Work number - M 46 FILED
Presented Institute for Single Crystals NAS of Ukraine
Ph.D. Vorona I.O., Ph.D. Taranets Y.V., Kostenyukova E.I.
The present cycle of work was devoted to establishing new physical relations and to obtaining at their basis new functional materials with improved characteristics - laser ceramics based on YAG complex oxide with impurity states of lanthanide ions, as well as KDP crystals of complex structure and calcium oxalate of monohydrate with incorporated organic molecules.
First part of cycle devoted to research of consolidation processes, luminescence properties and laser characteristics of highly-doped transparent ceramics (Y1‑xREx)3Al5O12 (RE=Nd3+, Yb3+). The influence of the concentration of Nd3+ and Yb3+ ions on consolidation processes and microstructure of ceramics 1-4 at.% Nd3+:YAG, 5-15 at.% Yb3+:YAG was studied. The mechanism of luminescence quenching were investigated and the structure of optical centers in Nd3+:YAG and Yb3+:YAG ceramics was determined. The influence of ion concentration RE=Nd3+, Yb3+ on the laser characteristics of ceramics RE3+:YAG has been established. The key differences in consolidation conditions, optical properties and laser characteristics of YAG-based ceramics due to activators of Nd3+ and Yb3+ influence were described.
In second part, the influence оf amino acids (L-Asp, L-Arg, L-Thr) and vitamins (B1, B6, B12) on the processes of nucleation, morphology and size of COM crystals was studied. It is established that L-Asp and L-Arg inhibit nucleation of COM, that increases their induction time ten fold in comparison with the one of the pure crystals. L-Thr is shown to promote the processes of COM nucleation and to diminish the induction time by two times. It is found that B1 and B6 vitamins inhibit the growth of COM crystals: the inhibition degree exceeds 95% and lead to 70-fold increase in the induction time of pure COM. The value of surface energy of COM crystals diminishes to 19.8–20.8 mJ/m2 at the introduction of the crystallization inhibitor molecules (L-Asp, L-Arg, B1, B6) into COM solution.
The third part is devoted to the growth of single crystals of potassium dihydrophosphate doped with organic molecules: N,N'-dimethyl urea (NN'DU), L-arginine phosphate (LAP) and L-arginine (L-arg). For the first time, the KDP crystals with incorporated organic molecules NN'DU, LAP and L-arg were grown using the temperature reduction method with advanced growth sectors and optical quality, that making these composite materials promising for use in optoelectronics, etc. The was analyzed complex study of the structure, optical, strength and nonlinear-optical properties of the composite systems KDP:NN'DU, KDP:LAP and KDP:L-arg. It was shown that doping of the crystal with organic molecules NN'DU, LAP and L-arg led to an increase in the efficiency of the second harmonic generation (SHG) by -~2-3,5 times as compared with pure crystal.
Number of publications: is 22 scientific articles in the Scopus database, 2 scientific articles in the Ukrainian journals and 39 conference abstracts. The total number of references to the scientific publications by Scopus presented in the work is 88 and the h-index of the work is 6; by Google Scholar the total number of references is 96 and the h-index of the work is 6; the total number of references by Web of Science is 76 and the h-index of the work is 5.