We present a novel detection scheme for coherent anti-Stokes Raman scattering (CARS) which is capable of substantially suppressing coherent background signals which are a basic problem associated with CARS. It exploits the fixed phase relationship between pump, Stokes and CARS fields together with the strong phase coherence in supercontinua generated by femtosecond pulses. Three phase-locked noncollinearly phase-matched optical parametric amplifiers (NOPAs) seeded by a common white-light continuum are used for the realization of a heterodyne signal detection. In combination with proper pulse timing, i.e. appropriately time-delayed probing and heterodyning, a gating mechanism is provided to significantly suppress resonant and nonresonant solvent background signals. Therefore the demonstrated technique is suitable for high-contrast vibrational imaging.