Lead barium boron nitrogen oxide compound and lead barium boron nitrogen oxide nonlinear optical crystal and preparation method and use thereof

Abstract

The present invention provides a lead barium boron nitrogen oxide compound and a lead barium boron nitrogen oxide nonlinear optical crystal as well as a preparation method and use thereof. The chemical formula of the compound is Pb2Ba3(BO3)3(NO3), the molecular weight is 1039.98, and the compound is prepared by a solid phase synthesis method or a vacuum packaging method. The chemical formula of the crystal compound is Pb2Ba3(BO3)3(NO3), the molecular weight is 1039.98, and the crystal belongs to the orthorhombic system with a space group of C 2221, the unit cell parameters are a =10.4818(5)Å, b =14.4102(7)Å, c =8.0332(4)Å, α= 90°, β= 90°, c= 90°, the unit cell volume is 1213.37(10)Å 3 The frequency doubling effect of the crystal is about 3.2 times that of KH2PO4 (KDP), and the ultraviolet cutoff edge is about 320 nm. The crystal is grown by melt method, high-temperature melt method, or vacuum packaging method. The crystal has good chemical stability and can be used as a short-wavelength ultraviolet nonlinear optical crystal in all-solid-state lasers.

Description

Technical Field

[0001] The present invention relates to a compound lead barium boron nitrogen oxide (Pb2Ba3(BO3)3(NO3)) and a lead barium boron nitrogen oxide (Pb2Ba3(BO3)3(NO3)) nonlinear optical crystal, as well as a preparation method and application thereof. Background Art

[0002] Short-wavelength nonlinear optical crystals can utilize their frequency conversion properties to convert lasers in near-infrared and visible bands into short-wavelength lasers, possessing important applications in fields such as medicine, communications, and scientific research. Currently, short-wavelength nonlinear optical crystals are commonly found in materials such as KBe2BO3F2 (KBBF), BaB2O4 (BBO), and LiB3O5 (LBO). However, these crystals suffer from limitations such as low birefringence and difficulty growing large crystals, which limit their applications. Therefore, the preparation and synthesis of novel short-wavelength nonlinear optical crystal materials with superior overall performance is of great significance and practical value.

[0003] When designing and developing new short-wavelength nonlinear optical crystals, researchers aim to achieve crystals with a large second-order nonlinear coefficient, a wide transmittance range, a short cutoff edge, and a moderate birefringence. However, some known compounds often struggle to achieve a balance between the SHG, bandgap, and birefringence. For example, Ba5(BO3)3Cl exhibits a short UV cutoff edge, but its SHG efficiency is only 0.5 times that of KDP. Replacing Ba with lone-pair Pb ions significantly improves the SHG efficiency, but the birefringence remains unchanged. Therefore, increasing birefringence for applications in shorter wavelengths without compromising SHG is a current research hotspot. Since the π-conjugated NO3 group has the same valence as a halogen ion, replacing the halogen atoms in this compound with a more anisotropic NO3 group can yield greater birefringence. Summary of the Invention

[0004] The present invention provides a lead barium boron nitrogen oxide compound and a lead barium boron nitrogen oxide nonlinear optical crystal as well as a preparation method and use thereof. The chemical formula of the compound is Pb2Ba3(BO3)3(NO3), the molecular weight is 1039.98, and the compound is prepared by a solid phase synthesis method or a vacuum packaging method. The chemical formula of the crystal compound is Pb2Ba3(BO3)3(NO3), the molecular weight is 1039.98, the crystal belongs to the orthorhombic crystal system, the space group is C2221, and the unit cell parameters are α=90°,β=90°,γ=90°, the unit cell volume is Prepared by solid phase reaction method or vacuum packaging method.

[0005] Another object of the present invention is to provide a lead barium boron nitrogen oxide Pb2Ba3(BO3)3(NO3) nonlinear optical crystal, the chemical formula of the crystal is Pb2Ba3(BO3)3(NO3), the molecular weight is 1039.98, belongs to the orthorhombic crystal system, the space group is C2221, and the unit cell parameters are α=90°, β=90°, γ=90°.

[0006] Another object of the present invention is to provide a method for preparing lead barium boron nitrogen oxide Pb2Ba3(BO3)3(NO3) nonlinear optical crystals, using a melt method, a high-temperature melt method or a vacuum packaging method to grow the crystals.

[0007] Another object of the present invention is to provide a use of lead barium boron nitrogen oxide Pb2Ba3(BO3)3(NO3) nonlinear optical crystal.

[0008] The present invention discloses a compound of lead, barium, boron, nitrogen and oxygen, the chemical formula of which is Pb2Ba3(BO3)3(NO3), the molecular weight is 1039.98, belongs to the orthorhombic crystal system, the space group is C2221, and the unit cell parameters are α=90°,β=90°,γ=90°, the unit cell volume is It is made by solid phase method or vacuum packaging method.

[0009] The preparation method of the lead barium boron nitrogen oxide compound adopts a solid phase synthesis method or a vacuum packaging method, and the specific operation is carried out according to the following steps:

[0010] The solid phase synthesis method is used to prepare the compound lead barium boron nitrogen oxide:

[0011] A Pb-containing compound, a Ba-containing compound, a B-containing compound, and a N-containing compound are uniformly mixed in a molar ratio of Pb:Ba:B:N=2:3:3:1, placed in a platinum crucible, placed in a muffle furnace, heated to 500-600°C, and kept at this temperature for 48-120 hours to obtain a compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2, or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2, or BaCO3; the B-containing compound is H3BO3 or B2O3; and the N-containing compound is PbF2 and BaF2;

[0012] The vacuum packaging method is used to prepare the lead barium boron nitrogen oxide compound:

[0013] The Pb-containing compound, the Ba-containing compound, the B-containing compound, and the N-containing compound were mixed evenly in a molar ratio of Pb:Ba:B:N=2:3:3:1, and placed in a quartz tube. The quartz tube was evacuated to a vacuum degree of 1×10 -3Pa, high temperature sealed and placed in a muffle furnace, heated to 450-550°C at a rate of 5-10°C / h, and kept at this temperature for 60-240 hours to obtain the compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2 or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2 or BaCO3; the B-containing compound is H3BO3 or B2O3; the N-containing compound is Ba(NO3)2 and Pb(NO3)2.

[0014] A lead-barium-boron-nitrogen-oxygen nonlinear optical crystal, the chemical formula of the crystal is Pb2Ba3(BO3)3(NO3), the molecular weight is 968.05, belongs to the orthorhombic crystal system, the space group is C2221, and the unit cell parameters are α=90°,β=90°,γ=90°, the unit cell volume is

[0015] The preparation method of the lead-barium-boron-nitrogen-oxygen nonlinear optical crystal adopts a melt method, a high-temperature melt method or a vacuum packaging method to grow the crystal;

[0016] The melt method for growing the lead-barium-boron-nitrogen-oxygen nonlinear optical crystal is specifically performed in the following steps:

[0017] a. Evenly mix a Pb-containing compound, a Ba-containing compound, a B-containing compound, and a N-containing compound in a molar ratio of Pb:Ba:B:N=2:3:3:1, put the mixture into a platinum crucible, place the mixture in a muffle furnace, heat it to 500-600°C, and keep the temperature constant for 48-120 hours to obtain a compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2, or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2, or BaCO3; the B-containing compound is H3BO3 or B2O3; and the N-containing compound is Ba(NO3)2 and Pb(NO3)2;

[0018] b. The compound Pb2Ba3(BO3)3(NO3) prepared in step a is placed in a platinum crucible, placed in a muffle furnace, heated to 550-600°C, and kept at this temperature for 10-120 hours to obtain a mixed melt;

[0019] c. Slowly cooling the mixed melt obtained in step b to 500° C. at a rate of 0.1-4° C. / h, and then rapidly cooling to room temperature at a rate of 5-20° C. / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0020] d. Growing crystals in the compound melt using the Czochralski method: Fix the seed crystal obtained in step c on a seed crystal rod, place the seed crystal from above the mixed melt obtained in step b, apply a crystal rotation of 2-8 rpm using a crystal growth controller, pull the seed crystal at a speed of 1-10 mm / day, and simultaneously cool it at a rate of 0.1-10°C / h. After the crystal growth stops, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal is obtained;

[0021] Alternatively, a crystal is grown in a compound melt using the kyvo method: the seed crystal obtained in step c is fixed on a seed crystal rod, and the seed crystal is placed from above the melt obtained in step b. The temperature is lowered at a rate of 0.1-10°C / h, and the crystal is allowed to grow for 50-100 hours. The crystal is slowly lifted but does not leave the liquid surface to continue growing. This process is repeated until the crystal growth stops, thereby obtaining a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal.

[0022] Alternatively, a crucible lowering method is used to grow crystals in a compound melt: the seed crystal prepared in step c is placed at the bottom of the crucible, and the compound Pb2Ba3(BO3)3(NO3) prepared in step a is placed in the crucible, and then the platinum crucible is sealed, and the temperature of the growth furnace is raised to 550-580°C, and the temperature is kept constant for 48-240 hours. The position of the crucible is adjusted to slightly melt the seed crystal, and then the crucible is lowered at a rate of 1-15 mm / day. At the same time, the growth temperature is kept constant, or the temperature is lowered to 500°C at a cooling rate of 1.5°C / h. After the growth is completed, the temperature is quickly lowered to room temperature at a rate of 5-15°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal;

[0023] The high-temperature melt method for growing the lead-barium-boron-nitrogen-oxygen nonlinear optical crystal is specifically performed in the following steps:

[0024] a. Evenly mix a Pb-containing compound, a Ba-containing compound, a B-containing compound, and a N-containing compound in a molar ratio of Pb:Ba:B:N=2:3:3:1, put the mixture into a platinum crucible, place the mixture in a muffle furnace, heat it to 540-570°C, and keep the temperature constant for 48-100 hours to obtain a polycrystalline powder of the compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2, or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2, or BaCO3; the B-containing compound is H3BO3 or B2O3; and the N-containing compound is Ba(NO3)2 and Pb(NO3)2;

[0025] b. Mix the compound Pb2Ba3(BO3)3(NO3) obtained in step a with a flux in a molar ratio of 1:0.1-3, then put the mixture into a platinum crucible, heat the mixture to 680-720°C, and keep the temperature constant for 10-120 hours to obtain a mixed solution; the flux is H3BO3, B2O3 or PbO;

[0026] c. Preparation of seed crystals: placing the mixed melt obtained in step b in a single crystal furnace, slowly cooling the temperature to 500°C at a rate of 0.1-3°C / h, and then rapidly cooling the temperature to room temperature at a rate of 5-10°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0027] d. Growing a crystal: Fix the seed crystal obtained in step c on a seed crystal rod, place the seed crystal from above the mixed melt obtained in step b, apply crystal rotation at 3-8 rpm using a crystal growth controller, and cool at a rate of 0.1-3°C / h. After the crystal growth stops, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal is obtained;

[0028] The vacuum packaging method for growing lead-barium-boron-nitrogen-oxygen nonlinear optical crystals is specifically performed in the following steps:

[0029] a. Mix the Pb-containing compound, Ba-containing compound, B-containing compound and N-containing compound in a molar ratio of Pb:Ba:B:N=2:3:3:1, put them into a quartz tube, and evacuate the quartz tube to a vacuum degree of 1×10 -3 Pa, high temperature sealed and placed in a muffle furnace, heated to 450-550°C at a rate of 5-10°C / h, and kept at this temperature for 60-150 hours to obtain the compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2 or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2 or BaCO3; the B-containing compound is H3BO3 or B2O3; the N-containing compound is Ba(NO3)2 and Pb(NO3)2;

[0030] b. Mix the compound Pb2Ba3(BO3)3(NO3) obtained in step a with flux in a molar ratio of 1:0.1-3, put them into a quartz tube, and evacuate the quartz tube to a vacuum degree of 1×10 -3 Pa, high-temperature sealed and placed in a muffle furnace, heated to 450-550°C, kept constant at this temperature for 60-100 hours, then cooled to 400°C at a rate of 1-3°C / h, and then quickly cooled to room temperature at a rate of 5-10°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal, wherein the flux is H3BO3, B2O3 or PbO.

[0031] The lead-barium-boron-nitrogen-oxygen nonlinear optical crystal is used in preparing a harmonic light output of a 1064nm fundamental frequency light output by an Nd:YAG laser for frequency doubling.

[0032] The lead barium boron nitrogen oxide nonlinear optical crystal is used in preparing ultraviolet frequency-doubled light output below 532 nm.

[0033] The lead-barium-boron-nitrogen-oxygen nonlinear optical crystal is used in preparing a frequency doubling generator, an up- or down-frequency converter or an optical parametric oscillator.

[0034] The present invention discloses a method for preparing a lead-barium-boron-nitrogen-oxide nonlinear optical crystal. The containers used during the preparation process include platinum crucibles, iridium crucibles, ceramic crucibles, quartz tubes, Erlenmeyer flasks, and beakers. When using a quartz tube as the container, vacuuming is required before sealing to prevent volatilization of the raw materials during the reaction and the resulting rupture of the quartz tube. When using an Erlenmeyer flask or beaker as the container, the container must first be cleaned with acid, rinsed with deionized water, and air-dried.

[0035] In the preparation method of the lead-barium-boron-nitrogen-oxygen nonlinear optical crystal described in the present invention, the resistance furnace used in the preparation process is a muffle furnace or a drying box.

[0036] The preparation method of the lead barium boron nitrogen oxide nonlinear optical crystal described in the present invention is adopted to obtain Pb2Ba3(BO3)3(NO3) nonlinear optical crystals with a size of centimeters. By using a large-sized crucible or container and extending the growth period of the crystal, a corresponding large-sized nonlinear optical crystal Pb2Ba3(BO3)3(NO3) can be obtained. During the growth of the Pb2Ba3(BO3)3(NO3) nonlinear optical crystal, the crystal is easy to grow, transparent and without wrapping, and has the advantages of fast growth rate, low cost, and easy acquisition of large-sized crystals.

[0037] By adopting the preparation method of the lead-barium-boron-nitrogen-oxygen nonlinear optical crystal described in the present invention, a large-sized Pb2Ba3(BO3)3(NO3) nonlinear optical crystal is obtained. According to the crystallographic data of the crystal, the crystal blank is oriented, the crystal is cut according to the required angle, thickness and cross-sectional size, and the light-transmitting surface of the crystal is polished, and then it can be used as a nonlinear optical device. The Pb2Ba3(BO3)3(NO3) nonlinear optical crystal has the advantages of a light transmission band of 330nm, stable physical and chemical properties, not easy to deliquesce, and easy to process and preserve. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The powder XRD spectrum of the compound Pb2Ba3(BO3)3(NO3) of the present invention;

[0039] Figure 2 This is a structural diagram of the Pb2Ba3(BO3)3(NO3) crystal of the present invention;

[0040] Figure 3 This is a working principle diagram of the nonlinear optical device made of Pb2Ba3(BO3)3(NO3) crystal of the present invention, where 1 is the laser, 2 is the emitted light beam, 3 is the Pb2Ba3(BO3)3(NO3) crystal, 4 is the output light beam, and 5 is the filter. DETAILED DESCRIPTION

[0041] The present invention is further described below with reference to the following examples. It should be noted that the following examples are not intended to limit the scope of the present invention, and any improvements made based on the present invention do not violate the spirit of the present invention. Unless otherwise specified, the raw materials and equipment used in the present invention are commercially available.

[0042] Example 1

[0043] Preparation of compounds:

[0044] According to the reaction formula: 2PbO+3Ba(NO3)2+3H3BO3→Pb2Ba3(BO3)3(NO3)+5NO2+4.5H2O+2.25O2, the compound Pb2Ba3(BO3)3(NO3) is synthesized by solid phase reaction method:

[0045] PbO, Ba(NO3)2 and H3BO3 were mixed evenly in a molar ratio of 2:3:3, loaded into a platinum crucible, placed in a muffle furnace, heated to 560°C, and kept at this temperature for 60 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0046] Example 2

[0047] Preparation of compounds:

[0048] According to the reaction formula: 2PbO+0.5Ba(NO3)2+2.5BaCO3+3H3BO3→Pb2Ba3(BO3)3(NO3)+2.5CO2+4.5H2O, the compound Pb2Ba3(BO3)3(NO3) is synthesized by solid phase reaction method:

[0049] PbO, Ba(NO3)2, BaCO3 and H3BO3 were mixed evenly in a molar ratio of 2:0.5:2.5:3, loaded into a platinum crucible, placed in a muffle furnace, heated to 520°C, and kept at this temperature for 60 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0050] Example 3

[0051] Preparation of compounds:

[0052] According to the reaction formula: 2PbF2+2.5BaCO3+0.5Ba(NO3)2+3H3BO3→Pb2Ba3(BO3)3(NO3)+2.5CO2+4HF+2.5H2O+1.5O2, the compound Pb2Ba3(BO3)3(NO3) is synthesized by solid phase reaction method:

[0053] PbF2, BaCO3, Ba(NO3)2, and H3BO3 were mixed uniformly in a molar ratio of 2:2.5:0.5:3, loaded into a platinum crucible, placed in a muffle furnace, heated to 510°C, and kept at this temperature for 80 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0054] Example 4

[0055] Preparation of compounds:

[0056] According to the reaction formula: 1.5PbF2+0.5Pb(NO3)2+3BaCO3+3H3BO3→Pb2Ba3(BO3)3(NO3)+3CO2+3HF+3H2O, the compound Pb2Ba3(BO3)3(NO3) is synthesized by solid phase reaction method:

[0057] PbF2, Pb(NO3)2, BaCO3 and H3BO3 were mixed evenly in a molar ratio of 1.5:0.5:3:3, loaded into a platinum crucible, placed in a muffle furnace, heated to 515°C, and kept at this temperature for 80 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0058] Example 5

[0059] Preparation of compounds:

[0060] According to the reaction formula: 2.5BaF2+0.5Ba(NO3)2+2PbCO3+3H3BO3→Pb2Ba3(BO3)3(NO3)+2CO2+5HF+2H2O, the compound Pb2Ba3(BO3)3(NO3) is synthesized by solid phase reaction method:

[0061] BaF2, Ba(NO3)2, PbCO3, and H3BO3 were mixed uniformly in a molar ratio of 2.5:0.5:2:3, loaded into a platinum crucible, placed in a muffle furnace, heated to 485°C, and kept at this temperature for 240 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0062] Example 6

[0063] Preparation of compounds:

[0064] According to the reaction formula: 2PbCO3+0.5Ba(NO3)2+2.5BaCO3+1.5B2O3→Pb2Ba3(BO3)3(NO3)+4.5CO2, the compound Pb2Ba3(BO3)3(NO3) is synthesized by solid phase reaction method:

[0065] PbCO3, Ba(NO3)2, BaCO3 and B2O3 were mixed evenly in a molar ratio of 2:0.5:2.5:1.5, loaded into a platinum crucible, placed in a muffle furnace, heated to 525°C, and kept at this temperature for 60 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0066] Example 7

[0067] Preparation of compounds:

[0068] According to the reaction formula: 2PbO+0.5Ba(NO3)2+2.5BaCO3+1.5B2O3→Pb2Ba3(BO3)3(NO3)+2.5CO2, the compound Pb2Ba3(BO3)3(NO3) is synthesized by vacuum packaging method:

[0069] PbO, Ba(NO3)2, BaCO3 and B2O3 were mixed evenly in a molar ratio of 2:0.5:2.5:1.5, and placed in a Φ40 mm quartz tube. The quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature, placed in a muffle furnace, heated to 470°C at a rate of 5°C / h, and kept at this temperature for 50 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0070] Example 8

[0071] Preparation of compounds:

[0072] According to the reaction formula: 2PbF2+0.5Ba(NO3)2+2.5BaF2+3B2O3→Pb2Ba3(BO3)3(NO3)+3BF3, the compound Pb2Ba3(BO3)3(NO3) is synthesized by vacuum packaging method:

[0073] PbO, Ba(NO3)2, BaF2 and B2O3 were mixed evenly in a molar ratio of 2:0.5:2.5:3, and placed in a Φ40 mm quartz tube. The quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature, placed in a muffle furnace, heated to 510°C at a rate of 5°C / h, and kept at this temperature for 80 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0074] Example 9

[0075] Preparation of compounds:

[0076] According to the reaction formula: 2PbCO3+3Ba(NO3)2+1.5B2O3→Pb2Ba3(BO3)3(NO3)+2CO2+5NO2+3.5O2, the compound Pb2Ba3(BO3)3(NO3) is synthesized by vacuum packaging method:

[0077] PbCO3, Ba(NO3)2 and B2O3 were mixed evenly in a molar ratio of 2:3:1.5, and placed in a Φ40 mm quartz tube. The quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature, placed in a muffle furnace, heated to 490°C at a rate of 8°C / h, and kept at this temperature for 100 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0078] Example 10

[0079] Preparation of compounds:

[0080] According to the reaction formula: 1.5Pb0+0.5Pb(NO3)2+3BaCO3+1.5B2O3→Pb2Ba3(BO3)3(NO3)+3CO2, the compound Pb2Ba3(BO3)3(NO3) is synthesized by vacuum packaging method:

[0081] PbO, Pb(NO3)2, BaCO3 and B2O3 were mixed evenly in a molar ratio of 1.5:0.5:3:1.5, and placed in a Φ40 mm quartz tube. The quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature, placed in a muffle furnace, heated to 470°C at a rate of 7°C / h, and kept at this temperature for 70 hours to obtain the compound Pb2Ba3(BO3)3(NO3).

[0082] Example 11

[0083] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0084] The compound Pb2Ba3(BO3)3(NO3) powder prepared according to Example 1 was placed in a platinum crucible, placed in a muffle furnace, heated to 530°C, and kept at this temperature for 60 hours to obtain a mixed melt;

[0085] The mixed melt was slowly cooled to 430°C at a rate of 0.1°C / h, and then rapidly cooled to room temperature at a rate of 12°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0086] The crystal was grown by the pulling method: the obtained seed crystal was fixed on the seed crystal rod, and the seed crystal was placed from above the mixed melt. The crystal rotation was applied at 6 rpm by the crystal growth controller, the seed crystal was pulled at a speed of 0.5 mm / day, and the temperature was lowered at a rate of 0.1°C / h. After the crystal growth stopped, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 12 mm×10 mm×6 mm was obtained.

[0087] Example 12

[0088] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0089] The compound Pb2Ba3(BO3)3(NO3) prepared in Example 2 was placed in a platinum crucible, placed in a muffle furnace, heated to 520°C, and kept at this temperature for 15 hours to obtain a mixed melt;

[0090] The obtained mixed melt was slowly cooled to 420°C at a rate of 1°C / h, and then rapidly cooled to room temperature at a rate of 3°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0091] The crystals were grown in the compound melt using the Czochralski method: the resulting seed crystal was fixed on a seed crystal rod and placed from above the prepared mixed melt. The crystal was rotated at 4 rpm using a crystal growth controller, and the seed crystal was pulled at a rate of 2 mm / day while being cooled at a rate of 1°C / h. After the crystal growth stopped, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 11 mm × 4 mm × 3 mm was obtained.

[0092] Example 13

[0093] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0094] The compound Pb2Ba3(BO3)3(NO3) prepared in Example 3 was placed in a platinum crucible, placed in a muffle furnace, heated to 515°C, and kept at this temperature for 70 hours to obtain a mixed melt;

[0095] The obtained mixed melt was slowly cooled to 550°C at a rate of 3°C / h, and then rapidly cooled to room temperature at a rate of 15°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0096] The crystals were grown in the compound melt using the Czochralski method: the obtained seed crystal was fixed on a seed crystal rod, and the seed crystal was lowered from the top of the prepared mixed melt. The crystal was rotated at 6 rpm using a crystal growth controller, and the seed crystal was pulled at a speed of 12 mm / day. At the same time, the temperature was lowered at a rate of 10°C / h. After the crystal growth stopped, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 8 mm × 6 mm × 4 mm was obtained.

[0097] Example 14

[0098] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0099] The compound Pb2Ba3(BO3)3(NO3) powder prepared in Example 4 was placed in a platinum crucible, placed in a muffle furnace, heated to 490°C, and kept at this temperature for 120 hours to obtain a mixed melt;

[0100] The obtained mixed melt was slowly cooled to 440°C at a rate of 1°C / h, and then rapidly cooled to room temperature at a rate of 8°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0101] The crystal was grown by the kyropoulos method: the obtained seed crystal was fixed on the seed crystal rod, and the seed crystal was placed from above the prepared mixed melt. The temperature was lowered at a rate of 0.2℃ / h, and the crystal was grown for 60 hours. The crystal was slowly lifted but not out of the liquid surface and continued to grow. This was repeated 3 times to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 5mm×3mm×2mm.

[0102] Example 15

[0103] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0104] The compound Pb2Ba3(BO3)3(NO3) prepared in Example 5 was placed in a platinum crucible, placed in a muffle furnace, heated to 515°C, and kept at this temperature for 70 hours to obtain a mixed melt;

[0105] The obtained mixed melt was slowly cooled to 460°C at a rate of 0.1°C / h, and then rapidly cooled to room temperature at a rate of 3°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0106] Crystals were grown in a compound melt using the pyrolysis method: the obtained seed crystal was fixed on a seed crystal rod, the seed crystal was placed from above the prepared melt, the temperature was lowered at a rate of 1°C / h, the crystal was allowed to grow for 20 hours, the crystal was slowly lifted but not out of the liquid surface to continue growing, and this was repeated three times. After the crystal growth stopped, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 7mm×4mm×3mm was obtained.

[0107] Example 16

[0108] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0109] The compound Pb2Ba3(BO3)3(NO3) prepared in Example 6 was placed in a platinum crucible, placed in a muffle furnace, heated to 530°C, and kept at this temperature for 40 hours to obtain a mixed melt;

[0110] The obtained mixed melt was slowly cooled to 650°C at a rate of 4°C / h, and then rapidly cooled to room temperature at a rate of 15°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0111] Crystals were grown in a compound melt using the kyropoulos method: a seed crystal was fixed to a seed crystal rod, and the seed crystal was lowered from the upper surface of the melt. The temperature was lowered at a rate of 10°C / h, and the crystal was allowed to grow for 40 hours. The crystal was then slowly lifted but not removed from the liquid surface to continue growing. This process was repeated three times. After the crystal growth stopped, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with dimensions of 11 mm × 5 mm × 3 mm was obtained.

[0112] Example 17

[0113] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0114] The Pb2Ba3(BO3)3(NO3) powder prepared in Example 7 was placed in a platinum crucible, heated to 525°C, and kept at this temperature for 50 hours to obtain a mixed melt;

[0115] The obtained mixed melt was slowly cooled to 470°C at a rate of 1.2°C / h, and then rapidly cooled to room temperature at a rate of 6°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0116] A crucible lowering method is used to grow crystals in a compound melt: the obtained seed crystal is placed at the bottom of the crucible, and the polycrystalline powder of the compound Pb2Ba3(BO3)3(NO3) prepared in Example 7 is placed in the crucible, and then the platinum crucible is sealed, the temperature of the growth furnace is raised to 530°C, and the temperature is kept constant for 60 hours. The position of the crucible is adjusted to allow the seed crystal to melt slightly, and then the crucible is lowered at a rate of 4 mm / day and cooled to 420°C at a cooling rate of 2°C / h. After the growth is completed, the temperature is quickly lowered to room temperature at a rate of 20°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 7mm×5mm×4mm.

[0117] Example 18

[0118] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0119] The compound Pb2Ba3(BO3)3(NO3) prepared in Example 4 was placed in a platinum crucible, placed in a muffle furnace, heated to 525°C, and kept at this temperature for 80 hours to obtain a mixed melt;

[0120] The obtained mixed melt was slowly cooled to 450°C at a rate of 0.1°C / h, and then rapidly cooled to room temperature at a rate of 15°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0121] The crystal was grown in the compound melt using the crucible lowering method: the prepared seed crystal was placed at the bottom of the crucible, and then the prepared compound Pb2Ba3(BO3)3(NO3) was placed in the crucible. The platinum crucible was then sealed, and the growth furnace temperature was raised to 530°C and kept constant for 30 hours. The crucible position was adjusted to slightly melt the seed crystal, and then the crucible was lowered at a rate of 1 mm / day while maintaining the growth temperature. After the growth was completed, the crucible was rapidly lowered to room temperature at a rate of 5°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 12 mm × 7 mm × 5 mm.

[0122] Example 19

[0123] Melt-grown Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0124] The compound Pb2Ba3(BO3)3(NO3) prepared in Example 9 was placed in a platinum crucible, placed in a muffle furnace, heated to 480°C, and kept at this temperature for 10 hours to obtain a mixed melt;

[0125] The obtained mixed melt was slowly cooled to 380°C at a rate of 4°C / h, and then rapidly cooled to room temperature at a rate of 2.5°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0126] The crystal was grown in the compound melt using the crucible lowering method: the prepared seed crystal was placed at the bottom of the crucible, and then the prepared compound Pb2Ba3(BO3)3(NO3) was placed in the crucible. The platinum crucible was then sealed, and the growth furnace temperature was raised to 740°C and kept constant for 240 hours. The crucible position was adjusted to slightly melt the seed crystal, and then the crucible was lowered at a rate of 10 mm / day while maintaining the growth temperature. After the growth was completed, the crucible was rapidly lowered to room temperature at a rate of 15°C / h, resulting in a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 12 mm × 7 mm × 3 mm.

[0127] Example 20

[0128] High temperature melt method for growing Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0129] The polycrystalline powder of the compound Pb2Ba3(BO3)3(NO3) prepared in Example 6 was mixed evenly with the flux B2O3 in a molar ratio of 1:0.3, placed in a platinum crucible, heated to 490°C, and kept at this temperature for 120 hours to obtain a mixed melt;

[0130] Preparation of seed crystals: The obtained mixed melt was placed in a single crystal furnace, slowly cooled to 420°C at a rate of 0.2°C / h, and then rapidly cooled to room temperature at a rate of 8°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0131] Growing crystals: The obtained seed crystals were fixed on a seed crystal rod, and the seed crystals were lowered from above the prepared mixed melt. The crystal rotation was applied at 2 rpm by a crystal growth controller, and the temperature was lowered at a rate of 0.1°C / h. After the crystal growth stopped, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 6 mm × 4 mm × 3 mm was obtained.

[0132] Example 21

[0133] High temperature melt method for growing Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0134] The compound Pb2Ba3(BO3)3(NO3) obtained in Example 4 was mixed evenly with flux H3BO3 in a molar ratio of 1:2, and then placed in a platinum crucible. The mixture was heated to 470°C and kept at this temperature for 20 hours to obtain a mixed melt.

[0135] Preparation of seed crystals: The obtained mixed melt was placed in a single crystal furnace, slowly cooled to 420°C at a rate of 1°C / h, and then rapidly cooled to room temperature at a rate of 12°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0136] Growing crystals: The obtained seed crystals were fixed on a seed crystal rod, and the seed crystals were placed from above the prepared mixed melt. The crystals were rotated at 5 rpm using a crystal growth controller, and the temperature was lowered at a rate of 2°C / h. After the crystal growth stopped, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 9 mm × 4 mm × 3 mm was obtained.

[0137] Example 22

[0138] High temperature melt method for growing Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0139] The compound Pb2Ba3(BO3)3(NO3) obtained in Example 8 was mixed evenly with flux PbO in a molar ratio of 1:0.5, and then placed in a platinum crucible, heated to 475°C, and kept at this temperature for 70 hours to obtain a mixed melt;

[0140] Preparation of seed crystals: The obtained mixed melt was placed in a single crystal furnace, slowly cooled to 430°C at a rate of 1.5°C / h, and then rapidly cooled to room temperature at a rate of 6°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0141] Growing crystals: The obtained seed crystals were fixed on a seed crystal rod, and the seed crystals were placed from above the prepared mixed melt. The crystals were rotated at 8 rpm using a crystal growth controller, and the temperature was lowered at a rate of 0.8°C / h. After the crystal growth stopped, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 6 mm × 2 mm × 2 mm was obtained.

[0142] Example 23

[0143] High temperature melt method for growing Pb2Ba3(BO3)3(NO3) nonlinear optical crystals:

[0144] The compound Pb2Ba3(BO3)3(NO3) obtained in Example 7 was mixed evenly with flux PbF2 in a molar ratio of 1:2.5, and then placed in a platinum crucible. The mixture was heated to 500°C and kept at this temperature for 100 hours to obtain a mixed melt.

[0145] Preparation of seed crystals: The obtained mixed melt was placed in a single crystal furnace, slowly cooled to 450°C at a rate of 1.5°C / h, and then rapidly cooled to room temperature at a rate of 7°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals;

[0146] Growing crystals: Fix the obtained seed crystals on the seed crystal rod, place the seed crystals from above the prepared mixed melt, apply crystal rotation of 12 rpm through the crystal growth controller, cool at a rate of 2°C / h, and after the crystal growth stops, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 4mm×3mm×3mm is obtained.

[0147] Example 24

[0148] Growth of Pb2Ba3(BO3)3(NO3) nonlinear optical crystals by vacuum encapsulation method:

[0149] The compound Pb2Ba3(BO3)3(NO3) prepared in Example 8 was mixed evenly with flux H3BO3 in a molar ratio of 1:0.2, and placed in a quartz tube of Φ40 mm. The quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature and placed in a muffle furnace, heated to 485°C, kept constant at this temperature for 40 hours, then cooled to 350°C at a rate of 1.5°C / h, and then quickly cooled to room temperature at a rate of 9°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 5mm×2mm×1mm.

[0150] Example 25

[0151] Growth of Pb2Ba3(BO3)3(NO3) nonlinear optical crystals by vacuum encapsulation method:

[0152] The compound Pb2Ba3(BO3)3(NO3) obtained in Example 9 was mixed evenly with the flux B2O3 in a molar ratio of 1:0.5, and placed in a Φ40 mm quartz tube. The quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature and placed in a muffle furnace, heated to 675°C, kept constant at this temperature for 80 hours, then cooled to 450°C at a rate of 1°C / h, and then quickly cooled to room temperature at a rate of 5°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 3mm×4mm×2mm.

[0153] Example 26

[0154] Growth of Pb2Ba3(BO3)3(NO3) nonlinear optical crystals by vacuum encapsulation method:

[0155] The compound Pb2Ba3(BO3)3(NO3) obtained in Example 10 was mixed evenly with the flux PbO in a molar ratio of 1:1, and placed in a Φ40 mm quartz tube. The quartz tube was evacuated to a vacuum degree of 1×10 -3Pa, sealed at high temperature, placed in a muffle furnace, heated to 495°C, kept constant at this temperature for 80 hours, then cooled to 455°C at a rate of 2°C / h, and then quickly cooled to room temperature at a rate of 6°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal with a size of 6mm×3mm×1mm.

[0156] Example 27

[0157] The random Pb2Ba3(BO3)3(NO3) nonlinear optical crystals obtained in Examples 11-26 are processed in the matching direction, and the attached Figure 3 As shown, it is placed at position 3. At room temperature, a Q-switched Nd:YAG laser is used as the light source with an incident wavelength of 1064nm. The infrared beam 2 with a wavelength of 1064nm emitted by the Q-switched Nd:YAG laser 1 is incident on the Pb2Ba3(BO3)3(NO3) single crystal 3, generating green frequency-doubled light with a wavelength of 532nm. The output intensity is about 3 times that of KDP under the same conditions.

Claims

1. A compound of lead, barium, boron, nitrogen and oxygen, characterized in that The chemical formula of this compound is Pb2Ba3(BO3)3(NO3), the molecular weight is 1039.98, it belongs to the orthorhombic system, and the space group is C 2221, the unit cell parameters are a =10.4818(5) Å, b =14.4102(7) Å, c =8.0332(4) Å, α= 90°, β= 90°, γ= 90°, unit cell volume is 1213.37(10) Å 3 , made by solid phase method or vacuum packaging method.

2. A method for preparing the compound lead, barium, boron, nitrogen and oxygen as claimed in claim 1, characterized in that The solid phase synthesis method or vacuum encapsulation method is used for preparation, and the specific operation is carried out according to the following steps: The solid phase synthesis method is used to prepare the compound lead barium boron nitrogen oxide: A Pb-containing compound, a Ba-containing compound, a B-containing compound, and a N-containing compound are uniformly mixed in a molar ratio of Pb:Ba:B:N=2:3:3:1, placed in a platinum crucible, placed in a muffle furnace, heated to 500-600°C, and kept at this temperature for 60-120 hours to obtain a compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2, or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2, or BaCO3; the B-containing compound is H3BO3 or B2O3; and the N-containing compound is Pb(NO3)2 and Ba(NO3)2. The vacuum packaging method is used to prepare the lead barium boron nitrogen oxide compound: The Pb-containing compound, the Ba-containing compound, the B-containing compound, and the N-containing compound were mixed evenly in a molar ratio of Pb:Ba:B:N=2:3:3:1, and placed in a quartz tube. The quartz tube was evacuated to a vacuum degree of 1×10 −3 Pa, high temperature sealed and placed in a muffle furnace, heated to 450-550°C at a rate of 5-10°C / h, and kept at this temperature for 60-120 hours to obtain the compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2 or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2 or BaCO3; the B-containing compound is H3BO3 or B2O3; the N-containing compound is Pb(NO3)2 and Ba(NO3)2.

3. A lead-barium-boron-nitrogen-oxygen nonlinear optical crystal, characterized in that The chemical formula of the crystal is Pb2Ba3(BO3)3(NO3), the molecular weight is 1039.98, it belongs to the orthorhombic system, and the space group is C 2221, the unit cell parameters are a =10.4818(5) Å, b =14.4102(7) Å, c =8.0332(4) Å, α= 90°, β= 90°, γ= 90°, unit cell volume is 1213.37(10) Å 3 .

4. A method for preparing a lead-barium-boron-nitrogen-oxygen nonlinear optical crystal as claimed in claim 3, characterized in that Crystals are grown using melt method, high temperature melt method or vacuum packaging method; The melt method for growing the lead-barium-boron-nitrogen-oxygen nonlinear optical crystal is specifically performed in the following steps: a. Evenly mix a Pb-containing compound, a Ba-containing compound, a B-containing compound, and a N-containing compound in a molar ratio of Pb:Ba:B:N=2:3:3:1, put the mixture into a platinum crucible, place the mixture in a muffle furnace, heat it to 500-600°C, and keep the temperature constant for 48-120 hours to obtain a compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2, or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2, or BaCO3; the B-containing compound is H3BO3 or B2O3; and the N-containing compound is Pb(NO3)2 and Ba(NO3)2; b. The compound Pb2Ba3(BO3)3(NO3) prepared in step a is placed in a platinum crucible, placed in a muffle furnace, heated to 500-600°C, and kept at this temperature for 10-60 hours to obtain a mixed melt; c. Slowly cooling the mixed melt obtained in step b to 450° C. at a rate of 0.1-4° C. / h, and then rapidly cooling to room temperature at a rate of 5-10° C. / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals; d. Growing crystals in the compound melt using the Czochralski method: Fix the seed crystal obtained in step c on a seed crystal rod, place the seed crystal from above the mixed melt obtained in step b, apply a crystal rotation of 2-15 rpm using a crystal growth controller, pull the seed crystal at a rate of 1-15 mm / day, and simultaneously cool it at a rate of 0.1-5°C / h. After the crystal growth stops, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal is obtained; Alternatively, a crystal is grown in a compound melt using the kyvo method: the seed crystal obtained in step c is fixed on a seed crystal rod, and the seed crystal is placed from above the melt obtained in step b. The temperature is lowered at a rate of 0.1-3°C / h, and the crystal is allowed to grow for 50-80 hours. The crystal is slowly lifted but does not leave the liquid surface to continue growing. This process is repeated until the crystal growth stops, thereby obtaining a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal. Alternatively, a crystal is grown in a compound melt using a crucible lowering method: the seed crystal prepared in step c is placed at the bottom of the crucible, and the compound Pb2Ba3(BO3)3(NO3) prepared in step a is placed in the crucible, and the platinum crucible is then sealed. The temperature of the growth furnace is raised to 480-520°C and maintained at this temperature for 48-240 hours. The position of the crucible is adjusted to slightly melt the seed crystal, and the crucible is then lowered at a rate of 1-10 mm / day. At the same time, the growth temperature is maintained constant, or the temperature is lowered to 450°C at a rate of 2°C / h. After the growth is completed, the temperature is rapidly lowered to room temperature at a rate of 5-15°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal. The high-temperature melt method for growing the lead-barium-boron-nitrogen-oxygen nonlinear optical crystal is specifically performed in the following steps: a. Evenly mix a Pb-containing compound, a Ba-containing compound, a B-containing compound, and a N-containing compound in a molar ratio of Pb:Ba:B:N=2:3:3:1, put the mixture into a platinum crucible, place the mixture in a muffle furnace, heat it to 490-530°C, and keep the temperature constant for 48-240 hours to obtain a polycrystalline powder of the compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2, or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2, or BaCO3; the B-containing compound is H3BO3 or B2O3; and the N-containing compound is Pb(NO3)2 and Ba(NO3)2; b. Mix the compound Pb2Ba3(BO3)3(NO3) obtained in step a with a flux in a molar ratio of 1:0.1-3, then put the mixture into a platinum crucible, heat the mixture to 450-550°C, and keep the temperature constant for 10-150 hours to obtain a mixed solution; the flux is H3BO3, B2O3 or PbO; c. Preparation of seed crystals: placing the mixed melt obtained in step b in a single crystal furnace, slowly cooling the temperature to 600°C at a rate of 0.1-3°C / h, and then rapidly cooling the temperature to room temperature at a rate of 5-10°C / h to obtain Pb2Ba3(BO3)3(NO3) seed crystals; d. Growing crystals: Fix the seed crystal obtained in step c on a seed crystal rod, place the seed crystal from above the mixed melt obtained in step b, apply crystal rotation at 3-10 rpm using a crystal growth controller, and cool at a rate of 0.1-3°C / h. After the crystal growth stops, a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal is obtained; The vacuum packaging method for growing lead-barium-boron-nitrogen-oxygen nonlinear optical crystals is specifically performed in the following steps: a. Mix the Pb-containing compound, Ba-containing compound, B-containing compound and N-containing compound in a molar ratio of Pb:Ba:B:N=2:3:3:1, put them into a quartz tube, and evacuate the quartz tube to a vacuum degree of 1×10 −3 Pa, high temperature sealed and placed in a muffle furnace, heated to 450-550°C at a rate of 5-10°C / h, and kept at this temperature for 60-100 hours to obtain the compound Pb2Ba3(BO3)3(NO3), wherein the Pb-containing compound is PbF2, PbO, Pb(NO3)2 or PbCO3; the Ba-containing compound is Ba(NO3)2, BaF2 or BaCO3; the B-containing compound is H3BO3 or B2O3; the N-containing compound is Pb(NO3)2 and Ba(NO3)2; b. Mix the compound Pb2Ba3(BO3)3(NO3) obtained in step a with flux in a molar ratio of 1:0.1-3, put them into a quartz tube, and evacuate the quartz tube to a vacuum degree of 1×10 −3 Pa, high-temperature sealed and placed in a muffle furnace, heated to 450-480°C, kept constant at this temperature for 60-120 hours, then cooled to 400°C at a rate of 1-3°C / h, and then quickly cooled to room temperature at a rate of 5-10°C / h to obtain a Pb2Ba3(BO3)3(NO3) nonlinear optical crystal, wherein the flux is H3BO3, B2O3 or PbO.

5. A use of the lead-barium-boron-nitrogen-oxygen nonlinear optical crystal as claimed in claim 3 in preparing a harmonic light output of the 1064nm fundamental frequency light output by an Nd:YAG laser for frequency doubling.

6. Use of the lead barium boron nitrogen oxide nonlinear optical crystal as claimed in claim 5 in the preparation of ultraviolet frequency-doubled light output below 532 nm.

7. Use of the lead barium boron nitrogen oxide nonlinear optical crystal as claimed in claim 3 in the preparation of a frequency doubling generator, an up or down frequency converter or an optical parametric oscillator.

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