Directional light scattering from individual Au nanocup

We investigate the optical scattering properties of gold nanocup with different orientation and fractional height by full vector finite element method. All of the scattering cross section, the distribution of electric field intensity, and the ability of directional light scattering are simulated, respectively. It is demonstrated that the scattering cross section of Au nanocup is a superposition of scattering spectrum of a transverse mode and an axial mode. The wavelength and the intensity of the maximum value of the scattering cross section increase initially then reduce with the fractional height increasing for transverse mode, while they increase monotonously with the fractional height increasing for axial mode. Furthermore, the calculation results show that the ability of redirecting incident light of Au nanocup mainly depends on the transverse mode. And the deflected angle of scattering increases with the fractional height of Au nanocup decreasing. These results indicate that Au nanocup has a promising application in the planar plasmon devices.