High-resolution Fabry-Perot interferometric emission measurements of the 535.046 nm thallium line in a see-through hollow cathode discharge

A thallium see-through hollow cathode lamp, or galvatron, is investigated for applications as a narrow band atomic line filter. In order to determine the resolving power of this atom reservoir, high resolution emission profile measurements of the 535.046 nm line were obtained by a scanning Fabry--Perot interferometer coupled to a spectrometer. The resulting spectra are modeled by a two-layer model which takes into account line broadening due to self-absorption and allows the calculation of the Doppler temperature and optical depths of the two layers. The results obtained for the galvatron are compared to a traditional thallium hollow cathode lamp and a thallium electrodeless discharge lamp. The galvatron was found to produce Doppler temperatures from 495 K to 630 K from currents of 10.0 mA to 30.0 mA, respectively, which were lower than the values found from the traditional hollow cathode lamp at similar currents. These results make this atomic reservoir attractive for applications as an atomic line filter.