OPTOACOUSTIC RAMAN GAIN SPECTROSCOPY OF LIQUIDS

We report the first optoacoustic Raman gain spectroscopy (OARS) of liquids, using two synchronized pulsed dye lasers, and gated optoacoustic detection of the energy deposited in the liquid due to the stimulated Raman (Stokes) scattering. We demonstrate this sensitive technique with several neat liquids, including benzene, acetone, 1,1,1-trichloroethane, toluene, and n-hexane. This technique seems competitive or superior to other techniques like intracavity inverse Raman scattering or coherent anti-Stokes Raman spectroscopy. OARS can thus be advantageously used in many liquids, including water.