Sub-Doppler cooling discovery thermometry
ID: sub-doppler-cooling-discovery-thermometry
The 1988 experiment loaded sodium optical molasses from a slowed atomic beam. After stopping loading, a shutter extinguished the six cooling beams. Released atoms crossed a lower probe; a photomultiplier recorded fluorescence versus arrival time. Calculations integrated the measured initial cloud distribution and an assumed three-dimensional Maxwell-Boltzmann distribution, including gravity and detection geometry. The minimum was , versus the Doppler cooling limit.[ref]
Observation of Atoms Laser Cooled below the Doppler Limit by Paul D. Lett and others. pp. 169–170, preparation, TOF apparatus, Fig. 1 and uncertainty
Probe separation, probe intensity, cloud density and shutter timing were varied. Fountain-height, horizontal-spreading and release/recapture measurements also gave below-limit results. Geometry remained an uncertainty; agreement among complementary thermometers made a detector artifact less plausible. These measured released atoms, rather than an in-situ velocity distribution.[ref]
Observation of Atoms Laser Cooled below the Doppler Limit by Paul D. Lett and others. pp. 170–171, controls, four thermometers and release limitation
Steven Chu's account connects the explanation to optical pumping, Stark effect shifts and spatially changing electromagnetic polarization; Claude Cohen-Tannoudji's lecture separates this mechanism from subrecoil schemes. Their lectures and William D. Phillips's describe complementary experimental and theoretical routes.[ref]
The manipulation of neutral particles by Steven Chu. pp. 693–695, Fig. 6
[ref]Nobel Lecture: Manipulating atoms with photons by Claude Cohen-Tannoudji. pp. 710–713, §§II–III
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