Waveguide-based optical parametric amplification for coherent Raman imaging

Silicon nitride (Si 3 N 4 ) waveguides offer a versatile on-chip platform, on which nonlinear processes such as four-wave mixing (FWM) can be driven very efficiently due to the high nonlinearity [1] . Therefore, lower pump energies and shorter interaction lengths are necessary in comparison to fibers [2] . We experimentally exploit these advantages in a tunable waveguide-based optical parametric amplifier (WOPA) by stimulated FWM in Si 3 N 4 waveguides for narrowband coherent anti-Stokes Raman scattering (CARS) imaging.