Metallic nanocluster gratings generated by near-field coupling of localized surface plasmons

Metallic nanocluster gratings composed of a 3-dimensionally periodic distribution of silver nanoparticles are successfully formed in a dielectric. A periodic arrangement of silver nanoclusters are created by holographic interference of two continuous-wave laser beams in a glass medium with embedded ~10 nm silver nanoparticles. The diffraction efficiency is much higher for the nanocluster gratings formed by TE-polarized (parallel to grating fringes) beams than those formed by TM-polarized beams. This strong polarization dependence in the formation of nanocluster gratings reveals that strong near-field coupling between localized surface plasmons excited at the metallic nanoparticles is one of the dominant mechanisms governing the rearrangement of the silver nanoparticles. The nonlinear response of metallic nanoparticles is greatly enhanced when the incident light is polarized along the lines of the silver nanoparticles.