Hot-Band Absorption Can Mimic Entangled Two-Photon Absorption
Hot-Band Absorption Can Mimic Entangled Two-Photon Absorption
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DOI：
10.1021/acs.jpclett.1c03751
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发表时间：
2022-02-17
影响因子：
5.7
通讯作者：
Jimenez, Ralph
中科院分区：
文献类型：
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作者：
Mikhaylov, Alexander;Wilson, Ryan N.;Jimenez, Ralph
有人提出，纠缠双光子吸收(E2PA)可以在比经典双光子吸收低1010个光子的情况下观察到，从而实现了超低倍双光子荧光显微镜。然而，关于这种量子增强在激发效率上的幅度存在着重大的争议。我们研究了罗丹明6G和LDS798在1060 nm附近用连续激光或纠缠光子对激发的荧光信号。我们观察到一个来自热带吸收(HBA)的信号，这是来自基电子态的热填充振动能级的单光子吸收。该机制以前没有在E2PA的上下文中讨论过，它产生具有线性功率依赖性的信号，正如对于E2PA所期望的那样。对于进行E2PA测量的典型条件，HBA过程的贡献可能导致对量子优势的几个数量级的高估。
It has been proposed that entangled two-photon absorption (E2PA) can be observed with up to 1010 lower photon flux than its classical counterpart, therefore enabling ultralow-power two-photon fluorescence microscopy. However, there is a significant controversy regarding the magnitude of this quantum enhancement in excitation efficiency. We investigated the fluorescence signals from Rhodamine 6G and LDS798 excited with a CW laser or an entangled photon pair source at similar to 1060 nm. We observed a signal that originates from hot-band absorption (HBA), which is one-photon absorption from thermally populated vibrational levels of the ground electronic state. This mechanism, which has not been previously discussed in the context of E2PA, produces a signal with a linear power dependence, as would be expected for E2PA. For the typical conditions under which E2PA measurements are performed, contributions from the HBA process could lead to a several orders of magnitude overestimate of the quantum advantage.