Enhancement of gain without inversion in hybrid systems

Sunnel Singh, Charles M. Bowden, Jagdish Rai

A. K. Popov, Vasily G. Arkhipkin, T. Muller-Wirts +1 more

Peter B. Sellin, Geoffrey A. Wilson, Krishna K. Meduri +1 more

We experimentally study the production of laser gain (phase-insensitive optical amplification) with and without atomic population inversion in a doubly driven three-level system in atomic barium. The external fields are found to create inversionless gain and to enhance gain available in the presence of inversion. Laser oscillation based on enhanced gain is observed. In analysis of the driven system, we identify an irreversible multiphoton process that is intrinsically supportive of gain in the absence of population inversion. \textcopyright{} 1996 The American Physical Society.

Fan Xi-jun

We put forward a model of an open quasi Λ-type four-level atomic system,and then investigate the effect of spontaneously generated coherence(SGC) on the gain of lasing without inversion from different respects by using the numerical calculation results of the system in the steady state.The study results show that,the switching from absorption to lasing without inversion(LWI) and the enhancement of the LWI gain can be realized by adjusting the strength of SGC;the variety of the two factors p1 to p2 which represent the SGC effect will produce remarkable different influence on the LWI gain.We also find that,the LWI gain is much larger in open system than that in the corresponding closed system;moreover,when the incoherent pump field is absent,the LWI gain can be obtained in the open system but cant in the closed system.