Kavli Affiliate: Scott K. Cushing
| First 5 Authors: Manni He, Bryce P. Hickam, Nathan Harper, Scott K. Cushing,
| Summary:
Resonant intermediate states have been proposed to increase the efficiency of
entangled two-photon absorption (ETPA). Although resonance-enhanced ETPA
(r-ETPA) has been demonstrated in atomic systems using bright squeezed vacuum,
it has not been studied in organic molecules. We investigate for the first time
r-ETPA in an organic molecular dye, indocyanine green (ICG), when excited by
broadband entangled photons in near-IR. Similar to many reported virtual state
mediated ETPA (v-ETPA) measurements, no r-ETPA signals are measured, with an
experimental upper bound for the cross section placed at $6 times 10^{-23}$
cm$^2$/molecule. In addition, the classical resonance-enhanced two-photon
absorption (r-TPA) cross section of ICG at 800 nm is measured for the first
time to be $20(pm13)$ GM, suggesting that having a resonant intermediate state
does not significantly enhance two-photon processes in ICG. The
spectrotemporally resolved emission signatures of ICG excited by entangled
photons are also presented to support this conclusion.
| Search Query: ArXiv Query: search_query=au:”Scott K. Cushing”&id_list=&start=0&max_results=3