Optical Characterization of Bi-pyramid Gold and Silver Nanoshells by Finite Difference Time Domain Method

Abstract

Optical characterization of both gold and silver bi-pyramid nano-shells are investigated using the finite difference time domain (FDTD) method. This method is a convenient way for describing both quantitatively and qualitatively the optical response of nano-oshells/nanoparticles of arbitrary geometry and shape that surrounding the active medium. The surface plasmon peaks of gold and silver bi-pyramid nano-shell can be tuned from visible to the near infrared region by controlling the size (aspect ratio), surface sharpness and polarization of light. Surface plasmons provide a powerful means of confining light to nano-shells, which in turn can enhance local electromagnetic fields and significantly amplify the signal finally used for surface enhanced Raman scattering (SERS).