Three-color multiplex CARS for fast imaging and microspectroscopy in the entire CHn stretching vibrational region.

We present a three-color multiplex coherent anti-Stokes Raman scattering (CARS) setup that facilitates a prompt recording of broadband CARS spectra along with a fast CARS imaging. With separate narrowband Stokes and probe beams being introduced in the near IR, we are able to incorporate a stable, wideband Ti:sapphire femtosecond laser as a pump beam that covers the full range of Raman shift for CHn stretching vibrational modes. Experimentally, high-resolution multiplex CARS signals are allowed to investigate molecular vibrations over the range of 2650 cm-1 - 3050 cm-1, which are spectrally integrated to construct lipid-sensitive images. It is demonstrated that the proposed implementation promises a particular benefit on CARS imaging of lipid-rich tissue structures by providing detailed information on CHn Raman-active vibrations at points of interest on the CARS images that can be obtained at high frame rates.