Femtosecond stimulated Raman microscopy

A novel type of non-linear Raman microscopy, femtosecond stimulated Raman microscopy (FSRM), is introduced. It employs femtosecond white light pulses and intense picosecond pulses which are derived from a femtosecond laser/amplifier system. The pulses are coupled into a microscope set-up and induce a stimulated Raman process at the focus. The Raman interaction spectrally modulates the white light. These modulations are read-out in multi-channel fashion and allow recording of a complete Raman spectrum of the focal region. By raster-scanning the sample, complete Raman images can be obtained. Raman images of polystyrene beads in water demonstrate the feasibility of the approach.