Skip to main content
Chemistry LibreTexts

3.5: CARS (Coherent Anti-Stoke Raman Scattering)

  • Page ID
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    Used to drive ground state vibrations with optical pulses or cw fields.

    • Two fields, with a frequency difference equal to a vibrational transition energy, are used to excite the vibration.
    • The first field is the “pump” and the second is the “Stokes” field.
    • A second interaction with the pump frequency lead to a signal that radiates at the anti-Stokes frequency: \(\omega_{sig}=2\omega_P-\omega_S\) and the signal is observed background-free next to the transmitted pump field: \(\bar k_{sig}=2\bar k_P-\bar k_S\).


    The experiment is described by R1 to R4, and the polarization is

    \[\begin{aligned} R^{(3)} &=\bar \mu_{ev'} \bar \mu_{v'g} e^{-i\omega_{eg}\tau-\Gamma_{eg}\tau} \bar \mu_{gv} \bar \mu_{ve} +c.c. \\ &=\bar\alpha_{eg}e^{-i\omega_{eg}\tau-\Gamma_{eg}\tau}\bar\alpha_{ge}+c.c. \end{aligned} \nonumber\]

    The CARS experiment is similar to a linear experiment in which the lineshape is determined by the Fourier transform of \(C(\tau)=\langle\bar\alpha(\tau)\bar\alpha(0)\rangle\).

    The same processes contribute to Optical Kerr Effect Experiments and Impulsive Stimulated Raman Scattering.

    3.5: CARS (Coherent Anti-Stoke Raman Scattering) is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

    • Was this article helpful?