A movie of trapped rubidium atoms

In this video you see a cloud of roughly 107 rubidium atoms as they are being trapped. This is done by arranging six 1-cm diameter laser beams along the principal cartesian axes (see the logo on our home page), which exert slowing and confining forces on the atoms. Because the lasers are precisely tuned to interact with the atomic resonance line, the atoms strongly scatter the photons in the laser light. This can cool the atoms to ultralow temperatures, around 200 microkelvin. By adding a magnetic field in combination with the laser light, we can also confine the atoms to a form a small ball about 0.05 cm in diameter. What you see in the movie is the laser light which is scattered by the atoms in this ball; this light is detected and imaged by a regular, everyday CCD video camera. This all takes place inside a ultra-high vacuum chamber with only a very small pressure of room-temperature rubidium atoms. At the end of the movie the magnetic field is turned off, removing the confining force on the atoms, and as a result the atoms escape from the trap. Note that the atoms move relatively slowly once the magnetic field is turned off; this is evidence of how cold the atoms really are.

You can download the movie, too, if you want.