[en] Influence of induced by gamma radiation (up to 8 x 10 R) and by fast neutron flux (up to 10¹³ neutron/cm²) defects in KTP crystals on their laser strength at λ = 1.06 and 0.53 μm at the pulse duration of 10 ± 1 ns under single and repeated action of laser radiation is investigated. The laser strength of samples depends essentially on the level and character of their irradiation. For considered actions the laser strength decreases up to 5 times

[en] Radiation-induced defects in potassium titanate-phosphate (PTP) monocrystals, preliminary subjected to gamma-radiation in the absorbed dose range from 10³ to 10⁶ Gy at 77-300 K and having optical homogeneity with the transparency region from 350to 4000 nm have been studied. Thermoluminescence in the temperature range from 77 to 530 K and thermostimulated currents from 300 to 650 K have been investigated. It is shown that the centers induced by gamma-radiation in PTP monocrystals may be identified as electron Ti³⁺-V₀-Ti⁴⁺ and hole PO₄^2--centers. The band of optical absorption of PO₄^2- ion radical has maximum in the region of 400-450 nm and is overlapped by the intensive band of Ti³⁺ ion with λ_max=490 and 550 nm. The number of electron and hole centers grows proportionally to each other up to the absorbed dose of 5x10⁴ Gy, and then saturation upto 10⁷ Gy is observed.At 430 K total annealing of the radiation-induced defects investigated and colour disappearance are observed

[en] Single crystals of KTiOPO₄ (KTP) are a promising nonlinear optics material having high nonlinearity coefficients comparable in magnitude with analogous coefficients for Ba₂NaNb₅O₁₅. In the initial KTP crystals, using the EPR method, they detected paramagnetic Fe³⁺ impurities and other ions giving a complex multi-line spectrum over a wide field range (up to 7000 Oe). After γ-irradiation, the single crystal takes on a cream color. The induced optical absorption spectrum, represented by a broad band with weakly resolved maxima in the 490 and 550 nm region, has significant anisotropy. The intensity, shape, and position of the bands in the extrinsic absorption spectrum vary with a change in orientation of the crystal relative to the probe beam of the spectrophotometer. Simultaneously with induced absorption in the optical spectrum, two groups of high-field and low-field lines appear in the EPR spectrum in the g = 2 region. The high-field signal has a complex structure, changing with the orientation of the crystal in the resonant cavity, and also has a weak anisotropy in the g-factor and hyperfine coupling constants

[en] Investigation of the absorption and luminescence spectra of the MNd(PO₃)₄-monocrystals is conducted. The measurements are made at 77 and 300 K. It has been established that a weaker concentrational extinguishing is characteristic for the MNd(PO₃)₄ crystals as compared with NdPO₄, Nd(PO₃)₃ and NdP₅O₁₄. The spark structures of the sup(4)Isub(9/2), sup(4)Isub(11/2), sup(4)Fsub(3/2), sup(4)Gsub(7/2) and sup(2)Psub(1/2) levels of the Nd ions for the whole series of the compounds investigated are singled out