Femtosecond stimulated Raman spectroscopy of methanol and acetone in a noncollinear geometry using a supercontinuum probe

The design of a femtosecond stimulated Raman spectroscopy (FSRS) setup capable of recording high contrast Raman spectra is presented. The Raman transition is stimulated by a supercontinuum pulse and pumped by the second-harmonic of a Ti:sapphire amplifier system fundamental wavelength. This scheme alleviates rapid amplitude modulation near 800 nm using the smooth amplitude region in the continuum near the 400 nm pump. Raman spectra of acetone and methanol are presented in which the Raman peak intensity is the most pronounced feature of the spectrum. A mechanism limiting the resolution and peak intensity based on the nonlinear index of refraction effects is suggested.