Four-Wave Scattering of a Laser Beam by Induced Collective Oscillations of Solid Nanoparticles in Suspensions

Spectra of coherent scattering at four-wave mixing of two diode laser radiation in liquid suspensions of dielectric nanoparticles are obtained for the first time. Dependence of the scattering resonance width on the concentration of nanoparticles in the suspension is studied. It is shown that the experimentally observed dependences of the width of the scattered radiation spectrum on the concentration of nanoparticles in the suspension result from the collective excitation of acoustic phonons.