High‐precision femtosecond CARS of simple liquids

A novel non‐degenerate CARS spectrometer is described with an 80‐fs time resolution, improved measuring accuracy of ca . 1% for the vibrational dephasing time and adjustable frequency positions of the input pulses. Experimental data are reported for CH stretching vibrations of acetone, acetonitrile and bromoform. Negligible inhomogeneous broadening (<4%) is deduced from the observed exponential decay for the vibrational transitions. The effect of orientational motion on the dephasing observations is discussed.