Wj. Brown et al., AMPLIFICATION OF LASER-BEAMS PROPAGATING THROUGH A COLLECTION OF STRONGLY DRIVEN, DOPPLER-BROADENED 2-LEVEL ATOMS, Physical review. A, 55(3), 1997, pp. 1601-1604
We investigate theoretically the amplification of a laser beam propaga
ting through a collection of Doppler-broadened two-level atoms driven
by an intense counterpropagating laser beam. Large amplification of th
e beam is predicted when the pump-beam Rabi frequency is comparable to
the Doppler width of the atomic transition, even without including th
e effects of atomic recoil. The microscopic origin of the gain can be
attributed to the coherent driving of the atomic dipole moment, sugges
ting that amplification and lasing due to collective atomic recoil may
be influenced by this process.