Fleischhauer M
Opt Express. 1999 Jan 18;4(2):107-12. doi: 10.1364/oe.4.000107.
The preparation of an optically dense ensemble of three- level systems in dark states of the interaction with coherent radiation is discussed. It is shown that methods involving spontaneous emissions of photons such as Raman optical pumping fail to work beyond a critical density due to multiple scattering and trapping of these photons and the associated decay of the dark state(s). In optically thick media coherent-state preparation is only possible by entirely coherent means such as stimulated Raman adiabatic passage (STIRAP). It is shown that STIRAP is the underlying physical mechanism for electromagnetically induced transparency (EIT).
讨论了在与相干辐射相互作用的暗态中制备光学密集的三能级系统系综的问题。结果表明，诸如拉曼光泵浦等涉及光子自发发射的方法，由于这些光子的多次散射和俘获以及相关暗态的衰减，在超过临界密度时无法起作用。在光学厚介质中，只有通过诸如受激拉曼绝热通道（STIRAP）等完全相干的手段才能实现相干态制备。结果表明，STIRAP是电磁感应透明（EIT）的潜在物理机制。
