The influence of density of modes on dark lines in spontaneous emission

We study two distinct multi-level atomic models in which one transition is coupled to a Markovian reservoir, while another linked transition is couple d to a non-Markovian reservoir. We show that by choosing appropriately the density of modes of the non-Markovian reservoir the spontaneous emission to the Markovian reservoir is greatly altered. The existence of 'dark lines' in the spontaneous emission spectrum in the Markovian reservoir due to the coupling to specific density of modes of the non-Markovian reservoir is als o predicted. (C) 1999 Elsevier Science B.V. All rights reserved.