Investigation of the emission line width of an injection laser in strong and weak fields

An investigation was made of the behavior of the temporal coherence length of the radiation emitted from single-channel injection lasers when the radiation intensity was varied. The rate of rise of the coherence length with increasing intensity slowed down sharply in the range ~ 10⁵W/cm², which corresponded to a transition from a weak to a strong field. The field was considered strong when the interband stimulated emission time became shorter than the energy relaxation time. Measurements indicated that the temporal and spatial coherence of the radiation emitted from single-channel injection lasers was comparable with the coherence of the radiation emitted from gas lasers.