Trapped like atoms

Magneto Optical Trap

~50 million Rubidium atoms confined in a cloud 5 mm across. These atoms are only several millionths of a degree above absolute zero.

The photonics and quantum optics lab took a detour away from atom trapping last summer and investigated some phenomena in warm atomic vapor for a change (will be covered in a future post). That means it has been about a year since we last had a working atom trap, so the time has come to trap atoms again… and trap we did. Here is a picture of roughly 50 million rubidium atoms confined to a region of space ~5 mm in diameter. They glow a dim red as they scatter light at 780 nm. The camera is more sensitive than our eyes so it appears bright in the image. The most remarkable feature of these atoms is that they are traveling at a speed of only a few centimeters per second. Compare this to the room-temperature atom speeds of several hundred meters-per-second and the power of an atom trap is obvious. These atoms are so cold, they almost stop moving. The temperature (a measure of average kinetic energy) is measured in microKelvin… millionths of a degree above absolute zero. Cool stuff!

Cold-Atom Lab in a Box

The ColdQuanta miniMOT atom trap

I was quoted in a recent Photonics Spectra article “Cold-Atom Lab in a Box“. The article describes the new Rubidium miniMOT available from ColdQuanta. My Photonics and Quantum Optics Lab at Pacific University was among their first customers. We’ve really enjoyed being involved with the early stages of this product and look forward to contributing to MOT research at the undergraduate (and perhaps high school) level.

For pictures of our trap in operation, see my earlier post “MOT!“. We have done a variety of experiments and have trapped atoms in several different geometries since then. More details are described in the talk given by Simone Carpenter at the Northwest APS section meeting: Off-the-shelf atom trapping [PDF] and the corresponding poster Off-the-shelf atom trapping.

Please feel free to contact me with any questions.

NOVA | Absolute Zero | PBS

Part II of a very cool NOVA series airs on PBS stations tonight. Pun absolutely intended. Second pun not as intended, but still amusing.

Many all-star players from the Atomic, Molecular and Optical physics world, several of which are Nobel Laureates, make appearances on this second part of the program. The first part aired last week and covered many interesting aspects of early thermodynamics. One great piece of trivia was about the original Celsius scale, and the fact that it was originally reversed, with zero for the boiling point of water, and 100 for the freezing point. This is really too bad, since he was very close to getting the right sense of temperature. Many argue that the thermodynamic beta is a more direct representation of temperature. Since Beta scales as the inverse of T, Celsius’ original scale at least went the right direction, even if the degree sizes weren’t right.

NOVA | Absolute Zero | PBS