Slowing Down Atoms And Biomolecules With Lasers

Tokyokid writes "In an interview on Berkeley Groks, Nobel Laureate Steve Chu talks about cooling atoms down using lasers. In another words, the atoms or molecules are slowed down in this "optical molasses." Scientists now are using these techniques to study the interactions and forces between biomolecules. These studies may give a better understanding of how life works on the molecular level."

Comments

nope

[H4x0r Jim Duggan]

Lasers heat things up, not cool things down. Jeez, hasn't this guy ever seen a movie?

Re:nope

[ciaran_o_riordan]

The idea is that you want to reduce the average velocity of these atoms down to a very very low speed and that's what they really mean by cooling the temperatures and measuring the average motional energy of these atoms. You do this by shining light on the atoms.

As the light scatters from the atoms, they cool down. The trick is to arrange the light to preferentially scatter off of photons opposing the motion and this is done simply by tuning the frequency of the light so that when the atoms are moving towards this laser beam, it has a frequency shift called the Doppler shift that actually shifts it more into resonance.

Re:nope

[jabberjaw]

According to this, about 100 billionths a degree above absolute zero. This just turned up with a quick google and it has most likely gotten lower since then. As for refridgeration, not in the near... or distant future.

Compton scattering

[aurum42]

Is this related to Compton scattering (usually between an electron and a photon)? As I recall, there's a cos(Theta) term there, so the energy transfer could go either way between the electron and the photon. This also sounds a lot like how the bose-einstein condensate (a recently discovered "new state" of matter, and cause of a nobel) was created.