A compound ammonium fluoroborate, a nonlinear optical crystal of ammonium fluoroborate, and a preparation method and use thereof; the compound has the chemical formula of NH.sub.4B.sub.4O.sub.6F with a molecular weight of 176.28, and is prepared by a solid phase reaction process; the crystal has the chemical formula of NH.sub.4B.sub.4O.sub.6F with a molecular weight of 176.28, belongs to the orthorhombic system, and has a space group of Pna2.sub.1 and the following unit cell parameters: a=7.615(3) , b=11.207(4) , c=6.604(3) , Z=4, V=563.6 .sup.3. The nonlinear optical crystal can be obtained by the method of the present invention. The present invention provides uses of the nonlinear optical crystal in producing harmonic light and a deep-ultraviolet frequency-multiplied light below 200 nm; and in making a frequency multiplication generator, a frequency up or down converter or an optical parametric oscillator.

A compound ammonium fluoroborate, a nonlinear optical crystal of ammonium fluoroborate, and a preparation method and use thereof; the compound has the chemical formula of NH.sub.4B.sub.4O.sub.6F with a molecular weight of 176.28, and is prepared by a solid phase reaction process; the crystal has the chemical formula of NH.sub.4B.sub.4O.sub.6F with a molecular weight of 176.28, belongs to the orthorhombic system, and has a space group of Pna2.sub.1 and the following unit cell parameters: a=7.615(3) , b=11.207(4) , c=6.604(3) , Z=4, V=563.6 .sup.3. The nonlinear optical crystal can be obtained by the method of the present invention. The present invention provides uses of the nonlinear optical crystal in producing harmonic light and a deep-ultraviolet frequency-multiplied light below 200 nm; and in making a frequency multiplication generator, a frequency up or down converter or an optical parametric oscillator.

A compound ammonium fluoroborate, a nonlinear optical crystal of ammonium fluoroborate, and a preparation method and use thereof; the compound has the chemical formula of NH.sub.4B.sub.4O.sub.6F with a molecular weight of 176.28, and is prepared by a solid phase reaction process; the crystal has the chemical formula of NH.sub.4B.sub.4O.sub.6F with a molecular weight of 176.28, belongs to the orthorhombic system, and has a space group of Pna2.sub.1 and the following unit cell parameters: a=7.615(3) , b=11.207(4) , c=6.604(3) , Z=4, V=563.6 .sup.3. The nonlinear optical crystal can be obtained by the method of the present invention. The present invention provides uses of the nonlinear optical crystal in producing harmonic light and a deep-ultraviolet frequency-multiplied light below 200 nm; and in making a frequency multiplication generator, a frequency up or down converter or an optical parametric oscillator.

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.

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.

In a method for manufacturing a group 13 nitride crystal, a seed crystal made of a group 13 nitride crystal is arranged in a mixed melt containing an alkali metal and a group 13 element, and nitrogen is supplied to the mixed melt to grow the group 13 nitride crystal on a principal plane of the seed crystal. The seed crystal is manufactured by vapor phase epitaxy. At least a part of contact members coming into contact with the mixed melt in a reaction vessel accommodating the mixed melt is made of Al.sub.2O.sub.3. An interface layer having a photoluminescence emission peak whose wavelength is longer than the wavelength of a photoluminescence emission peak of the grown group 13 nitride crystal is formed between the seed crystal and the grown group nitride crystal.