Guided atom laser

A trapped cloud of atoms chilled into a Bose–Einstein condensate is a single coherent structure. When extracted from the trap and allowed to propagate, it acts like a laser beam, except that the coherent waves are of matter rather than light. In a typical atom laser, the atoms are released and accelerated by gravity, a process that decreases the atom laser’s de Broglie wavelength. Now, physicists from the Institut d’Optique Graduate School in Palaiseau, France, have coupled atoms from an optomagnetic BEC trap to a horizontal optical waveguide, which generated a quasi-continuous atom laser, impervious to gravity and having a constant de Broglie wavelength of 0.5 μm. The RF coupling converts the atoms from a magnetic to a nonmagnetic state, and they emerge with a typical velocity of 9 mm/s and a velocity spread of just a few μm/s, driven along a confining beam of light, as shown in the...