Simulation of molecular imaging using nanowire optical probe with flat end face

Abstract

In this paper, the output near field of nanowire with flat end face is calculated, and the nanowire as light-emitting probe for near-field imaging of 30nm diameter spherical gold nanoparticles representing biomarkers for labeling biological cells or molecules is simulated by using the three-dimensional finite-difference time-domain (3D FDTD) method. Due to the near-field enhancement effect at the edge of the nanowire and the local surface plasmon enhancement effect of gold nanoparticles induced by the output near field of the nanowire, the near field at the nanoparticles has the strongest peak when the x–y positions of the nanoparticles are close to the perimeter of the nanowire. Simulation results also show that the near field at the gold nanoparticles highly depends on the polarization vector of the incident light and the nanowire can work effectively as optical probe for molecular imaging. Results presented here can offer valuable references for molecular imaging technology with nanowires as optical probes.