Femtosecond stimulated Raman spectroscopy by six-wave mixing.
Femtosecond stimulated Raman spectroscopy by six-wave mixing.
复制标题
飞秒通过六波混合受激拉曼光谱。
DOI：
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复制
发表时间：
2015
影响因子：
4.4
通讯作者：
Andrew M. Moran
中科院分区：
文献类型：
--
作者：
Brian P. Molesky;Zhenkun Guo;Andrew M. Moran
飞秒受激拉曼光谱（FSRS）是由亚皮秒化学反应伴随的分子几何结构变化的知识所激发的。用FSRS技术可以相当简单地实现在整个光谱指纹区域内以低于100 fs的延迟精度检测振动共振。尽管它的实用性，FSRS必须应对大量的技术挑战，从一个大的背景下的剩余激光和低阶非线性时，所有的激光脉冲是电子谐振的平衡系统。在这项工作中，一个几何形状的基础上五个入射激光束被用来消除这种不希望的背景在实验中进行高铁肌红蛋白。与具有所有电子共振激光脉冲的三光束FSRS几何结构相比，这里描述的五光束方法在数据采集速率、灵敏度和背景抑制方面提供了重大改进。使用对照实验和模型计算研究了五束几何结构对实验伪影的敏感性。特别值得关注的是不希望的级联的三阶非线性，这是众所周知的挑战FSRS测量上进行电子非谐振系统。人们普遍认为，在非共振条件下，所需的非线性光学过程中的“禁戒”步骤是所遇到的问题的根源。相比之下，本实验是在电子共振条件下进行的，这种不幸的选择规则不适用。尽管如此，控制实验的基础上，光谱线的形状，信号相位，和样品浓度进行排除显着的贡献级联的三阶过程。理论计算进一步用于估计直接和级联响应的相对强度。总体而言，在这项工作中提出的控制实验和模型计算表明，多维共振拉曼调查血红素蛋白的承诺。
Femtosecond Stimulated Raman Spectroscopy (FSRS) is motivated by the knowledge of the molecular geometry changes that accompany sub-picosecond chemical reactions. The detection of vibrational resonances throughout the entire fingerprint region of the spectrum with sub-100-fs delay precision is fairly straightforward to accomplish with the FSRS technique. Despite its utility, FSRS must contend with substantial technical challenges that stem from a large background of residual laser light and lower-order nonlinearities when all laser pulses are electronically resonant with the equilibrium system. In this work, a geometry based on five incident laser beams is used to eliminate much of this undesired background in experiments conducted on metmyoglobin. Compared to a three-beam FSRS geometry with all electronically resonant laser pulses, the five-beam approach described here offers major improvements in the data acquisition rate, sensitivity, and background suppression. The susceptibility of the five-beam geometry to experimental artifacts is investigated using control experiments and model calculations. Of particular concern are undesired cascades of third-order nonlinearities, which are known to challenge FSRS measurements carried out on electronically off-resonant systems. It is generally understood that "forbidden" steps in the desired nonlinear optical processes are the origin of the problems encountered under off-resonant conditions. In contrast, the present experiments are carried out under electronically resonant conditions, where such unfortunate selection rules do not apply. Nonetheless, control experiments based on spectroscopic line shapes, signal phases, and sample concentrations are conducted to rule out significant contributions from cascades of third-order processes. Theoretical calculations are further used to estimate the relative intensities of the direct and cascaded responses. Overall, the control experiments and model calculations presented in this work suggest promise for multidimensional resonance Raman investigations of heme proteins.
使用双中红外脉冲整形器的全吸收 3D 红外光谱。
DOI：
10.1063/1.4824638
发表时间：
2013
期刊：
The Journal of chemical physics
影响因子：
--
作者：
Mukherjee,SudiptaS;Skoff,DavidR;Middleton,ChrisT;Zanni,MartinT
通讯作者：
Zanni,MartinT
影响因子：
1.6
作者：
McCamant, DW;Kukura, P;Mathies, RA
通讯作者：
Mathies, RA
影响因子：
3.3
作者：
McCamant, David W.
通讯作者：
McCamant, David W.