Department of Chemistry, University of California, Irvine, CA 92614.
Department of Physics and Astronomy, University of California, Irvine, CA 92614.
Proc Natl Acad Sci U S A. 2023 Jul 25;120(30):e2304737120. doi: 10.1073/pnas.2304737120. Epub 2023 Jul 17.
We propose a time-frequency resolved spectroscopic technique which employs nonlinear interferometers to study exciton-exciton scattering in molecular aggregates. A higher degree of control over the contributing Liouville pathways is obtained as compared to classical light. We show how the nonlinear response can be isolated from the orders-of-magnitude stronger linear background by either phase matching or polarization filtering. Both arise due to averaging the signal over a large number of noninteracting, randomly oriented molecules. We apply our technique to the Frenkel exciton model which excludes charge separation for the photosystem II reaction center. We show how the sum of the entangled photon frequencies can be used to select two-exciton resonances, while their delay times reveal the single-exciton levels involved in the optical process.
我们提出了一种时频分辨光谱技术，该技术采用非线性干涉仪研究分子聚集体中的激子-激子散射。与经典光相比，我们获得了对贡献的里维路径的更高程度的控制。我们展示了如何通过相位匹配或偏振滤波从数量级更强的线性背景中分离出非线性响应。这两种情况都是由于对大量非相互作用的、随机取向的分子进行信号平均而产生的。我们将我们的技术应用于排除光系统 II 反应中心电荷分离的 Frenkel 激子模型。我们展示了如何使用纠缠光子频率的和来选择双激子共振，而它们的延迟时间则揭示了光学过程中涉及的单激子能级。
