IUPAC - coherent anti-Stokes Raman spectroscopy (08579)

coherent anti-Stokes Raman spectroscopy

initialism: CARS

https://doi.org/10.1351/goldbook.08579

Measurement method of Raman spectroscopy that uses third-order susceptibility and is one of several four-wave mixing spectroscopies. The excitation is through lasers of wavenumber

{\tilde{ν}}_{1}

and

{\tilde{ν}}_{2}

, which coincide spatially and temporally in the sample and produce an output laser of wavenumber

{\tilde{ν}}_{3} = 2 {\tilde{ν}}_{1} - {\tilde{ν}}_{2}

Notes:

Experimentally, ${\tilde{ν}}_{1}$ is kept constant and ${\tilde{ν}}_{2}$ is scanned. A laser beam output is observed at the wavenumber for anti-Stokes Raman scattering ${\tilde{ν}}_{1} + {\tilde{ν}}_{M}$ when ${\tilde{ν}}_{1} - {\tilde{ν}}_{2} = {\tilde{ν}}_{M}$ , where ${\tilde{ν}}_{M}$ is the wavenumber of an active vibration in the sample.
The Raman scattered radiation emerges as a laser beam instead of being scattered into three dimensions, thus greatly enhancing the sensitivity over that in normal Raman scattering.

Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 741 [Terms] [Paper]

Citation: 'coherent anti-Stokes Raman spectroscopy' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.08579 RIS BibTex EndNote

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coherent anti-Stokes Raman spectroscopy