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Humboldt-Universität zu Berlin - Faculty of Mathematics and Natural Sciences - Optical Metrology

BECCAL - Bose-Einstein Condensate and Cold Atom Lab

Photo: NASA, public domain

 

C. Grzeschik, M. Krutzik, and A. Peters
 

Bose-Einstein Condensate and Cold Atom Laboratory

Cold atoms have found their way in many today's lab experiments. They serve as highly sensitive probes for various forces, key elements for quantum computers and simulators as well as for fundamental studies of the underlying principles of quantum physics.

However, in any earthbound experiment, the gravitational force acting on the atoms adds to the optical or magnetic trapping potential in which the atoms are prepared and confined. This puts a fundamental limit on the achievable lowest energy levels and time of free evolution of the ensemble after release from the trapping potential. It is thus desirable to conduct experiments in microgravity, where the gravitational acceleration is strongly reduced.

First experiments with cold atoms and Bose-Einstein condensates in microgravity have been conducted within the QUANTUS and MAIUS collaboration utilizing a drop tower or sounding rocket for achieving microgravity times of up to six minutes. CAL will be a facility for the study of ultra-cold quantum gases in the microgravity environment of the International Space Station (ISS), developed by NASA's Jet Propulsion Lab.

The Bose-Einstein Condensate and Cold Atom Laboratory (BECCAL) is a DLR-NASA bilateral collaboration. The goal is to establish a multi-user and multi-purpose cold atom facility aboard the ISS. The wide range of possible scientific experiments include, amongst others, dual-species atom interferometry for testing the Einstein equivalence principle, scalar and spinor Bose gas physics, matter wave optics, studies on quantum decoherence and quantum reflection, as well as strongly interacting atoms and molecules.

In our current project phase, the scientific goals and technological requirements are elaborated. Coming from these boundary conditions, a design concept is prepared and the feasibility investigated.

 

Dual-species laser system for cold atom experiments aboard the ISS

The physics package, the control electronics and the laser system are the three main subsystems forming the BECCAL experiment. Within the collaboration, our group leads and coordinates the laser system design, production and qualification. The micro-integrated diode laser sources itself will be produced by the Ferdinand-Braun-Institut in Berlin, while the free beam Zerodur-based spectroscopy and distribution modules will be provided by the Johannes-Gutenberg Universität in Mainz.

 

This project is supported by the German Space Agency DLR with funds provided by the Federal Ministry for Economic Affairs and Energy under grant number DLR 50WP1702