Compound lead barium borate oxyfluoride and lead barium borate oxyfluoride nonlinear optical crystal, preparation method and use thereof

Abstract

This invention provides a compound, lead-barium-boron-oxy-fluorine, and a lead-barium-boron-oxy-fluorine nonlinear optical crystal, along with their preparation methods and applications. The chemical formula of the compound is Pb. 1.23 Ba 3.77 (BO3)3F, with a molecular weight of 968.05, was synthesized using solid-state synthesis or vacuum encapsulation. The chemical formula of the compound in this crystal is Pb. 1.23 Ba 3.77 (BO3)3F, with a molecular weight of 968.05, belongs to the orthorhombic crystal system and has a space group of [missing information]. C 2221, cell parameters are a =10.346(8)Å, b =14.759(11)Å, c =7.632(6)Å, α= 90° β= 90° γ = 0.5 90°, unit cell volume is 1165.4(15) Å 3 The frequency doubling effect of the crystal is about 2.8 times that of KH2PO4 (KDP), and the ultraviolet cutoff edge is about 280 nm. The crystal can be grown by melt method, high temperature melt method or vacuum encapsulation 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] This invention relates to a compound, lead, barium, boron, oxyfluorine (Pb). 1.23 Ba 3.77 (BO3)3F and lead-barium-boron-oxygen-fluorine Pb 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal, its preparation method and applications. Background Technology

[0002] Short-wavelength nonlinear optical crystals can convert near-infrared and visible lasers into short-wavelength lasers using their frequency conversion properties, which has significant application value in fields such as medicine, communications, and scientific research. Currently, the commonly used short-wavelength nonlinear optical crystals are Chinese-made crystals such as KBa2BO3F2 (KBBF), BaB2O4 (BBO), and LiB3O5 (LBO). However, these crystals suffer from drawbacks such as low birefringence and difficulty in growing large-size crystals, which limits their applications to some extent. Therefore, the preparation and synthesis of novel short-wavelength nonlinear optical crystal materials with excellent comprehensive properties is of great significance and practical value.

[0003] When designing and developing new short-wavelength nonlinear optical crystals, people hope to obtain crystals with large second-order nonlinear coefficients, wide transmission range, short cutoff edge, and moderate birefringence. Summary of the Invention

[0004] With a molecular weight of 968.05, it was prepared using solid-state synthesis or vacuum encapsulation; the chemical formula of the compound in this crystal is Pb. 1.23 Ba 3.77 (BO3)3F, with a molecular weight of 968.05, belongs to the orthorhombic crystal system, space group C2221, and cell parameters are... α = 90°, β = 90°, γ = 90°, unit cell volume is Prepared using solid-state reaction or vacuum encapsulation methods.

[0005] Another object of the present invention is to provide a lead-barium-boron-oxygen-fluorine Pb. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal, the chemical formula of which is Pb 1.23 Ba 3.77 (BO3)3F, with a molecular weight of 968.05, belongs to the orthorhombic crystal system, space group C2221, and cell parameters are... α=90°, β=90°, γ=90°.

[0006] Another objective of this invention is to provide lead-barium-boron-oxygen-fluorine Pb. 1.23 Ba 3.77The preparation methods of (BO3)3F nonlinear optical crystals include crystal growth by melt method, high-temperature melt method or vacuum encapsulation method.

[0007] Another object of the present invention is to provide lead-barium-boron-oxygen-fluorine Pb. 1.23 Ba 3.77 Applications of (BO3)3F nonlinear optical crystals.

[0008] The present invention discloses a compound, lead-barium-boron-oxyfluorine, with the chemical formula Pb. 1.23 Ba 3.77 (BO3)3F, with a molecular weight of 968.05, belongs to the orthorhombic crystal system, space group C2221, and cell parameters are... α = 90°, β = 90°, γ = 90°, unit cell volume is It is manufactured using solid-state method or vacuum encapsulation method.

[0009] The compound lead-barium-boron-oxygen-fluorine is prepared by solid-phase synthesis or vacuum encapsulation, and the specific operation is carried out according to the following steps:

[0010] The solid-phase synthesis method was used to prepare the compound lead-barium-boron-oxygen-fluorine.

[0011] The Pb-containing compound, Ba-containing compound, B-containing compound, and F-containing compound were mixed evenly in a molar ratio of Pb∶Ba∶B∶F = 1.23∶3.77∶3∶1, placed in a platinum crucible, and heated to 700-750℃ in a muffle furnace, where the temperature was maintained for 48-240 hours to obtain the compound Pb. 1.23 Ba 3.77 (BO3)3F, 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 F-containing compounds are PbF2 and BaF2.

[0012] The vacuum encapsulation method was used to prepare the compound lead-barium-boron-oxygen-fluorine.

[0013] A mixture of Pb-containing, Ba-containing, B-containing, and F-containing compounds was prepared in a molar ratio of Pb∶Ba∶B∶F = 1.23∶3.77∶3∶1. The mixture was then placed into a quartz tube, which was evacuated to a vacuum level of 1×10⁻⁶. -3 Pa was placed in a high-temperature sealed muffle furnace and heated to 650-700℃ at a rate of 5-10℃ / h, and held at that temperature for 60-120 hours to obtain compound Pb. 1.23 Ba 3.77(BO3)3F, 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 F-containing compound is PbF2 and BaF2.

[0014] A lead-barium-boron-oxygen-fluorine nonlinear optical crystal with the chemical formula Pb 1.23 Ba 3.77 (BO3)3F, with a molecular weight of 968.05, belongs to the orthorhombic crystal system, space group C2221, and cell parameters are... α = 90°, β = 90°, γ = 90°, unit cell volume is

[0015] The preparation method of the lead-barium-boron-oxygen-fluorine nonlinear optical crystal adopts the melt method, high-temperature melt method or vacuum encapsulation method to grow the crystal.

[0016] The melt growth of the lead-barium-boron-oxygen-fluorine nonlinear optical crystal is carried out according to the following steps:

[0017] a. Mix the Pb-containing compound, Ba-containing compound, B-containing compound, and F-containing compound evenly in a molar ratio of Pb∶Ba∶B∶F=1.23∶3.77∶3∶1, place the mixture in a platinum crucible, and heat it in a muffle furnace to 700-750℃. Maintain the temperature for 48-240 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F, 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 F-containing compounds are PbF2 and BaF2.

[0018] b. The compound Pb prepared in step a. 1.23 Ba 3.77 (BO3)3F was placed in a platinum crucible and then placed in a muffle furnace. The temperature was raised to 700-730℃ and held for 10-120 hours to obtain a mixed melt.

[0019] c. The mixed melt obtained in step b is slowly cooled to 650°C at a rate of 0.1-4°C / h, and then rapidly cooled to room temperature at a rate of 5-15°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0020] d. Crystal growth in the compound melt using the Czochralski method: The seed crystal obtained in step c is fixed on a seed crystal rod. The seed crystal is lowered from above the mixed melt prepared in step b. A crystal rotation of 2-10 rpm is applied through a crystal growth controller, and the seed crystal is pulled at a speed of 1-15 mm / day. Simultaneously, the temperature is reduced at a rate of 0.1-10℃ / h. After crystal growth stops, Pb is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0021] Alternatively, crystals can be grown in the compound melt using the bubble-growth method: The seed crystal obtained in step c is fixed on a seed crystal rod, and the seed crystal is lowered from above the melt obtained in step b. The temperature is lowered at a rate of 0.1-10℃ / h to allow the crystal to grow for 50-80 hours. The crystal is then slowly raised without leaving the liquid surface to continue growth. This process is repeated until crystal growth stops, at which point Pb is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0022] Alternatively, crystals can be grown in the compound melt using the crucible lowering method: place the seed crystal prepared in step c at the bottom of the crucible, and then place the compound Pb prepared in step a into the crucible. 1.23 Ba 3.77 (BO3)3F is placed in a crucible, which is then sealed. The growth furnace temperature is raised to 680-720℃ and held constant for 48-240 hours. The crucible position is adjusted to allow the seed crystal to slightly melt. The crucible is then lowered at a rate of 1-10 mm / day while maintaining the growth temperature, or the temperature is lowered to 650℃ at a rate of 2℃ / h. After growth is complete, the temperature is rapidly reduced to room temperature at a rate of 5-15℃ / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0023] The high-temperature melt method for growing lead-barium-boron-oxygen-fluorine nonlinear optical crystals is specifically carried out according to the following steps:

[0024] a. Mix the Pb-containing compound, Ba-containing compound, B-containing compound, and F-containing compound evenly in a molar ratio of Pb∶Ba∶B∶F=1.23∶3.77∶3∶1, place the mixture in a platinum crucible, and heat it in a muffle furnace to 720-750℃. Maintain the temperature for 48-240 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F polycrystalline powder, 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 F-containing compounds are PbF2 and BaF2.

[0025] b. The compound Pb obtained in step a 1.23 Ba 3.77 (BO3)3F and flux are mixed evenly at a molar ratio of 1:0.1-3, then placed in a platinum crucible and heated to 680-720℃, and held at that temperature for 10-120 hours to obtain a mixed melt; the flux is H3BO3, B2O3 or PbO.

[0026] c. Seed crystal preparation: The mixed melt obtained in step b is placed in a single crystal furnace and slowly cooled to 550℃ at a rate of 0.1-3℃ / h, then rapidly cooled to room temperature at a rate of 5-10℃ / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0027] d. Crystal growth: Fix the seed crystal obtained in step c onto the seed crystal rod, lower the seed crystal from above the mixed melt prepared in step b, apply a crystal rotation of 3-15 rpm using a crystal growth controller, and cool at a rate of 0.1-3℃ / h. After crystal growth stops, Pb is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0028] The vacuum encapsulation method for growing lead-barium-boron-oxygen-fluorine nonlinear optical crystals is specifically performed according to the following steps:

[0029] a. Mix the Pb-containing compound, Ba-containing compound, B-containing compound, and F-containing compound evenly according to the molar ratio Pb∶Ba∶B∶F=1.23∶3.77∶3∶1, and fill the mixture into a quartz tube. Evacuate the quartz tube to a vacuum degree of 1×10⁻⁶. -3 Pa was placed in a high-temperature sealed muffle furnace and heated to 670-700℃ at a rate of 5-10℃ / h, and held at that temperature for 60-120 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F, 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 F-containing compounds are PbF2 and BaF2.

[0030] b. The compound Pb obtained in step a 1.23 Ba 3.77 (BO3)3F and flux are mixed evenly at a molar ratio of 1:0.1-3, and the mixture is then placed into a quartz tube. The quartz tube is then evacuated to a vacuum level of 1×10⁻⁶. -3Pa, after being sealed at high temperature, is placed in a muffle furnace and heated to 670-700℃, held at that temperature for 60-120 hours, then cooled to 550℃ at a rate of 1-3℃ / h, and then rapidly cooled to room temperature at a rate of 5-10℃ / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal, wherein the flux is H3BO3, B2O3 or NH4H2PO4.

[0031] The lead-barium-boron-oxygen-fluorine nonlinear optical crystal is used in the preparation of second-harmonic output of the 1064nm fundamental frequency light from an Nd:YAG laser.

[0032] The use of the lead-barium-boron-oxygen-fluorine nonlinear optical crystal in the preparation of ultraviolet frequency-doubled light output below 532 nm.

[0033] The lead-barium-boron-oxygen-fluorine nonlinear optical crystal is used in the fabrication of frequency multiplier generators, up or down frequency converters, or optical parametric oscillators.

[0034] This invention discloses a method for preparing a lead-barium-boron-oxygen-fluorine nonlinear optical crystal. The containers used in the preparation process include platinum crucibles, iridium crucibles, ceramic crucibles, quartz tubes, conical flasks, and beakers. When using a quartz tube, a vacuum must be applied before sealing to prevent the quartz tube from cracking due to the volatilization of raw materials during the reaction. When using a conical flask or beaker, the container must first be cleaned with acid, then rinsed with deionized water, and finally dried.

[0035] The method for preparing a lead-barium-boron-oxygen-fluorine nonlinear optical crystal according to the present invention uses a muffle furnace or a drying oven in the preparation process.

[0036] Using the preparation method of lead-barium-boron-oxygen-fluorine nonlinear optical crystal described in this invention, Pb crystals with dimensions on the order of centimeters can be obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystals can be obtained by using large-sized crucibles or containers and extending the crystal growth period, resulting in correspondingly large-sized Pb nonlinear optical crystals. 1.23 Ba 3.77 (BO3)3F, in this Pb 1.23 Ba 3.77 (BO3)3F nonlinear optical crystals are easy to grow and are transparent without encapsulation. They have advantages such as fast growth rate, low cost, and easy acquisition of large-size crystals.

[0037] Using the preparation method of lead-barium-boron-oxygen-fluorine nonlinear optical crystal described in this invention, large-size Pb crystals are obtained. 1.23 Ba 3.77(BO3)3F nonlinear optical crystals, based on crystallographic data, are oriented into crystal blanks, cut to the required angles, thicknesses, and cross-sectional dimensions, and then polished to produce crystals suitable for use as nonlinear optical devices. This Pb... 1.23 Ba 3.77 (BO3)3F nonlinear optical crystals have advantages such as a light transmission band of up to 310nm, stable physicochemical properties, resistance to deliquescence, and ease of processing and storage. Attached Figure Description

[0038] Figure 1 The compound Pb of this invention 1.23 Ba 3.77 Powder XRD pattern of (BO3)3F;

[0039] Figure 2 Pb of the present invention 1.23 Ba 3.77 Structural diagram of (BO3)3F crystal;

[0040] Figure 3 Pb of the present invention 1.23 Ba 3.77 A schematic diagram illustrating the working principle of a nonlinear optical device fabricated from (BO3)3F crystal, where 1 represents the laser, 2 represents the emitted beam, and 3 represents Pb. 1.23 Ba 3.77 (BO3)3F crystal, 4 is the output beam, and 5 is the filter. Detailed Implementation

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

[0042] Example 1

[0043] Preparation of compounds:

[0044] According to the reaction formula: 2.46PbCO3 + 6.54Ba(NO3)2 + BaF2 + 6H3BO3 → 2Pb 1.23 Ba 3.77 The compound Pb was synthesized by solid-state reaction using the reaction (BO3)3F + 13.08NO2 + 9H2O + 3.27O2 + 2.46CO2. 1.23 Ba 3.77 (BO3)3F:

[0045] PbCO3, Ba(NO3)2, BaF2, and H3BO3 were mixed thoroughly in a molar ratio of 2.46:6.54:1:6, placed in a platinum crucible, and heated to 730°C in a muffle furnace. The mixture was held at this temperature for 48 hours to obtain the compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0046] Example 2

[0047] Preparation of compounds:

[0048] According to the reaction formula: 2.46PbO + 6.54Ba(NO3)2 + BaF2 + 6H3BO3 → 2Pb 1.23 Ba 3.77 (BO3)3F + 13.08NO2 + 9H2O + 3.27O2, compound Pb was synthesized by solid-state reaction. 1.23 Ba 3.77 (BO3)3F:

[0049] PbO, Ba(NO3)2, BaF2, and H3BO3 were mixed thoroughly in a molar ratio of 2.46:6.54:1:6, placed in a platinum crucible, and heated to 700°C in a muffle furnace. The mixture was held at this temperature for 60 hours to obtain the compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0050] Example 3

[0051] Preparation of compounds:

[0052] According to the reaction equation: PbF2 + 1.46PbCO3 + 7.54Ba(NO3)2 + 6H3BO3 → 2Pb 1.23 Ba 3.77 (BO3)3F + 1.46CO2 +

[0053] The compound Pb was synthesized by a solid-state reaction method using the reaction: 15.08NO₂ + 9H₂O + 3.77O₂. 1.23 Ba 3.77 (BO3)3F:

[0054] PbF2, PbCO3, Ba(NO3)2, and H3BO3 were mixed thoroughly in a molar ratio of 3:4:1, placed in a platinum crucible, and heated to 720°C in a muffle furnace. The mixture was held at this temperature for 120 hours to obtain the compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0055] Example 4

[0056] Preparation of compounds:

[0057] According to the reaction formula: PbF2 + 1.46Pb(NO3)2 + 7.54Ba(NO3)2 + 6H3BO3 → 2Pb 1.23 Ba 3.77 The compound Pb was synthesized by solid-state reaction method using the reaction (BO3)3F + 18NO2 + 9H2O + 4.5O2. 1.23 Ba 3.77 (BO3)3F:

[0058] PbF2, Pb(NO3)2, Ba(NO3)2, and H3BO3 were mixed thoroughly in a molar ratio of 1:1.46:7.54:6, placed in a platinum crucible, and heated to 710°C in a muffle furnace. The mixture was held at this temperature for 120 hours to obtain the compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0059] Example 5

[0060] Preparation of compounds:

[0061] According to the reaction equation: BaF2 + 6.54Ba(NO3)2 + 2.46Pb(NO3)2 + 3B2O3 → 2Pb 1.23 Ba 3.77 The compound Pb was synthesized by solid-state reaction method using the reaction (BO3)3F + 18NO2 + 4.5O2. 1.23 Ba 3.77 (BO3)3F:

[0062] BaF₂, Ba(NO₃)₂, Pb(NO₃)₂, and B₂O₃ were mixed thoroughly in a molar ratio of 1:6.54:2.46:3, placed in a platinum crucible, and heated to 685°C in a muffle furnace. The mixture was held at this temperature for 240 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0063] Example 6

[0064] Preparation of compounds:

[0065] According to the reaction formula: 2.46PbCO3 + BaF2 + 6.54BaCO3 + 3B2O3 → 2Pb 1.23 Ba 3.77 (BO3)3F + 9CO2, compound Pb was synthesized by solid-state reaction. 1.23 Ba 3.77 (BO3)3F:

[0066] PbCO3, BaF2, BaCO3, and B2O3 were mixed thoroughly in a molar ratio of 2.46:1:6.54:3, placed in a platinum crucible, and heated to 705°C in a muffle furnace. The mixture was held at this temperature for 48 hours to obtain the compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0067] Example 7

[0068] Preparation of compounds:

[0069] According to the reaction formula: 2.46PbO + BaF2 + 6.54BaCO3 + 3B2O3 → 2Pb 1.23 Ba 3.77 (BO3)3F + 5O2 + 6CO2, compound Pb was synthesized using a vacuum encapsulation method. 1.23 Ba 3.77 (BO3)3F:

[0070] PbO, BaF2, BaCO3, and B2O3 were mixed evenly in a molar ratio of 2.46:1:6.54:3 and then packed into a Φ40mm quartz tube. The quartz tube was then evacuated to a vacuum level of 1×10⁻⁶. -3 Pa, after being sealed at high temperature, was placed in a muffle furnace and heated to 670°C at a rate of 5°C / h, and held at that temperature for 72 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0071] Example 8

[0072] Preparation of compounds:

[0073] According to the reaction formula: 2.46PbO + 6.54Ba(NO3)2 + BaF2 + 3B2O3 → 2Pb 1.23 Ba 3.77 (BO3)3F + 13.08NO2 + 3.27O2, compound Pb was synthesized by vacuum encapsulation. 1.23 Ba 3.77 (BO3)3F:

[0074] PbO, Ba(NO3)2, BaF2, and B2O3 were mixed evenly in a molar ratio of 2.46:6.54:1:3 and then placed into a Φ40mm quartz tube. The quartz tube was then evacuated to a vacuum level of 1×10⁻⁶. -3 Pa, after being sealed at high temperature, was placed in a muffle furnace and heated to 710°C at a rate of 5°C / h, and held at that temperature for 80 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0075] Example 9

[0076] Preparation of compounds:

[0077] According to the reaction formula: 2.46PbO + BaF2 + 6.54BaCO3 + 3B2O3 → 2Pb 1.23 Ba 3.77 (BO3)3F + 6.54CO2, compound Pb was synthesized by vacuum encapsulation. 1.23 Ba 3.77 (BO3)3F:

[0078] PbO, BaF2, BaCO3, and B2O3 were mixed evenly in a molar ratio of 2.46:1:6.54:3 and then packed into a Φ40mm quartz tube. The quartz tube was then evacuated to a vacuum level of 1×10⁻⁶. -3 Pa, after being sealed at high temperature, was placed in a muffle furnace and heated to 670°C at a rate of 8°C / h, and held at that temperature for 100 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0079] Example 10

[0080] Preparation of compounds:

[0081] According to the reaction formula: 1.46PbO + PbF2 + 7.54BaCO3 + 3B2O3 → 2Pb 1.23 Ba 3.77 (BO3)3F + 7.54CO2, compound Pb was synthesized by vacuum encapsulation. 1.23 Ba 3.77 (BO3)3F:

[0082] PbO, PbF2, BaCO3, and B2O3 were mixed evenly in a molar ratio of 1.46:1:7.54:3 and then placed into a Φ40mm quartz tube. The quartz tube was then evacuated to a vacuum level of 1×10⁻⁶. -3 Pa, after being sealed at high temperature, was placed in a muffle furnace and heated to 700℃ at a rate of 7℃ / h, and held at that temperature for 70 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F.

[0083] Example 11

[0084] Pb grown by melt method 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0085] Compound Pb prepared according to Example 1 1.23 Ba 3.77(BO3)3F powder was placed in a platinum crucible and placed in a muffle furnace. The temperature was raised to 730°C and held for 80 hours to obtain a mixed melt.

[0086] The resulting mixed melt was slowly cooled to 650°C at a rate of 0.1°C / h, and then rapidly cooled to room temperature at a rate of 10°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0087] The crystal was grown using the Czochralski method: The seed crystal was fixed on a seed crystal rod, and the seed crystal was lowered from above the prepared mixed melt. A crystal rotation of 4 rpm was applied through a crystal growth controller, and the seed crystal was pulled at a rate of 1 mm / day. The temperature was lowered at a rate of 0.1℃ / h. After the crystal growth stopped, a Pb crystal with dimensions of 15 mm × 10 mm × 6 mm was obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0088] Example 12

[0089] Pb grown by melt method 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0090] The compound Pb prepared in Example 2 1.23 Ba 3.77 (BO3)3F was placed in a platinum crucible and then placed in a muffle furnace. The temperature was raised to 720°C and held for 10 hours to obtain a mixed melt.

[0091] The resulting mixed melt was slowly cooled to 650°C at a rate of 1°C / h, and then rapidly cooled to room temperature at a rate of 5°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0092] Crystals were grown in the compound melt using the Czochralski method: A seed crystal was fixed on a seed crystal rod, and the seed crystal was lowered from above the prepared mixed melt. A crystal rotation of 2 rpm was applied using a crystal growth controller, and the seed crystal was pulled at a rate of 4 mm / day while simultaneously cooling at a rate of 1℃ / h. After crystal growth stopped, a Pb crystal with dimensions of 11 mm × 6 mm × 2 mm was obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0093] Example 13

[0094] Pb grown by melt method 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0095] The compound Pb prepared in Example 3 1.23 Ba 3.77 (BO3)3F was placed in a platinum crucible and then placed in a muffle furnace. The temperature was raised to 715°C and held for 120 hours to obtain a mixed melt.

[0096] The resulting 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 Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0097] Crystals were grown in the compound melt using the Czochralski method: a seed crystal was fixed on a seed crystal rod, and the seed crystal was lowered from above the prepared mixed melt. A crystal rotation of 10 rpm was applied using a crystal growth controller, and the seed crystal was pulled at a rate of 15 mm / day while simultaneously cooling at a rate of 10 °C / h. After crystal growth stopped, a Pb crystal with dimensions of 12 mm × 9 mm × 4 mm was obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0098] Example 14

[0099] Pb grown by melt method 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0100] Compound Pb prepared according to Example 4 1.23 Ba 3.77 (BO3)3F powder was placed in a platinum crucible and placed in a muffle furnace. The temperature was raised to 690°C and held for 120 hours to obtain a mixed melt.

[0101] The resulting mixed melt was slowly cooled to 650°C at a rate of 1°C / h, and then rapidly cooled to room temperature at a rate of 15°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0102] Crystals were grown using the bubble-growth method: The obtained seed crystal was fixed on a seed crystal rod, and the seed crystal was lowered from above the prepared mixed melt. The temperature was lowered at a rate of 0.1℃ / h to allow the crystal to grow for 20 hours. The crystal was then slowly raised without leaving the liquid surface, and growth continued. This process was repeated 3 times to obtain Pb crystals with dimensions of 6mm × 10mm × 8mm. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0103] Example 15

[0104] Pb grown by melt method 1.23 Ba 3.77(BO3)3F nonlinear optical crystal:

[0105] The compound Pb prepared in Example 5 1.23 Ba 3.77 (BO3)3F was placed in a platinum crucible and then placed in a muffle furnace. The temperature was raised to 710°C and held for 100 hours to obtain a mixed melt.

[0106] The resulting mixed melt was slowly cooled to 650°C at a rate of 0.1°C / h, and then rapidly cooled to room temperature at a rate of 5°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0107] Crystal growth in a compound melt using the Czochralski method: The obtained seed crystal is fixed on a seed crystal rod, and the seed crystal is lowered from above the prepared melt. The temperature is lowered at a rate of 1℃ / h to allow the crystal to grow for 10 hours. The crystal is then slowly raised without leaving the liquid surface to continue growth. This process is repeated 3 times. After the crystal growth stops, a Pb crystal with dimensions of 7mm × 9mm × 6mm is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0108] Example 16

[0109] Pb grown by melt method 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0110] The compound Pb prepared in Example 6 1.23 Ba 3.77 (BO3)3F was placed in a platinum crucible and then placed in a muffle furnace. The temperature was raised to 690°C and held for 80 hours to obtain a mixed melt.

[0111] The resulting 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 Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0112] Crystal growth in a compound melt using the Czochralski method: The obtained seed crystal is fixed on a seed crystal rod, and the seed crystal is lowered from above the prepared melt. The temperature is lowered at a rate of 10℃ / h to allow the crystal to grow for 30 hours. The crystal is then slowly raised without leaving the liquid surface to continue growth. This process is repeated 3 times. After the crystal growth stops, a Pb crystal with dimensions of 8mm × 3mm × 2mm is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0113] Example 17

[0114] Pb grown by melt method 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0115] The compound Pb prepared according to Example 7 1.23 Ba 3.77 (BO3)3F powder was placed in a platinum crucible, heated to 695°C, and held at that temperature for 60 hours to obtain a mixed melt.

[0116] The resulting mixed melt was slowly cooled to 650°C at a rate of 1.5°C / h, and then rapidly cooled to room temperature at a rate of 8°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0117] Crystal growth in a compound melt using the crucible lowering method: The obtained seed crystal is placed at the bottom of the crucible, and then the compound Pb prepared in Example 7 is added. 1.23 Ba 3.77 (BO3)3F polycrystalline powder was placed in a crucible, which was then sealed. The growth furnace temperature was raised to 710℃ and held for 120 hours. The crucible position was adjusted to allow the seed crystal to slightly melt. The crucible was then lowered at a rate of 5 mm / day, and the temperature was reduced to 650℃ at a rate of 2℃ / h. After growth was completed, the temperature was rapidly reduced to room temperature at a rate of 15℃ / h, resulting in a Pb crystal with dimensions of 13 mm × 8 mm × 6 mm. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0118] Example 18

[0119] Pb grown by melt method 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0120] The compound Pb prepared in Example 4 1.23 Ba 3.77 (BO3)3F was placed in a platinum crucible and then placed in a muffle furnace. The temperature was raised to 725°C and held for 120 hours to obtain a mixed melt.

[0121] The resulting mixed melt was slowly cooled to 650°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 Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0122] Crystal growth in a compound melt using the crucible lowering method: The prepared seed crystal is placed at the bottom of the crucible, and then the prepared compound Pb is added. 1.23 Ba 3.77(BO3)3F was placed in a crucible, which was then sealed. The growth furnace temperature was raised to 730℃ and held constant for 48 hours. The crucible position was adjusted to allow the seed crystal to slightly melt. The crucible was then lowered at a rate of 1 mm / day while maintaining the growth temperature. After growth was complete, the temperature was rapidly reduced to room temperature at a rate of 5℃ / h, resulting in a Pb crystal with dimensions of 8 mm × 7 mm × 8 mm. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0123] Example 19

[0124] Pb grown by melt method 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0125] The compound Pb prepared in Example 9 1.23 Ba 3.77 (BO3)3F was placed in a platinum crucible and then placed in a muffle furnace. The temperature was raised to 730°C and held for 10 hours to obtain a mixed melt.

[0126] The resulting 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 5°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0127] Crystal growth in a compound melt using the crucible lowering method: The prepared seed crystal is placed at the bottom of the crucible, and then the prepared compound Pb is added. 1.23 Ba 3.77 (BO3)3F was placed in a crucible, which was then sealed. The growth furnace temperature was raised to 740℃ and held constant for 240 hours. The crucible position was adjusted to allow the seed crystal to slightly melt. The crucible was then lowered at a rate of 10 mm / day while maintaining the growth temperature. After growth was complete, the temperature was rapidly reduced to room temperature at a rate of 15℃ / h, resulting in a Pb crystal with dimensions of 12 mm × 7 mm × 3 mm. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal;

[0128] Example 20

[0129] High-temperature melt growth of Pb 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0130] The compound Pb prepared in Example 6 was mixed at a molar ratio of 1:0.6. 1.23 Ba 3.77(BO3)3F polycrystalline powder was mixed evenly with flux B2O3, placed in a platinum crucible, heated to 680℃, and held at that temperature for 60 hours to obtain a mixed melt.

[0131] Seed crystal preparation: The obtained mixed melt was placed in a single crystal furnace and slowly cooled to 650°C at a rate of 0.1°C / h, then rapidly cooled to room temperature at a rate of 5°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0132] Crystal growth: The obtained seed crystal is fixed on a seed crystal rod and lowered from above the prepared mixed melt. A crystal rotation of 3 rpm is applied through a crystal growth controller, and the temperature is reduced at a rate of 0.1℃ / h. After crystal growth stops, a Pb crystal with dimensions of 12mm×6mm×2mm is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0133] Example 21

[0134] High-temperature melt growth of Pb 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0135] The compound Pb obtained in Example 4 was used in a molar ratio of 1:1 1.23 Ba 3.77 (BO3)3F and flux H3BO3 are mixed evenly, then placed in a platinum crucible, heated to 670°C, and kept at that temperature for 10 hours to obtain a mixed melt.

[0136] Seed crystal preparation: The obtained mixed melt was placed in a single crystal furnace and slowly cooled to 550°C at a rate of 1°C / h, then rapidly cooled to room temperature at a rate of 8°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0137] Crystal growth: The obtained seed crystal is fixed on a seed crystal rod, and the seed crystal is lowered from above the prepared mixed melt. A crystal rotation of 8 rpm is applied through a crystal growth controller, and the temperature is reduced at a rate of 1℃ / h. After the crystal growth stops, a Pb crystal with dimensions of 9mm×3mm×2mm is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0138] Example 22

[0139] High-temperature melt growth of Pb 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0140] The compound Pb obtained in Example 8 was mixed at a molar ratio of 1:0.3. 1.23 Ba 3.77 (BO3)3F was mixed evenly with flux PbO, then placed in a platinum crucible and heated to 675°C. The mixture was kept at that temperature for 120 hours to obtain a mixed melt.

[0141] Seed crystal preparation: The obtained mixed melt was placed in a single crystal furnace and slowly cooled to 600℃ at a rate of 2℃ / h, then rapidly cooled to room temperature at a rate of 10℃ / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0142] Crystal growth: The obtained seed crystal is fixed on a seed crystal rod, and the seed crystal is lowered from above the prepared mixed melt. A crystal rotation of 10 rpm is applied through a crystal growth controller, and the temperature is reduced at a rate of 0.5℃ / h. After the crystal growth stops, a Pb crystal with dimensions of 6mm×2mm×1mm is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0143] Example 23

[0144] High-temperature melt growth of Pb 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0145] The compound Pb obtained in Example 7 was mixed at a molar ratio of 1:0.4. 1.23 Ba 3.77 (BO3)3F is mixed evenly with flux PbF2, then placed in a platinum crucible, heated to 700℃, and held at that temperature for 100 hours to obtain a mixed melt.

[0146] Seed crystal preparation: The obtained mixed melt was placed in a single crystal furnace and slowly cooled to 550°C at a rate of 2°C / h, then rapidly cooled to room temperature at a rate of 7°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal;

[0147] Crystal growth: The obtained seed crystal is fixed on a seed crystal rod, and the seed crystal is lowered from above the prepared mixed melt. A crystal rotation of 15 rpm is applied through a crystal growth controller, and the temperature is lowered at a rate of 2℃ / h. After the crystal growth stops, a Pb crystal with dimensions of 4mm×3mm×2mm is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0148] Example 24

[0149] Vacuum encapsulation method for growing Pb 1.23 Ba3.77 (BO3)3F nonlinear optical crystal:

[0150] The compound Pb prepared in Example 8 was mixed at a molar ratio of 1:0.1. 1.23 Ba 3.77 (BO3)3F and flux H3BO3 are mixed evenly and then placed into a Φ40mm quartz tube. The quartz tube is then evacuated to a vacuum level of 1×10⁻⁶. -3 Pa was sealed at high temperature and placed in a muffle furnace, heated to 685℃ and held at that temperature for 60 hours. Then, it was cooled to 550℃ at a rate of 1.5℃ / h, and then rapidly cooled to room temperature at a rate of 9℃ / h, yielding Pb with dimensions of 3mm × 2mm × 1mm. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0151] Example 25

[0152] Vacuum encapsulation method for growing Pb 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0153] The compound Pb obtained in Example 9 was mixed at a molar ratio of 1:0.5. 1.23 Ba 3.77 (BO3)3F and flux B2O3 are mixed evenly and then placed into a Φ40mm quartz tube. The quartz tube is then evacuated to a vacuum level of 1×10⁻⁶. -3 Pa was sealed at high temperature and placed in a muffle furnace, heated to 675℃ and held at that temperature for 80 hours. Then, it was cooled to 450℃ at a rate of 1℃ / h, and then rapidly cooled to room temperature at a rate of 5℃ / h, yielding Pb deposits with dimensions of 3mm × 4mm × 2mm. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0154] Example 26

[0155] Vacuum encapsulation method for growing Pb 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal:

[0156] The compound Pb obtained in Example 10 was used in a molar ratio of 1:1 1.23 Ba 3.77 (BO3)3F and flux PbO are mixed evenly and then placed into a Φ40mm quartz tube. The quartz tube is then evacuated to a vacuum level of 1×10⁻⁶. -3Pa was sealed at high temperature and placed in a muffle furnace, heated to 690℃ and held at that temperature for 100 hours. Then, it was cooled to 550℃ at a rate of 2℃ / h, and then rapidly cooled to room temperature at a rate of 7℃ / h, thus obtaining Pb with dimensions of 3mm×2mm×2mm. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal.

[0157] Example 27

[0158] Any Pb obtained in Examples 11-26 1.23 Ba 3.77 (BO3)3F nonlinear optical crystals are processed according to matching directions, and according to the attached... Figure 3 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 the Pb. 1.23 Ba 3.77 (BO3)3F single crystal 3 produces green frequency-doubled light with a wavelength of 532nm, and the output intensity is about 3 times that of KDP under the same conditions.

Claims

1. A compound lead barium boroxynifluoride characterized by The chemical formula of this compound is Pb. 1.23 Ba 3.77 (BO3)3F, with a molecular weight of 968.05, belongs to the orthorhombic crystal system and has a space group of [missing information]. C 2221, cell parameters are a =10.346(8) Å, b =14.759(11) Å, c =7.632(6) Å, α= 90° β= 90° γ= 90°, unit cell volume is 1165.4(15) Å 3 It is manufactured using solid-state method or vacuum encapsulation method.

2. A process for the preparation of the compound lead barium boroxynifluoride as claimed in claim 1, characterized in that The preparation method is either solid-state synthesis or vacuum encapsulation, and the specific operation is carried out according to the following steps: The solid-phase synthesis method was used to prepare the compound lead-barium-boron-oxygen-fluorine. The Pb-containing compound, Ba-containing compound, B-containing compound, and F-containing compound were mixed evenly in a molar ratio of Pb∶Ba∶B∶F = 1.23∶3.77∶3∶1, placed in a platinum crucible, and heated to 700-750℃ in a muffle furnace, where the temperature was maintained for 48-240 hours to obtain the compound Pb. 1.23 Ba 3.77 (BO3)3F, 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 F-containing compounds are PbF2 and BaF2. The vacuum encapsulation method was used to prepare the compound lead-barium-boron-oxygen-fluorine. A mixture of Pb-containing, Ba-containing, B-containing, and F-containing compounds was prepared in a molar ratio of Pb∶Ba∶B∶F = 1.23∶3.77∶3∶1. The mixture was then placed into a quartz tube, which was evacuated to a vacuum level of 1×10⁻⁶. −3 Pa was placed in a high-temperature sealed muffle furnace and heated to 650-700℃ at a rate of 5-10℃ / h, and held at that temperature for 60-120 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F, 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 F-containing compound is PbF2 and BaF2.

3. A lead barium oxyfluoroborate nonlinear optical crystal, characterized by The chemical formula of this crystal is Pb. 1.23 Ba 3.77 (BO3)3F, 968.05, belongs to the orthorhombic crystal system, space group is C 2221, cell parameters are a =10.346(8) Å, b =14.759(11) Å, c =7.632(6) Å, α= 90° β= 90° γ= 90°, unit cell volume is 1165.4(15) Å 3 .

4. A method of producing a lead barium oxyfluoroborate nonlinear optical crystal as claimed in claim 3, characterized by Crystals are grown using the melt method, the high-temperature melt method, or the vacuum encapsulation method. The melt growth of the lead-barium-boron-oxygen-fluorine nonlinear optical crystal is carried out according to the following steps: a. Mix the Pb-containing compound, Ba-containing compound, B-containing compound, and F-containing compound evenly in a molar ratio of Pb∶Ba∶B∶F=1.23∶3.77∶3∶1, place the mixture in a platinum crucible, and heat it in a muffle furnace to 700-750℃. Maintain the temperature for 48-240 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F, 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 F-containing compounds are PbF2 and BaF2. b. The compound Pb prepared in step a. 1.23 Ba 3.77 (BO3)3F was placed in a platinum crucible and then placed in a muffle furnace. The temperature was raised to 740-780℃ and held for 10-120 hours to obtain a mixed melt. c. The mixed melt obtained in step b is slowly cooled to 660°C at a rate of 0.1-4°C / h, and then rapidly cooled to room temperature at a rate of 5-15°C / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal; d. Crystal growth in the compound melt using the Czochralski method: The seed crystal obtained in step c is fixed on a seed crystal rod. The seed crystal is lowered from above the mixed melt prepared in step b. A crystal rotation of 2-10 rpm is applied through a crystal growth controller, and the seed crystal is pulled at a speed of 1-15 mm / day. Simultaneously, the temperature is reduced at a rate of 0.1-10℃ / h. After crystal growth stops, Pb is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal; Alternatively, crystals can be grown in the compound melt using the bubble-growth method: The seed crystal obtained in step c is fixed on a seed crystal rod, and the seed crystal is lowered from above the melt obtained in step b. The temperature is lowered at a rate of 0.1-10℃ / h to allow the crystal to grow for 50-80 hours. The crystal is then slowly raised without leaving the liquid surface to continue growth. This process is repeated until crystal growth stops, at which point Pb is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal; Alternatively, crystals can be grown in the compound melt using the crucible lowering method: place the seed crystal prepared in step c at the bottom of the crucible, and then place the compound Pb prepared in step a into the crucible. 1.23 Ba 3.77 (BO3)3F was placed in a crucible, which was then sealed. The growth furnace temperature was raised to 680-720℃ and held constant for 48-240 hours. The crucible position was adjusted to allow the seed crystal to slightly melt. The crucible was then lowered at a rate of 1-10 mm / day while maintaining the growth temperature, or the temperature was lowered to 650℃ at a rate of 2℃ / h. After growth was completed, the temperature was rapidly reduced to room temperature at a rate of 5-15℃ / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal; The high-temperature melt method for growing lead-barium-boron-oxygen-fluorine nonlinear optical crystals is specifically carried out according to the following steps: a. Mix the Pb-containing compound, Ba-containing compound, B-containing compound, and F-containing compound evenly in a molar ratio of Pb∶Ba∶B∶F=1.23∶3.77∶3∶1, place the mixture in a platinum crucible, and heat it in a muffle furnace to 690-730℃, then hold the temperature for 48-240 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F polycrystalline powder, 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 F-containing compounds are PbF2 and BaF2. b. The compound Pb obtained in step a 1.23 Ba 3.77 (BO3)3F and flux are mixed evenly at a molar ratio of 1:0.1-3, then placed in a platinum crucible and heated to 650-700℃, and kept at the temperature for 10-120 hours to obtain a mixed melt; the flux is H3BO3, B2O3 or PbO. c. Seed crystal preparation: The mixed melt obtained in step b is placed in a single crystal furnace and slowly cooled to 600℃ at a rate of 0.1-3℃ / h, then rapidly cooled to room temperature at a rate of 5-10℃ / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F seed crystal; d. Crystal growth: Fix the seed crystal obtained in step c onto the seed crystal rod, lower the seed crystal from above the mixed melt prepared in step b, apply a crystal rotation of 3-15 rpm using a crystal growth controller, and cool at a rate of 0.1-3℃ / h. After crystal growth stops, Pb is obtained. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal; The vacuum encapsulation method for growing lead-barium-boron-oxygen-fluorine nonlinear optical crystals is specifically performed according to the following steps: a. Mix the Pb-containing compound, Ba-containing compound, B-containing compound, and F-containing compound evenly according to the molar ratio Pb∶Ba∶B∶F=1.23∶3.77∶3∶1, and fill the mixture into a quartz tube. Evacuate the quartz tube to a vacuum degree of 1×10⁻⁶. −3 Pa was placed in a high-temperature sealed muffle furnace and heated to 650-700℃ at a rate of 5-10℃ / h, and held at that temperature for 60-120 hours to obtain compound Pb. 1.23 Ba 3.77 (BO3)3F, 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 F-containing compounds are PbF2 and BaF2. b. The compound Pb obtained in step a 1.23 Ba 3.77 (BO3)3F and flux are mixed evenly at a molar ratio of 1:0.1-3, and the mixture is then placed into a quartz tube. The quartz tube is then evacuated to a vacuum level of 1×10⁻⁶. −3 Pa, after being sealed at high temperature, is placed in a muffle furnace and heated to 650-670℃, held at that temperature for 60-120 hours, then cooled to 550℃ at a rate of 1-3℃ / h, and then rapidly cooled to room temperature at a rate of 5-10℃ / h to obtain Pb. 1.23 Ba 3.77 (BO3)3F nonlinear optical crystal, wherein the flux is H3BO3, B2O3 or PbO.

5. The use of the lead-barium-boron-oxygen-fluorine nonlinear optical crystal as described in claim 3 in preparing second-harmonic output of the 1064nm fundamental frequency light output by an Nd:YAG laser.

6. The use of the lead-barium-boron-oxygen-fluorine nonlinear optical crystal as described in claim 3 in the fabrication of a frequency multiplier, an up or down frequency converter, or an optical parametric oscillator.

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