Spatial coherence produced in laser radiation on passing through the generation threshold
Akhmanov S.A., Pakhalov V.B., Chirkin A.S.
The behavior of the spatial statistics of a laser field when the generation threshold is approached is investigated. It is established that the correlation radius #cor~(8—5thr)~U2, where dcor is the loss at which lasing sets in. The data obtain* can be used to identify the laser regime. Attention is called to the fact that the experimentally obtained relations Rcar = rLOr(6) is in good agreement with the Landau self-consistent-field theory for second-order phase transitions. (The critical exponent is very close to the theoretical value 0.5; experiment yields 0.49 ±0.05.)