Generalisation of the atomic polarisability for optical pumping with lasers

Abstract

The dependence of the polarisability of atoms subjected to optical pumping with a strong laser beam on the coherence between atomic levels is considered. The polarisability tensor is expressed as an expectation value of the generalised polarisability operator permitting the derivation of the explicit dependence of the polarisability on all coherences introduced between Zeeman sublevels of the ground and excited state by optical pumping without the limitations inherent in previous approaches. The particular usefulness of the generalised polarisability operator in the case of large momentum values and perturbative calculations is emphasised.