Optical second harmonic generation from nanostructure-covered micro-cubes on nickel

In this study, we aimed to create the nano-micro hierarchical surface structures on Ni and analyze their optical second harmonic generation (SHG) response. The hierarchical surface structures were found to significantly modify the optical nonlinearity of the metal surface. The macroscopic symmetry of the surface's shape influenced SHG, and the excitation of surface plasmon (SP) enhanced SHG. On the other hand, the nanostructures on the micro-cubes had an additional effect on the generated SHG. The mechanism of anisotropic SHG enhancement by the nano-micro structures has been investigated. (C) 2016 Optical Society of America