The dependence of Fourier transform nonlinear Raman spectroscopies on the temporal characteristics of the excitation fields

Abstract

A perturbation theory analysis of Fourier transform (interferometric) versions of coherent Raman scattering and ionization-detected (or fluorescence-detected) stimulated Raman scattering is presented. The analysis has the principal aim of examining the information content of these spectroscopies as a function of the temporal characteristics of the excitation fields. The general conclusion of the analysis is that the information content of the techniques does not depend on excitation pulsewidths and, in particular, that spectral resolution is not limited by such pulsewidths. This is an important result because it allows for the use of short-pulse laser systems in implementing the methods. It is also shown, however, that the temporal characteristics of the excitation fields do influence the practical implementations of the spectroscopies significantly in that signal-to-noise ratios, Doppler broadening, etc. can be dependent on these characteristics.