Stimulated Raman Microscopy Implemented by Three Femtosecond Laser Sources

In this work, the implementation of a femtosecond Stimulated Raman Scattering microscope, equipped with three femtosecond laser sources: a Titanium-Sapphire (Ti:Sa), an optical parametric oscillator (OPO), and a second harmonic generator (SHG); is presented. Our microscope is designed so that it can cover all the regions of Raman spectra, taking advantage of two possible laser combinations. The first, Ti:Sa and OPO laser beams, which cover the C-H region (>2800 cm -1 ) in stimulated Raman gain (SRG) modality, whereas the second, Ti:Sa and SHG laser beams, covering the C-H region and the fingerprint region in stimulated Raman losses (SRL) modality. The successful realization of the microscope is demonstrated, reporting images of polystyrene beads using both SRL and SRG modalities.