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