Abstract

Nonlinearity of Sound Wave Propagation and Stimulated Brillouin Scattering Process

A.I.Erokhin (Nonlinear Optics and Light Scattering Laboratory, Lebedev Physical Institute, Moscow, Russia)

e-mail: aerokhin@mail1.lebedev.ru

Hypersound intensity in SBS process usually exceeds some kW/cm2 and is naturally expected to reveal nonlinear features. But this type of sound is strongly coupled with light. It causes the atypical acoustic nonlinearity appearance. Familiar acoustical harmonic generation during SBS is mostly suppressed. New experimental approaches for investigation of intense hypersound propagation in liquids have been tried. It was based on time domain high resolution Doppler spectroscopy that showed the route of sound velocity modification in time. Theoretically shown was the spectral split of initially monochromatic hyperacoustic wave in SBS due to its nonlinearity. Unique opportunity to generate acoustic waves with a prescribed velocity values in liquids is suggested and realized. It turned out that those values evolve to predetermined stable states. These states were determined experimentally and their nature discussed. Possibilities of flow generations in SBS case were evaluated and investigated experimentally.

Section : 9