According to quantum mechanics, particles like atoms are also considered to behave like waves and we can build ‘atom lasers’ containing coherent waves of matter. However, it is an issue to make these matter waves last, so that they may be used in practical applications.
A team of Amsterdam physicists has now made it possible through some manipulation of the concept that underlies the atom laser, the so-called Bose-Einstein Condensate, or BEC for short, according to a press release published on June 10.
Florian Schreck, the team leader, explained in the statement how they did it.
“In previous experiments, the gradual cooling of atoms was all done in one place. In our setup, we decided to spread the cooling steps, not over time, but in space: we make the atoms move while they progress through consecutive cooling steps. In the end, ultracold atoms arrive at the heart of the experiment, where they can be used to form coherent matter waves in a BEC. But while these atoms are being used, new atoms are already on their way to replenish the BEC. In this way we can keep the process going – essentially forever,” said Schrek.
While the idea was relatively simple, putting it into practice was not. Chun-Chia Chen, the first author of the study recalled:
“Already in 2012, the team – then still in Innsbruck – realized a technique that allowed a BEC to be protected from laser cooling light, enabling for the first-time laser cooling all the way down to the degenerate state needed for coherent waves. While this was a critical first step towards the long-held challenge of constructing a continuous atom laser, it was also clear that a dedicated machine would be needed to take it further. On moving to Amsterdam in 2013, we began with a leap of faith, borrowed funds, an empty room, and a team entirely funded by personal grants. Six years later, in the early hours of Christmas morning in 2019, the experiment was finally on the verge of working. We had the idea of adding an extra laser beam to solve a last technical difficulty, and instantly every image we took showed a BEC, the first continuous-wave BEC.”
After creating a continuous Bose-Einstein Condensate, researchers aim to use the laser to create a stable output beam of matter. If they produce lasers that can not only operate forever but can also produce stable beams, the applications will be beyond limits.
The results of the study were published in the journal Nature.
