Search academic texts

Information × Registration Number 0208U004864, 0106U003117 , R & D reports Title Nonlinear optical properties and spectroscopy of photosensitive and complex dielectrical thin-films' systems popup.stage_title Head Ageev Leonid Opanasovich; Milislavsky Volodimir Kostyantinovich, Registration Date 23-12-2008 Organization Kharkov Natuional university named after V.N.Karazin popup.description2 Object of research - thin films with real-time light sensitivity; films of quasi-one-dimensional, ferroelastic and ferroelectric dielectrics with admixtures. The purpose of work - to study nonlinear optical effects in photosensitive films, exciton spectra and electronic spectrum structure in films of dielectrics mentioned. Methods of investigation - vacuum deposition of films, irradiating the films with monochromatic light, spectroscopic and diffraction measurements, microscopic examinations of morphology and structure. Formation of spontaneous S--gratings on boundary waveguide TE0- and TM0-modes was studied in AgCl-Ag films. It was found that S--ТМ0-gratings are of better quality as compared to S--ТЕ0-gratings. Mechanisms of TE0- and TM0-mode competition at development of spontaneous gratings were determined. At small incidence angles of laser beam, grating evolution is described by Lottki-Volterra equations. At large angles, evolution is described by two-dimensional Bragg diffraction. A new method oflaser implantation of Ag nanoparticles into amorphous quartz was developed. With the help of AF microscopy and spectral studies, it was revealed that the particles have diameters of 5 nm and Lorentz form of colloidal band. The band is situated at Frolich frequency. We studied influence of admixtures on absorption spectra and phase changes in RbAg4I5 type ferroelastics and quasi-one-dimensional dielectrics of M2AgI3 type (M: K, Rb, Cs). It was revealed that admixtures in ferroelastics promote extraction of non-conducting phases and decrease of phase change temperature in solid solutions RbxK1-xAg4I5 with and 1. In solid solutions of one-dimensional (MI)2(Ag1-xCuxI) dielectrics, at small x Cu+ ions form local excitons with Rashba effect, while at larger x mixed type solitons are formed. Exciton spectrum of Rb2ZnI4 ferroelectric was studied for the first time. Exciton band parameters were determined in temperature interval 90ё290 K. Plasma resonance spectra in granular films of Ag-In and Au-Al alloys were studied and interpreted. The results SIW are applied to further development of nonlinear optics of thin films; for prediction of properties of compounds with an abnormal ionic conductivity. Assumptions on development of object of examinations: further detailed study of the nature and mechanisms of unusual optical effects in various thin films. Product Description popup.authors popup.nrat_date 2020-04-02 Close