Batignani G, Fumero G, Mukamel S, Scopigno T
Dipartimento di Fisica, Universitá di Roma "Sapienza", I-00185 Roma, Italy.
Phys Chem Chem Phys. 2015 Apr 28;17(16):10454-61. doi: 10.1039/c4cp05361c.
We introduce a general theoretical description of non resonant impulsive femtosecond stimulated Raman spectroscopy in a multimode harmonic model. In this technique an ultrashort actinic pulse creates coherences of low frequency modes and is followed by a paired narrowband Raman pulse and a broadband probe pulse. Using closed-time-path-loop (CTPL) diagrams, the response on both the red and the blue sides of the broadband pulse with respect to the narrowband Raman pulse is calculated, the process couples high and low frequency modes, which share the same ground state. The transmitted intensity oscillates between the red and the blue side, while the total number of photons is conserved. The total energy of the probe signal is periodically modulated in time by the coherence created in the low frequency modes.
我们在多模谐波模型中引入了非共振脉冲飞秒受激拉曼光谱的一般理论描述。在该技术中，一个超短光化脉冲产生低频模式的相干性，随后是一个配对的窄带拉曼脉冲和一个宽带探测脉冲。使用闭时路径环（CTPL）图，计算了宽带脉冲相对于窄带拉曼脉冲在红边和蓝边的响应，该过程耦合了共享相同基态的高频和低频模式。透射强度在红边和蓝边之间振荡，而光子总数守恒。探测信号的总能量由低频模式中产生的相干性随时间周期性调制。
