Experimental upper bounds for resonance-enhanced entangled two-photon absorption cross section of indocyanine green

被引：3

作者：

He, Manni ^{[1
]}

Hickam, Bryce P. ^{[1
]}

Harper, Nathan ^{[1
]}

Cushing, Scott K. ^{[1
]}

机构：

[1] CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA

来源：

JOURNAL OF CHEMICAL PHYSICS | 2024年 / 160卷 / 09期

关键词：

FLUORESCENCE QUANTUM YIELDS; ATOMIC COHERENCE; EXCITATION; DYES; STANDARDS; STATES;

D O I：

10.1063/5.0193311

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

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(+/- 2) x 10(-23) cm(2). 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(+/- 13) GM, where 1 GM equals 10(-50) cm(4) s, 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.

引用

页数：9

共 69 条

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