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≡ωl/ωd of generated laser frequency to driving laser frequency that can be achieved using a vapor cell is modest (R<~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∼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.