Dresden 2011 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 57: Poster 3: Quantengase, Ultrakalte Atome, Ultrakalte Moleküle, Materiewellen Optik, Präzisionsmessungen, Metrologie

Q 57.70: Poster

Donnerstag, 17. März 2011, 16:30–19:30, P1

Laser cooling of dense atomic gases by collisional redistribution of radiation — •Simon Haßelmann, Anne Saß, Ulrich Vogl, and Martin Weitz — Institut für Angewandte Physik der Universität Bonn, Wegelerstr. 8, 53115 Bonn

We report on a laser cooling mechanism based on collisional redistribution of fluorescence in high pressure gas mixtures of alkali- and noble gas atoms. During atomic collisions in such a strongly pressure broadened system, far red detuned radiation can be absorbed and afterwards be reemitted closer to the unperturbed resonance. During each excitation cycle, kinetic energy of the order of the thermal energy kT is extracted from the sample. In our experiments we use alkali atoms in argon buffer gas at a pressure of several hundred bar and we observe temperature changes up to 527 K within a tenth of a second from an initial temperature of 680 K. The cooling power of this method is four to five orders of magnitude larger than in the Doppler cooling of dilute atomic gases.

Further prospects of the method include the rapid laser cooling of dense gases beyond the critical point of the gas, where investigations of supercooled fluids become viable. We are also planning to explore the cooling of molecular gases with redistribution laser cooling.