Integrated four-wave mixing source for coherent anti-stokes Raman scattering based on silicon nitride

Coherent anti-Stokes Raman scattering (CARS) offers label-free detection with chemical selectivity. In order to achieve spectral and therefore chemical resolution two synchronized narrowband pulses have to be provided by an appropriate light source. The often used complex laser systems as well as the more recently introduced all- fiber approaches based on seeded four-wave mixing (FWM) all lack the compatibility with integrated photonics. Here, we present theoretical investigations of a CARS light source based on silicon nitride waveguides, which is compatible, for instance, with integrated microfluidic channels and integrated light sources and therefore is of great interest for analyzing CARS spectra in a lab-on-a-chip setup. Furthermore, the required laser intensities are found to be reduced by one order of magnitude based on the higher efficiency of FWM in silicon nitride waveguides.