The lifetimes of several states in a thallium see-through hollow cathode discharge, or galvatron, are obtained to characterize its potential as an atomic line filter. The lifetimes of the thallium 6<sup>2</sup>D<sub>3/2</sub>, 6<sup>2</sup>D<sub>5/2</sub>, and 7<sup>2</sup>S<sub>1/2</sub> states are measured by time-resolved single-step laser-excited fluorescence by use of a 276.787 nm laser pulse or a 535.046 nm laser pulse and measuring the resulting fluorescence waveform at the appropriate wavelength. Values of 6.4 ± 0.1, 7.5 ± 1.1, and 7.7 ± 0.2 ns were obtained for the 6<sup>2</sup>D<sub>3/2</sub>, 6<sup>2</sup>D<sub>5/2</sub>, and 7<sup>2</sup>S<sub>1/2</sub> states, respectively, which agree with values obtained by previous authors, as well as calculated values. No current dependence was observed for each of these states. The lifetime of the long-lived thallium 6<sup>2</sup>P<sub>3/2</sub>° metastable state was measured by two-step laser-excited fluorescence at various applied currents. The metastable level was pumped by a 276.787 nm laser pulse, and a temporally delayed 535.046 nm laser pulse interrogated the population of the metastable state. Relating the fluorescence intensity to the population of the metastable state as a function of delay time yielded a decay curve for the 6<sup>2</sup>P<sub>3/2</sub>° metastable state. Values of 2.1 ± 0.2, 2.8 ± 0.1, 3.1 ± 0.3, 3.8 ± 0.4, and 4.8 ± 0.6 μs were found for applied currents of 14.0, 12.0, 10.0, 8.0, and 6.0 mA, respectively. The resulting lifetimes for the 6<sup>2</sup>P<sub>3/2</sub>° metastable state clearly show a dependence on the applied current and are expected to be due to collisions with the wall of the cathode, as well as a contribution due to collisions with electrons.

PDF Article

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
Login to access OSA Member Subscription