Lasing without inversion via decay induced coherence
Additional Document Info
The steady state lasing without inversion through decay induced coherence in the closed four-level atomic system is proven to be possible and it does not require a presence of any coherent driving field. The analysis is based on self-consistent quantum description of both decay and incoherent pump process. The gain threshold in the method under consideration lies below inversion threshold under condition that the temperature of the field reservoir coupled to the higher frequency atomic transition is higher than those coupled to the lower frequency transition.