  A new interferometric technique is demonstrated for measuring Coherent
Anti-Stokes Raman Scattering (CARS) signals. Two forward-directed CARS signals
are generated, one in each arm of an interferometer. The deterministic nature
of the CARS process allows for these two signals, when spatially and temporally
overlapped, to interfere with one another. Heterodyne detection can therefore
be employed to increase the sensitivity in CARS signal detection. In addition,
nonlinear CARS interferometry will facilitate the use of this spectroscopic
technique for molecular contrast in Optical Coherence Tomography (OCT).
