Mainz 1997 – scientific programme
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Q: Quantenoptik
Q 45: Quanteneffekte V
Q 45.5: Talk
Thursday, March 6, 1997, 17:15–17:30, N 3
Temporal Evolution of Coherent Optical Pumping — •W. Maichen, E.A. Korsunsky, and L. Windholz — Institut für Experimentalphysik, T.U. Graz, Petersgasse 16, A-8010 Graz, Österreich.
Coherent optical pumping (COP) is a process where optical pumping and coherent population trapping (CPT) are combined. In the present report we investigate the dynamics of COP in a sodium atomic beam excited by a bichromatic laser beam with parallel linear polarization and frequency difference matching the hyperfine splitting of the ground state of Na. In this configuration, two lambda schemes: F=1−F′=2−F=2, mF=± 1 are formed, and the Zeeman sublevel F=2, mF=0 is not excited by the laser radiation. When the laser frequency difference is exactly equal to the frequency between F=1 and F=2, superpositional dark states appear in the lambda systems. Therefore atomic population is pumped not only into the F=2, mF=0 state (’incoherent dark state’) but also into those ’coherent dark states’. The temporal behaviour of this process is studied on atomic beam where the temporal evolution is translated into a spatial profile. We recorded this profile by imaging the fluorescence zone onto a rectangular detector slit by a lens. We have performed measurements with and without shielding of the Earth magnetic field, and for different laser intensities. Supported by the Fonds zur Förderung der wissenschaftlichen Forschung, project no. S 6508.