Abstract The paper briefly describes the main achievements in the area of laser technologies and the application of diffractive computer optics of Academician of the Russian Academy of Sciences, Doctor of technical sciences, Professor, Honoured Scientist and Engineer of the RSFSR, Laureate of the State Award of the Russian Federation in the area of science and technology Vladimir P. Shorin.

By means of computer simulation, the influence of absorption index, κ, on the accuracy of determining the refractive index, n, of optical materials by the minimum deviation method (prism method) is studied at different measuring angular accuracies from 5'' to 0.1''. The n values within 1.0-4.0 and κ values within 0-0.1 are considered. It is shown that (1) except for the far-infrared region, the error in determining n by formula (1) commonly used in the minimum deviation method, i.e., neglecting absorption, is less than the error due to the accuracy of measuring the prism and minimum deviation angles; (2) the difference between n values calculated with and without absorption taken into consideration is, in most cases, negligible throughout the optical range; (3) however, the total error in determination of n is higher when absorption is taken into account than that in the case when absorption is neglected. The further the increase in accuracy of measuring the angles and sensitivity of radiation detectors, the more the proposed calculation technique will allow one to optimize the prism angle value and to calculate more correctly the values of n and error in its determination.

Fe x Mn1−x S belongs to the group of strong electron correlations compounds MnO. We present here experimental results for the antiferromagnetic iron–manganese sulfide system, based on X-ray and neutron diffraction studies. The neutron diffraction investigations were carried out at ambient conditions and at hydrostatic pressures up to 4.2 GPa in the temperature range from 65 to 300 K. Our results indicate that the Néel temperature of α-MnS increases up to room temperature by applying chemical (x Fe) or weak hydrostatic pressure P. In Fe0.27Mn0.73S, the Néel temperature increases from 205(2) K (P = 0 GPa) to 280(2) K (P = 4.2 GPa) and the magnetization at 100 K decreases by a factor of 2.5 when the hydrostatic pressure increases from 0 to 4.2 GPa.

Main error sources and their contribution to the total error of measuring the optical loss spectrum by the cut-back method are analyzed in the mid-IR range (2-20 mu m) for multimode optical fibers made from materials with high (2-4) refractive index values. It is shown that in case of insufficient fiber length, neglecting the refractive index value leads to a systematic overestimation of the measured optical losses: the higher the refractive index of a fiber core material, the greater an overestimation. The main errors are typically introduced by a bad repeatability of preparation quality of fiber ends and a lower signal-to-noise ratio of mid-IR range experimental setups in comparison with the near-IR range. (C) 2017 Optical Society of America

A preform and holey fibers with Te: SiO2 core composition were fabricated. Spectroscopic properties of the fibers drawn in different redox conditions were studied. Intensive absorption bands near 430, 600, 820, 1050 nm and absorption edge near 250 nm were observed. Broad luminescence bands had maxima located near 700, 910, and 1500 nm. Drawing in oxidizing conditions led to the considerable decrease of the absorption bands and to the suppression of the similar to 1500 nm luminescence band. Characteristic peaks at 245 and 232 cm(-1) associated with Te-2(0) dimers were observed in the Raman spectra. Modeling of Te dimers in Te: SiO2 glass allows suggesting that a Te-2(0) dimer can be responsible for 700 and 910 nm luminescence bands and a Te-2(-) dimer for similar to 1500 nm luminescence band. (C) 2016 Optical Society of America

A method for recovering some rare-earth oxides (Dy2O3, Y2O3, and Pr6O11) with their simultaneous purification via the breakdown of aluminosilicate sludges by soda has been proposed using an example of model samples that contain these oxides sintered with 11 admixture oxides. The developed process has been shown to be efficient for the recovery of rare-earth oxides of chemically pure grade from chemically complicated sinters.

Absorption, luminescence and luminescence excitation spectra of MCVD-prepared SiO2:Pb glasses with Pb content up to 035 wt% were studied. IN and visible luminescence was observed in the 0.3-0.45 and 0.5-0.6 mu m ranges. IR luminescence was found in the 0.85-0.95, 1.1-1.2 and 13-1.4 mu m ranges. Computer modeling of SiO2:Pb glass was performed. The main possible forms of Pb in the SiO2 glass network were found to be threefold coordinated Pb atom, diatomic Pb center, twofold coordinated Pb atom, and possibly fourfold coordinated Pb atom. Structure, electronic properties, absorption and luminescence of the centers corresponding to these forms and of possible lead-related centers responsible for the IR luminescence were calculated. The results of the experiments and modeling suggest that (1) the 0.3-0.45 pm luminescence band is caused mainly by twofold coordinated Pb atoms and partly by threefold coordinated Pb atoms, (2) the 0.5-0.6 mu m luminescence band is caused by twofold coordinated Pb atoms, (3) 1.1-12 mu m IR luminescence band is caused by Pb+ interstitial ions, and (4) 0.85-0.95 and 13-1.4 pm IR luminescence bands are caused by complexes formed by interstitial Pb-0 atom and a pair of Si-Si oxygen vacancies. (C) 2016 Elsevier B.V. All rights reserved.

Изучено влияние ионов Al и Се на оптическое поглощение и люминесценцию монокристаллических пленок (Pb,Gd)3 - уСеуAlхGa5 - хO12, где х = 2.02, 2.09, 2.13, 2.17, 2.22 и у = 0.02, 0.06, 0.07, выращенных методом жидкофазной эпитаксии из переохлажденных растворов-расплавов на основе системы PbO B2O3 на монокристаллических подложках Gd3Ga5O12 с ориентацией (111) при концентрациях оксида алюминия 2.0, 2.1 и 2.2 мол. % и оксида церия 0.03 и 0.2 мол. % в шихте. Определен сдвиг полос поглощения уровней 5d1 и 5d2 ионов Ce3+ в зависимости от концентрации Al в пленках. Показано, что интенсивность полос люминесценции иона Се3+ увеличивается с ростом содержания Al и Се в пленках.

First-principle study of bismuth-related oxygen-deficient centers (= Bi center dot center dot center dot Ge equivalent to, = Bi center dot center dot center dot Si equivalent to, and = Bi center dot center dot center dot Bi = oxygen vacancies) in Bi2O3-GeO2, Bi2O3-SiO2, Bi2O3-Al2O3-GeO2, and Bi2O3-Al2O3-SiO2 hosts is performed. A comparison of the calculation results with the experimental emission and excitation spectra of IR luminescence suggests that luminescence in the 1.2-1.3 mu m and 1.8-3.0 mu m ranges in Bi2O3-GeO2 glasses and crystals is likely caused by = Bi center dot center dot center dot Ge equivalent to and = Bi center dot center dot center dot Bi = centers, respectively, and the luminescence near 1.1 mu m in Bi2O3-Al2O3-GeO2 glasses and crystals may be caused by = Bi center dot center dot center dot Ge equivalent to center with (AlO4)(-) center in the second coordination shell of Ge atom. (C) 2014 Optical Society of America

We have studied the effect of Al and Ce ions on the optical absorption and luminescence of singlecrystal (Pb,Gd)3–y Ce y Al x Ga5–x O12 (x = 2.02, 2.09, 2.13, 2.17, 2.22; y = 0.02, 0.06, 0.07) films grown on (111)-oriented single-crystal Gd3Ga5O12 substrates by liquid-phase epitaxy from supercooled high-temperature solutions using solvents of the PbO–B2O3 system and growth charges containing 2.0, 2.1, or 2.2 mol % aluminum oxide and 0.03 or 0.2 mol % cerium oxide. The shift of the absorption bands of the Ce3+ 5d 1 and 5d 2 levels has been determined as a function of Al concentration in the films. The intensity of the Ce3+ luminescence bands of the films has been shown to increase with increasing Al and Ce concentrations.

First-principle study of bismuth-related oxygen-deficient centers ($=$Bi$\cdots$Ge$\equiv$, $=$Bi$\cdots$Si$\equiv$, and $=$Bi$\cdots$Bi$=$ oxygen vacancies) in Bi$_2$O$_3$-GeO$_2$, Bi$_2$O$_3$-SiO$_2$, Bi$_2$O$_3$-Al$_2$O$_3$-GeO$_2$, and Bi$_2$O$_3$-Al$_2$O$_3$-SiO$_2$ hosts is performed. A comparison of calculated spectral properties of the centers with the experimental data on luminescence emission and excitation spectra suggests that luminescence in the 1.2-1.3 $\mu$m and 1.8-3.0 $\mu$m ranges in Bi$_2$O$_3$-GeO$_2$ glasses and crystals is likely caused by $=$Bi$\cdots$Ge$\equiv$ and $=$Bi$\cdots$Bi$=$ centers, respectively, and the luminescence near 1.1 $\mu$m in Bi$_2$O$_3$-Al$_2$O$_3$-GeO$_2$ glasses and crystals may be caused by $=$Bi$\cdots$Ge$\equiv$ center with (AlO$_4$)$^-$ center in the second coordination shell of Ge atom.

Experimental and theoretical studies of spectral properties of chalcogenide Ge–S and As–Ge–S glasses and fibers are performed. A broad infrared (IR) luminescence band which covers the 1.2 – 2.3 μm range with a lifetime about 6 μs is discovered. Similar luminescence is also present in optical fibers drawn from these glasses. Arsenic addition to Ge–S glass significantly enhances both its resistance to crystallization and the intensity of the luminescence. Computer modeling of Bi-related centers shows that interstitial Bi+ ions adjacent to negatively charged S vacancies are most likely responsible for the IR luminescence.

A comparative first-principles study of possible bismuth-related centers in TlCl and CsI crystals is performed and the results of computer modeling are compared with the experimental data. The calculated spectral properties of the bismuth centers suggest that the IR luminescence in TlCl:Bi is most likely caused by Bi(+)···V(Cl)(-) centers (Bi(+) ion in thallium site and a negatively charged chlorine vacancy in the nearest anion site). On the contrary, Bi(+) substitutional ions and Bi(2)(+) dimers are most likely responsible for the IR luminescence in CsI:Bi.

Experimental and computer-modeling studies of the spectral properties of crystalline AgCl doped with metal bismuth or bismuth chloride are performed. The broad near-IR luminescence band in the 0.8-1.2 μm range with time dependence described by two exponential components corresponding to the lifetimes of 1.5 and 10.3 μs is excited mainly by 0.39-0.44 μm radiation. Computer modeling of probable Bi-related centers in the AgCl lattice is performed. On the basis of experimental and calculation data, a conclusion is drawn that IR luminescence can be caused by Bi+ ion centers substituted for Ag+ ions.

First-principle study of possible bismuth-related centers in SiO2 and GeO2 hosts is performed and the results are compared with the experimental data. The following centers are modeled: trivalent and divalent Bi substitutional centers; BiO interstitial molecule; interstitial ion, Bi^+, and atom, Bi^0; Bi...Si-Si and Bi...Ge-Ge complexes formed by interstitial Bi atoms and glass intrinsic defects, Si-Si or Ge-Ge oxygen vacancies; interstitial dimers, Bi0 and Bi_2^-. Experimental data available on bismuth-related IR luminescence in SiO2:Bi and GeO2:Bi glasses, visible (red) luminescence in SiO2:Bi glass and the luminescence excitation are analyzed. Comparison of the calculated spectral properties of the bismuth-related centers with the experimental data shows that IR luminescence in SiO2:Bi and GeO2:Bi is most likely caused by Bi...Si-Si and Bi...Ge-Ge complexes and divalent Bi substitutional center is probably responsible for the red luminescence in SiO2:Bi.

Epitaxial films of Ce-doped Gd-3(AlxGa1-x)(5)O-12 with x = 0.00, 0.22, 0.31, 0.38 formula units were grown using liquid-phase epitaxy method, and their optical properties were studied. The emission of Ce3+ ions can be observed only when Al3+ ions are incorporated into the garnet structure, resulting in a shift of the 5d Ce3+ states from the conduction band to the bandgap. It is shown that the shift is caused by the cumulative effect of gradual low-energy shift of the lowest 5d level of Ce3+ and the raise of the garnet bandgap energy with increasing Al3+ concentration. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.