Self-pulsing lasing without inversion in the double-Λ scheme

Lasing without inversion (LWI) is investigated from a nonlinear dynamics point of view for an atomic system with three coupled J = 0-1 transitions. The driving and generated fields couple two of these transitions defining a double- ##IMG## [http://ej.iop.org/images/1355-5111/10/2/005/img7.gif] scheme. In addition, two incoherent pump fields are acting on the system. We find that LWI can occur not only in a continuous wave regime but also in a self-pulsing regime. A clear physical interpretation of the origin of this self-pulsing LWI is given. We obtain analytically the threshold driving field intensity needed to achieve both continuous wave and self-pulsing LWI emission. For large enough cavity losses, the system can reach either continuous wave or self-pulsing regimes by only changing the driving field intensity.