Compounds strontium lanthanum chloroborate and barium lanthanum chloroborate and their nonlinear optical crystals and methods for their preparation and uses thereof

Abstract

This invention relates to the compounds strontium lanthanum chloroborate and barium lanthanum chloroborate, as well as nonlinear optical crystals of strontium lanthanum chloroborate and barium lanthanum chloroborate, their preparation methods, and their uses. The general chemical formula for both the compounds and crystals is A3La4B3O. 13 Cl, where A = Sr, Ba, space group P63, belongs to the hexagonal crystal system, and cell parameter Z = 2. The compounds lanthanum strontium chloroborate and lanthanum barium chloroborate are synthesized by a solid-state reaction method. The nonlinear optical crystals of lanthanum strontium chloroborate and lanthanum barium chloroborate are grown using a high-temperature melt method. This material can be used to manufacture second harmonic generators, up-down frequency converters, optical parametric oscillators, etc.

Description

Technical Field

[0001] This invention relates to the chemical formula A3La4B3O 13 The compounds strontium lanthanum chloroborate and barium lanthanum chloroborate of Cl (A=Sr,Ba) and nonlinear optical crystals of strontium lanthanum chloroborate and barium lanthanum chloroborate, the preparation method of the crystals and the nonlinear optical devices made using the crystals. Background Technology

[0002] Nonlinear optical crystals are important optoelectronic functional materials and a crucial material foundation for optoelectronic technology, particularly laser technology. Nonlinear optical crystal materials can be used to convert laser frequencies and extend laser wavelengths, adjust laser intensity and phase, and achieve holographic storage of laser signals. Therefore, nonlinear optical crystals are indispensable key materials in high-tech and modern military technologies. Countries worldwide prioritize information technology development and incorporate it into their high-tech development plans as a highly valued and supported strategic initiative.

[0003] The requirements for second-order nonlinear optical crystals mainly include a non-centrosymmetric structure, appropriate birefringence, a wide transmission range in the ultraviolet region, a high laser damage threshold, and excellent physicochemical properties. Borate crystals have significant application value in semiconductor lithography, laser micromachining, and photochemical synthesis, and their performance has attracted widespread attention. Due to their large band gap, high laser damage threshold, and stable physicochemical properties, they are ideal for obtaining strong nonlinear optical effects, making them an ideal choice for novel ultraviolet nonlinear optical crystals. Furthermore, the introduction of alkaline earth metal cations and rare earth elements (Sr or Ba, La) into borates eliminates dd and ff electronic transitions, making them ideal for ultraviolet transmission. Introducing highly electronegative Cl... - It can broaden the transmittance range, shifting the blue cutoff edge to the ultraviolet and even deep ultraviolet regions. Therefore, Cl-containing... - The synthesis of alkaline earth metal rare earth borates will be an effective means of designing high frequency doubling effects for use in ultraviolet and deep ultraviolet nonlinear optical materials. Summary of the Invention

[0004] The purpose of this invention is to provide two compounds, strontium lanthanum chloroborate and barium lanthanum chloroborate, as well as two nonlinear optical crystals, strontium lanthanum chloroborate and barium lanthanum chloroborate, with the general chemical formula A3La4B3O. 13 Cl, where A = Sr, Ba.

[0005] Another objective of this invention is to provide a method for synthesizing lanthanum strontium chloroborate and lanthanum barium chloroborate using a solid-state reaction method, and for growing nonlinear optical crystals of lanthanum strontium chloroborate and lanthanum barium chloroborate using a high-temperature melt method or a Czochralski method.

[0006] Another object of the present invention is to provide the use of strontium lanthanum chloroborate and barium lanthanum chloroborate nonlinear optical devices for the fabrication of frequency multipliers, up or down frequency converters or optical parametric oscillators.

[0007] The technical solution of the present invention is as follows:

[0008] The strontium lanthanum chloroborate and barium lanthanum chloroborate compounds provided by this invention have the general chemical formula A3La4B3O. 13 Cl, where A = Sr, Ba, is used to prepare lanthanum strontium chloroborate and lanthanum barium chloroborate compounds by solid-state reaction according to the following chemical reaction formula:

[0009] 1)5ACO3+6H3BO3+1ACl2+4La2O3→2A3La4B3O 13 Cl + 5CO₂↑ + 9H₂O↑, where A = Sr, Ba

[0010] 2)3ACO3+3H3BO3+2La2O3+1NH4Cl→A3La4B3O 13 Cl + 1NH3↑ + 3CO2↑ + 5H2O↑, where A = Sr, Ba

[0011] 3)5A(OH)2+1SrCl2+6H3BO3+4La2O3→2A3La4B3O 13 Cl + 14H₂O↑, where A = Sr, Ba

[0012] 4)3AO+3H3BO3+2La2O3+1NH4Cl→A3La4B3O 13 Cl + 5H₂O↑ + NH₃↑, where A = Sr, Ba

[0013] 5)3A(OH)2+1NH4Cl+3H3BO3+2La2O3→A3La4B3O 13 Cl + 8H₂O↑ + 1NH₃↑, where A = Sr, Ba

[0014] 6)5AO+6H3BO3+4La2O3+1ACl2→2A3La4B3O 13 Cl + 9H₂O↑, where A = Sr, Ba

[0015] 7)5ACO3+6H3BO3+1ACl2+8La(NO3)3·6H2O→2A3La4B3O 13 Cl + 24NO₂↑ + 57H₂O↑ + 5CO₂↑ + 6O₂↑, where A = Sr, Ba

[0016] 8)3ACO3+3H3BO3+4La(NO3)3·6H2O+1NH4Cl→A3La4B3O 13 Cl + 1NH3↑ + 3CO2↑ + 12NO2↑ + 29H2O↑ + 3O2↑, where A = Sr, Ba

[0017] 9)1A(OH)2+2ACO3+1NH4Cl+2La2O3+3H3BO3→A3La4B3O 13 Cl + 1NH3↑ + 6H2O↑ + 2CO2↑, where A = Sr, Ba

[0018] 10)2A(OH)2+1ACO3+1NH4Cl+2La2O3+3H3BO3→A3La4B3O 13 Cl + 1NH3↑ + 7H2O↑ + 1CO2↑, where A = Sr, Ba

[0019] 11)1A(OH)2+2ACO3+1NH4Cl+4La(NO3)3·6H2O+3H3BO3→A3La4B3O 13 Cl + 1NH3↑ + 30H2O↑ + 2CO2↑ + 15O2↑, where A = Sr, Ba

[0020] 12)2A(OH)2+1ACO3+1NH4Cl+4La(NO3)3·6H2O+3H3BO3→A3La4B3O 13 Cl + 1NH3↑ + 31H2O↑ + 1CO2↑ + 15O2↑, where A = Sr, Ba

[0021] 13)10ASO4+12H3BO3++2ACl2+8La2O3→4A3La4B3O 13 Cl + 10SO₂↑ + 18H₂O↑ + 5O₂↑, where A = Sr, Ba

[0022] 14)6ASO4+6H3BO3+4La2O3+2NH4Cl→2A3La4B3O 13 Cl + 2NH3↑ + 6SO2↑ + 10H2O↑ + 3O2↑, where A = Sr, Ba

[0023] 15)5ANO3+6H3BO3+1ACl2+4La2O3→2A3La4B3O 13 Cl + 5CO₂↑ + 9H₂O↑, where A = Sr, Ba

[0024] 16)3ANO3+3H3BO3+2La2O3+1NH4Cl→A3La4B3O 13Cl + 1NH3↑ + 3NO2↑ + 5H2O↑, where A = Sr, Ba

[0025] 17)1A(OH)2+2ANO3+1NH4Cl+2La2O3+3H3BO3→A3La4B3O 13 Cl + 1NH3↑ + 6H2O↑ + 2NO2↑, where A = Sr, Ba

[0026] 18)2A(OH)2+1ANO3+1NH4Cl+2La2O3+3H3BO3→A3La4B3O 13 Cl + 1NH3↑ + 7H2O↑ + 1NO2↑, where A = Sr, Ba

[0027] This invention provides two nonlinear optical crystals: lanthanum strontium chloroborate and lanthanum barium chloroborate, characterized in that the chemical formula of the crystal is A3La4B3O. 13 Cl, where A = Sr, Ba, has a molecular weight of 1094.36-1243.48, lacks a center of symmetry, belongs to the hexagonal crystal system, has space group P63, and its unit cell parameters are...

[0028] A method for preparing lanthanum strontium chloroborate and lanthanum barium chloroborate nonlinear optical crystals, characterized by growing the crystals using a high-temperature melt method or a Czochralski method, with the specific operations as follows:

[0029] a. Mix the single-phase polycrystalline powders of strontium lanthanum chloroborate and barium lanthanum chloroborate with a flux, heat the mixture to 650-1000℃ at a heating rate of 1-30℃ / h, hold the temperature for 5-80 hours to obtain a mixed melt, and then cool it down to 500-800℃. The molar ratio of the single-phase polycrystalline powder to the flux is 1:0.5-25.

[0030] Alternatively, a mixture of strontium (barium) compounds, lanthanum compounds, boron compounds, and chlorine compounds, or a mixture of barium compounds, lanthanum compounds, boron compounds, and chlorine compounds with a flux, can be heated to 650-1000℃ at a heating rate of 1-30℃ / h, held at that temperature for 5-80 hours to obtain a mixed melt, and then cooled to 500-800℃. The molar ratio of strontium (barium) compounds, lanthanum compounds, boron compounds, and chlorine compounds to the flux is 2.5-3.3:3.5-4.2:2.5-0.7-1.3:0.1-30.

[0031] The fluxes mainly include single fluxes, such as SrCO3 (BaCO3), (SrCl2)BaCl2, SrO (BaO), H3BO3, PbO, NaCl, Na2CO3, LiCl, Li2CO3, KCl, K2CO3, LiBO2, and other composite fluxes.For example, SrCO3(BaCO3)-SrCl2, SrCO3(BaCO3)-SrO(BaO), SrCO3(BaCO3)-H3BO3, SrCO3(BaCO3)-NaCl, SrCO3(BaCO3)-KCl, SrCO3(BaCO3)-PbO, SrCO3(BaCO3)-LiCl, SrCl2(BaCl2)-SrO(BaO), SrCl2(BaCl2)-PbO, SrCl2(BaCl2)-NaCl, SrCl2(BaCl2)-Na2CO3, SrCl2(BaCl2)-LiCl, SrCl2(BaCl2)-KCl, SrCl2(BaCl2)-K2CO3, SrO(BaO)-H3BO3, SrO(BaO)-PbO, SrO(BaO)-NaCl, SrO(BaO)-Na2CO3, SrO(BaO)-LiCl, SrO(BaO)-Li2CO3, SrO(BaO)-KCl, SrO(BaO)-K2CO3, SrO(BaO)-LiBO2, H3BO3-PbO, H3BO3-Na2CO3, H3BO3-Li2CO3, H3BO3-KCl, H3BO3-K2CO3, H3BO3-LiBO2, SrCO3(BaCO3)-NaCl-H3BO3, SrCO3(BaCO3)-SrO-H3BO3, SrCO3(BaCO3)-LiCl-H3BO3, SrCO3(BaCO3)-KCl-H3BO3, SrCl2(BaCl2)-SrO(BaO)-H3BO3, SrCl2(BaCl2)-NaCl-H3BO3, SrCl2(BaCl2)-LiCl-H3BO3, SrO(BaO)-SrCl2(BaCl2)-H3BO3, SrO(BaO)-NaCl-H3BO3, H3BO3-PbO-SrCl2(BaCl2), NaCl-PbO-H3BO3, KCl-PbO-H3BO3, Li2CO3-PbO-H3BO3, LiBO2-PbO-H3BO3, H3BO3-KCl-NaCl, H3BO3-K2CO3-Na2CO3, H3BO3-K2CO3-NaCl, H3BO3-KCl-Na2CO3, H3BO3-KCl-Na2CO3-SrCl2(BaCl2), H3BO3-K2CO3-NaCl-SrCl2(BaCl2), H3BO3-PbO-NaCl-SrCl2(BaCl2), H3BO3-LiCl-NaCl-SrCl2(BaCl2), H3BO3-K2CO3-LiCl-SrCl2(BaCl2), etc.

[0032] A method for preparing strontium lanthanum chloroborate and barium lanthanum chloroborate nonlinear optical crystals, characterized by using single-phase polycrystalline powders of strontium lanthanum chloroborate and barium lanthanum chloroborate for solid-state synthesis, comprising the following steps: mixing a strontium (barium)-containing compound, a lanthanum-containing compound, a boron-containing compound, and a chlorine-containing compound and preparing the compounds strontium lanthanum chloroborate and barium lanthanum chloroborate by solid-state reaction, wherein the strontium (barium) in the strontium (barium)-containing compound, the lanthanum in the lanthanum-containing compound, the boron in the boron-containing compound, and the chlorine in the chlorine-containing compound are... The molar ratio is 2.5-3.3:3.5-4.2:2.5-3.5:0.7-1.3. Strontium (barium) compound, lanthanum compound, boron compound, and chlorine compound raw materials are mixed evenly, ground, and then placed in a muffle furnace for pre-calcination to remove moisture and gas from the raw materials. After cooling to room temperature, the raw materials are removed, ground again, and then placed in a muffle furnace for calcination. The temperature is raised to 600-1000℃ and held at a constant temperature for 72 hours. After cooling to room temperature, the raw materials are removed and ground to obtain single-phase polycrystalline powders of strontium lanthanum chloroborate and barium lanthanum chloroborate compounds.

[0033] b. Preparation of seed crystals for strontium lanthanum chloroborate and barium lanthanum chloroborate nonlinear optical crystals: The mixed melt obtained in step a is slowly cooled to room temperature at a rate of 3-10℃ / h, and seed crystals for strontium lanthanum chloroborate and barium lanthanum chloroborate nonlinear optical crystals are obtained by spontaneous crystallization.

[0034] c. Place the crucible containing the mixed melt obtained in step a into the crystal growth furnace, fix the seed crystal obtained in step b on the seed crystal rod, lower the seed crystal from the top of the crystal growth furnace, preheat the seed crystal for 5-60 minutes, lower the seed crystal to the surface of the mixed melt or the mixed melt for remelting, keep the temperature constant for 5-60 minutes, and reduce the temperature to the saturation temperature at a rate of 1-60℃ / h.

[0035] d. Then, slowly cool down at a rate of 0.1-5℃ / day, and grow the crystal by rotating the seed crystal rod at a speed of 0-60 rpm. After the single crystal grows to the required size, lift the crystal off the surface of the mixed melt and cool it down to room temperature at a rate of 1-80℃ / h. Then take the crystal out of the furnace to obtain lanthanum strontium chloroborate and lanthanum barium chloroborate nonlinear optical crystals.

[0036] The fluxing agents SrCO3(BaCO3)-SrCl2(BaCl3) system has a molar ratio of SrCO3(BaCO3) to SrCl2(BaCl3) of 1-3:2-5; the fluxing agent SrCO3(BaCO3)-SrO(BaO) system has a molar ratio of SrCO3(BaCO3) to SrO(BaO) of 1-3:3-6; the fluxing agent SrCO3(BaCO3)-H3BO3 system has a molar ratio of SrCO3(BaCO3) to H3BO3 of 1-5:3-7; the fluxing agent SrCO3(BaCO3)-NaCl system has a molar ratio of SrCO3(BaCO3) to NaCl of 1-5:2-8; and the fluxing agent SrCO3(BaCO3)-KC In the SrCO3-PbO system, the molar ratio of SrCO3 (BaCO3) to KCl is 1-8:2-5; in the SrCO3-PbO system, the molar ratio of SrCO3 to PbO is 1-10:3-6; in the SrCO3-LiCl system, the molar ratio of SrCO3 (BaCO3) to LiCl is 1-7:1-6; in the SrCl2 (BaCl2)-PbO system, the molar ratio of SrCl2 (BaCl2) to PbO is 1-7:1-6; in the SrCl2 (BaCl2)-NaCl system, the molar ratio of SrCl2 (BaCl2) to NaCl is 1-8:2-5; in the SrCl2 (BaCl2)-Na2CO3 system, the molar ratio of SrCl2 (BaCl2) to KCl is 1-8:2-5. The molar ratio of SrCl2 (BaCl2) to Na2CO3 in the SrCl2-LiCl system is 1-10:3-6; the molar ratio of SrCl2 (BaCl2) to LiCl in the SrCl2-LiCl system is 1-7:5-6; the molar ratio of H3BO3 to PbO in the H3BO3-PbO system is 1-7:2-6; the molar ratio of H3BO3 to Na2CO3 in the H3BO3-Na2CO3 system is 1-6:1-5; the molar ratio of H3BO3 to Li2CO3 in the H3BO3-Li2CO3 system is 1-6:2-6; the molar ratio of H3BO3 to KCl in the H3BO3-KCl system is 1-6:4-6; the molar ratio of H3BO3 to K2CO3 in the H3BO3-K2CO3 system is... The molar ratios of SrO (BaO) to Na2CO3 in the SrO(BaO)-Na2CO3 system are 1-6:2-6; in the SrO(BaO)-KCl system, the molar ratio of Sr(Ba)CO3, NaCl, and H3BO3 is 1-5:2-6:3-8; and in the Sr(Ba)CO3-SrO-H3BO3 system, the molar ratios of SrCO3 (BaCO3), SrO (BaO), and H3BO3 are 0.The molar ratio of SrCO3(BaCO3), LiCl, and H3BO3 in the SrCO3(BaCO3)-LiCl-H3BO3 system is 1-5:0.5-6:2.9-8; the molar ratio of SrCl2(BaCl2)-LiCl-H3BO3 in the SrCl2(BaCl2)-LiCl-H3BO3 system is 1-6:1-7:3-8; the molar ratio of SrO(BaO)-SrCl2-H3BO3 in the SrO(BaO)-SrCl2-H3BO3 system is 1-3:1-4:3-10; the molar ratio of SrO(BaO)-NaCl-H3BO3 in the SrO(BaO)-NaCl-H3BO3 system is 1-5:1 The molar ratio of H3BO3, PbO, and SrCl2 (BaCl2) in the H3BO3-PbO-SrCl2(BaCl2) system is 2-5:1-6:3-8; the molar ratio of NaCl, PbO, and H3BO3 in the NaCl-PbO-H3BO3 system is 2-9:1-7:1-10; the molar ratio of KCl, PbO, and H3BO3 in the KCl-PbO-H3BO3 system is 2-5:1-6:2-8; the molar ratio of Li2CO3, PbO, and H3BO3 in the Li2CO3-PbO-H3BO3 system is 2-5:1-10:2-11; and the molar ratio of LiBO2, PbO, and H3BO3 in the LiBO2-PbO-H3BO3 system is 0.5-5:1.The molar ratio of H3BO3, KCl, and NaCl in the H3BO3-KCl-NaCl system is 2-5:1-10:2-9; the molar ratio of H3BO3, KCl, Na2CO3, and SrCl2 (BaCl2) in the H3BO3-KCl-Na2CO3-SrCl2 (BaCl2) system is 1-21:1-10:2-8:1-8; the molar ratio of H3BO3, KCl, Na2CO3, and SrCl2 (BaCl2) in the H3BO3-K2CO3-NaCl-SrCl2 (BaCl2) system is 1-21:1-10:2-8:1-8; the molar ratio of H3BO3, K2CO3, NaCl, and SrCl2 (BaCl2) in the H3BO3-PbO-NaCl-SrCl2 (BaCl2) system is 1-21:1-10:2-8:1-8; the molar ratio of H3BO3, K2CO3, NaCl, and SrCl2 (BaCl2) in the H3BO3-PbO-NaCl-SrCl2 (BaCl2) system is 1-21:1-10:2-8:1-8. The molar ratio of L2 (BaCl2) is 1-20:1-10:2-8:1-8; in the H3BO3-LiCl-NaCl-SrCl2(BaCl2) system, the molar ratio of H3BO3, K2CO3, NaCl to SrCl2 (BaCl2) is 1-21:1-10:3-8:1-8; in the H3BO3-K2CO3-LiCl-SrCl2(BaCl2) system, the molar ratio of H3BO3, K2CO3, NaCl to SrCl2 (BaCl2) is 1-21:2-10:2-9:1-7; and in the H3BO3-KCl-NaCl-SrCl2(BaCl2) system, the molar ratio of H3BO3, KCl, NaCl to SrCl2 (BaCl2) is 1-18:1-9:2-10:1-9.

[0037] This invention provides two nonlinear optical crystals: lanthanum strontium chloroborate and lanthanum barium chloroborate, characterized in that the chemical formula of the crystal is A3La4B3O. 13 Cl, where A = Sr, Ba, with a molecular weight of 1094.36-1243.48, lacks a center of symmetry, belongs to the hexagonal crystal system, and has space group P63. The compound is A3La4B3O. 13 Cl, where A = Sr, and the unit cell parameters of Ba are...

[0038] During the growth of lanthanum strontium borate and lanthanum barium borate nonlinear optical crystals, self-fluxing fluxes such as SrCO3 (BaCO3), SrCl2 (BaCl2), Sr(OH)2 (BaOH2), SrO (BaO), H3BO3, and B2O3 are used, along with other fluxes such as NaCl, LiCl, KCl, Na2CO3, Li2CO3, and K2CO3, as well as fluxes such as SrCl2 (BaCl2)-Sr(Ba)(OH)2, SrCl2 (BaCl2)-SrO (BaO), SrCl2 (BaCl2)-H3BO3, SrCl2 (BaCl2)-B2O3, and Sr(OH)2 (BaOH2)-SrO (BaO), Sr(OH)2(BaOH2)-H3BO3, Sr(OH)2(BaOH2)-B2O3, SrO(BaO)-H3BO3, SrCO3(BaCO3)-SrCl2, SrCO3(BaCO3)-SrO(BaO), SrCO3(BaCO3)-H3BO3, S rCO3(BaCO3)-NaCl, SrCO3(BaCO3)-KCl, SrCO3(BaCO3)-PbO, SrCO3(BaCO3)-LiCl, SrCl2(BaCl2)-Sr(Ba)O, SrCl2(BaCl2)-PbO, SrCl2(BaCl2)-NaC l. SrCl2(BaCl2)-Na2CO3, SrCl2(BaCl2)-LiCl, SrCl2(BaCl2)-KCl, SrCl2(BaCl2)-K2CO3, SrO(BaO)-H3BO3, SrO(BaO)-PbO, SrO(BaO)-NaCl, SrO(B aO)-Na2CO3, SrO(BaO)-LiCl, SrO(BaO)-Li2CO3, SrO(BaO)-KCl, SrO(BaO)-K2CO3, SrO(BaO)-LiBO2, H3BO3-PbO, H3BO3-Na2CO3, H3BO3-Li2CO3, H3B O3-KCl, H3BO3-K2CO3, H3BO3-LiBO2, SrCO3(BaCO3)-NaCl-H3BO3, SrCO3(BaCO3)-Sr(Ba)O-H3BO3, SrCO3(BaCO3)-LiCl-H3BO3, SrCO3(BaCO3)-KCl- H3BO3, SrCl2(BaCl2)-SrO(BaO)-H3BO3, SrCl2(BaCl2)-NaCl-H3BO3, SrCl2(BaCl2)-LiCl-H3BO3, SrO(BaO)-SrCl2-H3BO3, SrO(BaO)-NaCl-H3BO3,H3BO3-PbO-SrCl2(BaCl2), NaCl-PbO-H3BO3, KCl-PbO-H3BO3, Li2CO3-PbO-H3BO3, LiBO2-PbO-H3BO3, H3BO3-KCl-Na Cl, H3BO3-K2CO3-Na2CO3, H3BO3-K2CO3-NaCl, H3BO3-KCl-Na2CO3, H3BO3-KCl-Na2CO3-SrCl2(BaCl2), H3BO3-K2CO3 The product uses composite fluxes such as NaCl-SrCl2 (BaCl2), H3BO3-PbO-NaCl-SrCl2 (BaCl2), H3BO3-LiCl-NaCl-SrCl2 (BaCl2), or others. It boasts high product purity, easy crystal growth, and transparent, unencapsulated crystals, offering advantages such as rapid growth, low cost, and ease of obtaining large-sized crystals. The strontium lanthanum chloroborate and barium lanthanum chloroborate nonlinear optical crystals are used to fabricate frequency doublers, up-frequency converters, down-frequency converters, or optical parametric oscillators. The obtained crystals exhibit a wide transmission band, high hardness, good mechanical properties, are not easily broken or deliquescent, and are easy to process and store. The strontium lanthanum chloroborate and barium lanthanum chloroborate nonlinear optical crystals obtained using the method described in this invention can be used to fabricate nonlinear optical devices for laser frequency conversion. Attached Figure Description

[0039] Figure 1 The present invention is based on Sr3La4B3O 13 X-ray diffraction pattern of Cl powder.

[0040] Figure 2 This is a schematic diagram illustrating the working principle of the nonlinear optical device fabricated according to the present invention, where 1 is a laser, 2 is the emitted beam, and 3 is A3La4B3O. 13 Cl, where A = Sr, Ba is a nonlinear optical crystal, 4 is the outgoing beam, and 5 is the filter. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0042] Example 1:

[0043] According to the reaction formula: 5ACO3 + 6H3BO3 + 1ACl2 + 4La2O3 → 2A3La4B3O 13 Cl + 5CO₂↑ + 9H₂O↑, synthesizing A₃La₄B₃O 13 Cl (A = Sr, Ba) compounds, where A = Sr, Ba:

[0044] SrCO3 (BaCO3), H3BO3, SrCl2 (BaCl2), and La2O3 were weighed out in a molar ratio of 5:6:1:4 and placed in a mortar. The mixture was then carefully ground and placed into an open corundum crucible (Φ100mm×100mm). The crucible was placed in a muffle furnace and slowly heated to 300℃, held at that temperature for 24 hours, and then cooled to room temperature. After a second grinding, the mixture was placed back into the muffle furnace and heated to 950℃, held at that temperature for 24 hours, and then cooled to room temperature. After a third grinding, the mixture was placed back into the muffle furnace and held at 950℃ for 48 hours. The resulting powders were single-phase polycrystalline powders of strontium lanthanum chloroborate and barium lanthanum chloroborate compounds (A3La4B3O3). X-ray analysis of the product was performed. The obtained X-ray spectra were consistent with those of strontium lanthanum chloroborate and barium lanthanum chloroborate (A3La4B3O3). 13 The X-ray spectra obtained from Cl (A = Sr, Ba) single crystal structures are consistent;

[0045] The obtained strontium lanthanum chloroborate and barium lanthanum chloroborate A3La4B3O 13 Cl (A = Sr, Ba) compound single-phase polycrystalline powder and flux H3BO3-KCl-NaCl in molar ratio A3La4B3O 13 Cl(A=Sr,Ba):H3BO3-KCl-NaCl=1:3, wherein the molar ratio of H3BO3, KCl and NaCl is 6:3:5, is mixed and placed in an open platinum crucible with a diameter of 80mm×80mm, and heated to 900℃ at a heating rate of 30℃ / h, held at the temperature for 15 hours to obtain a mixed melt, and then cooled to 880℃.

[0046] Strontium lanthanum chloroborate and barium lanthanum chloroborate seed crystals were obtained by slow cooling to room temperature at a rate of 0.5℃ / h.

[0047] Crystal growth in the compound melt: The obtained A3La4B3O 13 Cl (A = Sr, Ba) seed crystals are fixed on the seed crystal rods and the seed crystals are lowered from the top of the crystal growth furnace. The seed crystals are preheated on the surface of the mixed melt for 10 minutes, then immersed in the melt to allow the seed crystals to remelt in the mixed melt. The temperature is kept constant for 30 minutes and then rapidly cooled to the saturation temperature of 865℃.

[0048] The temperature is then lowered at a rate of 2℃ / day, and the seed crystal rod is rotated at 10 rpm. After crystal growth is complete, the crystal is removed from the liquid surface and cooled to room temperature at a rate of 10℃ / hour. This yields an A3La4B3O crystal with dimensions of 56mm×40mm×30mm. 13 Cl (A = Sr, Ba) crystals.

[0049] In the reaction formula, the raw material strontium carbonate (barium carbonate) can be replaced by other strontium (barium) salts such as strontium chloride (barium chloride), strontium nitrate (barium nitrate), strontium oxalate (barium oxalate), or strontium sulfate (barium sulfate), or strontium oxide (barium oxide) or strontium hydroxide (barium hydroxide). Lanthanum oxide can be replaced by other lanthanum salts such as lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, or lanthanum sulfate, or lanthanum hydroxide. Boric acid can be replaced by boron oxide.

[0050] Example 2:

[0051] According to the reaction formula: 3ACO3 + 3H3BO3 + 2La2O3 + 1NH4Cl → A3La4B3O 13 Cl + NH3↑ + 4NO2↑ + 3CO2↑ + 5H2O↑ synthesizes A3La4B3O 13 Cl compounds, where A = Sr, Ba:

[0052] SrCO3 (BaCO3), H3BO3, La2O3, and NH4Cl were weighed directly in a molar ratio of 3:3:2:1. The weighed raw materials were mixed with flux H3BO3-PbO in a molar ratio of 1:4, wherein the molar ratio of H3BO3 to PbO was 3:5. The mixture was placed in an open platinum crucible with a diameter of 80mm and a diameter of 80mm, heated to 650℃, and held at that temperature for 60 hours to obtain a mixed melt. The melt was then cooled to 600℃.

[0053] Strontium lanthanum chloroborate and barium lanthanum chloroborate seed crystals were obtained by slow cooling to room temperature at a rate of 1.5℃ / h.

[0054] A3La4B3O will be obtained 13 Cl, where A = Sr, Ba seed crystal is fixed on seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. First, the seed crystal is preheated on the surface of the mixed melt for 10 minutes, then immersed below the liquid surface, so that the seed crystal is remelted in the mixed melt, kept at a constant temperature for 30 minutes, and then rapidly cooled to the saturation temperature of 620℃.

[0055] The temperature is then slowly reduced at a rate of 1℃ / day without rotating the seed crystal rod. Once the crystal has grown to the desired size, it is lifted off the surface of the melt and cooled to room temperature at a rate of 20℃ / h. The crystal is then removed from the furnace to obtain an A3La4B3O crystal with dimensions of 36mm × 22mm × 15mm. 13 Cl crystals, where A = Sr, Ba.

[0056] In the reaction formula, the raw material strontium carbonate (barium carbonate) can be replaced by other strontium (barium) salts such as strontium chloride (barium chloride), strontium nitrate (barium nitrate), strontium oxalate (barium oxalate), or strontium sulfate (barium strontium sulfate), or strontium oxide (barium oxide) or strontium hydroxide (barium hydroxide). Lanthanum oxide can be replaced by other lanthanum salts such as lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, or lanthanum sulfate, or lanthanum hydroxide. Boric acid can be replaced by boron oxide.

[0057] Example 3:

[0058] According to the reaction formula: 5A(OH)₂ + 1SrCl₂ + 6H₃BO₃ + 4La₂O₃ → 2A₃La₄B₃O 13 Cl + 14H₂O↑ synthesizes A₃La₄B₃O 13 Cl compounds, where A = Sr, Ba:

[0059] Sr(OH)2(Ba(OH)2), SrCl2(BaCl2), H3BO3, and La2O3 were weighed directly in a molar ratio of 5:1:6:4. The weighed raw materials were mixed with the flux SrCl2(BaCl2)-H3BO3 in a molar ratio of 1:3, wherein the molar ratio of SrCl2(BaCl2) to H3BO3 was 1:3. The mixture was placed in an open platinum crucible with a diameter of 80mm and a diameter of 80mm, heated to 1000℃, held at that temperature for 60 hours to obtain a mixed melt, and then cooled to 880℃.

[0060] Strontium lanthanum chloroborate and barium lanthanum chloroborate seed crystals were obtained by slow cooling to room temperature at a rate of 3.5℃ / h.

[0061] The obtained A3La4B3O 13 Cl, where A = Sr, Ba seed crystal is fixed on seed crystal rod and the seed crystal is dropped from the top of the crystal growth furnace. First, the seed crystal is preheated on the surface of the mixed melt for 15 minutes, then immersed below the liquid surface, so that the seed crystal is remelted in the mixed melt, kept at a constant temperature for 30 minutes, and then rapidly cooled to the saturation temperature of 867℃.

[0062] The temperature is then slowly reduced at a rate of 3℃ / day, and the seed crystal crucible is rotated at a speed of 5 rpm. After the crystal grows to the desired size, it is lifted off the surface of the melt and cooled to room temperature at a rate of 1℃ / h. Finally, the crystal is removed from the furnace to obtain an A3La4B3O crystal with dimensions of 25mm × 24mm × 10mm. 13 Cl crystals, where A = Sr, Ba.

[0063] In the reaction formula, the raw material strontium hydroxide (barium hydroxide) can be replaced by other strontium (barium) salts such as strontium chloride (barium chloride), strontium nitrate (barium nitrate), strontium oxalate (barium oxalate), or strontium sulfate (barium sulfate), or strontium oxide (barium oxide) or strontium hydroxide (barium hydroxide). Lanthanum oxide can be replaced by other lanthanum salts such as lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, or lanthanum sulfate, or lanthanum hydroxide. Boric acid can be replaced by boron oxide.

[0064] Example 4:

[0065] According to the reaction equation: 3AO + 3H3BO3 + 2La2O3 + 1NH4Cl↑ → A3La4B3O 13 Cl + 5H₂O↑ + NH₃↑ synthesizes A₃La₄B₃O 13 Cl compounds, where A = Sr, Ba:

[0066] SrO(BaO), H3BO3, La2O3, and NH4Cl were weighed directly in a molar ratio of 3:3:2:1. The weighed raw materials were mixed with the flux PbO-H3BO3 in a molar ratio of 1:3, where the molar ratio of PbO to H3BO3 was 1:3. The mixture was placed in an open platinum crucible with a diameter of 80mm and a diameter of 80mm, heated to 890℃, and held at that temperature for 80 hours to obtain a mixed melt. The temperature was then lowered to 875℃.

[0067] Strontium lanthanum chloroborate and barium lanthanum chloroborate seed crystals were obtained by slow cooling to room temperature at a rate of 5℃ / h.

[0068] The obtained A3La4B3O 13 Cl, where A = Sr, Ba seed crystal is fixed on seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. First, the seed crystal is preheated on the surface of the mixed melt for 20 minutes, then immersed below the liquid surface, so that the seed crystal is remelted in the mixed melt, kept at a constant temperature for 5 minutes, and then rapidly cooled to the saturation temperature of 860℃.

[0069] Then, the temperature is slowly reduced at a rate of 3℃ / day, and the seed crystal rod is rotated at a speed of 15 rpm. After the crystal grows to the required size, the crystal is removed from the molten surface and cooled to room temperature at a rate of 15℃ / h. Finally, the crystal is removed from the furnace to obtain an A3La4B3O crystal with dimensions of 35mm×25mm×20mm. 13 Cl crystals, where A = Sr, Ba.

[0070] In the reaction formula, barium oxide (strontium oxide) can be replaced by other strontium (barium) salts such as strontium chloride (barium chloride), strontium nitrate (barium nitrate), strontium oxalate (barium oxalate), or strontium sulfate (barium sulfate), or strontium oxide (barium strontium oxide) or strontium hydroxide (barium strontium hydroxide). Lanthanum oxide can be replaced by other lanthanum salts such as lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, or lanthanum sulfate, or lanthanum hydroxide. Boric acid can be replaced by boron oxide.

[0071] Example 5

[0072] According to the reaction formula: 3A(OH)₂ + 1NH₄Cl + 3H₃BO₃ + 2La₂O₃ → A₃La₄B₃O 13 Cl, + 8H₂O↑ + 1NH₃↑ synthesizes A₃La₄B₃O 13 Cl compounds, where A = Sr, Ba:

[0073] Sr(OH)2(Ba(OH)2), NH4Cl, H3BO3, and La2O3 were weighed directly in a molar ratio of 3:1:3:2. The weighed raw materials were mixed with flux H3BO3-KCl-Na2CO3 in a molar ratio of 1:2, with the molar ratio of H3BO3, KCl, and Na2CO3 being 5:1:3. The mixture was placed in an open platinum crucible with a diameter of 80mm and a diameter of 80mm. The temperature was raised to 850℃ and held for 80 hours to obtain a mixed melt. The temperature was then lowered to 830℃.

[0074] Strontium lanthanum chloroborate and barium lanthanum chloroborate seed crystals were obtained by slow cooling to room temperature at a rate of 10℃ / h.

[0075] The obtained A3La4B3O 13 Cl, where A = Sr, Ba seed crystal is fixed on seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. First, the seed crystal is preheated on the surface of the mixed melt for 25 minutes, then partially immersed below the liquid surface, so that the seed crystal is remelted in the mixed melt. The temperature is kept constant for 25 minutes and then rapidly cooled to the saturation temperature of 820℃.

[0076] The temperature is then lowered at a rate of 5℃ / day, and the seed crystal rod is rotated at 30 rpm. After the crystal grows to the desired size, it is lifted off the surface of the melt and cooled to room temperature at a rate of 35℃ / h. Finally, the crystal is removed from the furnace to obtain an A3La4B3O crystal with dimensions of 22mm×32mm×20mm. 13 Cl crystals, where A = Sr, Ba.

[0077] In the reaction formula, the raw material strontium hydroxide (barium hydroxide) can be replaced by other strontium (barium) salts such as strontium chloride (barium chloride), strontium nitrate (barium nitrate), strontium oxalate (barium oxalate), or strontium sulfate (barium sulfate), or strontium oxide (barium oxide) or strontium hydroxide (barium hydroxide). Lanthanum oxide can be replaced by other lanthanum salts such as lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, or lanthanum sulfate, or lanthanum hydroxide. Boric acid can be replaced by boron oxide.

[0078] Example 6

[0079] According to the reaction formula: 5AO + 6H3BO3 + 4La2O3 + 1SrCl2 → 2A3La4B3O 13 Cl + 9H₂O↑ synthesizes A₃La₄B₃O 13 Cl compounds, where A = Sr, Ba:

[0080] SrO(BaO), H3BO3, La2O3, and SrCl2(BaCl2) were weighed directly in a molar ratio of 5:6:4:1. The weighed raw materials were mixed with flux H3BO3-KCl in a molar ratio of 1:4, wherein the molar ratio of H3BO3 to KCl was 3:2. The mixture was placed in an open platinum crucible with a diameter of 80mm and a diameter of 80mm, heated to 900℃, and kept at that temperature for 5 hours to obtain a mixed melt. The temperature was then lowered to 880℃.

[0081] Strontium lanthanum chloroborate and barium lanthanum chloroborate seed crystals were obtained by slow cooling to room temperature at a rate of 4.0℃ / h.

[0082] The obtained A3La4B3O 13 Cl, where A = Sr, Ba seed crystal is fixed on seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. First, the seed crystal is preheated on the surface of the mixed melt for 20 minutes, then immersed below the liquid surface, so that the seed crystal is remelted in the mixed melt, kept at a constant temperature for 25 minutes, and then rapidly cooled to the saturation temperature of 865℃.

[0083] Then, the temperature is lowered at a rate of 3℃ / day, and the seed crystal rod is rotated at a speed of 50 rpm. After the crystal grows to the required size, the crystal is removed from the molten surface and cooled to room temperature at a rate of 70℃ / h. Finally, the crystal is removed from the furnace to obtain an A3La4B3O crystal with dimensions of 22mm×21mm×16mm. 13 Cl crystals, where A = Sr, Ba.

[0084] In the reaction formula, the raw material strontium oxide (barium oxide) can be replaced by other strontium (barium) salts such as strontium chloride (barium strontium chloride), strontium nitrate (barium strontium nitrate), strontium oxalate (barium oxalate), or strontium sulfate (barium sulfate), or strontium oxide (barium strontium oxide) or strontium hydroxide (barium hydroxide). Lanthanum oxide can be replaced by other lanthanum salts such as lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, or lanthanum sulfate, or lanthanum hydroxide. Boric acid can be replaced by boron oxide.

[0085] Example 7

[0086] According to the reaction formula: 5ACO3 + 6H3BO3 + 1SrCl2(BaCl2) + 8La(NO3)3·6H2O → 2A3La4B3O 13 Cl + 24NO₂↑ + 57H₂O↑ + 5CO₂↑ + 6O₂↑ Synthesis: A₃La₄B₃O 13 Cl compounds, where A = Sr, Ba:

[0087] SrCO3(BaCO3), H3BO3, SrCl2(BaCl2), and La(NO3)3·6H2O were placed in a mortar in a molar ratio of 5:6:1:8, mixed, and carefully ground. The mixture was then placed into a 100mm×100mm open-face corundum crucible, compacted, and placed in a muffle furnace. The temperature was slowly raised to 400℃ and held for 4 hours. After cooling, the crucible was removed. At this point, the sample was relatively porous. The sample was then removed, re-ground until homogeneous, and placed back into the crucible. The mixture was then held in a muffle furnace at 950℃ for another 48 hours. Finally, the sample was removed, crushed, and ground in a mortar to obtain A3La4B3O. 13 The Cl (A=Sr,Ba) compound was subjected to X-ray diffraction analysis. The resulting X-ray spectrum was similar to that of lanthanum strontium borate and lanthanum barium borate (A3La4B3O). 13 The X-ray spectra obtained from Cl (A = Sr, Ba) single crystal structures are consistent;

[0088] The synthesized A3La4B3O 13 The Cl (A=Sr,Ba) compound and the flux H3BO3-PbO-SrCl2(BaCl2) were mixed in a molar ratio of 1:4, wherein the molar ratio of H3BO3, PbO and SrCl2(BaCl2) was 5:1:1. The mixture was placed in an open platinum crucible with a diameter of 80mm×80mm, heated to 900℃, held at that temperature for 50 hours to obtain a mixed melt, and then cooled to 880℃.

[0089] Strontium lanthanum chloroborate and barium lanthanum chloroborate seed crystals were obtained by slow cooling to room temperature at a rate of 4.0℃ / h.

[0090] The obtained A3La4B3O 13Cl, where A = Sr, Ba seed crystal is fixed on seed crystal rod and the seed crystal is taken down from the top of the crystal growth furnace. First, the seed crystal is preheated on the surface of the mixed melt for 20 minutes, then immersed below the liquid surface, so that the seed crystal is remelted in the mixed melt, kept at a constant temperature for 25 minutes, and then cooled to the saturation temperature of 850℃.

[0091] Then, the temperature is lowered at a rate of 2℃ / day, and the seed crystal rod is rotated at a speed of 28 rpm. After the crystal grows to the required size, the crystal is removed from the molten surface and cooled to room temperature at a rate of 25℃ / h. Finally, the crystal is removed from the furnace to obtain an A3La4B3O crystal with dimensions of 30mm×22mm×15mm. 13 Cl crystals, where A = Sr, Ba.

[0092] In the reaction formula, the raw material strontium carbonate (barium carbonate) can be replaced by other strontium (barium) salts such as strontium chloride (barium chloride), strontium nitrate (barium nitrate), strontium oxalate (barium oxalate), or strontium sulfate (barium sulfate), or strontium oxide (barium oxide) or strontium hydroxide (barium hydroxide). Lanthanum oxide can be replaced by other lanthanum salts such as lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, or lanthanum sulfate, or lanthanum hydroxide. Boric acid can be replaced by boron oxide.

[0093] Example 8

[0094] According to the reaction formula: 3SrCO3(BaCO3) + 3H3BO3 + 4La(NO3)3·6H2O + 1NH4Cl → A3La4B3O 13 Cl + 1NH3↑ + 3CO2↑ + 12NO2↑ + 29H2O↑ + 3O2↑ synthesizes compound A3La4B3O13Cl, where A = Sr, Ba:

[0095] Sr(Ba)CO3, H3BO3, La(NO3)3·6H2O, NH4Cl, and O2 were placed in a mortar in a molar ratio of 3:3:4:1:1. The weighed raw materials were mixed with the flux H3BO3-PbO-NaCl-SrCl2(BaCl2) in a molar ratio of 1:1, wherein the molar ratio of H3BO3, PbO, NaCl to SrCl2(BaCl2) was 5:3:4:1. The mixture was placed in an open platinum crucible with a diameter of 80mm × 80mm, heated to 890℃, and held at that temperature for 80 hours to obtain a mixed melt. The temperature was then lowered to 865℃.

[0096] Strontium lanthanum chloroborate and barium lanthanum chloroborate seed crystals were obtained by slow cooling to room temperature at a rate of 10℃ / h.

[0097] The obtained A3La4B3O 13Cl, where A = Sr, Ba seed crystal is fixed on seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. First, the seed crystal is preheated on the surface of the mixed melt for 25 minutes, then partially immersed below the liquid surface, so that the seed crystal is remelted in the mixed melt. The temperature is kept constant for 25 minutes and then rapidly cooled to the saturation temperature of 840℃.

[0098] The temperature is then lowered at a rate of 5℃ / day, and the seed crystal rod is rotated at 30 rpm. After the crystal grows to the desired size, it is lifted off the surface of the melt and cooled to room temperature at a rate of 35℃ / h. Finally, the crystal is removed from the furnace to obtain an A3La4B3O crystal with dimensions of 22mm×32mm×20mm. 13 Cl crystals, where A = Sr, Ba.

[0099] In the reaction formula, the raw material strontium carbonate (barium) can be replaced by other strontium (barium) salts such as strontium (barium) chloride, strontium (barium) nitrate, strontium (barium) oxalate, or strontium (barium) sulfate, or strontium (barium) oxide or strontium (barium) hydroxide. Lanthanum oxide can be replaced by other lanthanum salts such as lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, or lanthanum sulfate, or lanthanum hydroxide. Boric acid can be replaced by boron oxide.

[0100] Example 9

[0101] Any A3La4B3O obtained in Examples 1-8 13 A frequency multiplier device measuring 5mm × 5mm × 6mm is fabricated from a Cl (A = Sr, Ba) crystal in a matching orientation. Figure 2 As shown, the laser is positioned at location 3. At room temperature, a Q-switched Nd:YAG laser is used as the light source, with an incident wavelength of 1064 nm. An infrared beam 2 with a wavelength of 1064 nm emitted from the Q-switched Nd:YAG laser 1 is incident on A3La4B3O. 13 Cl(A=Sr,Ba) single crystal 3 produces green frequency-doubled light with a wavelength of 532nm. The emitted beam 4 contains infrared light with a wavelength of 1064nm and green light with a wavelength of 532nm. After being filtered by filter 5, a green laser with a wavelength of 532nm is obtained.

Claims

1. A compound consisting of strontium lanthanum chloroborate or barium lanthanum chloroborate, characterized in that, The general chemical formula of this compound is A3La4B3O. 13 Cl, where A = Sr, Ba, belongs to the hexagonal crystal system, space group [missing information]. P 63, cell parameters are: 1) Sr3La4B3O 13 Cl: a =10.707(2)Å, b =10.707(2)Å, c=6.936(2)Å, Z =2, V =688.5(3)Å 3 ;2) Ba3La4B3O 13 Cl: a =10.907(6)Å, b =10.907(6)Å, c = 7.017(6)Å, Z =2, V=723.1(10)Å 3 .

2. The method for preparing the compound strontium lanthanum chloroborate or barium lanthanum chloroborate according to claim 1, characterized in that, Includes the following steps: The compounds strontium- or barium-containing compounds, lanthanum-containing compounds, boron-containing compounds, and chlorine-containing compounds are mixed and prepared by solid-phase reaction to obtain strontium-lanthanum chloroborate or barium-lanthanum chloroborate. The molar ratio of strontium- or barium-containing compounds, lanthanum-containing compounds, boron-containing compounds, and chlorine-containing compounds is 2.5-3.3:3.5-4.2:2.5-3.5:0.7-1.

3. The strontium- or barium-containing compounds, lanthanum-containing compounds, boron-containing compounds, and chlorine-containing compounds are mixed evenly, ground, and then pre-calcined in a muffle furnace. After cooling to room temperature, they are removed, ground again, and then calcined in a muffle furnace to obtain strontium-lanthanum chloroborate or barium-lanthanum chloroborate.

3. The method for preparing the compound strontium lanthanum chloroborate or barium lanthanum chloroborate according to claim 2, characterized in that, The strontium or barium-containing compound includes at least one of strontium hydroxide or barium hydroxide, strontium oxide or barium oxide, or strontium or barium salt; The lanthanum-containing compound includes at least one of lanthanum oxide, lanthanum hydroxide, and lanthanum salts; The boron-containing compound is boron oxide, boron hydroxide, and boron salts; The chlorine-containing compound is at least one of barium chloride and ammonium chloride.

4. The method for preparing the compound strontium lanthanum chloroborate or barium lanthanum chloroborate according to claim 3, characterized in that, Strontium or barium salts include at least one of strontium chloride or barium chloride, strontium carbonate or barium carbonate, strontium sulfate or barium sulfate, strontium nitrate or barium nitrate, strontium oxalate or barium oxalate, and strontium acetate or barium acetate. Lanthanum salts include at least one of lanthanum carbonate, lanthanum nitrate, lanthanum chloride, lanthanum oxalate, and lanthanum sulfate.

5. A strontium lanthanum chloroborate or barium lanthanum chloroborate nonlinear optical crystal, characterized in that... The chemical formula is A3La4B3O 13 Cl, where A = Sr, Ba, belongs to the hexagonal crystal system, space group [missing information]. P 63, cell parameters are: 1) Sr3La4B3O 13 Cl: a =10.707(2)Å, b =10.707(2)Å, c=6.936(2)Å, Z =2, V =688.5(3)Å 3 ;2) Ba3La4B3O 13 Cl: a =10.907(6)Å, b =10.907(6)Å, c =7.017(6)Å, Z =2, V=723.1(10)Å 3 .

6. The method for preparing the strontium lanthanum chloroborate or barium lanthanum chloroborate nonlinear optical crystal according to claim 5, characterized in that, Strontium lanthanum chloroborate or barium lanthanum chloroborate nonlinear optical crystals are grown using the high-temperature melt method or the Czochralski method.

7. The method according to claim 6, characterized in that, The specific operation is carried out according to the following steps: a. A mixture of the compound strontium lanthanum chloroborate or barium lanthanum chloroborate obtained in claim 2 and a flux is heated to melt to obtain a mixed melt, and then cooled or grown at a constant temperature to prepare crystals of the compound strontium lanthanum chloroborate or barium lanthanum chloroborate. Alternatively, a mixture of barium or strontium-containing compounds, lanthanum-containing compounds, boron-containing compounds, and chlorine-containing compounds, or a mixture of barium-containing compounds, lanthanum-containing compounds, boron-containing compounds, and chlorine-containing compounds with a flux, can be heated to melt to obtain a mixed melt, and then cooled or grown at a constant temperature to prepare strontium lanthanum chloroborate or barium lanthanum chloroborate crystals. b. Place the crucible containing the mixed melt obtained in step a into a crystal growth furnace, fix the seed crystal on the seed crystal rod, lower the seed crystal to the surface of the mixed melt or into the mixed melt for remelting, and reduce it to the saturation temperature; cool down or grow at a constant temperature to prepare the compound strontium lanthanum chloroborate or the compound barium lanthanum chloroborate.

8. The method according to claim 7, characterized in that... The molar ratio of strontium lanthanum chloroborate or barium lanthanum chloroborate compound to flux is 1:1-20; or the molar ratio of barium or strontium-containing compound, lanthanum-containing compound, boron-containing compound and chlorine-containing compound to flux is 3:4:3:1:1-20; single flux includes one of barium oxide or strontium oxide, boric acid, barium chloride or strontium chloride, sodium chloride, lithium chloride, potassium chloride, lead oxide, sodium carbonate, potassium carbonate, and lithium carbonate; composite flux includes SrCl2-H3BO3 and BaCl2-H3BO3. 3、 One or more of PbO-H3BO3, NaCl-H3BO3, LiCl-H3BO3, Na2CO3-H3BO3, Li2CO3-H3BO3, K2CO3-H3BO3, SrCl2-PbO, BaCl2-PbO, NaCl-PbO, LiCl-PbO, Na2CO3-PbO, Li2CO3-PbO, K2CO3-PbO, PbO-H3BO3, SrCl2-H3BO3-PbO, BaCl2-H3BO3-PbO, NaCl-H3BO3-PbO, LiCl-H3BO3-PbO, Na2CO3-H3BO3-PbO, Li2CO3-H3BO3-PbO, K2CO3-H3BO3-PbO, LiCl-SrCl2-H3BO3, LiCl-BaCl2-H3BO3, NaCl-SrCl2-H3BO3, NaCl-BaCl2-H3BO3, NaCl-LiCl-H3BO3, LiCl-Na2CO3-H3BO3, LiCl-K2CO3-H3BO3, NaCl-Na2CO3-H3BO3, NaCl-K2CO3-H3BO3, KCl-Na2CO3-H3BO3-SrCl2, KCl-Na2CO3-H3BO3-BaCl2, KCl-Na2CO3-H3BO3, KCl-K2CO3-H3BO3, KCl-K2CO3-H3BO3-SrCl2, KCl-K2CO3-H3BO3-BaCl2, NaCl-Na2CO3-H3BO3, NaCl-Na2CO3-H3BO3-SrCl2, NaCl-Na2CO3-H3BO3-BaCl2, NaCl-LiCl-H3BO3-SrCl2, NaCl-LiCl-H3BO3-BaCl2, KCl-LiCl-H3BO3-SrCl2, KCl-LiCl-H3BO3-BaCl2, PbO-H3BO3-SrCl2, PbO-H3BO3-BaCl2, K2CO3-PbO-SrCl2, K2CO3-PbO-BaCl2, NaCl-PbO-SrCl2, NaCl-PbO-BaCl2, NaCl-H3BO3-SrCl2, NaCl-H3BO3-BaCl2, NaCl-H3BO3-SrCl2, NaCl-H3BO3-BaCl2, LiCl-H3BO3-SrCl2, LiCl-H3BO3-BaCl2, LiCl-Na2CO3-H3BO3-SrCl2, LiCl-Na2CO3-H3BO3-BaCl2 9. The use of the strontium lanthanum chloroborate or barium lanthanum chloroborate nonlinear optical crystal according to claim 5, characterized in that... The strontium lanthanum chloroborate or barium lanthanum chloroborate nonlinear optical crystals are used to prepare frequency multipliers, up-frequency converters, down-frequency converters, or optical parametric oscillators.

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