The Principle, Application and Imaging of SRS

Stimulated Raman spectroscopy, also known as stimulated Raman scattering (SRS) is a spectroscopy technique used in physics, chemistry, biology and other fields. The generation mechanism is similar to that of spontaneous Raman spectroscopy: an excited photon with a corner frequency of \( \omega _{p}\) , when absorbed by the molecule, has a certain probability to induce a vibration (or rotation) transition (Unlike inducing a simple Rayleigh transition). This will result in a photon with an offset frequency emitted by the molecule. However, SRS, unlike spontaneous Raman spectroscopy, is a third-order nonlinear phenomenon that requires the second Stokes photon (angular frequency \( \omega _{S}\) ) to stimulate the transition of a specific frequency. When the frequency difference between two photons ( \(\omega _{p}-\omega _{S}\) ) is equal to a specific Vibration (or rotation) transition ( \(\omega _{\nu }\) ), the number of such transitions will increase resonantly.