Lasing without inversion with frequency up-conversion in a Doppler-broadened V-type three-level system

We study lasing without inversion in a Doppler-broadened V-type three-level system in the frequency up-conversion regime. We show that the ratio R=omega(l)/omega(d) of generated laser frequency to driving laser frequency that can be achieved using a vapor cell is modest (R less than or equal to 2). Our analysis demonstrates that using an atomic beam the frequency of the generated field can be substantially larger than that of the driving field R similar to 10. Two different configurations are considered: (a) copropagating driving and laser beams orthogonal to the atomic beam, and (b) counterpropagating driving and atomic beams and laser beam at a determined angle with the driving beam.