In entangled two-photon absorption (eTPA) spectroscopy, information about the energy-level structure of an arbitrary sample is retrieved by Fourier transforming sets of measured two-photon absorption probabilities of entangled photon pairs where the degree of entanglement and the delay time between the photons are varied. This works well for simple systems but quickly becomes rather difficult when many intermediate states are involved. We propose and discuss an extension of eTPA spectroscopy that solves this problem by means of repeated measurements at different pump wavelengths, thus reducing the experimental complexity of eTPA spectroscopy by removing the need to control the correlations of the entangled photons. Specifically, we demonstrate that our extension works well for a variety of realistic experimental setups.

中文翻译：

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具有不同泵浦波长的纠缠双光子吸收光谱

在纠缠双光子吸收 (eTPA) 光谱中，通过对纠缠光子对的测量双光子吸收概率的傅立叶变换组检索有关任意样品能级结构的信息，其中纠缠程度和之间的延迟时间光子是多种多样的。这对简单系统很有效，但当涉及许多中间状态时，很快就会变得相当困难。我们提出并讨论了 eTPA 光谱的扩展，它通过在不同泵浦波长下重复测量解决了这个问题，从而通过消除控制纠缠光子相关性的需要来降低 eTPA 光谱的实验复杂性。具体来说，我们证明我们的扩展适用于各种现实的实验设置。