Abstract: Disclosed in this invention is an optical recording material having high speed crystallization and excellent erasability, which comprises a composition having the formula of:

Abstract: A sintered ceramic for a scintillator having a composition represented by the general formula of Gd3-xCexAlySizGa5-y-zO12, wherein 0.001≦x≦0.05, 1≦y≦4, and 0.0015≦z≦0.03, is produced by mixing gadolinium oxide, aluminum oxide, gallium oxide, a cerium salt, a silicon compound and a fluorine compound in such proportions as to provide the above composition; calcining the resultant mixture at a temperature of 1400-1600° C.; disintegrating the resultant calcined body to ceramic powder; pressing the ceramic powder to provide a green body; and sintering the green body at a temperature of 1600-1700° C. in a non-oxidizing atmosphere at 5×104 Pa or more, and optionally further by hot isostatic pressing at a temperature of 1400-1600° C. in an argon atmosphere.

Abstract: A substrate 2 is autorotatably installed in a vacuum chamber 1 at an upper part thereof. MgF2 granules 3 as a film source material are put in a quartz boat 4 and mounted on a magnetron cathode 5. The magnetron cathode 5 is connected through a matching box 6 to a 13.56 MHz radio frequency power source 7. Cooling water 8 for holding the temperature of the magnetron cathode 5 constant flows on a lower face of the magnetron cathode 5. A side face of the vacuum chamber 1 is provided with gas introduction ports 9, 10 for introducing gas in the vacuum chamber 1. A shutter 11 is placed between the magetron cathode 5 and the substrate 2. This structure provides a process enabling forming a thin film at a high speed by sputtering, especially, a high speed sputtering enabling forming a thin fluoride film free of light absorption.

Abstract: The invention features an optical medium for calibrating UV absorbance detectors, methods for making such an optical medium, and methods for calibrating UV absorbance detectors using such a medium. The optical calibration medium includes a gel-sol silica glass monolith with a rare-earth dopant therein. The rare-earth dopant exhibits at least one spectral feature in at least the far UV range. The constituents of the gel-sol silica glass monolith are selected so the rare-earth doped sol-gel glass monolith exhibits a transmittance in the far UV range so each distinct spectral feature of the rare-earth dopant in the far UV range is discernable.

Abstract: A process for oxidizing iron ions contained within iron-doped lithium niobate. The process comprises the steps of protonating the iron-doped lithium niobate crystal and then placing the same into a pressure chamber where between 10-100 atmospheres of dry, ultra-pure pressurized oxygen are applied. While under pressure, the crystal is heated to approximately 950° C. at a rate not to exceed 50° C. per minute, and preferably at a rate not less than 25° C. per minute. The resulting lithium niobate crystal will thereafter contain iron ions wherein the divalent iron ion ratio to the trivalent iron ion ratio is approximately 1:100.

Abstract: Nonlinear optical materials, methods of crystal growth, and devices employing such materials satisfy the general formula (&Sgr;i=1-3M&agr;i1)(&Sgr;j=1-3M&bgr;j2)(&Sgr;k=1-6M&ggr;k3)B14O25  Formula 1 wherein M1, M2, and M3 are mono-, di, or tri-valent metal ions respectively; wherein (&Sgr;i=1-3&agr;i)=X and ranges from 0 to 2, (&Sgr;j=1-3&bgr;j)=Y and ranges from 0 to 4, and (&Sgr;k=1-6&ggr;k)=Z and ranges from 0 to 2, and wherein X+Y+Z=4.0. Other nonlinear optical compounds according to this invention also generally satisfy Formula 2 through 7 below: (&Sgr;j=1-3M&bgr;j2)B14O25, where (&Sgr;j=1-3&bgr;j)=4  Formula 2 M42B14O25  Formula 3 (&Sgr;i=1-3M&agr;i1)(&Sgr;k=1-6M&ggr;k3)B14O25  Formula 4 where (&Sgr;i=1-3&agr;i)=2, and (&Sgr;k=1-6&ggr;k)=2.

Abstract: The present invention provides fully tunable photonic band gap (PBG) materials. These materials are periodic composite materials comprising a high refractive index dielectric material and another optically anisotropic, birefringent, electro-optically tunable, or magneto-optically tunable material with a lower dielectric constant in which the photonic band structure can be globally or locally changed in a controlled manner by application of an external electric, magnetic, or electromagnetic field, whereby changing the refractive index properties of one or more of the dielectric constituents by application of the field modulates the photonic band structure. In one aspect of the invention, when an optically birefringent nematic liquid crystal is infiltrated into the void regions of full bandgap (PBG) material based on an inverse opal, the resulting composite material exhibits a completely tunable PBG.

Abstract: A borate single crystal which can stably perform light wavelength conversion with high efficiency down to the ultraviolet region is represented by the chemical formula (A2O).(B2O3)x, and is an orthorhombic crystal belonging to the P212121 space group, wherein A includes two elements selected from the group consisting of Li, Na, K, Rb, and Cs, and 1.5<x<2.5.

Abstract: A substrate 2 is autorotatably installed in a vacuum chamber 1 at an upper part thereof. MgF2 granules 3 as a film source material are put in a quartz boat 4 and mounted on a magnetron cathode 5. The magnetron cathode 5 is connected through a matching box 6 to a 13.56 MHz radio frequency power source 7. Cooling water 8 for holding the temperature of the magnetron cathode 5 constant flows on a lower face of the magnetron cathode 5. A side face of the vacuum chamber 1 is provided with gas introduction ports 9, 10 for introducing gas in the vacuum chamber 1. A shutter 11 is placed between the magetron cathode 5 and the substrate 2. This structure provides a process enabling forming a thin film at a high speed by sputtering, especially, a high speed sputtering enabling forming a thin fluoride film free of light absorption.

Abstract: A substrate 2 is autorotatably installed in a vacuum chamber 1 at an upper part thereof. MgF2 granules 3 as a film source material are put in a quartz boat 4 and mounted on a magnetron cathode 5. The magnetron cathode 5 is connected through a matching box 6 to a 13.56 MHz radio frequency power source 7. Cooling water 8 for holding the temperature of the magnetron cathode 5 constant flows on a lower face of the magnetron cathode 5. A side face of the vacuum chamber 1 is provided with gas introduction ports 9, 10 for introducing gas in the vacuum chamber 1. A shutter 11 is placed between the magnetron cathode 5 and the substrate 2. This structure provides a process enabling forming a thin film at a high speed by sputtering, especially, a high speed sputtering process enabling forming a thin fluoride film free of light absorption.

Abstract: A semiconductor magneto-optical material includes a semiconductor dispersed with fine magnetic material particles and is characterized by exibiting magneto-optical optical effect at ordinary room temperature.

Abstract: A calcium fluoride crystal in which the light transparency does not deteriorate with consecutive irradiation by high output short wavelength light over long time periods. A calcium fluoride crystal in accordance with the present invention has an internal transmittance of 70% or more for light of a 135-nm wavelength or more. A calcium fluoride crystal contains any one of strontium, aluminum, silicon and magnesium, with the strontium content ranging from 1 ppm to 600 ppm, the aluminum content ranging from 1 ppm to 50 ppm, the silicon content ranging from 1 ppm to 50 ppm, or the magnesium content ranging from 1 ppm to 10 ppm. A calcium fluoride crystal has an internal transmittance of 70% or more for light of a 135-nm wavelength or more and contains 1 ppm or less of La and 10 ppm or less of Y. An optical system for an excimer laser in accordance with the present invention comprises a lens comprising any calcium fluoride crystal set forth above.

Abstract: The present invention provides a cesium-lithium-borate crystal, which can be used as a high-performance wavelength converting crystal, having a chemical composition expressed as CsLiB6O10, and substituted cesium-lithium-borate crystals expressed by the following formula:

Abstract: A magneto-optical device using a rare earth iron garnet material, wherein the rare earth garnet material is expressed in the following formula: (BixGdyRzY3−x−y−z)(Fe5−wGaw)O12, wherein x is defined in a range of 0.84≦x≦1.10, y is defined in the range of 0.73≦y≦1.22, z is defined in the range of 0.02≦z≦0.03, and w is defined in the range of 0.27≦w≦0.32, and wherein R is at least one element selected from rare earth elements.

Abstract: Crystals of lithium niobate and lithium tantalate are preconditioned to intentionally increase their electrical conductivity, thus providing crystals with an increased ability to reduce surface charging. Reducing surface charging reduces the risk that the crystals may catastrophically discharge, and adversely affect the performance of devices in which the crystal is incorporated.

Abstract: There are provided mesoporous silica materials containing in their pores stabilized clusters of silicon atoms, of size 2 nanometers or less, and capable of photoluminescence to emit fast photons. They are prepared by chemical vapour deposition of silicon or a silicon precursor such as disilane, under soft conditions such as temperature of 100-150° C., into the mesopores of silicate films which have mesoporous channels prepared by growth of the films using a template to control their sizes, but without removing the template residues from the films prior to the chemical vapour deposition. The template residues serve to limit the size of the silicon clusters which conform. The use of the soft conditions on CVD retains the template residues in an intact, substantially unchanged form. The resultant films have clusters of silicon, of 2 nanometer size or less, anchored to the mesopores, and air stable, so that they can be used in optoelectronic devices in conjunction with standard silicon semiconductors.

Abstract: The present invention provides a cesium-lithium-borate crystal, which can be used as a high-performance wavelength converting crystal, having a chemical composition expressed as CsLiB6O10, and substituted cesium-lithium-borate crystals expressed by the following formula: Cs1−xLi1−yMx+yB6O10 or Cs2(1−z)Li2LzB12O20 (where, M is an alkali metal element, and L is an alkali earth metal element); a method for manufacturing same by heating and melting; and an optical apparatus using such crystals

Abstract: Bismuth borates in crystalline form with non-linearly optical properties. Bismuth borate crystals are used for radiation conversion. The crystal is created with non-linearly optical properties which has non-linearly optical coefficients which exceed those of crystals used hitherto in the application and which is easy, inexpensive to produce and of high optical quality.

Abstract: A second harmonic wave-generating element for generating a second harmonic wave from a fundamental wave, having an optical waveguide layer made of first epitaxial material having a fundamental composition of K3Li2−x(Nb1−YTaY)5+XO15+Z, an underclad part made of second epitaxial material having a fundamental composition of K3Li2−X+A(Nb1−Y−BTaY+B)5+X−AO15+Z, an overclad part made of third epitaxial material having a fundamental composition of K3Li2−X+C(Nb1−Y−DTaY+D)5+X−CO15+Z and formed on and contacting the optical waveguide layer, wherein X=0.006 to 0.5, Y=0.00 to 0.05, A=0.006 to 0.12, B=0.005 to 0.5, C=0.006 to 0.12, D=0.005 to 0.5, X−A≦0, X−C≧0, |A−C|≦0.006, and |B−D|≦0.005).

Abstract: In producing an optical single crystal epitaxial film from a melt containing a transition metal on a single crystal substrate by a liquid phase epitaxial method, this process contains the steps of: annealing the film at a predetermined temperature in an ozonic atmosphere; and temperature-increasing and -decreasing to and from the predetermined temperature, wherein at least one of temperature-increasing and -decreasing steps, the film is exposed to a substantially ozone-free atmosphere.

Abstract: A chemical composition is provided for the manufacture of devices for storing and/or displaying information, comprising a network having a molecule which is formed from a metallic element Fe(II) which is bonded to a 1-2-4 triazole ligand (H-Trz), which molecule further comprises one or more than one anions A selected from BF4−, ClO4−, CO32−, Br−, Cl−, in accordance with the formulation: FeII (H-Trz)3A2, characterized in that this composition is used in the pure state in either one of the two crystalline phases (&agr;, &bgr;) at least one of which, referred to as the second phase (&bgr;), can be thermally induced on the basis of the other phase, referred to as the first phase (&agr;), at a temperature which is equal to or higher than a first reference temperature (To), which phases each show thermally inducible spin transitions between a low-spin state at a low first temperature (T&agr;1, T&bgr;1) and a high-spin state at a high second temperature (T&agr;2, T&bgr;2), the spin tr

Abstract: An absorber of rays outside the visible region. The absorber includes a base made of a transparent synthetic resin with electroconductive anhydrous zinc antimonate incorporated therein; or a base made of a transparent synthetic resin with a layer formed of a synthetic resin and electroconductive anhydrous zinc antimonate incorporated therein, for absorbing rays outside the visible region, being disposed on a surface of the base; or wherein the layer is formed by depositing electron conductive anhydrous zinc antimonate powder on a surface of the base made of a transparent synthetic resin. The electroconductive anhydrous zinc antimonate can be a powder having a molar ratio of ZnO to Sb2O5 of 0.8 to 1.2 and a primary particle size of 5 to 200 nm. The light transmittances of the absorber are high in the visible region and low in both the ultraviolet and infrared wavelength regions.

Abstract: A second harmonic wave-generation device for generating a second harmonic wave composed of an extraordinary ray from a fundamental wave composed of an ordinary ray, including a solid crystal of lithium potassium niobate-lithium potassium tantalate solid solution crystal or a single crystal made of lithium potassium niobate, wherein a mode field diameter of the fundamental wave inside the second harmonic wave-generation device is greater than that of the second harmonic wave.

Abstract: The present invention relates to an optical thin film containing titanium oxide, cerium oxide and bismuth oxide, wherein the content ratio of the titanium oxide, cerium oxide, and bismuth oxide is within the area expressed by four-cornered shape ABCD consisting of A (4,1,95), B (98,1,1), C (20,79,1), and D (3,14,83) in term of coordinate points (TiO.sub.2 mol percent, CeO.sub.2 mol percent, and Bi.sub.2 O.sub.3 mol percent) of the mol ratio when being converted to oxides of TiO.sub.2, CeO.sub.2, and Bi.sub.2 O.sub.3. Furthermore, with the invention, a comparatively high refractive index film layer and a comparatively low refractive index film layer are alternately laminated at least three layers on a transparent glass substrate, at least two layers of said three layers are high refractive index films, and at least one layer of said high refractive index films is said optical thin film.

Abstract: An oxide single crystal having a nominal composition expressed BaM.sub.2 O.sub.4 (M is at least an element selected from the group consisting of Al and Ga), M of which is partially substituted with B, is provided. The BaM.sub.2 O.sub.4 oxide single crystal has an asymmetric central portion formed around B and thereby exhibits a non-linear optical property.

Abstract: The present invention provides a compound having the chemical formula of R.sub.2 MB.sub.10 O.sub.19, wherein R is one or more elements selected from the group consisting of rare-earth elements or Y; M is selected from the group consisting of Ca, Sr, Ba, a single crystal of the compound, a producing method and uses thereof. The compound is congruently melting, which is suitable for producing large size single crystal of R.sub.2 MB.sub.10 O.sub.19 with melt methods, especially pulling method, at a low cost. The crystal resulted therefrom has the same NLO effect as LBO with superior mechanical properties, and it is antideliquenscent. The crystal of the present invention can be used for the frequency-conversion of blue-green wavelength lasers.

Abstract: A charge storage device is resistant to degradation in reducing atmospheres for use in dynamic random access memories. The device consists of a dielectric layer that is sandwiched between two electrodes and grown on a suitable substrate such as silicon or silicon coated with silicon dioxide. The dielectric layer is either (a) a modified composition of Ba.sub.x Sr.sub.1-x TiO.sub.3, 0<x<1 (BST) doped with acceptor type dopants such as Mn, Co, Mg, Cr, Ga and Fe ions as the dielectric layer in the capacitor; the acceptor ions can occupy the titanium sites to prevent the formation of Ti.sup.3+ and inhibit the formation of conductive BST by compensating the charges of the oxygen vacancies, and by trapping the free electrons more freely than Ti.sup.4+, or (b) modified dielectric compositions with alkaline-earth ions with compositions [(Ba.sub.x M.sub.x)O].sub.y TiO.sub.2 (where M can be Ca, Sr or Mg) with the value of y slightly larger than unity.

Abstract: In an EL device in which a blue light emitting material obtained by doping Ce as a luminescent center into CaGa.sub.X S.sub.Y host material is used for a luminescent layer, values of X and Y in the CaGa.sub.X S.sub.Y host material are set in ranges of 1.4.ltoreq.X.ltoreq.1.9, 2.9.ltoreq.Y.ltoreq.3.8. The blue light emitting material thus obtained has a new structure defined by the fact that an X-ray diffraction spectrum obtained by using Cu K.alpha. radiation as a X-ray source has at least one peak in diffraction angles of 13.5.+-.0.2 degree, 14.6.+-.0.2 degree and 25.7.+-.0.2 degree. The blue light emitting EL device has a luminance higher than that of a conventional EL device.

Abstract: A coating comprised of a broadband transparent binder and multilayer thin film particles is applied to the surface of an object. Each particle has a flat principal surface and the dimensions of the particles are selected so that the flat surface of essentially every particle will align parallel to the nearest portion of the object surface to the particle. There is a leafing or an overlap of the particles parallel to the object surface. The particles form a continuous conformal coating over the object surface. It is preferred that the maximum dimension of the principal surface of each particle be at least 30 microns and, for best results the maximum dimension should exceed 50 microns. Metallic flakes and/or flakes or particles comprised of organic dyes may be included in the coating to further tailor its spectral characteristics. It is preferred that the weight of the particles equals 20 to 40% of the weight of the combination of the particles and the binder.

Abstract: A method of making a solid filter material which filters a predetermined wavelength band from a broader spectrum of radiation is provided. The method includes creating a colloidal structure composed of particles dispersed within a medium, and introducing a solvent thereto. Thereafter, the solvent is evaporated and the remaining structure solidifies into a solid crystalline array. The particles can also be fused together by polymerization using one of several methods which are provided. In another embodiment, methods of filtering submicron particles have been developed which consists of establishing a gel membrane from a crystalline colloidal array with an interstice size less than or equal to the particles to be filtered are disclosed. The gel membrane may employ anisotropic interstices of submicron size and is stretchable or compressible mechanically.

Abstract: A color filter composition, a color display device, and a production method of the same with which an increase of the luminance, an increase of the contrast, an increase in the range of color reproduction, and an improvement of the function for preventing reflection of outside light can be achieved. The color filter composition has a spectral characteristic allowing specific light of the visible region to pass therethrough and is composed of fine particles of an inorganic metal oxide containing 15 percent by weight or less of particles having a particle size of 0.1 .mu.m or more based on the weight of all of the particles and contains 70 percent by weight or more of particles having a particle size of 0.01 .mu.m to 0.07 .mu.m based on the weight of all of the particles. A color filter is formed on an inner surface of a panel of a display device by screen printing or heat transfer printing by using this color filter composition.

Abstract: An excellent axial refractive index distributed lens is disclosed, which has a refractive index distribution required for an optical design, high durability, and high quality (a low melting temperature) and is obtained, by an ion exchange method using silver, from a glass material having the following composition:10 <Na.sub.2 O.ltoreq.25 mol %8 <A1.sub.2 O.sub.3 .ltoreq.25 mol %0 .ltoreq.MgO.ltoreq.18 mol %0 .ltoreq.ZnO.ltoreq.18 mol %3 .ltoreq.B.sub.2 O.sub.3 .ltoreq.18 mol %35 .ltoreq.SiO.sub.2 .ltoreq.55 mol %0 .ltoreq.La.sub.2 O.sub.3 .ltoreq.5 mol %0 .ltoreq.BaO.ltoreq.5 mol %0 .ltoreq.Ta.sub.2 O.sub.5 .ltoreq.3 mol %0 .ltoreq.ZrO.sub.2 .ltoreq.3 mol %provided that2.5 .ltoreq.MgO+ZnO.ltoreq.18 mol %.The glass composition constituting the glass material has an ion exchange rate sufficient for practical use and is capable of allowing silver ions to be stably present therein.

Abstract: There are provided mesoporous silica materials containing in their pores stabilized clusters of silicon atom, of size 2 nanometers or less, and capable of photoluminescence to emit fast photons. They are prepared by chemical vapor deposition of silicon or a silicon precursor such as disilane, under soft conditions such as temperature of 100-150.degree. C., into the mesopores of silicate films which have mesoporous channels prepared by growth of the films using a template to control their sizes, but without removing the template residues from the films prior to the chemical vapor deposition. The template residues serve to limit the size of the silicon clusters which conform. The use of the soft conditions on CVD retains the template residues in an intact, substantially unchanged form. The resultant films have clusters of silicon, of 2 nanometer size or less, anchored to the mesopores, and air stable, so that they can be used in optoelectronic devices in conjunction with standard silicon semiconductors.

Abstract: A series of alkali metal bismuth or bismuth and antimony, antimony chalcogenides (Te or S) are described. The compounds have a unique combination electrical properties.

Abstract: A new method for improving the mechanical properties and nonlinear optical performance characteristics of gallium selenide crystals (GaSe) is disclosed. A charge of GaSe crystals was doped with indium before being made into a crystal. The indium-doped GaSe crystals have improved physical properties in that they can be cut along the cleave planes and the cleaved surfaces polished without the usual delaminations typically observed in prior art pure GaSe crystals. The indium-doped crystals were tested in a second harmonic generation (SHG) system and found to have nearly twice the SHG efficiency as pure, or undoped, GaSe crystals.

Abstract: The present invention provides a nonlinear optical element having a sufficient thickness that can be used as a thin film insusceptible to crack and a process for the preparation thereof. A novel nonlinear optical element which gives a nonlinear response to incident light is provided, comprising finely divided grains of a semiconductor or metal, which grains have been separated out with the reaction of a functional group in a matrix-forming substance containing said functional group, dispersed in a matrix. A process for the preparation of a nonlinear optical element which gives a nonlinear response to incident light is also provided, which comprises mixing a solution of a matrix-forming substance containing a functional group with a metal, a semiconductor or a precursor thereof to form a uniform solution, and then allowing said functional group to undergo reaction to form a matrix while allowing finely divided grains of said metal or semiconductor to be separated out in said matrix.

Abstract: An optical wavelength conversion element is formed of a ferroelectric material which has a nonlinear optical effect, and is provided with periodic domain reversals arranged in one direction and converts the wavelength of a fundamental wave impinging thereupon in the direction in which the periodic domain reversals are arranged. The ferroelectric material is LiNb.sub.x Ta.sub.1-x O.sub.3 (0.ltoreq..times..ltoreq.1) doped with at least one of Zn, Sc and In.

Abstract: An MOCVD precursor composition useful for MOCVD formation of a non-linear optically active metal borate thin film, comprising: (I) an organometallic source reagent for a metal reactively forming a non-linear optically active metal borate, and (II) an organoborate compound of the formula: B(OR).sub.3, wherein each R is independently selected from H, alkyl, aryl, alkaryl, arylalkyl, alkenyl, fluoroalkyl, fluoroaryl, fluoroaralkyl, fluoroalkaryl, trialkylsilyl, and C.sub.5 -C.sub.8 carbocylic groups, as the aforementioned borate source reagent. Such composition may be employed for forming a non-linear optically active metal borate thin film on a substrate, via depositing by CVD on said substrate a metal from the organometallic source reagent and a borate from the organoborate compound, to react the metal with the borate and yield the non-linear optically active metal borate on the substrate.

Abstract: Several crystals have been identified which can be grown using standard single crystals growth techniques and which have a high birefringence. The identified crystals include Li.sub.2 CO.sub.3, LiNaCO.sub.3, LiKCO.sub.3, LiRbCO.sub.3 and LiCsCO.sub.3. The condition of high birefringence leads to their application as optical polarizer materials. In one embodiment of the invention, the crystal has the chemical formula LiK.sub.(1-w-x-y) Na.sub.(1-w-x-z) Rb.sub.(1-w-y-z) Cs.sub.(1-x-y-z) CO.sub.3, where w+x+y+z=1. In another embodiment, the crystalline material may be selected from a an alkali metal carbonate and a double salt of alkali metal carbonates, where the polarizer has a Wollaston configuration, a Glan-Thompson configuration or a Glan-Taylor configuration. A method of making an LiNaCO.sub.3 optical polarizer is described. A similar method is shown for making an LiKCO.sub.3 optical polarizer.

Abstract: The invention relates to a process for obtaining a photochromic compound based on a transparent polymer matrix, in which:a) a silver sol is prepared comprising at least one essentially transparent polymer matrix and particles of silver of a mean size smaller than 500 nm,b) an emulsion is produced by mixing the said silver sol with an oxidizing agent in the presence of at least one halogen and/or pseudohalogen.The invention also relates to the compound obtained and, lastly, a transparent substrate coated with at least one layer consisting essentially of such a compound.

Abstract: Proposed is a powder of ytterbium phosphate having a non-stoichiometric phosphorus to ytterbium molar ratio of 1.08 to 2.0 and having a specified average particle diameter and specified diameter of the crystallites forming the particles. The powder is useful as an infrared-absorbing pigment in a printing ink invisible to naked eyes but detectable by an infrared detecting means for printing of stealth bar code patterns. The ytterbium phosphate powder can be prepared in a convenient and inexpensive method utilizing the precipitation reaction by mixing an aqueous phosphoric acid solution and ytterbium salt solution under specified conditions followed by calcination of the precipitates at a specified temperature and pulverization of the calcined precipitates to give the specified average particle diameter.

Abstract: A process for oxidizing iron ions contained within iron-doped lithium niobate. The process comprises the steps of protonating the iron-doped lithium niobate crystal and then placing the same into a pressure chamber where between 10-100 atmospheres of dry, ultra-pure pressurized oxygen are applied. While under pressure, the crystal is heated to approximately 950.degree. C. at a rate not to exceed 50.degree. C. per minute, and preferably at a rate not less than 25.degree. C. per minute. The crystals are then continuously heated at approximately 950.degree. C. for approximately 50 hours and then cooled to 30.degree. C. at a rate not to exceed 50.degree. C. per minute, and preferably at a rate not less than approximately 25.degree. C. per minute. The resulting lithium niobate crystal will thereafter contain iron ions wherein the divalent iron ion ration to the trivalent iron ion ratio is approximately 1:100.

Abstract: A method for forming relatively large and inexpensive crystals of KTiOPO.sub.4, which exhibit relatively low conductivities, is disclosed. In addition, electro-optic devices based on such crystals are also disclosed.

Abstract: A system for displaying luminescence comprises a crystalline structure comprising a compound having the formula:.alpha.-CuAlX.sub.4wherein the compound has lattice parameters a=b ranging from 5.430(1) .ANG. to 5.751(3) .ANG.; c ranging from 10.069(1) .ANG. to 10.570(4) .ANG.; and X is selected from the group consisting of chlorine, bromine, and a mixture thereof. The crystalline structure may also include a compound of the formula:.beta.-CUAlCl.sub.4wherein the compound has lattice parameters a=7.635(2) .ANG., b=12.842(2) .ANG., and c=6.127(1) .ANG.. The system also includes an excitation source which transmits energy to the crystalline structure such that the crystalline structure displays luminescence. The crystalline structure is also useful in a gas sensor application since the luminescence of the crystalline structure is capable of being quenched in the presence of gaseous material.

Abstract: The present invention provides a nonlinear optical element having a sufficient thickness that can be used as a thin film insusceptible to crack and a process for the preparation thereof. A novel nonlinear optical element which gives a nonlinear response to incident light is provided, comprising finely divided grains of a semiconductor or metal, which grains have been separated out with the reaction of a functional group in a matrix-forming substance containing said functional group, dispersed in a matrix. A process for the preparation of a nonlinear optical element which gives a nonlinear response to incident light is also provided, which comprises mixing a solution of a matrix-forming substance containing a functional group with a metal, a semiconductor or a precursor thereof to form a uniform solution, and then allowing said functional group to undergo reaction to form a matrix while allowing finely divided grains of said metal or semiconductor to be separated out in said matrix.

Abstract: Photorefractive crystals having the formula K.sub.1-y Li.sub.y Ta.sub.1-x Nb.sub.x O.sub.3 wherein x is between 0 and 1 and y is between 0.0001 and 0.15. The crystals are useful as a photorefractive material for use in optical systems. The crystals may be doped with various first transition elements and lanthanides including copper, vanadium, chromium, iron, and manganese, nickel, europium and cerium.

Abstract: A second harmonic generation element including a single crystal substrate having a fundamental composition of K.sub.3 Li.sub.2-2x (Nb.sub.1-y Ta.sub.y).sub.5+5z O.sub.15-x+12.5z and an optical waveguide made of an epitaxial film with a fundamental composition of K.sub.3 Li.sub.2-2a (Nb.sub.1-b Ta.sub.b).sub.5+5c O.sub.15-a+12.5c and refractive index different from that of the single crystal substrate, wherein:-0.5.ltoreq.a, x.ltoreq.0.6250.ltoreq.b, y.ltoreq.0.50.8.ltoreq.(5-2x)/(5+5z), (5-2a)/(5+5c).ltoreq.1.2.

Abstract: Ionic and impurity concentrations in a photorefractive holographic storage medium are optimized such that electronic and ionic Debye numbers match an expected grating wave number K, at fixing and recording temperatures, respectively. Simultaneous and sequential recording and fixing are evaluated. The photovoltaic effect is reduced, subject to response time and absorption constraints, by matching reduced and oxidized impurity concentrations.

Abstract: A family of cesium-germanium halide salts have utility as nonlinear optical crystals in applications including electro-optics and optical frequency conversion. These salts have the general formula CsGeCl.sub.x Br.sub.y I.sub.z, in which x, y, and z equal 0 through 3, inclusive, and where x+y+z=3. In contrast to well-known oxygen-containing materials, such as LiNbO.sub.3, these cesium-germanium halide salts exhibit optical nonlinearity with an extremely wide transparency range (without significant absorption) at wavelengths from about 0.4 .mu.m to greater than 25 .mu.m (covering the entire MWIR and LWIR regions). Based on Ge.sup.2+ ions, these halides have non-centrosymmetric perovskite structures. The halide ions form a strongly coordinating octahedral environment about the Ge.sup.2+ ions and resist migration in an electric field. The Ge2+ ions, however, are shifted slightly off center in the tetragonal phase, leading to a net electric dipole moment in each unit cell.

Abstract: A method and associated structures are disclosed for locating a laser beam that has a wavelength outside of the visible portion of the electromagnetic spectrum. The method comprises positioning a sample of a polycrystalline nonlinear frequency converting compound generally linearly downstream from a laser source, and then detecting the emission from the polycrystalline frequency converting compound to thereby identify the position of the original laser beam. In preferred embodiments, the polycrystalline nonlinear frequency converting compound comprises KTP.