Numerically investigating near-field scattering for spatial enhancement of single irregular nano plasma particle

Near-field scattering from a nano silver particle has been studied with an optical wave passing through it. The scattered field was found to be enhanced around the semi-sphere on which the incident wave impinges. Comparing it with the spherical particle, the irregular shape of a nanoparticle only changes the distribution of the scattered field. In this investigation, approached by finite difference time domain (FDTD), it was revealed that the peak value of the scattered field is proportional to the particle radius; this might be due to the fact that more plasmons could be excited. Furthermore, the highest enhancement occurred at the incident frequency close to plasma frequency of silver (?2000 THz). Thus, the numerical results could give a guide for optimizing AgOx type super resolution near-field structure (RENS) applications. When the red light source can be replaced with shorter wavelength ones, or larger silver particles can be segregated, the near-field scattered enhancement might result.