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Acta Physica Sinica

DEGENERATE TWO-PHOTON LASERS: LASING WITHOUT INVERSION AND INVERSION WITHOUT LASING

Xiangming Hu, 华中师范大学应用物理研究所

Published Jan 1, 1994• 0 citations
Publisher

Abstract

In this paper, it is revealed that, degenerate two-photon lasers can show both lasing without inversion and without lasing, for two proper atom-field coupling coefficients, under the condition of equal atomic decay rates, not too large single-photon detunings, and not too saturation.
DOI
10.7498/aps.43.1090

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We show lasing without population inversion in a closed four-level atomic system which is no longer incoherently pumped on the transition at which lasing occurs. The four-level system can overcome some limits in the typical lambda-type and V-type three-level systems, furthermore it is possible to achieve lasing even in the absence of the inversion condition for the thermal radiation fields or of the inversion of spontaneous decay rate. We find that when the detuning of probe field is equal to that of coherent coupling field, there is a peak value along with the increase of the detuning. To explain it, we bring forward that there are adiabatic and nonadiabatic stimulated Raman processes when a three-level atomic system is interacted with two coherent fields, so there are two mechanisms influencing the change of probe field. We believe that it can explain more general lasing without inversion processes because of quantum interference induced by coherent fields.
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