Probe spectroscopy in an inhomogeneously broadened three-level system saturated by an intense standing wave
Probe spectroscopy in an inhomogeneously broadened three-level system saturated by an intense standing wave
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DOI：
10.1103/physreva.23.1874
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发表时间：
1981-04
影响因子：
2.9
通讯作者：
E. Kyrölä;R. Salomaa
中科院分区：
文献类型：
--
作者：
E. Kyrölä;R. Salomaa
我们研究了非均匀展宽的三能级原子（$\ensuremath{\Lambda}$构型）。两个能级由一个强烈的驻波紧密耦合。相邻跃迁处的弱激光场用作探针。探针响应由格林函数计算，其中包括连分式。一般解决方案可扩展到其他三电平配置以及其他类型的多模饱和器。讨论了各种近似解与精确解的联系。我们集中讨论无多普勒的情况，其中两个跃迁具有几乎相等的频率。为此，我们导出了一个相当精确的闭型解，并对其参数依赖性进行了详细的研究。除了其平均变化外，饱和跃迁的动力学在稳态探针响应中起着重要作用。光谱显示出尖锐的共振，这不能用行波叠加模型来解释。速度分布的宽度对频谱的形状有很大的影响——由于不完全的多普勒减相，一些共振被抹去了。弛豫过程对共振的影响不同，这有利于它们的解释。
We study inhomogeneously broadened three-level atoms ($\ensuremath{\Lambda}$ configuration). Two energy levels are strongly coupled by an intense standing wave. A weak laser field at an adjacent transition is used as a probe. The probe response is calculated by Green's functions involving continued fractions. The general solution is extendable to other three-level configurations as well to other types of multimode saturators. The connection of various approximate solutions to the exact one is discussed. We concentrate on the Doppler-free case where both transitions have nearly equal frequencies. For this we derive a reasonably accurate closed-form solution, the parameter dependencies of which are investigated in detail. In addition to its average changes the dynamics of the saturated transition plays an important role in the steady-state probe response. The spectra show sharp resonances which cannot be explained in terms of traveling wave superposition models. The width of the velocity distribution has a strong effect on the shape of the spectrum---some resonances are smeared away because of incomplete Doppler dephasing. The relaxation processes influence differently the resonances, which facilitates their interpretation.