Properties of LiGa0.5In0.5Se2: A Quaternary Chalcogenide Crystal for Nonlinear Optical Applications in the Mid-IR

LiGaSe2 (LGSe) and LiInSe2 (LISe) are wide band-gap nonlinear crystals transparent in the mid-IR spectral range. LiGa0.5In0.5Se2 (LGISe) is a new mixed crystal, a solid solution in the system LGSe–LISe, which exhibits the same orthorhombic structure (mm2) as the parent compounds in the same time being more technological with regard to the growth process. In comparison with LGSe and LISe its homogeneity range is broader in the phase diagram. About 10% of the Li ions in LGISe occupy octahedral positions (octapores) with coordination number of 3. The band-gap of LGISe is estimated to be 2.94 eV at room temperature and 3.04 eV at 80 K. The transparency at the 0-level extends from 0.47 to 13 µm. LGISe crystals exhibit luminescence in broad bands centered near 1.7 and 1.25 eV which is excited most effectively by band-to-band transition. From the measured principal refractive indices and the fitted Sellmeier equations second-harmonic generation from 1.75 to 11.8 μm (fundamental wavelength) is predicted. The nonlinear coefficients of LGISe have values between those of LGSe and LISe. 6LGISe crystals are considered promising also for detection of thermal neutrons

Optical, vibrational, thermal, electrical, damage and phase-matching properties of lithium thioindate

Lithium thioindate (LiInS$_{2}$) is a new nonlinear chalcogenide biaxial material transparent from 0.4 to 12 $\mu$m, that has been successfully grown in large sizes and good optical quality. We report on new physical properties that are relevant for laser and nonlinear optics applications. With respect to AgGaS(e)$_2$ ternary chalcopyrite materials, LiInS$_{2}$ displays a nearly-isotropic thermal expansion behavior, a 5-times larger thermal conductivity associated with high optical damage thresholds, and an extremely low intensity-dependent absorption allowing direct high-power downconversion from the near-IR to the deep mid-IR. Continuous-wave difference-frequency generation (5-11$\mu$m) of Ti:sapphire laser sources is reported for the first time.Comment: 27 pages, 21 figures. Replaces the previous preprint (physics/0307082) with the final version as it will be published in J. Opt. Soc. Am. B 21(11) (Nov. 2004 issue

Magnetic and structural properties of barium hexaferrite BaFe12O19 from various growth techniques

Barium hexaferrite powder samples with grains in the m-range were obtained from solid-state sintering, and crystals with sizes up to 5 mm grown from PbO, Na2CO3, and BaB2O4 fluxes, respectively. Carbonate and borate fluxes provide the largest and structurally best crystals at significantly lower growth temperatures of 1533 K compared to flux-free synthesis (1623 K). The maximum synthesis temperature can be further reduced by the application of PbO-containing fluxes (down to 1223 K upon use of 80 at % PbO), however, Pb-substituted crystals Ba1-xPbxFe12O19 with Pb contents in the range of 0.23(2) x 0.80(2) form, depending on growth temperature and flux PbO content. The degree of Pb-substitution has only a minor influence on unit cell and magnetic parameters, although the values for Curie temperature, saturation magnetization, as well as the coercivity of these samples are significantly reduced in comparison with those from samples obtained from the other fluxes. Due to the lowest level of impurities, the samples from carbonate flux show superior quality compared to materials obtained using other methods

Consumer request of the parent community for transport service for schoolchildren

The article presents the results of an empirical study of the consumer demand of the parent community for transport service for schoolchildren. We formulated the leading trends of consumer demand and research methods of this subject area, based on a brief review of scientific publications on the development of school transport. The theoretical review of scientific publications is used in the development of the program and tools of empirical research. The empirical part of the study of the consumer demand of the parent community for transport services for schoolchildren was conducted in Stavropol Krai (Russia). The problems that exist in this area are collected as a result of discussions in the chats of parent communities (the total number of participants is 463 people), social networks (comments of 324 people), at parent meetings in educational organizations and discussions of teachers (16 parent meetings, 23 teachers from 10 educational organizations). In total, we analyzed opinions on the composition of the problem field of 1132 people. It was developed a logical and semantic model of consumer demand for transport service for schoolchildren, characteristic of residents of Stavropol Krai. The data obtained are important for the development of transport accessibility of educational institutions and the adoption of infrastructure decisions in the programs of socio-economic development of the region and individual territories

Properties of LiGa0.5In0.5Se2: A Quaternary Chalcogenide Crystal for Nonlinear Optical Applications in the Mid-IR

LiGaSe2 (LGSe) and LiInSe2 (LISe) are wide band-gap nonlinear crystals transparent in the mid-IR spectral range. LiGa0.5In0.5Se2 (LGISe) is a new mixed crystal, a solid solution in the system LGSe–LISe, which exhibits the same orthorhombic structure (mm2) as the parent compounds in the same time being more technological with regard to the growth process. In comparison with LGSe and LISe its homogeneity range is broader in the phase diagram. About 10% of the Li ions in LGISe occupy octahedral positions (octapores) with coordination number of 3. The band-gap of LGISe is estimated to be 2.94 eV at room temperature and 3.04 eV at 80 K. The transparency at the 0-level extends from 0.47 to 13 µm. LGISe crystals exhibit luminescence in broad bands centered near 1.7 and 1.25 eV which is excited most effectively by band-to-band transition. From the measured principal refractive indices and the fitted Sellmeier equations second-harmonic generation from 1.75 to 11.8 μm (fundamental wavelength) is predicted. The nonlinear coefficients of LGISe have values between those of LGSe and LISe. 6LGISe crystals are considered promising also for detection of thermal neutrons

Electronic Properties of undoped LiBaAlF6LiBaAlF_6 Single Crystals: Far-Ultraviolet Optical, Luminescence, and X-Ray Photoelectron Spectroscopy Studies

The electronic structure properties of undoped single crystals of LiBaAlF6 (LBAF) were determined using low-temperature (T=10  K) time-resolved far-ultraviolet (3.7–40 eV) synchrotron radiation spectroscopy, calculations for the spectra of optical functions, and x-ray photoelectron spectroscopy. The bandgap of the investigated compound was found at Eg=12.3  eV, the energy threshold for creation of the unrelaxed excitons at En=1=11.6  eV, and the low-energy fundamental absorption edge at 11.0 eV. The subnanosecond photoluminescence emission band at 6.6 eV in LBAF single crystal is due to radiative valence-core transitions 2p F−→5p Ba2+

Properties of LiGa0.5In0.5Se2: A Quaternary Chalcogenide Crystal for Nonlinear Optical Applications in the Mid-IR

LiGaSe2 (LGSe) and LiInSe2 (LISe) are wide band-gap nonlinear crystals transparent in the mid-IR spectral range. LiGa0.5In0.5Se2 (LGISe) is a new mixed crystal, a solid solution in the system LGSe–LISe, which exhibits the same orthorhombic structure (mm2) as the parent compounds in the same time being more technological with regard to the growth process. In comparison with LGSe and LISe its homogeneity range is broader in the phase diagram. About 10% of the Li ions in LGISe occupy octahedral positions (octapores) with coordination number of 3. The band-gap of LGISe is estimated to be 2.94 eV at room temperature and 3.04 eV at 80 K. The transparency at the 0-level extends from 0.47 to 13 µm. LGISe crystals exhibit luminescence in broad bands centered near 1.7 and 1.25 eV which is excited most effectively by band-to-band transition. From the measured principal refractive indices and the fitted Sellmeier equations second-harmonic generation from 1.75 to 11.8 μm (fundamental wavelength) is predicted. The nonlinear coefficients of LGISe have values between those of LGSe and LISe. 6LGISe crystals are considered promising also for detection of thermal neutrons

Structure and Optical Properties of Li2In2GeSe6 Crystal

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