Time-resolved fluorescence and population measurements in laser-pumped barium vapour
- 1 January 1985
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic and Molecular Physics
- Vol. 18 (1) , 35-50
- https://doi.org/10.1088/0022-3700/18/1/006
Abstract
Time-resolved measurements of fluorescence and level populations have been made on barium vapour illuminated by an intense pulse of laser radiation (1 MW cm-2, 50 ns FWHM) tuned to the resonance transition of Ba I, 6s2 1S0-6s6p 1P1, at 5535 AA. Barium number densities between 1013-1015 cm-3 were investigated, using a buffer gas of helium at 100 Torr. Fluorescence was measured with two different geometrical arrangements, one allowing partial spatial resolution. In neither case did the observed fluorescence saturate with increasing laser power, although the maximum flux was more than sufficient to burn through the vapour column, as confirmed by transmission measurements. The power loss from the laser beam was found to be compatible with the scattered radiation from the pumped column in the absence of radiation trapping. In contrast to other similar experiments, no significant ionisation was detected (3P2 and 6s5d 1D2 metastable levels yielded quenching cross sections for both Ba-Ba and Ba-He collisions, but gave anomalous result for the peak populations. A qualitative explanation of the fluorescence anomaly is proposed on the basis of the AC Stark effect, and it is shown that the same effect can inhibit the onset of stimulated emission to the metastable D levels.Keywords
This publication has 39 references indexed in Scilit:
- Super-elastic effects in laser-induced ionisation of Na vapourJournal of Physics B: Atomic and Molecular Physics, 1981
- Tunable dye laser spectroscopy of atomic calcium: collisional redistribution of radiationJournal of Physics B: Atomic and Molecular Physics, 1981
- Fast excitation and ionisation in a laser-pumped barium vapour: experiments and calculationsJournal of Physics B: Atomic and Molecular Physics, 1981
- An investigation of a discharge-heated barium laserJournal of Applied Physics, 1978
- Collisional redistribution and saturation of near-resonance scattered lightPhysical Review A, 1977
- Anomalous fluorescence scattering from shock-heated sodium vapour under maintained high-power laser illuminationJournal of Physics B: Atomic and Molecular Physics, 1976
- Oscillator strength of the barium 6s6p^1P_1–6s5d^1D_2 transition inferred from photodeflection efficiency*Journal of the Optical Society of America, 1976
- Absorption spectrum of the laser-populated3D metastable levels in bariumJournal of Physics B: Atomic and Molecular Physics, 1975
- Laser selective excitation of a three-level atom: BariumJournal of Physics B: Atomic and Molecular Physics, 1974
- Excited state absorption spectroscopy of alkaline earths selectively pumped by tunable dye lasers. I. Barium arc spectraJournal of Physics B: Atomic and Molecular Physics, 1973