Lasing without inversion in three-level systems without external coherent driving -: art. no. 053814

We have studied an incoherently pumped laser operating with a Doppler-broadened three-level system placed in a doubly resonant cavity. This system generates two laser fields, one of them without population inversion. Both ladder and V-type three-level schemes are considered with a ratio R = omega(alpha)/omega(beta) of inversionless laser frequency omega(alpha) to ordinary laser frequency omega(beta) of R = 0.67 and R = 1.88, respectively. Dual-wavelength lasing extends up to Doppler-broadening values for optical transitions of atoms in a vapor cell. Some considerations for the practical realization of this dual-wavelength laser are discussed.