Laser cooling via collisional redistribution of fluorescence utilizes dense mixtures of alkali metals with noble buffer gases. Typical pressure values of the buffer gas are of the order of a few hundred bar, ensuring a frequent number of collisions between the two atomic species. The energy levels of the alkali atoms are thus perturbed so that excitation using far red-detuned laser light becomes feasible. Energy is then extracted via spontaneous emission occuring close to the unperturbed atomic resonances. Optimization of the cooling effect strongly depends on excitation conditions, namely the choice of detuning of the cooling beam, which in turn is dependent on the used pressure. We here report on spectroscopy measurements of atomic rubidium under high pressure buffer gas conditions. While thermal deflection spectroscopy has been previously used to measure the temperature change of the laser-cooled gas, an alternative approach for temperature measurements utilizing the Kennard-Stepanov relation is also investigated. We here exhibit that the collisionally thermalized atomic resonances well follow this thermodynamic scaling, allowing for temperature extraction of the dense gas mixture.Laser cooling via collisional redistribution of fluorescence utilizes dense mixtures of alkali metals with noble buffer gases. Typical pressure values of the buffer gas are of the order of a few hundred bar, ensuring a frequent number of collisions between the two atomic species. The energy levels of the alkali atoms are thus perturbed so that excitation using far red-detuned laser light becomes feasible. Energy is then extracted via spontaneous emission occuring close to the unperturbed atomic resonances. Optimization of the cooling effect strongly depends on excitation conditions, namely the choice of detuning of the cooling beam, which in turn is dependent on the used pressure. We here report on spectroscopy measurements of atomic rubidium under high pressure buffer gas conditions. While thermal deflection spectroscopy has been previously used to measure the temperature change of the laser-cooled gas, an alternative approach for temperature measurements utilizing the Kennard-Stepanov relation is also investigated. We here exhibit that the collisionally thermalized atomic resonances well follow this thermodynamic scaling, allowing for temperature extraction of the dense gas mixture.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEMar 7, 20160 citations

The Spectroscopy of Highly Excited Atoms

Daniel Kleppner

Springer eBooksJan 1, 19798 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

Collision spectroscopy with optically prepared atoms

N. Andersen

Jan 1, 20010 citations

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.