PULSED PHOTOACOUSTIC TECHNIQUE TO STUDY NONLINEAR PROCESSES IN LIQUIDS - RESULTS IN TOLUENE

Pulsed photoacoustic measurements have been carried out in toluene at 532 nm wavelength using a Q-switched frequency doubled Nd:YAG laser. T he variation of photoacoustic signal amplitude with incident laser pow er indicates that at lower laser powers one photon absorption takes pl ace at this wavelength while a clear two photon absorption occurs in t his liquid at higher laser powers. The studies made here demonstrate t hat pulsed photoacoustic technique is simple and effective for the inv estigation of multiphoton processes in liquids.