Laboratory of functional optical crystalline materials is a subunit of NITIOM VNC GOI (Vavilov State Optical Institute). The laboratory is representative of the directions of research that were pursued by GOI for over 30 years, and it accumu- lated vast experience both in developing the techniques for creating and studying novel mono and polycrystalline materials, as well as in supplying finished optical ele- ments based on those materials. The laboratory concentrates its efforts mainly in the following directions: - technique development and industrial growing of monocrystalline materials from low and high-temperature solutions - creation of polycrystalline functional optical materials with given qualities: luminescent ceramics, photochromic and cathodochromic sodalite ceramics, polycrystalline optical ceramics. - X -ray structure investigations of crystals and ceramics. Functional optical ceramics are produced by recrystallization pressing technique (RP). The RP technique has following features: high dispersity powders of inorganic compounds are made to density at temperatures (2/3+1/6)Tmelt of the substance under pressing and 200 - 300 MPa pressure. In the process of RP, polycrystalline briquette density value approaches X-ray structure density (relative density is greater than or equal to 0,997 of X-ray structure density), which provides for its transparency in the optical spectrum. The laboratory acquired many years of experience in developing the growth techniques for such nonlinear crystals as: potassium pentaborate (KB5), potassium dihydrophosphate (KDP), potassium dideuterophosphate (DKDP), potassium titanylphosphate (KTP), barium nitrate (Ba(NO3)2), sodium nitrate (NaNO3), L-arginine phosphate (a- LAP), nickel sulphate crystalline hydrate monocrystals (NiSO4*6H2O), potassium acid phthalate (KAP) (C6H4COOKCOOH) and in manufacturing optical parts from these materials. Potassium titanyl phosphate crystals (KTiOPO4) are implemented in the 0.45-4.2 mm range for the second harmonic generation, for generating sum and difference frequencies in solid-state lasers. Major advantages of KTP crystals compared to other nonlinear materials are their high nonlinearity tensor value, low angular and temperature sensitivity of the synchronism angles, chemical stability. Potassium pentaborate crystals (K(H4B5O10)*2H2O). First nonlinear material for conversion in the short UV range. Potassium dihydrophosphate crystals (KH2PO4). Traditional nonlinear material, finds use in the 0.26-1 mm range for the second, third and fourth harmonic generation, for generating sum and difference frequencies. Compared to other nonlinear materials, KDP crystals offer the advantages of broad spectral synchronism and cheapness of the material. Potassium dideuterophosphate crystals (KD2PO4). Traditional material for nonlinear and electrooptic applications. Is used in the 0.26-1.3 mm range for the second, third and fourth harmonic generation, for generating sum and difference frequencies, for making Pokkels cells. Main advantages of DKDP crystals over other nonlinear materials lie in broad spectral synchronism and polyfunctionality of the material. Barium nitrate crystals (Ba(NO3)2) serve as material for elements of the SRS frequency conversion of laser radiation. Their distinguishing features - large Stokes shift - 1047 cm-1, high transparency (0.004 cm-1 at 635 nm) and optical homogeneity across broad spectral range (0.35-1.8 mm). Sodium nitrate crystals (NaNO3) - crystallographic analog of calcite. Features high birefringence (1.5 times greater than calcite), transparency (0.32-1.8 mm). The value for relative parameter of optical homogeneity for the o and e rays in the cuts along and at right angles to the optical axis varies from 4.5x10-5 to 8x10-6 cm-1. The Stokes shift is large, same as in barium nitrate. Offering splendid optical homogeneity and high beam strength, potassium nitrate can be successfully implemented in the power and wide-aperture polarization optics. Nickel sulfate crystalline hydrate (NiSO4*6H2O) monocrystal with diameter up to 50 mm, thickness up to 50 mm are grown for the UV range light filters. Luminescent ceramics are manufactured by recrystallization pressing technique applied to highly efficient crystalline phosphors - zinc sulfide powdersdoped with silver,cooper, aluminum,chlorine and the rare-earth doped yttrium, lanthanum, gadolinium oxysulfides. Screens made of luminescent optical ceramics feature high stability under large power loads in luminescence excitation, higher resolution and electrical strength than powder screens. Employing the diffusion welding to glass, composite cathodoluminescent screens are manufactured that furnish the resolution of 600 lines/mm. At present the laboratory is engaged in the research aimed at creating Gd2O2S.PR.Ce based scintillation optical ceramics for computer tomography and ZnS -Te based polycrystals for the charged particle detectors. Photochromic and cathodochromic sodalite ceramics are also produced by RP technique on basis of halogensodalites (Na6Al6Si6O24.Hal:-Cl,Br,I). Sodalites are the incongruently melting frame alumosilicates belonging to non-stoichiometric cage compounds. These materials attract huge interest because they are the best of all known photochromic and cathodochromic (employing the principle of photo transport of the charge) reversal materials. Sodalite ceramics are transparent in the 0,3-4,5 mkm range. Transmittance in the visible range is 85-90% with samples 1 mm thick. The materials acquire colour under ionizing radiation of any type. The peak of absorption bands for the F colour centres lies in the 525,555 and 605 nm range (for Cl, Br, I sodalites respectively) To impart photochromic qualities to the sodalite optical materials, donor impurities are introduced that become ionized under the UV radiation. The value for induced absorption reaches 104 cm-1 (for an electron beam) and 200 cm-1 (for UV radiation). Polycrystalline optical zeolites. In recent years GOI developing an original production technique for monolithic polycrystalline zeolites with the relative density of rrel > 0,9-099 rtheor. (where rtheor - corresponding monocrystal density). At high relative densities rrel> 0,997rtheor the zeolites crystals developed acquire optical transparency. Molecules of different compounds introduced into zeolite channels and hollows form angstrom -size clusters, which, thanks to the size factor, display hybrid (intermediate) properties lying between the properties of a molecule and the bulk phase. Inside the zeolite porous bulk it is possible to create both isolated compound clusters and the electronic-bound superlattice of these compounds. Such type of composite materials is now subject to intensive research exploring the possibilities of their implementation in the sun energy conversion, creation of zeolite batteries, solid zeolite ionic conductors zeolite chemical sensors, zeolite materials for data display and storage, zeolite lasers and displays. The laboratory undertakes the research into properties of optical zeolites and performs search for promising application areas. We are looking for partners interested in carrying out joint research projects. In the area of X -ray structure research,the laboratory is equipped with all necessary instruments and employs highly qualified staff for carrying out a broad spectrum of research: - study of monocrystalline substructure; - phase analysis of polycrystalline materials and ceramics; - analysis of solid solutions, determination of composition and parameters of monocrystal and ceramic lattices; - determination by the X-ray methods of monocrystal orientation.Сайт создан в системе uCoz