Pritula I. Intrinsic and extrinsic defects in KDP family crystals

The thesis is devoted to finding out structure-dependent mechanisms of the creation and transformation of the subsystem of defects in dielectric KDP family crystals, as well as to establishment of the interaction of incorporated nanoparticles and organic molecules with intrinsic defects of the dielectric at the formation of photo-induced response of the heterogeneous (composite) system. Found is the influence of the physico-chemical crystallization conditions on the formation of morphological defects. It is shown that in the process of -irradiation stable hole-type color centers are formed in the crystals. The extrinsic mechanism of electrical conduction in KDP crystals is established to change to the intrinsic one under -irradiation, due to radiation healing of the defects. The efficiency of the second harmonic generation and the laser damage threshold of KDP crystals with incorporated urea molecules are found to rise. It is ascertained that resonance excitation of delocalized -system of the dye incorporated into the matrix of KDP is accompanied with the decrease of the energy threshold of the nonlinear response of the composite. The mechanism of the formation of an ordered quasi-periodic zonal microstructure in KDP:TiO2 composite is proposed. The effect of the change of the sign is revealed for nonlinear refraction in the system KDP:TiO2, and a new type of media with controlled nonlinear refraction, including its compensation, is proposed.