Analysis of radiatively stable entanglement in a system of two dipole-interacting three-level atoms

We explore the possibilities of creating radiatively stable entangled states of two three-level dipole-interacting atoms in a Lambda configuration by means of laser biharmonic continuous driving or pulses. We propose three schemes for generation of entangled states which involve only the lower states of the Lambda system, not vulnerable to radiative decay. Two of them employ coherent dynamics to achieve entanglement in the system, whereas the third one uses optical pumping, i.e., an essentially incoherent process.