Polarisation dependence in three-level atom resonance fluorescence

Abstract
The resonance fluorescence from a three-level atom irradiated by a monochromatic laser is studied. Detailed spectra are calculated by using the Heisenberg source-field approach, and introducing Liouvillian space techniques. It is predicted that in the steady-state limit the fluorescence from an atom having two closely spaced excited states will have an anisotropically polarised seven-line spectrum. Graphs are shown of the predicted spectra in the case of on-resonance excitation and of far off-resonance excitation.