Coherent Optics and Localized Light

Interplay between the effects of coherent radiation and localization of light is analysed. A system of two-level atoms is placed in a medium interacting with electromagnetic field. The matter-light interaction can result in the appearance of a band gap in the spectrum of polariton states. If an atom with a resonance frequency inside the gap is incorporated into such a medium, the atomic spontaneous emission is suppressed, which is termed the localization of light. However, a system of resonance atoms inside the gap can radiate due to their coherent interactions. The peculiarity of the coherent radiation by a system of atoms, under the localization of light for a single atom, is studied.