The precision and stability of atom interferometers highly depends on the expansion temperature of the atomic ensembles. To achieve long pulse separation times, e.g. in a light pulse atom gravimeter, low expansion rates are necessary to enable high beam splitting contrast and preserve ensembles dense enough to be detectable after long times of free fall. The generation of ultracold atomic ensembles with high repetition rates is therefore a key technique for matter-wave sensors.
Optical dipole traps are a commonly used tool for trapping and cooling neutral atoms. However, typical dipole traps are disadvantaged compared to magnetic traps for example implemented with atom chips, due to their small trapping volume and lower evaporation speed.
A team of scientists around Henning Albers has now presented a new approach. They use dynamic time-averaged optical potentials to speed up the generation of large ultracold atomic ensembles and to study the feasibility of an all-optical matter-wave lens by rapid decompression of the trap. The latter induces oscillations of the ensemble size and can be applied in each temperature regime reached within our evaporation sequence. This matter-wave lens is used to collimate the expansion of Bose-Einstein condensates, but can also be used to shortcut the duration of evaporative cooling. The researchers have now published their results in the journal Communications Physics.
The current publication is an excellent example of the networking of researchers and institutions within the framework of QuantumFrontiers. Not only did scientists from several research institutions such as Leibniz Universität Hannover, the DLR Institute for Satellite Geodesy and Inertial Sensing and the Bremen ZARM cooperate, but they also collaborated with the Collaborative Research Centers DQ-mat and TerraQ and two QuantumFrontiers TopicalGroups.
Original publication:
Henning Albers, Robin Corgier, Alexander Herbst, Ashwin Rajagopalan, Christian Schubert, Christian Vogt, Marian Woltmann, Claus Lämmerzahl, Sven Herrmann, Eric Charron, Wofgang Ertmer, Ernst M. Rasel, Naceur Gaaloul & Dennis Schlippert
All-optical matter-wave lens using time-averaged potentials.
Communications Physics 5, 60 (2022).
https://doi.org/10.1038/s42005-022-00825-2
