Talk:Laser cooling
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This page has been cited as a source by a media organization. See the 2004 press source article for details.
The citation is in: "New technique could give super-cool molecules", NewScientist.com, March 3, 2004. |
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[edit] Mechanism needs clarification
We currently have this:
- Because the light is detuned to the "red" (i.e. at lower frequency) of the transition, the atoms will absorb more photons if they move towards the light source, due to the Doppler effect. Thus if one applies light from two opposite directions, the atoms will always scatter more photons from the laser beam pointing opposite to their direction of motion.
I don't think this is clear enough. The word "thus" joins a sentence about absorbtion with a conclusion about scattering, with no explanation of how the two are related. I don't know enough about the topic to fix this. --P3d0 13:25, Jun 24, 2005 (UTC)
I agree. I think a much easier-to-understand explanation is possible. ... Hmmm, that ended up being *much* longer than I expected. Feel free to condense it down and post to the article. --DavidCary 12:46, 26 July 2005 (UTC)
OK, I put my rough draft into the article. --DavidCary 00:14, 1 December 2005 (UTC)
the Laser Teaching Center at Stony Brook University http://laser.physics.sunysb.edu/projects/ seems to show a lot of people working with "Laser cooling", and with related ideas such as "MOT's" (magneto-optical traps), "Optical tweezers", etc. Should we ask nicely for some photos?
Overall, I think this article is very successful in explaining the basic concepts of laser cooling. I'd like to make a few more minor edits when I have time, especially on the history of the subject, which is subject to a surprising amount of misinformation. Dave Kielpinski 06:08, 18 December 2005 (UTC)
[edit] Old request for information
I apologize for the delay responding; I'd missed the original request, then gotten extremely busy. If any of the information in the laser cooling thread in my talk page archives is useful, by all means use it. --Christopher Thomas 03:54, 8 January 2006 (UTC)
[edit] question
How effective is laser cooling? does it cool fast? can it only cool to ex. 0 celcius, or can it cool to minus degrees too? Are there any real implementations? how much would such a cooling cost? how big would such a cooling device be? Imagine cooling your computer with that. ;) —The preceding unsigned comment was added by Frap (talk • contribs) on 21:13, 20 May 2006.
- First please use four ~ (~~~~) marks to automatically insert a signature with datestamp after your talk-page comments.
- Secondly several of your questions are already answered in the article. It cools far below 0 degrees centigrade. Target temperatures are millikelvin or lower (lowest I'd heard cited was nanokelvin). These cooling systems are in widespread use in physics laboratories for studying things like Bose-Einstein condensates.
- The cooling systems are fairly cheap as far as laboratory systems go, costing several thousand dollars to a few tens of thousands. I don't have information on rate of cooling, but I imagine it would be quite slow (you're using light pressure to bleed off kinetic energy of molecules, _and_ it's only a statistical average effect, _and_ absorption rate difference will drop as the molecules slow down, slowing cooling). The devices range from the size of a computer monitor on up (they're vacuum chambers with lasers shining into them and usually magnetic field coils around them, generally small enough to bolt to a lab bench).
- This would be useless for cooling a computer. What you need to do when cooling a computer is to keep the outer surface of the chip module (or die, for chips mounted with the bare die exposed) as cool as possible. The active parts of the silicon will still be at 50-100 degrees centigrade; you're just using a larger heat difference to the outer surface of the chip to increase the rate at which heat flows out of the system. This takes a system with high throughput, but doesn't require absolute temperatures anywhere near this low. See overclocking for more information.
- --Christopher Thomas 23:37, 20 May 2006 (UTC)
[edit] No mention of laser cooling of solids
There is no mention of laser cooling of solids in this article. The first instance I'm aware of this happening was published in: Phys. Rev. Lett. 78,1030 - 1033 (1997)
Since this kind of laser cooling uses an entirely different mechanism (that of anti-stokes fluorescence, should it be made into a separate article?
