A noninversion laser system which is closed lifetime broadened and free of the restriction on atomic decay rates is proposed. For the realization of lasing without inversion, the Rabi frequency of the applied field must exceed a lower threshold. Moreover, the coherence term in dressed states must enhance the gain. These results are obtained beyond the specific approximations

For atoms of three-state ladder or V configuration, a large population may be 'locked' into a single high-lying excited state via atomic lower-state coherence even when it exceeds the total population in the two lower states. The conditions are analysed and the two systems are compared.

Role of atomic coherence in lasing without inversion.

'Locking' large atomic population into an excited state via quantum interference

The three-level system subjected to electromagnetic fields is investigated. It is shown that when one of two fields is strong (the pumping field), the system can amplify the second (probe) field even if no population inversion is created, but some phase relations are satisfied. The conditions necessary for inversionless amplification to take place are discussed. The connection between this effect and stimulated Raman emission is shown. Numerical simulations for each one of the discussed cases were performed.

Role of atomic coherence in lasing without inversion.

Citations

'Locking' large atomic population into an excited state via quantum interference

Inversionless Amplification in a Three‐Level System Driven by a Single Field

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