Mainz 2017 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 57: Ultracold Atoms II
Q 57.2: Vortrag
Freitag, 10. März 2017, 14:45–15:00, P 104
Towards a Perpetual Bose-Einstein Condensate — •Shayne Bennetts, Chun-Chia Chen, Benjamin Pasquiou, and Florian Schreck — Institute of Physics, University of Amsterdam, Amsterdam, The Netherlands
Production of Bose-Einstein condensates (BECs) has always been a two stage process, first laser cooling a gas sample, then cooling evaporatively until degeneracy is reached. As a result, BECs and devices based on BEC such as atom lasers are pulsed. Applications like atom interferometers would benefit greatly from a perpetual source of condensate. We are developing such a perpetual source in which we separate the cooling stages in space rather than time and protect the condensate from scattered photons using distance, baffles and a "transparency" beam. We have now demonstrated a perpetual MOT of 2× 109 88Sr atoms with temperatures as low as 20µK on a 7.4-kHz wide laser cooling transition with a continuous loading rate of 7× 108 atoms/s. Using a different set of parameters and location we have also demonstrated a perpetual MOT of 2× 108 88Sr at 2µK with a loading rate of 9× 107 atoms/s which we have successfully loaded into a dipole trap. By switching to the 0.5% abundance 84Sr isotope we are able to evaporate to BECs of 3× 105 84Sr atoms. Critically, for the second location we have validated the effectiveness of our architecture in protecting a BEC from scattered broad-linewidth laser cooling light, which is used in the first cooling stages. These are crucial steps towards demonstrating a perpetual BEC and atom laser.