Multifrequency Stimulated Raman Scattering in Light and Heavy Water

Abstract

We establish the regularities of changes in the spectra of stimulated Raman scattering in light water (H2O) and heavy water (D2O) under changing laser excitation regimes. We find several satellites occurring in Stokes and anti-Stokes regions at high pumping intensities. We study the spectra of stimulated Raman scattering in H2O and D2O under excitation by the second optical harmonic (532 nm) of a YAG: Nd3+ laser generating ultrashort (60 ps) pulses with a recurrence frequency of 20 Hz and a peak power of 10-100 MW. We show that intense spectral bands determined by both intramolecular modes of light/heavy water and intermolecular modes - librations or translations of the molecular characteristic of ice - occur in stimulated Raman scattering spectra upon an increase in exciting radiation intensity. Our experiments demonstrate the prospects of using the phenomenon of stimulated Raman scattering for developing coherent waves corresponding to intramolecular and lattice modes of light and heavy water. The phenomenon can also be used for developing a deuterium plasma with high effective temperature in the region of laser radiation focusing in heavy water and low-temperature water in the boundary region.