Abstract

In atomic systems the concept of dark states is already well known.¹ Essentially, dark states are special dressed superposition states of the excited states that are not dipole coupled to the ground state of the atom even if the excited states themselves are. Therefore, they remain inactive during the interaction. Atoms with V- or A-type energy levels allow for the creation of dark states. Usually defined in terms of stationary light fields coupled to separate transitions with a common ground state, a dark state is created if the detunings of the two light fields from their respective transition frequencies in a V or A configuration are the same.

© 1995 Optical Society of America