Welcome to the Cold Atoms group at the Department of Molecular and Optical Physics, University of Freiburg, Germany.
Buffer Gas Effects on Dark Resonances: Theory and Experiment
Michael Erhard, Stefan Nußmann, and Hanspeter Helm
Department of Molecular and Optical Physics, Albert-Ludwigs-Universität, Hermann-Herder-Strasse 3, D-79104 Freiburg, Germany
Dark resonances with widths below 30 Hz have been observed in a rubidium cell filled with neon as buffer gas at room temperature.
We compare an approximate analytic solution of a Λ system to our data and show that under our experimental conditions the presence of the buffer gas reduces
the power broadening of the dark resonances by two orders of magnitude. We also present numerical calculations that take into
account the thermal motion and velocity-changing collisions with the buffer-gas atoms. The resulting dark-resonance features exhibit
strong Dicke-type narrowing effects and thereby explain the elimination of Doppler shifts and Doppler broadening, leading to
observation of a single ultranarrow dark line.
©2001 The American Physical Society
PACS: 42.40Gy, 32.70Jz, 32.80.Qk
42.50.Gy, 32.70.Jz, 32.80.Qk