Transparency near a photonic band edge

We study the absorption and dispersion properties of a R-ty-pe atom that de cays spontaneously near the edge of a photonic band gap (PBG). Using an iso tropic PEG model, we show that the atom can become transparent to a probe l aser held, even when other dissipative channels are present. This transpare ncy originates from the square-root singularity of the density of modes of the PEG material at threshold.