Inversionless superradiance of an ensemble of three-level atoms in a high-Q cavity.

We analyze the possibility of superradiance in an ensemble of three-level atoms in the absence of population inversion. We show that in the case of a A configuration of the active transitions this effect can occur for an initially coherent superposition of the states of the lower doublet. We also study how splitting of the lower levels influences this effect and discuss ways of creating low-frequency coherence. [ABSTRACT FROM AUTHOR]