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arXiv · 1511.00443

A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength

R. J. Rengelink·R. P. M. J. W. Notermans·W. Vassen
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Abstract

High precision spectroscopy on the $2 \ ^3 S \rightarrow 2 \ ^1 S$ transition is possible in ultracold optically trapped helium but the accuracy is limited by the ac-Stark shift induced by the optical dipole trap. To overcome this problem, we have built a trapping laser system at the predicted magic wavelength of 319.8 nm. Our system is based on frequency conversion using commercially available components and produces over 2 W of power at this wavelength. With this system, we show trapping of ultracold atoms, both thermal ($\sim0.2 \ \mathrm{μK}$) and in a Bose-Einstein condensate, with a trap lifetime of several seconds, mainly limited by off-resonant scattering.

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R. J. Rengelink, R. P. M. J. W. Notermans, W. Vassen. 2018-04-18. A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength. https://doi.org/10.1007/s00340-016-6395-y

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