Spectro-temporal shaping of supercontinuum for subnanosecond time-coded M-CARS spectroscopy.

A supercontinuum laser source was designed for multiplex-coherent anti-Stokes Raman scattering spectroscopy. This source was based on the use of a germanium-doped standard optical fiber with a zero dispersion wavelength at 1600 nm and pumped at 1064 nm. We analyzed the nonlinear spectro-temporal interrelations of a subnanosecond pulse propagating in a normal dispersion regime in the presence of a multiple Raman cascading process and strong conversion. The multiple Raman orders permitted the generation of a high-power flat spectrum with a specific nonlinear dynamics that can open the way to subnanosecond time-coded multiplex CARS systems.