Photon–Phonon Interactions in Nanostructured Systems

Abstract

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.

Вынужденное Низкочастотное Комбинационное Рассеяние Света В Монокристаллическом Алмазе С Заглубленным Графитизированным Слоем

“…Значения низкочастотного комбинационного рассеяния порядка 10 GHz характерны для наноструктур с размерами рассеивающих центров порядка сотен нанометров [2,3,[8][9][10], так как величина ВНКР обратно пропорциональна диаметру (размеру) наночастиц, совершающих собственные колебания в направлении, вдоль которого в рассеивающем объекте (молекуле, вирусе, нанопленке) распространяется наблюдаемая мода ВНКР. В наших экспериментах такая зависимость также обнаруживается: частоты ВНКР в монокристаллической алмазной пленке обратно пропорциональны размерам нанослоев -толщине графитизированного слоя внутри алмазной пленки и его глубине залегания, т. е. толщине восстановленного монокристаллического алмазного слоя над ним.…”

High efficiency stimulated low-frequency Raman scattering in a water suspension of dielectric submicron particles

“…Suspensions of various nanoscale and submicron particles are examples of disordered systems and if such a system is sufficiently monodisperse, then its coherent acoustic excitation can be realized by coherent laser radiation. As a result, stimulated low-frequency Raman scattering (SLFRS) [1][2][3], which is a stimulated analogue of low frequency Raman scattering (LFRS) [4][5][6], can be excited in the nanosystem. The advantages of using suspensions are in the ease of preparation as well as the ability to easily change the concentration and type of solvent.…”

Stimulated Low-Frequency Raman Scattering in Albumin

“…As a result, we have the vibrational modes resonance excitation that can be used as an effective method of influencing the virus system (like on any biological system). SLFRS was realized for a large number of various nanoparticles (metallic, dielectric, and semiconductor), nanostructured thin films and highly ordered samples such as opal matrices and nanocomposites on their base [18][19][20][21]. SLFRS was observed also in different viruses (Cauliflower mosaic virus, Tobacco mosaic virus and two types of Potato viruses) [22,23,24].…”