纠缠双光子吸收的弗兰森干涉测量界限
Franson-Interferometric Bounds on Entangled Two-Photon Absorption
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中文总结 AI 辅助
该研究利用弗兰森干涉法结合延迟依赖符合测量，对罗丹明6G的纠缠双光子吸收进行实验，得到其有效截面并建立了定量界限与无背景基准。
中文摘要 AI 辅助
纠缠光子具有无经典对应物的量子关联。在纠缠对双光子吸收（ETPA）中，吸收速率预计与光子通量呈线性而非二次方关系，有望在远低于经典阈值的通量下实现分子激发。然而，已报道的ETPA截面在不同实验中差异很大，这主要是因为可观测的透射通量或弱荧光的微分信号难以与散射和线性损耗分离。我们提出一种利用弗兰森（Franson）干涉研究染料分子中纠缠双光子吸收的方法，该方法通过延迟依赖的符合测量实现。将该方法应用于罗丹明6G（Rhodamine 6G）时，我们观察到弗兰森干涉包络存在微小不对称性，并得到模型推导的罗丹明6G有效截面约为2.1×10^-21平方厘米。不过，估计的系统不确定性无法明确确定ETPA的归属。相反，该实验建立了ETPA响应的定量界限，并为未来测量提供了无背景的基准。
英文摘要
Entangled photons offer quantum correlations with no classical analogue. In entangled pair two-photon absorption (ETPA), absorption rate is predicted to scale linearly rather than quadratically with photon flux, promising molecular excitation at fluxes far below the classical threshold. Reported ETPA cross sections nevertheless vary widely across experiments, largely since the observable, the differential of the transmitted flux or weak fluorescence, is difficult to separate from scattering and linear losses. We present a method which uses Franson interference to study entangled two-photon absorption through delay-dependent coincidence measurements on dye molecules. Applying the method to Rhodamine 6G, we observe a small asymmetry in the Franson interference envelope and obtain a model-derived effective cross section of approximately 2.1 E(-21) centimeter squared for Rhodamine 6G. However, the estimated systematic uncertainty does not allow a definitive ETPA assignment. Instead, the experiment establishes a quantitative bound on the ETPA response and provides a background-free benchmark for future measurements.
