Relaxation and depolarization of atomic states by collisions

A photon echo induced exclusively by collisions of ytterbium atoms with buffer gas atoms has been observed at a 0 ⟷ 1-type1 S 0(6s 2)-3 P 1(6s6p) 174Yb transition. The polarization properties of a collision echo and the buffer gas density dependence of its intensity agree with theoretical predictions of a model of depolarizing collisions that takes into account the dependence of a relaxation matrix on the velocity of active particles. Thus, direct experimental evidence of the relaxation anisotropy due to depolarizing collisions has been obtained.A photon echo induced exclusively by collisions of ytterbium atoms with buffer gas atoms has been observed at a 0 ⟷ 1-type1 S 0(6s 2)-3 P 1(6s6p) 174Yb transition. The polarization properties of a collision echo and the buffer gas density dependence of its intensity agree with theoretical predictions of a model of depolarizing collisions that takes into account the dependence of a relaxation matrix on the velocity of active particles. Thus, direct experimental evidence of the relaxation anisotropy due to depolarizing collisions has been obtained.

Journal of Experimental and Theoretical Physics LettersMar 1, 200814 citations

Collisional relaxation of excited-state Zeeman coherences in atomic ytterbium vapor

Arjun G. Yodh, J. E. Golub, THOMAS W. MOSSBERG

We present the results of an experiment designed to probe the collision-induced relaxation of excited-state Yb Zeeman coherences. Our experiment is sensitive not only to the depolarization-type relaxation mechanisms often observed in optical-pumping experiments, but also to the effects of collisionally induced velocity changes. Our measurements were performed in the 6s6p ${\mathrm{}}^{3}$ ${P}_{1}$ excited state of the even (I=0) isotopes of gas-phase atomic Yb by means of a trilevel photon-echo technique. Depolarization rates, velocity-change spectra, and total scattering cross sections of Yb-He (Yb-Ar) collisions were measured (deduced). Both rank-1 and rank-2 spherical tensor components of the $^{3}\mathrm{P}_{1}$ state play a role in our experiment, and our results represent averages of potentially different relaxation rates attributable to these quantities. Comparison of our results with rank-0 results obtained elsewhere reveals interesting similarities as well as differences.We present the results of an experiment designed to probe the collision-induced relaxation of excited-state Yb Zeeman coherences. Our experiment is sensitive not only to the depolarization-type relaxation mechanisms often observed in optical-pumping experiments, but also to the effects of collisionally induced velocity changes. Our measurements were performed in the 6s6p ${\mathrm{}}^{3}$${P}_{1}$ excited state of the even (I=0) isotopes of gas-phase atomic Yb by means of a trilevel photon-echo technique. Depolarization rates, velocity-change spectra, and total scattering cross sections of Yb-He (Yb-Ar) collisions were measured (deduced). Both rank-1 and rank-2 spherical tensor components of the $^{3}\mathrm{P}_{1}$ state play a role in our experiment, and our results represent averages of potentially different relaxation rates attributable to these quantities. Comparison of our results with rank-0 results obtained elsewhere reveals interesting similarities as well as differences.

Physical Review AAug 1, 198519 citations

Collisional Depolarization in the Excited State

W. E. Baylis

Springer eBooksJan 1, 197913 citations

{\mathrm{}}^{3}

{P}_{1}

excited state of the even (I=0) isotopes of gas-phase atomic Yb by means of a trilevel photon-echo technique. Depolarization rates, velocity-change spectra, and total scattering cross sections of Yb-He (Yb-Ar) collisions were measured (deduced). Both rank-1 and rank-2 spherical tensor components of the

^{3}\mathrm{P}_{1}

state play a role in our experiment, and our results represent averages of potentially different relaxation rates attributable to these quantities. Comparison of our results with rank-0 results obtained elsewhere reveals interesting similarities as well as differences.