A coherent anti-Stokes Raman spectroscopy (CARS) system comprises a laser light source for emitting pulsed light, a dichroic beam splitter for splitting a light pulse from the light source into a pump pulse and a Stokes pulse and directing these pulses along respective distinct paths, chirping means, e.g. dispersive glass blocks for chirping the pump and Stokes pulses, directing means for directing the chirped pump and Stokes samples to a sample in time overlap, and detecting means for detecting light stimulated from the sample by the interaction of the pump and Stokes pulses. The system may comprise a reflector connected to a linear motor, for adjusting the period between the arrival at the sample of the starts of the chirped pump and Stokes pulses. The system may further comprise a pulse replicating unit for converting a pulse from the light source into a plurality of pulses distributed in time.