Threshold behavior of superhyphen;radiance under continuous pumping

摘要

Recognizing that the superhyphen;radiance emission rate is proportional to the product of the number of cooperative atoms in the upper level and that in the lower level, we propose simple deterministic and stochastic equations to describe the evolution of the superhyphen;radiant atomic system pumped continuously at a constant rate. The steadyhyphen;state solutions of these equations display threshold behavior very similar to the laser. This provides yet another example of nonequilibrium phase transition of the second order.