Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Optics Letters

Photon-echo studies of collisional relaxation in weakly ionized noble-gas mixtures

M. R. Woodworth

Published Jun 1, 1983• 4 citations
Publisher

Abstract

Photon-echo relaxation rates are measured in weakly ionized plasmas of binary mixtures of noble gases, in which the photon echo generated on a transition in one noble-gas species is damped primarily by atoms of the second species. The special cases of pure krypton and xenon are extensions of previous work in pure helium, neon, and argon. With the exception of mixtures with helium as the perturber, measured relaxation rates are consistent with collisional line-broadening calculations.

DOI
10.1364/ol.8.000307

Related papers

Relaxation of photon echoes in weakly ionized noble-gas plasmas

Thomas M. Baer

Photon echoes generated from visible transitions in the noble gases helium, neon, and argon are observed and the collisional relaxation rates are measured. The photon echoes are excited on transitions initiating from metastable states which are populated by electron impact in an rf discharge. The photon-echo intensity is measured as a function of time after the discharge is turned off and as a function of gas pressure. The reduction of the echo intensity in these two experiments is attributed to relaxation of the metastable population in the afterglow and dephasing collisions, respectively. The dependence of the photon-echo damping time on transition wavelength and perturber gas is interpreted by means of a simple van der Waals model for the excited-atom and perturber-gas interaction.

Physical Review A•Dec 1, 1979•15 citations

Photon echo and stimulated photon echo study of various collisional-relaxation channels

Н. Н. Рубцова, L. S. Vasilenko, Хворостов Евгений Борисович

Collisional relaxation in SF6 gas and its mixtures with He and Xe is studied by photon echo and stimulated photon echo methods from the standpoint of the possibility of identifying the contributions of different types of collisions. The nonexponential nature of the kinetic curve of the photon echo is clearly observed for pure SF6, it is weaker in the mixture SF6+Xe, and it is virtually completely absent for high degrees of dilution of SF6 with helium. These features can be explained on the basis of estimates, made from experimental data, of the critical delay between the exciting pulses (for which the nonexponential behavior should be most strongly manifested). In pure SF6 it is possible to distinguish the contribution of the inelastic channel (rotational relaxation) and the contribution of weak collisions. To distinguish successfully the relaxation channels in mixtures with buffer gases a heavier buffer gas and a much better time resolution must be used. It is shown that data obtained on the orientation and alignment relaxation rates by the stimulated photon echo method can serve as an upper limit for the rates of inelastic processes which cannot be measured by the photon echo method. The combined use of photon echo and stimulated photon echo methods made it possible to obtain data on the cross sections for elastic and inelastic scattering of the collisional pairs SF6–SF6, SF6–Xe, and SF6–He.

Journal of Experimental and Theoretical Physics•Jul 1, 1999•1 citation

Relative noble-gas-induced broadening of the D lines of atomic lithium

Ravinder Kachru, T. J. Chen, THOMAS W. MOSSBERG +1 more

Photon echoes have been employed to measure the relative broadening rates of the lithium $D$ lines perturbed by the noble gases. We find that, for each noble-gas perturber, the ${D}_{1}$-line and ${D}_{2}$-line photon-echo-relaxation rates are identical. Our results are compared with those obtained in line-shape studies of pressure broadening.

Physical Review A•Mar 1, 1982•8 citations

Noble-gas-induced collisional line broadening of atomic lithium Rydberg superposition states 2S–nS and 2S–nD (n = 4 to 30) measured by trilevel echoes

Emily Y. Xu, Fred Moshary, Sven R. Hartmann

Collisional relaxation of 2S–nS and 2S–nD superposition states in atomic Li vapor is measured with the trilevel photon-echo technique. Principal quantum numbers range from n = 4 to well into the Rydberg regime with n = 30. For the rare-gas perturbers (He, Ne, Ar, Kr, and Xe) the variation of collisional cross section with n is considerably weaker than that previously found with Na vapor.

Journal of the Optical Society of America B•Apr 1, 1986•8 citations

Noble-gas broadening of the sodium D lines measured by photon echoes

Ravinder Kachru, THOMAS W. MOSSBERG, Sven R. Hartmann

Noble-gas-induced relaxation of photon echo signals is used to determine the broadening rates of the Na D lines. Since echo signals are 'Doppler free', precision measurements are possible at low perturber-gas pressures (<or=1 Torr), and are sensitive to the previously inaccessible central lineshape. Interestingly, the authors results disagree with other recently published broadening rates. The equivalence of linewidth measurements and echo measurements on transitions between states of low electronic angular momentum is discussed.

Journal of Physics B Atomic and Molecular Physics•Jun 28, 1980•26 citations

Photon echoes in plasmas: collisional relaxation in helium on 2 ^3S_1–3 ^3P_012

Thomas M. Baer, Isaac D. Abella

Photon echoes are observed for the first time in plasmas on atomic metastable states populated by rf discharge in helium at pressures from 0.01 to 0.5 Torr. The echoes are generated by tunable dye-laser excitation. The collision cross section for echo dephasing on the He 2 (3)S-3 (3)P transition at 3888 A by collisions with ground-state atoms is 5 x 10(-14) cm(2) +/- 20%. Echoes are also observed on the 3P metastable manifold in neon.

Optics Letters•Nov 1, 1978•7 citations
Photon-echo relaxation rates are measured in weakly ionized plasmas of binary mixtures of noble gases, in which the photon echo generated on a transition in one noble-gas species is damped primarily by atoms of the second species. The special cases of pure krypton and xenon are extensions of previous work in pure helium, neon, and argon. With the exception of mixtures with helium as the perturber, measured relaxation rates are consistent with collisional line-broadening calculations.
Photon echoes generated from visible transitions in the noble gases helium, neon, and argon are observed and the collisional relaxation rates are measured. The photon echoes are excited on transitions initiating from metastable states which are populated by electron impact in an rf discharge. The photon-echo intensity is measured as a function of time after the discharge is turned off and as a function of gas pressure. The reduction of the echo intensity in these two experiments is attributed to relaxation of the metastable population in the afterglow and dephasing collisions, respectively. The dependence of the photon-echo damping time on transition wavelength and perturber gas is interpreted by means of a simple van der Waals model for the excited-atom and perturber-gas interaction.
Collisional relaxation in SF6 gas and its mixtures with He and Xe is studied by photon echo and stimulated photon echo methods from the standpoint of the possibility of identifying the contributions of different types of collisions. The nonexponential nature of the kinetic curve of the photon echo is clearly observed for pure SF6, it is weaker in the mixture SF6+Xe, and it is virtually completely absent for high degrees of dilution of SF6 with helium. These features can be explained on the basis of estimates, made from experimental data, of the critical delay between the exciting pulses (for which the nonexponential behavior should be most strongly manifested). In pure SF6 it is possible to distinguish the contribution of the inelastic channel (rotational relaxation) and the contribution of weak collisions. To distinguish successfully the relaxation channels in mixtures with buffer gases a heavier buffer gas and a much better time resolution must be used. It is shown that data obtained on the orientation and alignment relaxation rates by the stimulated photon echo method can serve as an upper limit for the rates of inelastic processes which cannot be measured by the photon echo method. The combined use of photon echo and stimulated photon echo methods made it possible to obtain data on the cross sections for elastic and inelastic scattering of the collisional pairs SF6–SF6, SF6–Xe, and SF6–He.
Photon echoes have been employed to measure the relative broadening rates of the lithium DDD lines perturbed by the noble gases. We find that, for each noble-gas perturber, the D1{D}_{1}D1​-line and D2{D}_{2}D2​-line photon-echo-relaxation rates are identical. Our results are compared with those obtained in line-shape studies of pressure broadening.
Noble-gas-induced relaxation of photon echo signals is used to determine the broadening rates of the Na D lines. Since echo signals are 'Doppler free', precision measurements are possible at low perturber-gas pressures (<or=1 Torr), and are sensitive to the previously inaccessible central lineshape. Interestingly, the authors results disagree with other recently published broadening rates. The equivalence of linewidth measurements and echo measurements on transitions between states of low electronic angular momentum is discussed.