Non-resonant background suppression by destructive interference in coherent anti-Stokes Raman scattering spectroscopy.

Coherent anti-Stokes Raman scattering (CARS) with femtosecond interaction pulses has become a popular and powerful spectroscopic method. Non-resonant background is one of the most limiting factors for implementing this method more widely. We propose a new approach that suppresses the non-resonant background contribution to the measured signal in CARS spectroscopy while simultaneously yielding high spectral resolution. The method is based on femtosecond pulse shaping of probe, Stokes and pump beams. Destructive interference suppresses the non-resonant background, resulting only in the resonant contribution being detected.