G. Vemuri et Gs. Agarwal, ROLE OF INHOMOGENEOUS BROADENING IN LASING WITHOUT INVERSION IN LADDER SYSTEMS, Physical review. A, 53(2), 1996, pp. 1060-1064
We study the effect of Doppler broadening on the inversionless gain th
at can be realized in a ladder configuration. The gain is calculated w
hen the strong coherent pump and the weak probe are either copropagati
ng or counterpropagating. The results indicate that the counterpropaga
ting situation is the optimal one for obtaining maximum amplification,
since for identical Doppler broadening, the counterpropagating geomet
ry yields higher amplification than the copropagating geometry. The ef
fect of Doppler broadening on electromagnetically induced transparency
in the same atomic system is also briefly discussed.