Kosinova A. Regularities in the formation, structure and optical properties of KDP crystals doped with TiO2 nanoparticles and organic impurities

The thesis is devoted to creation of composite systems on the base of KDP crystals with incorporated nanoparticles and organic molecules, to be used as efficient nonlinear optical media. For the first time KDP crystals with incorporated TiО2 nanoparticles are grown. A method for the obtaining of KDP:TiО2 crystals with ordered distribution of the nanoparticles in the matrix is developed. The change of the sign of refractive nonlinear optical response in KDP:TiО2 crystals with respect to pure KDP is established. This allows to control the conditions of phase synchronism at frequency conversion of laser radiation of picosecond range. The possibility to create an orientation ordering of optically active molecules in the crystal matrix at the stage of crystal growth is shown for KDP crystals with incorporated molecules of the dye ХО. The spatial orientation of the dye molecules in the matrix is determined. The influence of the annealing temperature on the incorporated dye is studied. It is shown that annealing at a temperature up to 150 ?С does not cause destruction of the dye, and allows to raise the efficiency of photoluminescent and nonlinear optical responses of the crystal. KDP crystals doped with urea molecules are grown; the influence of the urea concentration on the growth, structure perfection and functional properties of the crystals is studied. The doped crystals show the rise of the second harmonic generation efficiency at urea concentrations of 0.3-4 wt. % which is due to local distortion of the crystal lattice.