Interaction of light with ordered dielectric spheres: Finite-difference time-domain analysis

Using the finite-difference time-domain (FDTD) method, interaction between a gaussian wave and ordered dielectric spheres has been numerical ly calcul ated for the first time. Real-time images of the spatial distribution of th e intensity of light coupling to the dielectric spheres have been presented for gaussian wave and plane-wave incidences. From the images for gaussian wave incidence, we have been able to clearly confirm a remarkable reduction in the light velocity for a flat photon band, i.e., a heavy photon band. I t has been pointed out that the situation of the propagation of the gaussia n wave is similar to that of the planewave. The transmittance T and reflect ance R for the normal incidence of light to the ordered spheres have also b een evaluated from the FDTD analyses. It has been found that T and R for th e gaussian wave can be exactly estimated for the heavy photon band, differi ng from the plane-wave case.