Coherent anti-stokes Raman scattering spectroscopy (CARS) and imaging of DNA on graphene layers and glass covers

•We obtained images of DNA on the graphene surfaces without staining using Coherent Anti-Stokes Raman scattering technique (CARS).•These images were registered with high contrast that was enhanced by up to 10 times or more in comparison with glass substrate.•CARS spectrum of DNA molecules shows a shift towards lower frequencies in comparison to Raman spectrum.•At high DNA concentration new bands overtones and combination tones appear in the CARS spectrum compared to the Raman spectrum.