What is the quantum mechanics descriptions for a plasma radiation

[xhtp2000]

Most ideal light radiates uniformly in all directions. It means that for each photon, the probability of each direction is the same for a single photon. The specific optical resonator design enables a laser beam to propagate in one definite direction. Could anyone tell me what modifications does the optical resonator offer in the state function of a photon? Is that possible to confine a plasma and let the plasma emit in one specific direction? Could anyone refer me to some literature in this field? What is the quantum mechanics descriptions of this modification?

 

[mfb]

Laser has induced light emission from a population inversion - something your plasma has not. The optical resonator "just" improves the quality of the laser light, as it can pass through the medium multiple times, and only "survives" with specific frequencies.