We report on an optically pumped laser where photons are simultaneously generated by population inversion and by stimulated Raman scattering in the same active medium, namely crystalline silicon doped by bismuth (Si:Bi). The medium utilizes three electronic levels: ground state (\textbar 1$\rangle $: 1s(A$_{1})$ in Si:Bi), upper (\textbar 3$\rangle $: 2p$_{\pm })$ and lower (\textbar 2$\rangle $: 1s(E)) laser levels. The \textbar 1$\rangle \leftrightarrow $\textbar 3$\rangle $ and \textbar 2$\rangle \leftrightarrow $\textbar 3$\rangle $ transitions are optically allowed and the \textbar 1$\rangle \leftrightarrow $\textbar 2$\rangle $ transition is Raman active. Lasing based on population inversion occurs between the states \textbar 3$\rangle $ and \textbar 2$\rangle $ while Raman scattering benefits from the Raman-active transition. At high pump power the inversion-based stimulated emission \textbar 3$\rangle \to $\textbar 2$\rangle $ disappears, because electronic scattering from \textbar 1$\rangle $~to~\textbar 2$\rangle $ via a virtual state dominates and the electrons are excited into \textbar 2$\rangle $ rather than into \textbar 3$\rangle $. Starting as population inversion based lasing, it ends as stimulated Raman scattering. Our model shows that such a competition occurs on the time scale of the 10~ps long pump pulse.

中文翻译：

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在掺杂硅中竞争基于反转的激光和拉曼激光

我们报道了一种光泵浦激光器，其中在相同的活性介质中，即由铋（Si：Bi）掺杂的晶体硅，通过人口反转和受激拉曼散射同时产生光子。该介质利用三个电子级别：基态（Si：Bi中的\ textbar 1 $ \ rangle $：1s（A $ _ {1}）$），上层状态（\ textbar 3 $ \ rangle $：2p $ _ {\ pm }）$和更低的水平（\ textbar 2 $ \ rangle $：1s（E））激光水平。\ textbar 1 $ \ rangle \ leftrightarrow $ \ textbar 3 $ \ rangle $和\ textbar 2 $ \ rangle \ leftrightarrow $ \ textbar 3 $ \ rangle $过渡在视觉上是允许的，而\ textbar 1 $ \ rangle \ leftrightarrow $ \ textbar 2 $ \ rangle $过渡激活拉曼。在状态\ textbar 3 $ \ rangle $和\ textbar 2 $ \ rangle $之间发生基于总体反转的激射，而拉曼散射则受益于拉曼主动跃迁。在高泵浦功率下，基于反转的受激发射\ textbar 3 $ \ rangle \ to $ \ textbar 2 $ \ rangle $消失，因为从\ textbar 1 $ \ rangle $〜to〜\ textbar 2 $ \ rangle $ via的电子散射虚拟状态起主导作用，电子被激发到\ textbar 2 $ \ rangle $中，而不是被激发到\ textbar 3 $ \ rangle $中。从基于种群反转的激光开始，直到受激拉曼散射结束。我们的模型表明，这种竞争发生在10ps长泵浦脉冲的时间尺度上。它结束于受激拉曼散射。我们的模型表明，这种竞争发生在10ps长泵浦脉冲的时间尺度上。它结束于受激拉曼散射。我们的模型表明，这种竞争发生在10ps长泵浦脉冲的时间尺度上。