Abstract: A process is disclosed for producing an integrated composite oxide single crystal body composed of a core portion made of an oxide single crystal and a clad portion integrated with the core portion and made of another oxide single crystal having a composition different from that of the oxide single crystal constituting the core portion, the process comprising the steps of: (1) preparing a first melt in a first crucible by melting a first material for a first oxide single crystal to constitute the core portion inside the first crucible, (2) preparing a second melt inside a second crucible by melting a second material for a second oxide single crystal to constitute the clad portion inside the second crucible, (3) contacting a seed crystal to the first and second melts, (4) pulling down the first melt through a pull-out opening of the first crucible, (5) pulling down the second melt through a pull-out opening of the second crucible and contacting the pulled-down second melt with a pulled-down portion of the firs

Abstract: A process for growing a crystalline silicon plate, including the steps of arranging a planar growth member and a growth crucible in which a melt of silicon is placed and which is provided with a melt draw-out opening at a lower side thereof, while at least a tip portion of the growth member is located under the draw-out opening, drawing out the melt from the crucible through the draw-out opening, bringing the drawn out melt into contact with the tip portion of the growth member, and further pulling down the melt through the tip portion of the growth member.

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 process is disclosed for continuously producing a single crystal by drawing downwardly a melt of a single crystal raw material, wherein a single crystal body grown from the melt is continuously pulled downwardly, and a plurality of single crystal products are continuously formed by intermittently cutting the single crystal body being downwardly moved.

Abstract: An optical waveguide substrate having a substrate made of ferroelectric optical single crystal and a ridge portion projected from a main plane of the substrate, has a construction such that the ridge portion has a base portion made of ferroelectric optical single crystal and an optical waveguide formed on the base portion. The optical waveguide substrate is formed by forming at least one optical waveguide layer on a main plane of a substrate made of ferroelectric optical single crystal, and mechanically working main planes of the optical waveguide layer and the substrate to form a ridge portion projected from the main plane of the substrate. The optical waveguide substrate can reduce a light transmission loss, increase an extinction ratio, and improve an electric field applying efficiency.

Abstract: Optoelectric article includes a substrate made of an optoelectric single crystal and a film of a single crystal of lithium niobate formed on the substrate by a liquid phase epitaxial process, wherein a ratio of lithium/niobium of a composition of the film of the lithium niobate single crystal falls in a range of 48.6/51.4 to 49.5 to 50.5 or 50.5/49.5 to 52.3/47.7.

Abstract: A process is disclosed for continuously producing a single crystal by drawing downwardly a melt of a single crystal raw material, wherein a single crystal body grown from the melt is continuously pulled downwardly, and a plurality of single crystal products are continuously formed by intermittently cutting the single crystal body being downwardly moved.

Abstract: An excellent periodic domain-inverted structure formed on a ferroelectric optical single crystal substrate is provided having an improved crystalline property of the substrate and an improved resistance to optical damage and output of the domain-inverted structure and the like optical waveguide structure by forming protruded and recessed portions on a single-domained ferroelectric optical single crystal substrate 1, growing a film of a ferroelectric optical single crystal film 4 on the respective recessed portion of the single crystal substrate 1 by a liquid phase epitaxial growing process. At that time, the Curie temperature of the film 4 is lower than the liquid phase epitaxial growing temperature of the film 4, and the Curie temperature of the substrate 1 is higher than the liquid phase epitaxial growing temperature of the film 4, and the film 4 is polarized in an opposite direction to the polarization direction of the substrate 1.

Abstract: When producing an oxide-series single crystal by continuously pulling downwardly by .mu. pulling down method, the composition of the single crystal can properly and quickly controlled to continuously produce the single crystal of a constant composition by changing the pulling rate of the single crystal. Preferably, the pulling rate is 20-300 mm/hr, and the pulling rate is decreased with the proceeding of growing of the single crystal.

Abstract: A process for producing an optical waveguide device including a substrate and a ridge-shaped optical waveguide projected at a main plane of the substrate, comprising the steps of: forming said ridge shaped optical waveguide at the main plane of the substrate by abrasion working.

Abstract: An optical single crystalline article comprising a substrate made of an optical single crystal and an epitaxial film formed on said substrate and made of an optical material, wherein a crystalline structure of said epitaxial film is a relaxed structure.

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: A process is disclosed for continuously producing a single crystal by drawing downwardly a melt of a single crystal raw material, wherein a single crystal body grown from the melt is continuously pulled downwardly, and a plurality of single crystal products are continuously formed by intermittently cutting the single crystal body being downwardly moved.

Abstract: A film made of lithium niobate-lithium tantalate solid solution may be formed on a single crystal substrate having a composition of LiNb.sub.1-z Ta.sub.z O.sub.3 (0.ltoreq.z<0.8) by the liquid phase epitaxial process. The substrate is contacted with supercooled liquid phase of a melt to produce the film thereon. The melt consists mainly of Li.sub.2 O.sub.3, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5 and a flux. A composition of the liquid phase is within a region encompassed by a straight line K linking a point A (95, 5, 0) and a point B (95, 2, 3), a straight line G linking the point A (95, 5, 0) and a point C (60, 40, 0), a straight line H linking the point C (60, 40, 0) and a point D (60, 0, 40), a straight line J linking the point B (95, 2, 3) and a point E (0, 40, 60) and a curved line I defining a composition whose saturation temperature is not more than 1200.degree. C. Each line is shown in a triangular diagram of a pseudo-ternary system of LiNbO.sub.3 -LiTaO.sub.3 --a melting medium.

Abstract: Optoelectric article includes a substrate made of an optoelectric single crystal and a film of a single crystal of lithium niobate formed on the substrate by a liquid phase epitaxial process, wherein a ratio of lithium/niobium of a composition of the film of the lithium niobate single crystal falls in a range of 48.6/51.4 to 49.5 to 50.5 or 50.5/49.5 to 52.3/47.7.

Abstract: A process is disclosed for producing a film of an oxide type single crystal on a substrate of such an oxide type single crystal by epitaxially growing the oxide type single crystal on the substrate through contacting the substrate onto a melt in an overcooled state. The substrate of the oxide type single crystal is contacted with the melt held in a first furnace, and the substrate of the oxide type single crystal is held inside a second furnace separated from said first furnace, and the temperature of the substrate is adjusted in the second furnace. An oxide type single crystal film-producing apparatus is also disclosed.

Abstract: A material for use in a 1.5 .mu.m wide-band optical isolator, includes a bismuth-substituted terbium-iron garnet single crystal having a composition of Bi.sub.x Tb.sub.3-x Fe.sub.5 O.sub.12 in which x is 0.35 to 0.45. This bismuth-substituted terbium-iron garnet single crystal is grown by a solid phase reaction. A process for producing such a material is also disclosed.

Abstract: According to the invention, a film of optoelectric single crystal may be formed on a substrate made of optoelectric single crystal by a liquid phase epitaxial process. The process comprises the steps of producing a melt of a solute and a melting medium, a solid phase and a liquid phase coexisting in the melt; then cooling the liquid phase for producing super cooling state in the liquid phase; and contacting the substrate to the liquid phase to form the film on the substrate by an epitaxial growing process. The film may be produced on the substrate, the film having a half value width of an X-ray rocking curve not more than that of the substrate.

Abstract: A process for producing optoelectric articles, in which an optoelectric single crystal film is formed on an optoelectric single crystal substrate, is disclosed. The optoelectric single crystal substrate is exposed to a liquid phase in a supercooling state of a melt including a solute and a melting medium, and the optoelectric single crystal film is formed by a liquid phase epitaxial process. In this case, a viscosity of the liquid phase is set to 75%.about.95% preferably 75%.about.90% with respect to a viscosity at which a degree of supercooling of the liquid phase is zero.

Abstract: A method of manufacturing ferrite crystals such as single crystal bodies and polycrystal bodies with garnet structure is disclosed, which includes the steps of effecting a composition controlling for raw powders, forming raw powders, sintering formed bodies and effecting hot isostatic press treatment for sintered bodies. Also, a method of producing ferrite powders preferably used for the ferrite crystal manufacturing method mentioned above.The thus obtained ferrite crystal bodies with garnet structure show good magnetooptical properties such as light transmissivity, Faraday rotation angle and Verdet constant, and are preferably used for magnetooptical elements such as optical isolators and optical magnetic field sensors etc.