Hyper and Stimulated Raman Spectroscopy

Stimulated Raman Spectroscopy (SRS) is a powerful spectroscopic technique to probe the vibrational structure of chemical and biological system of interest in both steady and transient state. In principle, SRS is based on Stimulated Raman Scattering, a coherent process, and has proven its capability to suppress or even reject limitation of spontaneous Raman. In Femtosecond stimulated Raman spectroscopy (SRS), a narrow bandwidth picosecond Raman pump pulse and a continuum broadband femtosecond probe pulse interact simultaneously with the sample to produce Raman signals at positions corresponding to the vibrational transitions in the sample. The observation of stimulated Raman signal as a gain on stoke side and as a loss on anti-stoke side with respect to Raman pump are referred to as Femtosecond stimulated Raman Gain spectroscopy or Femtosecond stimulated Raman spectroscopy (FSRS) and Ultrafast Raman loss Spectroscopy (URLS), respectively. In this chapter, theoretical concept SRS and experimental studies on excited state molecular dynamics using FSRS and URLS is presented. In addition, the theoretical basis and experimental studies of Hyper-Raman spectroscopy, an analogue to Raman spectroscopy, is also presented in this book chapter.