Optical pumping in thallium: spectroscopy, coherence and linewidths

Optical pumping experiments at 377 nm on the resonance transition of atomic thallium (6p(1/2)-7s(1/2)) are reported. The potential of this technique in the search for an electric dipole moment which arises through PT-violation is assessed. Linewidths of radiofrequency resonances within the ground state are measured and effects of coherent population trapping, laser linewidth and collisions are all considered. Some theoretical modelling is also presented.