Physical Review A

Comment on ‘‘Optical pumping to the 6s5dstates in atomic barium’’

A. Kallenbach, Manfred Kock

Published Jan 1, 1987• 8 citations

Abstract

In a barium vapor pumped with laser light on the resonance transition at 553.5 nm the level 6p $^{1}P_{1}$ is depopulated mainly by collisional processes. With neglect of this item, radiative lifetimes derived from fluorescence measurements come out systematically too short.

DOI: 10.1103/physreva.35.437

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Optical pumping to the6s5dstates in atomic barium

Edmund G. Myers, C. Bell, P. G. Pappas +1 more

Physical Review AApr 1, 198615 citations

Saturation spectroscopy with laser optical pumping in atomic barium

P. G. Pappas, Michael M. Burns, David D. Hinshelwood +2 more

The magnitude and sign of laser saturation resonances induced in atomic transitions with level degeneracy can be dramatically altered by the presence of optical pumping. This paper presents a detailed theoretical treatment of optical-pumping Lamb dips and crossover resonances, and their experimental observation in the 553-nm barium resonance transition. The physical principles underlying the laser optical-pumping saturation effect are also discussed.

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Journal of Physics B Atomic and Molecular PhysicsJan 14, 198531 citations

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Physical Review A

Comment on ‘‘Optical pumping to the 6s5dstates in atomic barium’’

A. Kallenbach, Manfred Kock

Published Jan 1, 1987• 8 citations

Publisher

Abstract

In a barium vapor pumped with laser light on the resonance transition at 553.5 nm the level 6p

^{1}P_{1}

is depopulated mainly by collisional processes. With neglect of this item, radiative lifetimes derived from fluorescence measurements come out systematically too short.

DOI: 10.1103/physreva.35.437

Related papers

Optical pumping to the6s5dstates in atomic barium

Edmund G. Myers, C. Bell, P. G. Pappas +1 more

Using a flow apparatus, the time dependence of 6 ${s}^{2}$ ${\mathrm{}}^{1}$ ${S}_{0}$ --6s6p ${\mathrm{}}^{1}$ ${P}_{1}$ (553.5 nm) resonance fluorescence in atomic barium has been studied following switch-on of cw laser excitation. It was found that the fluorescence decays with rates as great as 1.3\ifmmode\times\else\texttimes\fi{} ${10}^{6}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. Assuming this can be ascribed to the pumping of atoms to the 6s5d ${\mathrm{}}^{1}$ D and $^{3}\mathrm{D}$ metastable levels, a value for the sum of the transition probabilities can be extracted.Using a flow apparatus, the time dependence of 6${s}^{2}$ ${\mathrm{}}^{1}$${S}_{0}$--6s6p ${\mathrm{}}^{1}$${P}_{1}$ (553.5 nm) resonance fluorescence in atomic barium has been studied following switch-on of cw laser excitation. It was found that the fluorescence decays with rates as great as 1.3\ifmmode\times\else\texttimes\fi{}${10}^{6}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. Assuming this can be ascribed to the pumping of atoms to the 6s5d ${\mathrm{}}^{1}$D and $^{3}\mathrm{D}$ metastable levels, a value for the sum of the transition probabilities can be extracted.

Physical Review AApr 1, 198615 citations

Saturation spectroscopy with laser optical pumping in atomic barium

P. G. Pappas, Michael M. Burns, David D. Hinshelwood +2 more

Physical Review AJun 1, 1980181 citations

Energy-pooling collisions in barium

Jonathan Andrew Neuman, Alan C. Gallagher, J. Cooper

Rate coefficients for energy-pooling collisions between low-lying excited states of Ba have been measured. The 6s6p ${(}^{3}$ ${\mathit{P}}_{1}$ ) level in Ba is pumped by a cw diode laser, and radiative decay and collisions with buffer-gas atoms also populate the 5d6s ${(}^{1}$ D) and 5d6s ${(}^{3}$ D) metastable levels. The densities of these low-lying excited states are measured by the absorption of lines from a Ba hollow-cathode lamp, and the states populated by energy-pooling collisions are studied by comparing their fluorescence intensity to that of the laser-excited level. The rate coefficients are on the order of gas-kinetic rates, and they are not strongly dependent on energy defect, spin changes, or angular-momentum changes.Rate coefficients for energy-pooling collisions between low-lying excited states of Ba have been measured. The 6s6p${(}^{3}$${\mathit{P}}_{1}$) level in Ba is pumped by a cw diode laser, and radiative decay and collisions with buffer-gas atoms also populate the 5d6s${(}^{1}$D) and 5d6s${(}^{3}$D) metastable levels. The densities of these low-lying excited states are measured by the absorption of lines from a Ba hollow-cathode lamp, and the states populated by energy-pooling collisions are studied by comparing their fluorescence intensity to that of the laser-excited level. The rate coefficients are on the order of gas-kinetic rates, and they are not strongly dependent on energy defect, spin changes, or angular-momentum changes.

Physical Review AAug 1, 199420 citations

Pair-absorption-pumped barium laser

R. W. Falcone, G. Zdasiuk

This is the first reported demonstration of the use of pair-absorption transitions for optically pumping lasers. In a mixture of barium and thallium metal vapors, single-photon absorption of 3867-A laser light caused simultaneous excitation of colliding ground-state atoms to the Ba(6s6p 1P1(o)) and Tl(6p 2P(3/2)(o)) excited states. Excited-state densities of about 10(14) cm(-3) were created, and subsequent laser emission on the Ba(6s6p 1PI(o)) - Ba(6s5d 1D2) atomic transition at 1.5 microm was observed.This is the first reported demonstration of the use of pair-absorption transitions for optically pumping lasers. In a mixture of barium and thallium metal vapors, single-photon absorption of 3867-A laser light caused simultaneous excitation of colliding ground-state atoms to the Ba(6s6p 1P1(o)) and Tl(6p 2P(3/2)(o)) excited states. Excited-state densities of about 10(14) cm(-3) were created, and subsequent laser emission on the Ba(6s6p 1PI(o)) - Ba(6s5d 1D2) atomic transition at 1.5 microm was observed.

Optics LettersApr 1, 19809 citations

Time-resolved fluorescence and population measurements in laser-pumped barium vapour

J. LEONARD BOWEN, Anne P. Thorne

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, 6s 2 1 S 0 -6s6p 1 P 1 , at 5535 AA. Barium number densities between 10 13 -10 15 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 (<5%). Time-resolved population measurements by anomalous dispersion on the 6s6p 3 P 2 and 6s5d 1 D 2 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.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, 6s 2 1 S 0 -6s6p 1 P 1 , at 5535 AA. Barium number densities between 10 13 -10 15 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 (<5%). Time-resolved population measurements by anomalous dispersion on the 6s6p 3 P 2 and 6s5d 1 D 2 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.

Journal of Physics B Atomic and Molecular PhysicsJan 14, 198531 citations

Collisional and radiative processes in a laser-pumped barium vapour

A. Kallenbach, M Gunther, Rainer Künnemeyer +1 more

Dense barium vapour (10 19 -10 21 m -3 ) produced in a heat-pipe oven is irradiated by pulsed laser light tuned to the Ba I, 6s 2 1 S 0 -6s6p 1 P 1 0 , resonance transition at 553.55 nm. The transient population densities of various Ba I and Ba II states are measured and time-resolved by means of the hook method. Simultaneously, the IR forward scattering (1.5, 1.13, 2.55 mu m) in the barium vapour is measured. Emphasis is laid on the investigation and the interpretation of the IR emission, the 'anomalous' 6p 3 P 2 0 level overpopulation, and of processes which are responsible for the initiation of ionisation. In addition, the radial diffusion of excitation and ionisation energy in a barium vapour pumped with a focused laser pulse is investigated, as well as the energy transfer in a Ba-Sr vapour.Dense barium vapour (10 19 -10 21 m -3 ) produced in a heat-pipe oven is irradiated by pulsed laser light tuned to the Ba I, 6s 2 1 S 0 -6s6p 1 P 1 0 , resonance transition at 553.55 nm. The transient population densities of various Ba I and Ba II states are measured and time-resolved by means of the hook method. Simultaneously, the IR forward scattering (1.5, 1.13, 2.55 mu m) in the barium vapour is measured. Emphasis is laid on the investigation and the interpretation of the IR emission, the 'anomalous' 6p 3 P 2 0 level overpopulation, and of processes which are responsible for the initiation of ionisation. In addition, the radial diffusion of excitation and ionisation energy in a barium vapour pumped with a focused laser pulse is investigated, as well as the energy transfer in a Ba-Sr vapour.

Journal of Physics B Atomic and Molecular PhysicsSep 14, 198616 citations

In a barium vapor pumped with laser light on the resonance transition at 553.5 nm the level 6p

^{1}P_{1}

is depopulated mainly by collisional processes. With neglect of this item, radiative lifetimes derived from fluorescence measurements come out systematically too short.

Using a flow apparatus, the time dependence of 6

{s}^{2}

{\mathrm{}}^{1}

{S}_{0}

--6s6p

{\mathrm{}}^{1}

{P}_{1}

(553.5 nm) resonance fluorescence in atomic barium has been studied following switch-on of cw laser excitation. It was found that the fluorescence decays with rates as great as 1.3\ifmmode\times\else\texttimes\fi{}

{10}^{6}

${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. Assuming this can be ascribed to the pumping of atoms to the 6s5d

{\mathrm{}}^{1}

D and

^{3}\mathrm{D}

metastable levels, a value for the sum of the transition probabilities can be extracted.

Rate coefficients for energy-pooling collisions between low-lying excited states of Ba have been measured. The 6s6p

{(}^{3}

{\mathit{P}}_{1}

) level in Ba is pumped by a cw diode laser, and radiative decay and collisions with buffer-gas atoms also populate the 5d6s

{(}^{1}

D) and 5d6s

{(}^{3}

D) metastable levels. The densities of these low-lying excited states are measured by the absorption of lines from a Ba hollow-cathode lamp, and the states populated by energy-pooling collisions are studied by comparing their fluorescence intensity to that of the laser-excited level. The rate coefficients are on the order of gas-kinetic rates, and they are not strongly dependent on energy defect, spin changes, or angular-momentum changes.