Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Lasing action

  1. Sep 2, 2015 #1
    Hello
    I've been wondering how certain solid state lasers could have a continuous lasing action (Nd YAG laser for instance )
    If so,the understanding that the best lasing conditions are when the temperature Is lowest gets disproved(considering that a commendable quantity of heat is produced during the pumping process!
    Please help me with this idea and do correct me if I'm wrong!
     
  2. jcsd
  3. Sep 2, 2015 #2

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    Why not? What makes you think that a Nd:YAG laser cannot be operated in continuous mode?
    In which context are you speaking of?
     
  4. Sep 2, 2015 #3
    Isn't it a fact that the population inversion is known as a negative temperature process?
    If yes,increase in temperature hampers population inversion and hence lasing action becomes invalid.
    It's obvious that continuous operation of a krypton arc lamp generates tremendous heat.
    My question is :is there a coolant that could bring down the temperature as quickly as it heats up?
    Or is there an alternative explanation
     
  5. Sep 2, 2015 #4

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    Thermal effect does cause problem in a laser system, but this is mainly due to the thermal lensing where the index of refraction of the gain medium gets modified and photoelastic effect which can further cause birefringence effect. Heating process of the gain medium depends, among others, on the radiation intensity of the laser. Continuous operation is known to be limited to low intensity, due to this heating of the gain medium is supposed to be relatively minimal. For such low power laser system, air cooling (that is, the gain medium is simply exposed to an open space) is usually sufficient to prevent any pronounced thermal effects. Heating effect, instead, becomes serious in pulsed operation as the pulse intensity involved within the cavity may very high.
     
  6. Sep 2, 2015 #5
    Thanks
    It was very helpful
    I owe you a big deal
     
  7. Sep 2, 2015 #6

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    You are welcome.
     
  8. Sep 4, 2015 #7
    Also, keep in mind that population inversion should not be thought of as a temperature. The normal expression for temperature relates to to an average of an ensemble in equilibrium, but a population inversion is NOT in equilibrium. Even though you could still ascribe it a temperature it doesn't mean the same thing.
     
  9. Sep 4, 2015 #8
    Thanks Zarqon
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Lasing action
  1. Law of Mass Action (Replies: 8)

  2. Transistor Action (Replies: 3)

Loading...