Single source coherent anti-Stokes Raman microspectroscopy using spectral focusing

We demonstrate coherent anti-Stokes Raman scattering (CARS) microspectroscopy using a single Ti:sapphire laser oscillator and simple passive optical elements. Spectral selection by dichroic mirrors and linear chirping by glass elements creates a vibrational excitation tuneable over a large spectral range (∼800–2200 cm−1) with adjustable spectral resolution (∼10–100 cm−1). We furthermore demonstrate the applicability of differential CARS, enhancing the chemical selectivity, with the proposed single-laser configuration.