87 results about "Barium borate" patented technology

A laser beam in the ultraviolet region is generated at high power for along period. A green laser beam generated by a laser oscillator comes incident into a resonator from behind a first curved mirror, and circulates there, reflected by each mirror. By passing a barium borate crystal, it causes a secondary harmonic (a laser beam in the ultraviolet region) to be generated, which is taken out of the resonator via a second curved mirror. The beam waist of the laser beam passing the barium borate crystal is set to 46 mum, about double the conventional thickness, by adjusting the distance between the first curved mirror and a second flat mirror. As a result, the power density of the laser beam in the barium borate crystal is reduced to ¼ of the value according to the related art, and it is made possible to avoid rapid degradation of the barium borate crystal by excessive squeezing of the laser beam.

The invention relates to a large-sized bismuth barium borate non-linear optic crystal, which belongs to the orthorhombic system with a space group equal to Pna21 and a molecular formula equal to BaBiBo4. The crystal is made from a mixed system of bismuth barium borate, fluxing agent Bi2O3 and BaB2O4, or BaO and Bi2O3; the nonlinear optical effect of the crystal is approximately five times of that of (KH2PO4) KDP; and the crystal is transparent within a wave band of between 200 and 3,000 nm, and has the large size with 1 to 100mmx1 to 100mmx1 to 100mm. The large-sized bismuth barium borate non-linear optic crystal has the advantages of quick making speed, simple operation, low cost, large-sized and transparent crystal made by the non-linear optic crystal, wide light-transmission wave band, ideal mechanical property, infrequent fragmentation, stable physicochemical properties, no deliquescence and easy processing and preservation; moreover, the non-linear optic crystal can be used to make non-linear optical devices such as a multiple frequency generator, an upper frequency converter or a lower frequency converter and an optical parametric oscillator.

The invention relates to a compound tetrahydroxy barium borate and a tetrahydroxy barium borate nonlinear optical crystal as well as a preparation method and an application. The molecular formula of the compound is Ba2[B6O9(OH)4] and the molecular weight is 551.57. The molecular formula of the crystal is Ba2[B6O9(OH)4]; the crystal belongs to a monoclinic system; the space group is P21; the molecular weight is 551.57; the tetrahydroxy barium borate nonlinear optical crystal can be obtained by adopting a hydrothermal process through a method of programmed cooling or naturally cooling; the nonlinear optical effect of the crystal is three times that of a KDP (Potassinm Dihydengen Phosphate) crystal; a light-transmitting wave band is 190nm-2500nm long; the growth process of the crystal is simple to operate and low in cost; and the applied reagent is inorganic raw material and has the advantages of low toxicity, short growth period and stable physico-chemical property. The tetrahydroxy barium borate nonlinear optical crystal disclosed by the invention is widely used in nonlinear optical devices such as frequency conversion and optical parametric oscillators.

The invention relates to a compound boric acid barium cesium, a boric acid barium cesium nonlinear optical crystal, a preparation method and application. The compound has the chemical formula of CsBaB9O15 and the molecular weight of 607.54 and is synthesized through a solid phase reaction method. The boric acid barium cesium nonlinear optical crystal has the chemical formula of CsBaB9O15, the molecular weight of 607.54, the space group of -Cc-, the cell parameter a of 6.4918(4) , the cell parameter b of 11.4075(6) , the cell parameter c of 17.2571(9) , the cell parameter beta of 92.375(3), the cell parameter Z of 4 and the cell parameter V of 1276.88(12) <3>. The powder 1064 nm frequency-doubled effect of the compound is 2-3 times that of KDP; the 532 nm frequency-doubled effect is about 1 time that of KDP, the transmission region is 175 nm to 2600 nm, and the crystal grows through a flux growth method. The method is easy to operate and low in cost; the prepared crystal is free of deliquescence in the air, good in mechanical performance, not prone to breakage, stable in physiochemical property, easy to process and suitable for manufacturing ultraviolet / deep ultraviolet nonlinear optical devices.

The present invention relates to granules, which are a glass raw material mixture for the production of alkali-free glass containing substantially no alkali metal oxides, wherein the glass structure of glass obtained from the granules is, in mol% on an oxide basis, 60-75 mol% SiO2, 5-15 mol% Al2O3, 1-9 mol% B2O3, 0-15 mol% MgO, 0-20 mol% CaO, 0-12 mol% SrO, 0-21 mol% BaO, and more than 0 mol% for the total of CaO, SrO and BaO; and for which in an X-ray diffraction spectrum obtained by means of a CuKa X-ray powder diffraction, when the diffraction peak area of quartz (100) in which 2Theta is 19.85-21.71 degrees is taken as 1, the total of the relative value of the diffraction peak area of strontium borate hydrate in which 2Theta is 10.81-13.01 degrees, the relative value of the diffraction peak area of calcium borate hydrate in which 2Theta is 11.11-13.49 degrees, and the relative value of the diffraction peak area of barium borate hydrate in which 2Theta is in the range of 10.91-13.27 degrees, is at least 0.005. The present invention also relates to a production method for the granules, a method for producing molten glass using the granules, and a method for producing a glass article using the production method for molten glass.

Provided area deep ultraviolet non-linear optical crystal of barium borate hydrate, a preparation method therefor and the use thereof. The chemical formula of the crystal is Ba2BHO22H7, belonging to monoclinic system, with the space group thereof being P21, the crystal cell parameters thereof being a=6.7719(10) Å, b=21.1195(4) Å, c=6.8274(10) Å, β=119.3950(10)° , and the molecular weight thereof being 752.65. The non-linear optical crystal of borate is obtained by means of programmed cooling or natural cooling using a hydrothermal method. The crystal powder has a frequency-doubled effect of about 2 times that of KDP (KH2PO4) and an ultraviolet cut-off edge of below 175 nm and can be used as a deep ultraviolet non-linear optical crystal. The growth process of the crystal has advantages such as simple, a low cost, a low toxicity, a short growth cycle, stable physical and chemical properties, etc. The deep ultraviolet non-linear optical crystal of barium borate hydrate Ba2B11O22H7 is widely used in the preparation of non-linear optical devices such as frequency doubling generators, upper frequency converters, lower frequency converters, optical parametric oscillators etc.

The present invention relates to a compound chlorine barium borate, a chlorine barium borate nonlinear optical crystal, and a preparation method and uses of the chlorine barium borate nonlinear optical crystal. According to the present invention, the chemical formula of the compound is Ba7B3O11Cl, the molecular weight is 1205.26, and the compound is synthesized by adopting a solid phase reaction method; the chemical formula of the chlorine barium borate nonlinear optical crystal is Ba7B3O11Cl, the molecular weight is 1205.26, the crystal does not have the symmetry center and belongs to the hexagonal crystal system, the space group is P6[3]mc, and the cell parameters are as the follows: a is 11.2266 (17) angstrom, c is 7.214 (2) angstrom, Z is 2, and V is 787.4 (3) angstrom; the frequency doubling effect of the crystal powder achieves the 0.5 time of the KDP (KH2PO4); and the crystal has characteristics of large mechanical hardness, easy cutting, easy polish processing and easy preservation, and is widely applied in preparation of frequency doubling generators, frequency up-convertors, frequency down-convertors, or optical parameter oscillators and other nonlinear optical devices.

Provided are a deep ultraviolet non-linear optical crystal of barium borate hydrate, a preparation method therefor and the use thereof. The chemical formula of the crystal is Ba2B11O22H7, belonging to the monoclinic system, with the space group thereof being P2 1, the crystal cell parameters thereof being a = 6.7719(10)Å, b = 21.1195(4)Å, c = 6.8274(10)Å, β = 119.3950(10)°, and the molecular weight thereof being 752.65. The non-linear optical crystal of borate is obtained by means of programmed cooling or natural cooling using a hydrothermal method. The crystal powder has a frequency-doubling effect of about 2 times that of KDP(KH2PO4) and an ultraviolet cut-off edge of below 175 nm, and can be used as a deep ultraviolet non-linear optical crystal. The growth process of the crystal has advantages such as easy operation, a low cost, a low toxicity of raw materials, a short growth cycle, stable physical and chemical properties, etc. The deep ultraviolet non-linear optical crystal of barium borate hydrate Ba2B11O22H7 is widely used in the preparation of non-linear optical devices such as frequency doubling generators, upper frequency converters, lower frequency converters, optical parametric oscillators etc.

The invention provides a preparation method of a bivalent bismuth ion-doped chloro-barium pentaborate red fluorescent material, which comprises the following steps of: weighing a compound raw material containing barium, boracium, chlorine and bismuth according to mol ratio of barium to boracium to chlorine to bismuth being 2(1-x):5:1:2x, wherein x is more than or equal to 0.0001 and less than or equal to 0.10; uniformly grinding the raw materials and pre-sintering; controlling the temperature to be 400-750oC; taking out the pre-sintered sample; uniformly regrinding and sintering at high temperature; and controlling the temperature to be 800-1000oC; feeding the sintered sample in a reducing atmosphere with 800-1000oC and reacting for 15 minutes to 10 hours to obtain the required red fluorescent material. The fluorescent material prepared by the invention can be absorbed by ultraviolet and blue light spectrum regions and is excited by ultraviolet light or blue light to form red fluorescent light covering an interval of 600-750nm; and the fluorescent life of the fluorescent material is about 10 microseconds.

The invention discloses a preparation method of barium metaborate nano-powder. The preparation method comprises the following steps of: A, weighing barium hydroxide and boric acid in a molar ratio of 1:2, uniformly mixing the barium hydroxide and the boric acid at room temperature, grinding the mixture from a solid state to a wet state and then from the wet state to a viscous state, and then continuously grinding the mixture for 1 to 1.5 hours; and B, baking and / or air-drying and / or roasting a product obtained in the step A to obtain low-temperature phase barium metaborate nano-powder with different crystalline state. In the preparation method, a low-temperature solid-state reaction method is adopted, the barium hydroxide and the boric acid are taken as raw materials, barium metaborate is prepared by grinding and one-step reaction; without solvent, surfactant, precipitating agent or operation steps such as suction filtration, vacuum drying, centrifugal separation and the like, complete conversion of the raw materials into products is directly realized, and the method has low energy consumption and low cost, is environment-free, and accords with requirements of green chemistry.

The present invention provides a barium fluoroborate compound, a nonlinear optical crystal and the preparation method and use thereof. Both of the barium fluoroborate compound and the nonlinear optical crystal have a chemical formula of Ba4B11O20F. The crystal belongs to orthorhombic crystal system, has a space group Cmc21 with unit cell parameters of a=18.802(3) Å, b=10.7143(19) Å, c=8.6113(14) Å, V=1734.7(5) Å3. The crystal has a powder second harmonic generation efficiency of 10 times that of KDP (KH2PO4). The ultraviolet cutoff wavelength is about 170 nm. The barium fluoroborate compound is prepared by a solid-state reaction. The barium fluoroborate nonlinear optical crystal prepared by a high temperature melting liquid method has large hardness and is easy to be cut, polished and stored. This crystal can be used widely in preparing the nonlinear optical devices of the second harmonic generator, the up frequency converter, the down frequency converter or the optical parametric oscillator or the like.

The invention relates to a strontium-doped barium borate ultraviolet double-refraction crystal and a preparation method thereof. The crystal has a molecular formula of Ba1-xSrxB2O4 (x=0.001- 0.23) and belongs to a trigonal system. The cell parameters of the space group R3c and Ba0.9Sr0.1B2O4 are within the transmission range of 190 to 3500 nm, the transmission rate of ultraviolet band reaches 90%, and the double refraction rate of the wavelength 533nm is: ne=1.5379, n0=1.6619, and the crystal can be used as ultraviolet double refraction crystal. The crystal is grown by using pulling method. The crystal can be widely used for Glan-Taylor and Glan-laser polarizers, especially for high-power ultraviolet polarizers.

The invention discloses hydroxyalkylamide-cured outdoor type flame retardant powder coating which is prepared from the following components in parts by mass: 65 parts of outdoor polyester resin, 4 parts of a hydroxyalkylamide curing agent, 2 parts of a smooth degassing agent, 2 parts of a leveling agent, 5-10 parts of a compound flame retardant and 17-22 parts of pigments and fillers, wherein the compound flame retardant is prepared from the following raw materials in parts by weight: 5 parts of aluminum hydroxide, 5 parts of magnesium hydroxide, 16 parts of zinc borate, 32 parts of barium borate, 6 parts of antimony trioxide and 36 parts of diatom mud. The powder coating provided by the invention adopts the self-made compound flame retardant, so that the obtained coating has low thermal conductivity, can reduce the speed of heat transfer to a protected substrate, can also effectively isolate oxygen, increases heat absorption capacity, has excellent flame retardancy, and does not affect coating leveling, weather resistance, impact resistance and other properties.

The present invention relates to a barium tetraborate compound and a barium tetraborate non-linear optical crystal, and a preparation method and use thereof, wherein the chemical formulae of the barium tetraborate compound and the non-linear optical crystal thereof are both BaB4O7, with a molecular weight of 292.58; the barium tetraborate non-linear optical crystal has a non-centrosymmetric structure, which belongs to a hexagonal system, and has a space group P65 and lattice parameters of a=6.7233(6) Å, c=18.776(4) Å, V=735.01(17) Å3, and Z=6, wherein the powder frequency-doubled effect thereof is two times that of KDP (KH2PO4), and the ultraviolet cut-off edge is lower than 170 nm. The barium tetraborate compound is synthesized by a solid-phase reaction method; the barium tetraborate non-linear optical crystal is grown by a high-temperature molten solution method; and the crystal has a moderate mechanical hardness, is easy to cut, polish and store, and is widely applicable in the non-linear optics of a double-frequency doubling generator, an upper frequency converter, a lower frequency converter or an optical parameter oscillator etc.

This invention relates to the growth of zinc oxide (ZnO) single crystal by using molten-salt method. In this invention, the raw materials are: analytical agent barium oxide (BaO), boric acid (H3BO3) and specpure zinc oxide (ZnO). By using barium borate (BaB2O4) as fluxing agent, the invented single crystal is produce, with temperature reducing rate of 2-15 deg.C / d.

A nitric oxide sensor and method is disclosed. The sensor is based on sum-frequency mixing of a tunable, 395-nm external cavity diode laser with a 532-nm diode-pumped intracavity-frequency-doubled Nd:YAG laser in a beta-barium-borate crystal. The output from the BBO crystal is ultraviolet radiation at 227 nm and is split using a 50—50 beam splitter. Half of the radiation is directed into a reference photomultiplier tube, and the other half of the UV radiation is directed through the medium of interest and then directed into a signal photomultiplier tube. The output from the photomultiplier tubes is compared and the difference utilized to indicate the level of nitric oxide by absorption-based spectrosocpic techniques.

The invention discloses a preparation method of nano barium borate sol and application thereof in polyester flame retardance. The nano barium borate sol is prepared from barium hydroxide and boric acid through neutralizing reaction in a mixed solution of water and C2-C4 diol, wherein the highest concentration can reach 25% by weight, and the particle size is 5-80nm. The colloidal particles are dispersed uniformly, have good stability and do not form second agglomeration after long-time standing. The nano barium borate sol can be directly added into a polyester reaction system independently or after being compounded with other flame retardants, and a flame-retardant copolyester nano composite material is prepared through an in-situ polymerization way. Through the invention, the problems that the subsequence processing is difficult and the mechanical properties of materials are deteriorated seriously since an inorganic flame retardant with large powder particles is added for polyester flame retardance are solved. The preparation method disclosed by the invention has the advantages of low cost, simple process, easiness in realizing industrial production, high processability of the prepared material and the like, and brings obvious social and economic benefits.

The invention relates to a fluorin boric acid barium sodium ultraviolet birefringent crystal, as well as a growth method and an application thereof. A chemical formula of the fluorin boric acid barium sodium ultraviolet birefringent crystal is Ba2Na3(B3O6)2F and the crystal belongs to a uniaxial negative crystal; a refractive index of the crystal no is greater than ne; an ultraviolet end side is about 185nm; the crystal is moderate in hardness, easy to process and stable in air; the fluorin boric acid barium sodium ultraviolet birefringent crystal can grow by using a co-solvent method or a melt drawing method; the fluorin boric acid barium sodium ultraviolet birefringent crystal has a great birefringence delta n which is equal to no-ne; the birefringence delta n in a wavelength range of 2000nm-185nm is 0.087-0.192; and the fluorin boric acid barium sodium ultraviolet birefringent crystal has important application prospects in optics and optical communication fields and can be used for manufacturing polarization beam splitter prisms which are gland prisms, Wollaston prisms, Rochon prisms or beam splitting polarizers.

A method for preparing the nonagglomerate low-temperature phase BBO nanoparticles, belongs to the technical field of fine chemical industry, which comprises the following steps: depositing the aqueous solution of inorganic barium salt and boracic acid by organic amine as a precipitating agent, filtering and drying, calcining at a temperature of 650-850 Deg. C, to get the BBO nanoparticles in the average particle size about 40 nm and without agglomerates and impurity phases. The projecting characteristic of the method is: adopting the inorganic salt as a raw material, needing not to add surfactant and having no use for vacuum drying and centrifugal separating to get the high-purity BBO nanoparticles without agglomerates and impurity phases.

The invention discloses an aqueous heat-insulation heat-preservation fireproof material. The aqueous heat-insulation heat-preservation fireproof material is prepared from the following components in percentage by weight: 8 to 20 percent of nano silicon oxide composite material obtained by compounding structurally-controlled nano silicon oxide powder and a nano silicon oxide cake material with an ultrahigh specific surface area according to a proportion of 0.5:(1-5):1, 3 to 15 percent of glass micro-beads, 4 to 10 percent of nano titanium oxide, 1 to 8 percent of potassium titanate, 1 to 8 percent of titanium pyrophosphate, 1 to 3 percent of aluminum hydroxide, 1 to 3 percent of zinc borate, 1 to 3 percent of barium borate, 1 to 3 percent of calcium sodium metasilicate, 1 to 10 percent of aluminum silicate, 20 to 28 percent of acrylic hybrid emulsion, 1.5 to 3 percent of other assistants, and the balance of water. According to the aqueous heat-insulation heat-preservation fireproof material disclosed by the invention, the nano silicon oxide composite material obtained by compounding structurally-controlled nano silicon oxide powder and the nano silicon oxide cake material with the ultrahigh specific surface area as a core material, and by the components and corresponding optimized improvement of the proportions, the product has a good heat-flow stagnation function; and the heat conduction coefficient of the product is not more than 0.03W / (m.K), and the waterproof performance reaches A level.

An optical resonator fabricated from a uniaxial birefringent crystal, such as beta barium borate. The crystal is cut with the optical axis not perpendicular to a face of the cut crystal. In some cases the optical axis lies in the plane of the cut crystal face. An incident (input) electromagnetic signal (which can range from the infrared through the visible to the ultraviolet) is applied to the resonator. An output signal is recovered which has a frequency that is an integer multiple of the frequency of the input signal. In some cases a prism is used to evanescently couple the input and the output signals to the resonator.

A method for preparing a low-temperature phase barium metaborate single crystal thin film, comprising the following specific steps: placing a Li2CO3 and Al2O3 mixed material block with pores in a platinum crucible; placing or suspending a double-sided polished α-BBO wafer on On the platinum wire, add a crucible cover covered with Li2CO3 and Al2O3 mixed powder and a thermocouple, seal the top of the crucible with a platinum cover, and place it in a resistance furnace; the resistance furnace is heated to 700-1000°C and kept at a constant temperature for 2-100 hours , Li2O diffuses into the α-BBO wafer, and undergoes a solid-state reaction with the α-BBO wafer, so that the surface layer of the α-BBO wafer undergoes a phase change to form a β-BBO single crystal thin film. The method can grow micron-scale β-BBO single crystal thin films meeting requirements on α-BBO substrates, not only saves materials, but also can be produced in batches, which is of great significance to the development of laser technology and integrated optics.

The invention belongs to the field of ceramic production and particularly relates to a ground-glaze-free low-temperature transmutation zirconium white glaze formula, a preparation method and a use method thereof. The ground-glaze-free low-temperature transmutation zirconium white glaze formula includes feldspar powder, boric acid, barium borate, limestone, zinc oxide, lead oxide, lead silicate and bentonite. The glaze is low in cost, is convenient to use, is low in sintering temperature and has a unique artistic feel. Glaze surface produced by sintering the ground-glaze-free low-temperature transmutation zirconium white glaze has a zirconium white dark light bottom color, wherein irregular black spots are uniformly distributed on the glaze surface. The size and distribution density of the black spots are changed according to the model of a ceramic product and glaze thickness. The glaze surface has a stone-like appearance and a slight flowing-tendency effect, thereby achieving unique artistic effects. Porcelain produced with the glaze is increased in grade and market price and is high in economic value. The glaze can be produced in large scale, can be popularized quickly and is simple in use, thereby achieving strong market competitiveness.

The invention relates to a compound barium fluoborate, and a barium fluoborate nonlinear optical crystal, a preparation method and application thereof, wherein the chemical formula of the compound isBaBOF3, the molecular weight of the compound is 221.15, the compound is prepared by adopting a solid-phase synthesis method or a vacuum packaging method, the chemical formula of the crystal is BaBOF3,the molecular weight of the crystal is 221.15, the crystal belongs to a monoclinic system, the space group is P2[1], the unit cell parameters are as follows: a is 4.6145(17)angstrom, b is 4.3671(16)angstrom, c is 7.905(3)angstrom and beta is 105.519(6)angstrom, the unit cell volume is 153.49(10)angstrom<3>, the powder frequency doubling effect of the crystal is about 1.0 time that of KH2PO4(KDP),the ultraviolet absorption edge is shorter than 190 nm, the crystal grows by adopting a melt method, a high-temperature melt method, a vacuum packaging method, a hydrothermal method or a room-temperature solution method, the chemical stability of the crystal is good, and the crystal can be used as an ultraviolet and deep ultraviolet nonlinear optical crystal to be applied to an all-solid-state laser device.

The present invention discloses a preparation method and uses of a barium borate Yt crystal. Compared to the technology in existence, the monocrystal barium borate Yt in accordance with the present invention is characterized by its high luminescence intensity and light-emitting efficiency, sensitive responses and the like. Furthermore, in accordance with the present invention, said process can be used for getting barium borate Yt single crystal at conditions of air atmosphere and about 1019 DEG C, with mild experiment conditions and short reaction time; and the crystal obtained through the method possesses is characterized by its excellent quality, low material cost, simple equipment, being easy to extend. Said barium borate Yt crystal exhibits some characteristics such as high efficiency and quick-speed, when used for X-ray exploration.

The invention relates to a preparation method and application of a barium-cesium borate nonlinear optical crystal. The chemical formula of the crystal is CsBaB9O15, the molecular weight is 607.54, thecrystal belongs to a monoclinic system, the space group is Cc3; cell parameters are that a=6.4918(4) angstroms, b=11.4075(6) angstroms, c=17.2571(9) angstroms, beta=92.375(3), Z is equal to 4, and Vis equal to 1276.88 (12) angstrom<-3>. A Bridgman-Stockbarger method is adopted to grow the large-size cesium barium borate crystal, a powder frequency multiplication test method is adopted to measurethe phase matching ability of the CsBaB9O15 crystal, the powder frequency multiplication effect is 3KDP, and the ultraviolet absorption edge is close to 175 nm; the CsBaB9O15 crystal is a harmonic generator capable of realizing the quadruplicated frequency and the quintuplicated frequency of Nd:YAG(1064nm). In addition, the CsBaB9O15 crystal is colorless and transparent, does not deliquesce in the air, is stable in chemical performance, can be widely applied to various nonlinear optical fields, and can develop nonlinear optical application of an ultraviolet band.

An optical resonator fabricated from a uniaxial birefringent crystal, such as beta barium borate. The crystal is cut with the optical axis not perpendicular to a face of the cut crystal. In some cases the optical axis lies in the plane of the cut crystal face. An incident (input) electromagnetic signal (which can range from the infrared through the visible to the ultraviolet) is applied to the resonator. An output signal is recovered which has a frequency that is an integer multiple of the frequency of the input signal. In some cases a prism is used to evanescently couple the input and the output signals to the resonator.

The present invention provides a barium fluoroborate compound, a nonlinear optical crystal and the preparation method and use thereof. Both of the barium fluoroborate compound and the nonlinear optical crystal have a chemical formula of Ba4B11O20F. The crystal belongs to orthorhombic crystal system, has a space group Cmc21 with unit cell parameters of a=18.802(3) Å, b=10.7143(19) Å, c=8.6113(14) Å, V=1734.7(5) Å3. The crystal has a powder second harmonic generation efficiency of 10 times that of KDP (KH2PO4). The ultraviolet cutoff wavelength is about 170 nm. The barium fluoroborate compound is prepared by a solid-state reaction. The barium fluoroborate nonlinear optical crystal prepared by a high temperature melting liquid method has large hardness and is easy to be cut, polished and stored. This crystal can be used widely in preparing the nonlinear optical devices of the second harmonic generator, the up frequency converter, the down frequency converter or the optical parametric oscillator or the like.