Femtosecond Stimulated Raman Spectroscopy

Abstract

Femtosecond stimulated Raman spectroscopy is a method of time-resolved vibrational spectroscopy that has been developed since 1994. The method requires three ultrafast laser pulses: a 20–150 femtosecond (fs) actinic pump that excites a sample to an excited electronic state, a 1–3 picosecond (ps) Raman pump pulse that initiates the stimulated Raman transition, and a 20–150fs broad-bandwidth probe pulse. In femtosecond stimulated Raman spectroscopy, the probe experiences amplification at Raman resonances, that is, at wavelengths whose optical frequency differs from that of the Raman pump by an amount that matches a Raman-active molecular vibration in the sample.