3-D FDTD Analysis of Gold-Nanoparticle-Based Photonic Crystal on Slab Waveguide

In this paper, metallic photonic crystals (PC) based on 2-D periodic arrays of gold nanoparticles were investigated on indium tin oxide slab waveguides using 3-D finite-difference time domain simulations with nonuniform mesh techniques. The PC effects were studied by changing the lattice constants from 300 to 500 nm. The results obtained indicate that the waveguide-excited plasmon absorption peak of periodic array of gold nanoparticles is tunable from 672 to 707 nm due to the second grating order propagating backward at the grazing angle. The nanoparticle-induced extinction of the waveguide mode was also investigated by varying the slab thickness from 100 to 375 nm. The results show that the extinction peak shifts from 650 to 705 nm. The theoretical results predict that the interactions of the periodic array of gold nanoparticles are strongly affected by the dispersion of the waveguide.