Atom laser gets a full tank

How do you handle the coldest atoms on Earth without heating them up? With a laser, says Aaron E. Leanhardt of the Massachusetts Institute of Technology.

That may seem like precisely what you don’t need for the task. However, Leanhardt and his colleagues have now used a laser to grip clouds of ultracold atoms and drag them 30 centimeters. Known as Bose-Einstein condensates, such clouds are made of atoms that are all in the same quantum state. During the ride, the atoms stay cold because the laser beam is red–a color the atoms don’t absorb–yet they feel its tug because of a technique known as optical tweezing, Leanhardt explains.

By repeatedly creating condensates in a vacuum chamber and then laser-transporting them to a storage area, the scientists kept a condensate reservoir continuously stocked with no less than a million atoms, they report in an upcoming Science. That’s a long-awaited step toward another goal, a laser that fires atoms instead of photons and has an indefinitely refillable supply of atoms, Leanhardt says. When the researchers manage to increase the condensate reservoir’s capacity to about 10 million atoms, a nonstop atom laser may become a reality, he adds. Such lasers may open the way to novel fundamental-physics experiments and new realms of miniaturized circuits and other devices (SN: 5/8/99, p. 296).

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