Stimulated Raman spectroscopy of malachite green isothiocyante

Abstract

A broadband stimulated Raman scattering spectroscopy (SRS) setup have been developed and applied on the resonant SRS study of malachite green isothiocyanate (MGITC). The broadband SRS system, which uses 450~800 nm white light continuum as Raman probe, and 280~900 nm tuning range (≈7.5 cm-1 spectral width and ≈2.5 ps pulse duration) narrow band picosecond pulse as Raman pump, allows for simultaneously recording the Raman loss and gain spetrum at proper pump wavelength. The resonant SRS peaks of MGITC reach the maximum when the peak positions fall around the absorption maximum of MGITC (≈627 nm). The intensities of resonant SRS peaks rise with the increase of MGITC concentration, and rise rapidly with the increase of the pump power and then get saturated. The peak intensities of both resonant and non-resonant SRS peaks reach the maximum at time zero (zero delay between pump and probe pulses), and decrease with the increase of separation between the pump and probe pulses in time.