Theory of femtosecond stimulated Raman spectroscopy

Abstract

Femtosecond broadband stimulated Raman spectroscopy (FSRS), a technique that produces high-resolution vibrational spectra from either the ground or excited electronic states of molecules, free from background fluorescence, was analyzed. A narrow bandwidth ∼1-3 ps Raman pump pulse with a continuum ∼30-50 fs Stokes probe pulse to produce sharp Raman gains was simultaneously used by FSRS. It was shown that when FSRS is preceded by a femtosecond actinic pump pulse that initiates the photochemistry of interest, time-resolved Raman spectroscopy can be carried out. Extension of the quantum-mechanical description to the case where the Raman pump beam is on resonance with an excited electronic state, was also discussed.