Bezkrovnaya O. Composite materials based on matrices of KDP and SiO2 with incorporated nanoparticles of metal oxides, organic and semi-organic molecules for nonlinear optic.

Technical Sciences in speciality 05.02.01. – Materials Science. – Institute of Single Crystals of the National Academy of Sciences of Ukraine, Kharkiv, 2021. The thesis is devoted to the development of physico-technological foundations of creation of new composite materials based on KDP crystals with incorporated metal oxide nanoparticles, organic and semi-organic molecules, and increased nonlinear optical properties in comparison with pure KDP, as well as on composite materials based on transparent sol-gel SiO2-matrices with incorporated molecules of laser dyes (for the spectral region 610-750 nm) or organic molecules DAST (for infrared and terahertz radiation). There were established optimum conditions for the growth of KDP-based composites from aqueous solutions, and optimum ranges of concentrations of the corresponding impurities in solutions – nanoparticles of aluminum oxyhydroxide Al2O3•nH2O(n=3,5-3,6), and NN'-dimethylurea, L-arginine and L-arginine phosphate molecules. For the first time, a number of high-quality KDP-based composite materials was obtained and investigated. This demonstrates a useful combination of improved nonlinear optical, strength, structural and thermophysical properties. Proposed were different approaches to the obtaining of new composites based on amorphous SiO2-matrices: by incorporating active molecules either during the stage of synthesis, or into SiO2-matrices pre-annealed at temperatures of 600-700°C. There were established the optimum ratios of the components for the synthesis of composites based on SiO2-matrices with laser dyes. A high optical perfection of the created laser composites of both types based on unannealed and annealed SiO2-matrices is confirmed by the linear structure of the spectra of the obtained laser generation. The influence of the porosity of SiO2-matrices on the luminescent properties of the composites with DAST was determined. The developed SiO2-composites can be used to create modern sensors and lasers for the red, infrared and terahertz regions of the spectrum. Keywords: composite materials, single crystals of KDP group, nanoparticles, metal oxides, SiO2-matrice, laser dyes, DAST, luminescence, nonlinear optical response, laser radiation, terahertz radiation.