An oxychloride infrared nonlinear optical crystal and the preparation method and use thereof, the optical crystal has a general chemical formula of Pb.sub.2+xOCl.sub.2+2x, therein 0<x<0.139 or 0.141<x<0.159 or 0.161<x0.6. The crystal is non-centrosymmetric, belongs to orthonormal system with space group of Fmm2, cell parameter is a=35.4963(14)0.05 , b=5.8320(2)0.05 , c=16.0912(6)0.05 . The crystal is prepared by high temperature melt method or flux method. The crystal has a strong second harmonic generation efficiency of 4 times that of KDP (KH.sub.2PO.sub.4) tested by Kurtz method, it is phase machable, transparent in the range of 0.34-7 m. The laser damage threshold is 10 times that of the current commercial infrared nonlinear optical crystal AgGaS.sub.2. No crystalline water exists in lead oxychloride, and it is stable in the air and has good thermal stability.

The invention relates to a lithium metaborate crystal and a preparation method and use thereof. The crystal has a chemical formula of LiBO.sub.2, a molecular weight of 49.75, and is a member of the monoclinic crystal system. The crystal has a P2.sub.1/c space group and lattice constants of a=5.85(8) , b=4.35(7) , c=6.46(6) , =115(5), and Z=4. The crystal can be applied in wavelengths of infrared-visible-deep ultraviolet, and is grown by utilizing a melt crystallization method or a flux method. The crystal obtained using the method described in the invention is easily grown and processed, and can be used in the manufacture of a polarizing beam splitting prism such as a Glan prism, a Wollaston prism, a Rochon prism or a beam-splitting polarizer, and other optical components, enabling crucial applications in the fields of optics and communication.

The invention relates to a lithium metaborate crystal and a preparation method and use thereof. The crystal has a chemical formula of LiBO.sub.2, a molecular weight of 49.75, and is a member of the monoclinic crystal system. The crystal has a P2.sub.1/c space group and lattice constants of a=5.85(8) , b=4.35(7) , c=6.46(6) , =115(5), and Z=4. The crystal can be applied in wavelengths of infrared-visible-deep ultraviolet, and is grown by utilizing a melt crystallization method or a flux method. The crystal obtained using the method described in the invention is easily grown and processed, and can be used in the manufacture of a polarizing beam splitting prism such as a Glan prism, a Wollaston prism, a Rochon prism or a beam-splitting polarizer, and other optical components, enabling crucial applications in the fields of optics and communication.

A nonlinear optical crystal of cesium fluorooxoborate, and a method of preparation and use thereof. The crystal has a chemical formula of CsB.sub.4O.sub.6F and a molecular weight of 291.15. It belongs to an orthorhombic crystal system, with a space group of Pna2.sub.1, crystal cell parameters of a=7.9241 , b=11.3996 , c=6.6638 , and ===90, and a unit cell volume of 601.95 .sup.3. A melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method is used to grow the crystal of CsB.sub.4O.sub.6F.

A nonlinear optical crystal of cesium fluorooxoborate, and a method of preparation and use thereof. The crystal has a chemical formula of CsB.sub.4O.sub.6F and a molecular weight of 291.15. It belongs to an orthorhombic crystal system, with a space group of Pna2.sub.1, crystal cell parameters of a=7.9241 , b=11.3996 , c=6.6638 , and ===90, and a unit cell volume of 601.95 .sup.3. A melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method is used to grow the crystal of CsB.sub.4O.sub.6F.

The present invention relates to a method of manufacturing polycrystalline silicon ingot using a crucible in which an oxygen exhaust passage is formed by single crystal or polycrystalline rods, the method including the steps of: manufacturing the single crystal or polycrystalline silicon rods each having the shape of a quadrilateral pillar; putting the single crystal or polycrystalline quadrilateral pillar-shaped silicon rods into the crucible in such a manner as to be arranged close to one another along the inner peripheral surface of the crucible to thus form a space portion inside the single crystal or polycrystalline silicon rods, into which silicon chunks are put, and the oxygen exhaust passages between the inner peripheral surface of the crucible and the respective surfaces of the single crystal or polycrystalline silicon rods oriented toward the inner peripheral surface of the crucible; putting the silicon chunks into the space portion of the crucible; and melting and crystallizing the silicon chunks.

The present invention relates to a method of manufacturing polycrystalline silicon ingot using a crucible in which an oxygen exhaust passage is formed by single crystal or polycrystalline rods, the method including the steps of: manufacturing the single crystal or polycrystalline silicon rods each having the shape of a quadrilateral pillar; putting the single crystal or polycrystalline quadrilateral pillar-shaped silicon rods into the crucible in such a manner as to be arranged close to one another along the inner peripheral surface of the crucible to thus form a space portion inside the single crystal or polycrystalline silicon rods, into which silicon chunks are put, and the oxygen exhaust passages between the inner peripheral surface of the crucible and the respective surfaces of the single crystal or polycrystalline silicon rods oriented toward the inner peripheral surface of the crucible; putting the silicon chunks into the space portion of the crucible; and melting and crystallizing the silicon chunks.

A calcium metaborate birefringent crystal and a preparation method and use thereof, the crystal having a chemical formula of CaB.sub.2O.sub.4 and a molecular weight of 125.70, and belonging to the orthorhombic crystal system and space group Pbcn with unit-cell parameters a=11.60(4), b=4.28(8), c=6.21(6), and Z=4, wherein the calcium metaborate birefringent crystal is a negative biaxial crystal with a transmission range of 165-3400 nm and a birefringence between 0.09-0.36; the crystal is applicable to infrared-visible-ultraviolet-deep ultraviolet bands, and is grown by a melt method, a flux method, a Bridgman method or a heat exchange method; the crystal obtained by the method of the present invention is easy to grow and easy to process; and can be used for making polarizing beam-splitting prisms.

A calcium metaborate birefringent crystal and a preparation method and use thereof, the crystal having a chemical formula of CaB.sub.2O.sub.4 and a molecular weight of 125.70, and belonging to the orthorhombic crystal system and space group Pbcn with unit-cell parameters a=11.60(4), b=4.28(8), c=6.21(6), and Z=4, wherein the calcium metaborate birefringent crystal is a negative biaxial crystal with a transmission range of 165-3400 nm and a birefringence between 0.09-0.36; the crystal is applicable to infrared-visible-ultraviolet-deep ultraviolet bands, and is grown by a melt method, a flux method, a Bridgman method or a heat exchange method; the crystal obtained by the method of the present invention is easy to grow and easy to process; and can be used for making polarizing beam-splitting prisms.

A preparation method and application of a Na.sub.3Ba.sub.2(B.sub.3O.sub.6).sub.2F birefringent crystal, the crystal having a chemical formula of Na.sub.3Ba.sub.2(B.sub.3O.sub.6).sub.2F, and belonging to a hexagonal crystal system, the space group being P6.sub.3/m, and the lattice parameters comprising a=7.3490(6) , c=12.6340(2) , V=590.93(12) .sup.3, Z=2; the crystal is used for an infrared/deep ultraviolet waveband, and is an uniaxial negative crystal, n.sub.e<n.sub.o, the transmission range being 175-3,350 nm, the birefringence of 0.090 (3,350 nm)-0.240 (175 nm), and the crystal being grown by employing a melting method or a flux method; the crystal prepared via the method has a short growth cycle, high crystal quality and large crystal size, is easy to grow, cut, polish and store, is stable in the air, and difficult to deliquesce, and can be used for preparation of various polarization beam polarization beam splitter prism and infrared/deep ultraviolet waveband optical communication elements.