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Homework Help: Laser cooling, doppler limit

  1. May 22, 2015 #1
    1. The problem statement, all variables and given/known data
    I have to study laser cooling. I'm actually trying to understand the Doppler limit on temperature.
    On the net I have found "at a certain point the cooling mechanism is foiled by heating due to the random absorption and reemission of photons. (http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/lascool.html)" (A similar sentence is in Phillips' Paper "Laser cooling and trapping of neutral atoms")

    I can't understand in which way emission can heat the atom... Can you explain me? A lot of thanks
  2. jcsd
  3. May 22, 2015 #2
    In this paper http://users.phys.psu.edu/~dsweiss/PRA%20RC%20laser%20cooling%20in%20optical%20lattices.pdf [Broken] it says: "Laser cooling requires spontaneous emission,
    and spontaneously emitted photons can be reabsorbed by other atoms. Reabsorption causes heating, which makes equilibrium temperatures increase with the density and number of atoms".

    I don't understand why reabsorption causes heating...
    Last edited by a moderator: May 7, 2017
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