Coupled dipole method for radiation dynamics in finite photonic crystal structures.

We present a coupled-dipole treatment of radiation dynamics in the weak-coupling regime in a finite three-dimensional photonic crystal structure. The structure is discretized in real space and the self-consistent local field is computed. We illustrate the computation of radiation dynamics by calculating the spontaneous emission rate for a source located in a defect cavity inside a slab photonic crystal structure. We compute the cavity spectral response, the near-field modal structure, and the far-field radiation pattern of the microcavity. We also discuss our results in light of the recent experimental near-field observations of the optical modes of a photonic crystal microcavity.