Time‐resolved coherent Raman spectroscopy controlled by spectrally tailored noisy light

Abstract

A new type of frequency- and time-resolved coherent Raman scattering (CRS) spectroscopy using broadband non-transform limited noisy light is presented. The noisy light source is designed to have a doubly peaked spectrum, and the signal [called I(2)CRS(3c)] is observed to be similarly double peaked with one of the peaks being a new three-color ‘hybrid.’ Time resolution of the order of 100 fs is achieved by interferometric manipulation of the noisy light in the sample. Up-conversions and down-conversions of the vibrational transition frequency being studied [the 655.6 cm-1 vibration of CS2(l)], called radiation difference oscillations, are observed in the interferometrically time-resolved coordinate. It is shown how the oscillations and their decay can be explained in terms of spectral ‘filtering’ of the noisy light involving the vibrational resonance of the sample. © 1997 John Wiley & Sons, Ltd.