Theory of femtosecond stimulated Raman spectroscopy
Theory of femtosecond stimulated Raman spectroscopy
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DOI：
10.1063/1.1777214
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发表时间：
2004-08-22
影响因子：
4.4
通讯作者：
Mathies, RA
中科院分区：
文献类型：
--
作者：
Lee, SY;Zhang, DH;Mathies, RA
飞秒宽带受激拉曼光谱（FSRS）是一种新技术，它可以从分子的基态或激发态产生高分辨率（时间分辨）的振动光谱，而不受背景荧光的影响。FSRS同时使用类似于1 -3 ps的窄带宽拉曼泵浦脉冲和类似于30 -50 fs斯托克斯探测脉冲的连续谱，在样品中对应于振动跃迁的位置处产生陡峭的拉曼增益，骑在连续斯托克斯探测谱的顶部。当FSRS之前是引发感兴趣的光化学的飞秒光化泵浦脉冲时，可以进行时间分辨的拉曼光谱。我们提出了两种FSRS的理论方法：一种是基于拉曼泵浦和探测光波与介质振动的耦合，另一种是量子力学描述。后一种方法是用来讨论耦合波描述的适用性和局限性的条件。扩展的量子力学描述的情况下，其中的拉曼泵浦光束是共振与激发电子态，以及当FSRS是用来探测由光化泵浦脉冲制备的非稳态振动波包，也进行了讨论。(C)2004年，美国物理学会。
Femtosecond broadband stimulated Raman spectroscopy (FSRS) is a new technique that produces high-resolution (time-resolved) vibrational spectra from either the ground or excited electronic states of molecules, free from background fluorescence. FSRS uses simultaneously a narrow bandwidth similar to1-3 ps Raman pump pulse with a continuum similar to30-50 fs Stokes probe pulse to produce sharp Raman gains, at positions corresponding to vibrational transitions in the sample, riding on top of the continuum Stokes probe spectrum. When FSRS is preceded by a femtosecond actinic pump pulse that initiates the photochemistry of interest, time-resolved Raman spectroscopy can be carried out. We present two theoretical approaches to FSRS: one is based on a coupling of Raman pump and probe light waves with the vibrations in the medium, and another is a quantum-mechanical description. The latter approach is used to discuss the conditions of applicability and limitations of the coupled-wave description. Extension of the quantum-mechanical description to the case where the Raman pump beam is on resonance with an excited electronic state, as well as when FSRS is used to probe a nonstationary vibrational wave packet prepared by an actinic pump pulse, is also discussed. (C) 2004 American Institute of Physics.