Conventional microscopy techniques depend on the availability of fluorescent dyes and biological structures which can be labeled or show inherent fluorescence such as autofluorescence. For new applications, new labels are often needed to visualize interesting details. CARS (Coherent Anti-Stokes Raman Scattering) microscopy is a dye-free method which images structures by displaying the characteristic intrinsic vibrational contrast of their molecules. The crucial advantage of this method is that the sample remains almost unaffected.

This tutorial explains the molecular basics on Coherent Anti-Stokes Raman Scattering.