Photon–Phonon Interactions in Nanostructured Systems

A new type of stimulated scattering (SLFRS)—stimulated low-frequency Raman scattering—has been observed in different nanostructured materials: synthetic opal matrices, nanostructured thin films, and suspensions of nanodiamonds. SLFRS has been shown to be a result of laser pulse interactions with acoustic vibrations of nanostructured material elements. Experimentally the effect shows itself in the appearance of one or a few spectral lines in the Stokes range in both the forward and backward directions with a frequency shift from the exciting light of the order of a few tens of cm−1, which corresponds to the vibrations located in the GHz range. Measured values of frequency shifts correspond well to the eigenvalues of the vibration frequencies of the nanostructure elements.