Premium
A practical analysis for coherent anti‐stokes Raman scattering (CARS) spectra
Author(s) -
Fleming James W.,
Johnson Charles S.
Publication year - 1979
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250080513
Subject(s) - raman spectroscopy , raman scattering , coherent anti stokes raman spectroscopy , laser linewidth , amplitude , x ray raman scattering , spectral line , superposition principle , resonance (particle physics) , nonlinear system , chemistry , perturbation theory (quantum mechanics) , physics , optics , quantum mechanics , laser
In coherent anti‐Stokes Raman scattering (CARS) spectra for condensed phases, the shape and position of an isolated line depend on the Raman cross‐section, the linewidth, the vibrational frequency and the nonresonant electronic susceptibility. Equations are presented here which relate these quantities to the measured maximum and minimum intesities and the associated frequency shifts, ω L — ω s . In the case of electronic resonance enhancement, where the Raman amplitude has real and imaginary parts, a complete analysis was obtained using the intensity I mid measured at the mid‐frequency between the extrema as the fifth known quantity. However, when the electronic susceptibility is also complex, it is a completely general result that its real and imaginary parts are mixed with those for the Raman amplitude so that only certain combinations of quantities can be obtained. Equations are also presented to correct for the interference resulting from neighboring lines. The derivations are based on perturbation theory expressions for the third‐order nonlinear susceptibility χ (3) , and the results are interpreted in terms of susceptibility plots in the complex plane.