Transverse profile effects on lasing without population inversion

We analyse the effects of a Gaussian transverse profile for the driving and laser fields on lasing without population inversion, in four different thr ee-level schemes. We show that the lasing domains can be considerably reduc ed with respect to the plane-wave case in the V and in the cascade configur ation driven in the upper transition, while in the Lambda and in the cascad e configuration driven in the lower transition such domains are always larg er in the Gaussian case.