Raman scattering and vacuum fluctuation: An Einstein-coefficient-like equation for Raman cross sections.
Raman scattering and vacuum fluctuation: An Einstein-coefficient-like equation for Raman cross sections.
复制标题
拉曼散射和真空涨落：一个类似爱因斯坦系数的拉曼截面方程。
DOI：
10.1063/5.0171382
复制
发表时间：
2023-11-21
期刊：
影响因子：
--
通讯作者：
中科院分区：
文献类型：
--
作者：
自100年前首次预测以来，拉曼散射一直是分子光谱学的基石，对科学和技术产生了广泛的影响。几乎所有的理论框架都采用拉曼截面（σ拉曼）来表征和量化分子的拉曼响应。另一方面，最近引入的绝对受激拉曼散射截面（σSRS）提供了一种解释两个相干激光源下分子响应的替代方法。然而，σ拉曼和σSRS之间的理论联系仍然不清楚。在此，我们受到爱因斯坦的自发和受激发射的A和B系数的启发，并推导出类似的方程[Eq. (16)]从沿着量子电动力学的方法来研究拉曼散射。方程（16）将拉曼截面分解为来自真空电磁场的贡献和由受激拉曼截面捕获的潜在分子响应（以Göppert-Mayer为单位）。这种理论关系是支持最近的实验测量甲醇作为模型化合物。最重要的是，它提供了一个实验定义的σ拉曼和σSRS在某些近似之间的连接。另外，定量地说明了是斯托克斯通道的弱真空场导致了拉曼截面的减小，从而证实了传统的拉曼理论。受激拉曼散射截面是表征分子拉曼散射响应的真空解耦本征量。值得注意的是，受激拉曼截面证明是不弱时，与双光子吸收，缩小了传统的差距之间的截面自发拉曼和紫外-可见吸收超过1010倍。
Since it was first predicted 100 years ago, Raman scattering has been a cornerstone of molecular spectroscopy with a widespread impact on science and technology. Nearly all theoretical frameworks have employed Raman cross sections (σRaman) to characterize and quantify molecular Raman response. The recently introduced absolute stimulated Raman scattering cross section (σSRS), on the other hand, provides an alternative way of interpreting molecular responses under two coherent laser sources. However, the theoretical connection between σRaman and σSRS remains unclear. Herein, we are inspired by Einstein’s A and B coefficients for spontaneous and stimulated emissions and derived an analogous equation [Eq. (16)] for Raman scattering from an approach along quantum electrodynamics. Equation (16) decomposes Raman cross sections into a contribution from the vacuum electromagnetic field and an underlying molecular response captured by stimulated Raman cross sections (in the unit of Göppert–Mayer). This theoretical relation is supported by recent experimental measurements on methanol as a model compound. Foremost, it provides a connection between experimentally defined σRaman and σSRS under certain approximations. In addition, it quantitatively shows that it is the weak vacuum field of the Stokes channel that makes Raman cross sections appear so small, corroborating the conventional Raman theory. Moreover, it suggests stimulated Raman cross sections to be a vacuum-decoupled intrinsic quantity for characterizing molecular response during Raman scattering. Remarkably, stimulated Raman cross sections turn out to be not weak when compared to two-photon absorption, narrowing the conventional gap of cross sections between spontaneous Raman and UV–vis absorption by more than 1010 folds.
登录
查看更多内容
影响因子：
62.1
作者：
Prince RC;Frontiera RR;Potma EO
通讯作者：
Potma EO
影响因子：
2.5
作者：
KRISHNAN, RS;SHANKAR, RK
通讯作者：
SHANKAR, RK
影响因子：
2.9
作者：
Petrak, Benjamin;Djeu, Nicholas;Muller, Andreas
通讯作者：
Muller, Andreas
影响因子：
7.4
作者：
Burns, Kristen H.;Srivastava, Prasenjit;Elles, Christopher G.
通讯作者：
Elles, Christopher G.
影响因子：
8.6
作者：
CAIRO, F;DEMARTINI, F;MURRA, D
通讯作者：
MURRA, D