@article{12732,
  author = {Alexander Mikhaylov and Ryan Wilson and Kristen Parzuchowski and Michael Mazurek and Charles Camp and Martin Stevens and Ralph Jimenez},
  title = {Hot-Band Absorption Can Mimic Entangled Two-Photon Absorption},
  abstract = {It has been proposed that entangled two-photon absorption (E2PA) can be observed with up to 10^10 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 ∼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.},
  year = {2022},
  journal = {The Journal of Physical Chemistry Letters},
  volume = {13},
  number = {6},
  pages = {1489-1493},
  month = {2022-02},
  url = {https://doi.org/10.1021/acs.jpclett.1c03751},
  doi = {10.1021/acs.jpclett.1c03751},
  note = {PMID: 35129354},
}