Heidelberg 2015 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 31: Ultracold Atoms: Trapping and Cooling I (with Q)

A 31.5: Vortrag

Donnerstag, 26. März 2015, 12:15–12:30, P/H2

Redistributional laser cooling and thermalization in dense gaseous ensembles — •Benedikt Gerwers, Stavros Christopoulos, Roberto Cota, Katharina Knicker, Anne Saß, Lars Weller, Peter Moroshkin, and Martin Weitz — Institut für Angewandte Physik der Universität Bonn, Deutschland

Redistributional laser cooling is a novel cooling technique applicable to ultradense gaseous ensembles. Optically active atoms undergo frequent collisions with noble buffer gas at high pressure, thus shifting the atomic resonances. This enables the absorption of far red-detuned laser excitation, while subsequent spontaneous decay occurs closer to the unperturbed resonances. During such a cooling cycle, kinetic energy of the order of kT is extracted from the ensemble. Thermal deflection spectroscopy indicates temperature changes as high as 500K. Temperature determination is also possible through Kennard-Stepanov analysis of the pressure-broadened absorption and fluorescence spectra of thermalized atomic and molecular transitions. Alkali and noble dimers are also investigated for molecular redistribution cooling.