We study the spontaneous emission, absorption, and dispersion properties of a Λ-type atom where one transition interacts near resonantly with a double-band photonic crystal. Assuming an isotropic dispersion relation near the band edges, we show that two distinct coherent phenomena can occur. First the spontaneous emission spectrum of the adjacent free-space transition obtains “dark lines” (zeros in the spectrum). Second, the atom can become transparent to a probe laser field coupling to the adjacent free-space transition.
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