Physical Review A

Isotope-selective photoionization spectroscopy of barium

Darrell J. Armstrong, J. Cooper

Published Apr 1, 1993• 11 citations

Abstract

We demonstrate an experimental technique that selects the nuclear spin I=0 isotope $^{138}\mathrm{Ba}$ for spectroscopic measurements from a beam of natural barium containing seven stable isotopes. A cw dye laser is used to optically pump the I=3/2 isotopes $^{135}\mathrm{Ba}$ and $^{137}\mathrm{Ba}$ into the metastable 6s5d $^{1}$${\mathit{D}}_{2}$ and $^{3}$${\mathit{D}}_{1,2}$ levels via the 6s6p $^{1}$${\mathit{P}}_{1}$ excited state, leaving nearly pure $^{138}\mathrm{Ba}$ in the ground state. Photoionization spectra of the excited 5d6p $^{3}$${\mathit{D}}_{1}$ even isotope state recorded with optical pumping of $^{135}\mathrm{Ba}$ and $^{137}\mathrm{Ba}$ to the metastable levels are essentially devoid of forbidden features associated with the hyperfine interaction in the odd isotopes.

DOI: 10.1103/physreva.47.r2446

Related papers

Measurement of the photoionization cross section from the laser-populated3D metastable levels in barium

John L. Carlsten, Thomas J. Mcilrath, W. H. Parkinson

The authors have measured the absolute photoionization cross section from the 6s5d 3 D metastable level of barium. The 3 D levels were selectively populated with a high-power, tuneable dye laser. The cross section obtained at 303 nm was (18+or-4)*10 -18 cm 2 . The number density was determined by observing the resulting depopulation of the ground state when pumping occurred.

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Physical Review A

Isotope-selective photoionization spectroscopy of barium

Darrell J. Armstrong, J. Cooper

Published Apr 1, 1993• 11 citations

Publisher

Abstract

We demonstrate an experimental technique that selects the nuclear spin I=0 isotope

^{138}\mathrm{Ba}

for spectroscopic measurements from a beam of natural barium containing seven stable isotopes. A cw dye laser is used to optically pump the I=3/2 isotopes

^{135}\mathrm{Ba}

and

^{137}\mathrm{Ba}

into the metastable 6s5d

^{1}$${\mathit{D}}_{2}

and

^{3}$${\mathit{D}}_{1,2}

levels via the 6s6p

^{1}$${\mathit{P}}_{1}

excited state, leaving nearly pure

^{138}\mathrm{Ba}

in the ground state. Photoionization spectra of the excited 5d6p

^{3}$${\mathit{D}}_{1}

even isotope state recorded with optical pumping of

^{135}\mathrm{Ba}

and

^{137}\mathrm{Ba}

to the metastable levels are essentially devoid of forbidden features associated with the hyperfine interaction in the odd isotopes.

DOI: 10.1103/physreva.47.r2446

Related papers

Measurement of the photoionization cross section from the laser-populated3D metastable levels in barium

John L. Carlsten, Thomas J. Mcilrath, W. H. Parkinson

Journal of Physics B Atomic and Molecular PhysicsJun 1, 197416 citations

Laser modulation technique for single isotope spectroscopic studies

Jason R. Bochinski, Thomas H. Loftus, THOMAS W. MOSSBERG

We demonstrate an atomic-beam approach to obtaining isotope specific driven-atom spectra using samples of arbitrary isotopic composition. The method employs modulation of a target isotope ground-state population by an upstream preparation laser. Desired driven-atom signals generated downstream from the preparation laser are isolated using a lock-in amplifier referenced to the preparation laser modulation frequency. In our experiments, an intensity-modulated laser resonant with the barium ${(6s}^{2}{)}^{1}{S}_{0}{\ensuremath{-}(6s6p)}^{3}{P}_{1}$ 791.1-nm intercombination transition selectively pumps ${}^{138}\mathrm{Ba}$ atoms via radiative decays to the ${(6s5d)}^{3}{D}_{1,2}$ metastable states. Dressed-atom gain studies using the ${(6s}^{2}{)}^{1}{S}_{0}{\ensuremath{-}(6s6p)}^{1}{P}_{1}$ 553.5-nm transition demonstrate the efficacy of the method. This technique has general utility for selectively isolating specific isotopic signals in systems possessing optically controllable atomic-beam populations.We demonstrate an atomic-beam approach to obtaining isotope specific driven-atom spectra using samples of arbitrary isotopic composition. The method employs modulation of a target isotope ground-state population by an upstream preparation laser. Desired driven-atom signals generated downstream from the preparation laser are isolated using a lock-in amplifier referenced to the preparation laser modulation frequency. In our experiments, an intensity-modulated laser resonant with the barium ${(6s}^{2}{)}^{1}{S}_{0}{\ensuremath{-}(6s6p)}^{3}{P}_{1}$ 791.1-nm intercombination transition selectively pumps ${}^{138}\mathrm{Ba}$ atoms via radiative decays to the ${(6s5d)}^{3}{D}_{1,2}$ metastable states. Dressed-atom gain studies using the ${(6s}^{2}{)}^{1}{S}_{0}{\ensuremath{-}(6s6p)}^{1}{P}_{1}$ 553.5-nm transition demonstrate the efficacy of the method. This technique has general utility for selectively isolating specific isotopic signals in systems possessing optically controllable atomic-beam populations.

Physical Review AMar 17, 20004 citations

Laser isotope separation of barium using an inhomogeneous magnetic field

William Arie van Wijngaarden, Jin-Sun Ki

Isotopes of barium are selectively excited to a metastable state using a single ring dye laser. The excited atoms are then deflected out of an atomic beam by an inhomogeneous magnetic field. The deflection of the beam is studied using a hot wire detector and a quadrupole mass spectrometer. Measurements are presented showing that nearly all atoms of a particle isotope can be excited from the 6s{sup 2} ground still to the 6s5d state and subsequently spatially separated. This method of isotope separation requires metastable states having lifetimes greater than about 100 {mu}sec. These states can be readily excited from the ground state in atoms such as the Group II elements.Isotopes of barium are selectively excited to a metastable state using a single ring dye laser. The excited atoms are then deflected out of an atomic beam by an inhomogeneous magnetic field. The deflection of the beam is studied using a hot wire detector and a quadrupole mass spectrometer. Measurements are presented showing that nearly all atoms of a particle isotope can be excited from the 6s{sup 2} ground still to the 6s5d state and subsequently spatially separated. This method of isotope separation requires metastable states having lifetimes greater than about 100 {mu}sec. These states can be readily excited from the ground state in atoms such as the Group II elements.

Bulletin of the American Physical SocietyMay 1, 19930 citations

Observation of hyperfine structure and isotope shift in autoionizing states

R. J. de Graaff, Erwin A. J. M. Bente, W. Hogervorst +1 more

We report the first observation of hyperfine structure and isotope shift in autoionizing states. This structure was investigated in the $5{d}_{\frac{3}{2}}\mathrm{nf} J=4,5(n=36\ensuremath{-}40)$ barium Rydberg series, excited from the recently localized metastable $5{d}^{2}^{1}G_{4}$ level. An isotope-selective detection method was used in a cw laser spectroscopic experiment on a collimated atomic beam. The experimental data provide valuable additional information for the analyses of these doubly excited series.We report the first observation of hyperfine structure and isotope shift in autoionizing states. This structure was investigated in the $5{d}_{\frac{3}{2}}\mathrm{nf} J=4,5(n=36\ensuremath{-}40)$ barium Rydberg series, excited from the recently localized metastable $5{d}^{2}^{1}G_{4}$ level. An isotope-selective detection method was used in a cw laser spectroscopic experiment on a collimated atomic beam. The experimental data provide valuable additional information for the analyses of these doubly excited series.

Physical Review AJun 1, 19889 citations

Laser selective excitation of a three-level atom: Barium

John L. Carlsten

A simple theory describing selective excitation of a three-level atom with a tuneable laser is developed. Effects of number density, line widths and laser parameters on the final populations of the levels with laser excitation are discussed. An experiment is described in which a tuneable dye laser is used to pump large numbers of barium atoms into the 6s5d 3 D metastable term from the (bs) 2 1 S 0 ground state via the 6s6p 3 P term. The theory for the interaction of the laser with this 'three-level system' predicts that approximately 80% of the barium atoms should be excited into the 3 D term. Experimentally the largest amount of excitation to the 3 D term observed was (78+or-5)%.A simple theory describing selective excitation of a three-level atom with a tuneable laser is developed. Effects of number density, line widths and laser parameters on the final populations of the levels with laser excitation are discussed. An experiment is described in which a tuneable dye laser is used to pump large numbers of barium atoms into the 6s5d 3 D metastable term from the (bs) 2 1 S 0 ground state via the 6s6p 3 P term. The theory for the interaction of the laser with this 'three-level system' predicts that approximately 80% of the barium atoms should be excited into the 3 D term. Experimentally the largest amount of excitation to the 3 D term observed was (78+or-5)%.

Journal of Physics B Atomic and Molecular PhysicsSep 11, 197423 citations

High-Resolution Electron Spectroscopy of Laser-Excited Ba Rydberg Atoms

Herbert H. Rinneberg, Jörg Neukammer, U. Majewski +1 more

The ionization of $6sns^{1}S_{0}$ Rydberg states of $^{138}\mathrm{Ba}$ has been investigated by high-resolution electron spectroscopy. The Rydberg states were excited by two cw dye lasers via the $6s6p^{1}P_{1}$ level. The electron spectra show rich structure between 0.025 and 3 eV, largely attributable to collisional (Penning) ionization, photoionization, and autoionizing transitions. The first process might be interpreted as superelastic scattering of the Rydberg electron by optically pumped $\mathrm{Ba}(6s6p^{1}P_{1})$ or $\mathrm{Ba}(6s5d^{1}D_{2})$ atoms.The ionization of $6sns^{1}S_{0}$ Rydberg states of $^{138}\mathrm{Ba}$ has been investigated by high-resolution electron spectroscopy. The Rydberg states were excited by two cw dye lasers via the $6s6p^{1}P_{1}$ level. The electron spectra show rich structure between 0.025 and 3 eV, largely attributable to collisional (Penning) ionization, photoionization, and autoionizing transitions. The first process might be interpreted as superelastic scattering of the Rydberg electron by optically pumped $\mathrm{Ba}(6s6p^{1}P_{1})$ or $\mathrm{Ba}(6s5d^{1}D_{2})$ atoms.

Physical Review LettersOct 24, 198315 citations

We demonstrate an experimental technique that selects the nuclear spin I=0 isotope

^{138}\mathrm{Ba}

for spectroscopic measurements from a beam of natural barium containing seven stable isotopes. A cw dye laser is used to optically pump the I=3/2 isotopes

^{135}\mathrm{Ba}

and

^{137}\mathrm{Ba}

into the metastable 6s5d

^{1}$${\mathit{D}}_{2}

and

^{3}$${\mathit{D}}_{1,2}

levels via the 6s6p

^{1}$${\mathit{P}}_{1}

excited state, leaving nearly pure

^{138}\mathrm{Ba}

in the ground state. Photoionization spectra of the excited 5d6p

^{3}$${\mathit{D}}_{1}

even isotope state recorded with optical pumping of

^{135}\mathrm{Ba}

and

^{137}\mathrm{Ba}

to the metastable levels are essentially devoid of forbidden features associated with the hyperfine interaction in the odd isotopes.

{}^{138}\mathrm{Ba}

atoms via radiative decays to the

{(6s5d)}^{3}{D}_{1,2}

metastable states. Dressed-atom gain studies using the ${(6s}^{2}{)}^{1}{S}_{0}{\ensuremath{-}(6s6p)}^{1}{P}_{1}$ 553.5-nm transition demonstrate the efficacy of the method. This technique has general utility for selectively isolating specific isotopic signals in systems possessing optically controllable atomic-beam populations.

The ionization of

6sns^{1}S_{0}

Rydberg states of

^{138}\mathrm{Ba}

has been investigated by high-resolution electron spectroscopy. The Rydberg states were excited by two cw dye lasers via the

6s6p^{1}P_{1}

level. The electron spectra show rich structure between 0.025 and 3 eV, largely attributable to collisional (Penning) ionization, photoionization, and autoionizing transitions. The first process might be interpreted as superelastic scattering of the Rydberg electron by optically pumped

\mathrm{Ba}(6s6p^{1}P_{1})

\mathrm{Ba}(6s5d^{1}D_{2})

atoms.