Varying the volume fraction occupied by silver nanoparticles (NPs) suspended in acetone we could investigate the nonlinear (NL) response of the MDNC. In particular, we could cancel the NL refractive index related to the effective third-order susceptibility,x_(eff)~((3)) and thus the NL refractive behavior of the MDNC was due to the effective fifth-order susceptibility, χ_(eff)~((5)). Hence, in a cross-phase modulation experiment, we demonstrated the effect of spatial-modulation instability due to χ_(eff)~((5)). The experimental results are corroborated with numerical calculations based on a generalized Maxwell-Garnet model that includes the direct contributions of the NPs and the host medium as well as cascade contributions due to the third- and fifth-order susceptibilities of the NPs.