a College of Physics, Jilin University, Changchun 130023, China; b Chinese Center of Advanced Science and Technology (World Laboratory), Beijing 100080, China
Abstract We propose a new four-level atomic model for achieving light amplification at a short wavelength, where direct incoherent pumping into the top level is avoided by the advantage of coherent pumping. In this model, the lower level of the probe transition is an excited state but not the usual ground state. By analytical as well as numerical calculations, we find that the probe gain, either with or without population inversion, which depends on the relation between spontaneous decay rates $\gamma_{42}$ and $\gamma_{21}$, can be achieved with proper parameters. We note that the Raman scattering gain always plays an important role in achieving the probe amplification.
Received: 17 July 2002
Revised: 18 September 2002
Accepted manuscript online:
Fund: Project supported in part by the National Natural Science Foundation of China (Grant No 60078015), and the Doctoral Program Foundation of Institution of Higher Education of China (Grant No 19201038)
Cite this article:
Wu Jin-Hui (吴金辉), Wang Deng-Pan (王登攀), Zhang Hui-Fang (张惠芳), Xiao Zhi-Hong (肖志宏), Gao Jin-Yue (高锦岳) The probe gain with and without inversion in a four-level atomic model: light amplification at a short wavelength 2003 Chinese Physics 12 39
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