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Updated: Feb 4, 2026

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Investigations of Thienoacene Molecules for Classical and Entangled Two-Photon Absorption
Audrey Eshun1, Zhengxu Cai2, Mohammed Awies3
1Department of Chemistry , University of Michigan , 930 N University Avenue , Ann Arbor , Michigan 48109 , United States.
Abstract:
Investigations of the optical effects in thienoacene chromophores with different central atoms were performed. These chromophores provide a basis for the comparison of the linear, two-photon, and entangled two-photon properties in organic molecules with varying degrees of dipolar or quadrupolar character. Linear absorption and emission as well as time-dependent density functional theory calculations were performed for the chromophores investigated. Measurements of the classical two-photon absorption (TPA), entangled two-photon absorption (ETPA), as well as entangled two-photon fluorescence were experimentally performed for the four chromophores. Electronic structure calculations were utilized to provide estimates of the classical two-photon absorption coefficients. The results of the measured entangled two-photon cross sections were compared with theoretical estimates for the molecules investigated. It is found that the dipole (transition or permanent) pathway can have an effect on the trends in the entangled photon absorption process in dipolar organic chromophores. This study helps predict the properties of the entangled two-photon effect in chromophores with different dipolar and quadrupolar character.
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