The influence of virtual-photon processes on spontaneous emission from an atom in photonic band gap crystals

Spontaneous emission is studied without rotating-wave approximation in a three-level atom embedded in a photonic band gap structure (PBGS), and the edge of the PBG is not always located exactly at the center between the two upper levels. Some new quantum effects are found, such as a greater population of the atom trapped in its upper states, which results from interference between virtual photons and real photons. The effect of displacement of the edge of the PBG to the atomic populations is also studied, and we find that a greater population of the atom is trapped in the upper levels as the edge approaches one of the two upper levels, \a(1)]. (C) 2001 Elsevier Science B.V. All rights reserved.