Anisotropic and enhanced absorptive nonlinearities in a macroscopic film induced by aligned gold nanorods

Abstract

Anisotropic and enhanced nonlinear absorption (NLA) has been observed from aligned gold nanorods (GNRs) embedded in a poly(vinyl alcohol) film, which was realized by a stretched-film method. Open-aperture Z-scan experiments revealed that the stretch process enhanced the NLA coefficient by approximately nine times and increased the anisotropic factor of NLA to ∼20. The enhancement in the NLA coefficient reached as high as ∼91 times after increasing the concentration of GNRs by four times and this is attributed to the plasmonic interaction between densely packed GNRs.