Broadband Two-Photon Absorption Spectroscopy with Stimulated Raman Scattering as an Internal Standard
Broadband Two-Photon Absorption Spectroscopy with Stimulated Raman Scattering as an Internal Standard
复制标题
以受激拉曼散射作为内标的宽带双光子吸收光谱
DOI：
10.1021/acs.analchem.3c02298
复制
发表时间：
2023
影响因子：
7.4
通讯作者：
Elles, Christopher G.
中科院分区：
文献类型：
--
作者：
Srivastava, Prasenjit;Stierwalt, David A.;Elles, Christopher G.
双光子吸收（2PA）光谱提供了有关分子非线性特性的宝贵信息。与单波长方法相比，使用泵浦探针方法的宽带2PA光谱在不调整激发激光的情况下，在广泛的跃迁能量范围内提供连续的2PA光谱。这一贡献表明，溶剂的受激拉曼散射可以作为一种方便和强大的内标准，用于使用宽带方法获得精确的绝对2PA截面。受激拉曼散射具有与2PA相同的泵浦-探针重叠依赖性，因此无需直接测量泵浦和探针的强度相关重叠。消除重叠是一项重要的改进，因为强度分布通常是使用任何方法测量绝对2PA横截面时最大的不确定性来源。拉曼散射截面是溶剂的基本性质，因此提供了一个通用的标准，可以在任何时候应用2PA和拉曼信号在相同的探测波长范围内。我们使用香豆素153在甲醇、二甲二甲砜和甲苯中的样品溶液以及荧光素在水中的样品溶液来证明这种方法。
Two-photon absorption (2PA) spectroscopy provides valuable information about the nonlinear properties of molecules. In contrast with single-wavelength methods, broadband 2PA spectroscopy using a pump–probe approach gives a continuous 2PA spectrum across a wide range of transition energies without tuning the excitation laser. This contribution shows how stimulated Raman scattering from the solvent can be used as a convenient and robust internal standard for obtaining accurate absolute 2PA cross sections using the broadband approach. Stimulated Raman scattering has the same pump–probe overlap dependence as 2PA, thus eliminating the need to measure the intensity-dependent overlap of the pump and probe directly. Eliminating the overlap represents an important improvement because intensity profiles are typically the largest source of uncertainty in the measurement of absolute 2PA cross sections using any method. Raman scattering cross sections are a fundamental property of the solvent and therefore provide a universal standard that can be applied any time the 2PA and Raman signals are present within the same probe wavelength range. We demonstrate this approach using sample solutions of coumarin 153 in methanol, DMSO, and toluene, as well as fluorescein in water.