Fluorinated guanidinium borate nonlinear optical crystal, method for preparing the same, and use thereof

Abstract

The application provides a fluorinated guanidinium borate nonlinear optical crystal and a preparation method and application thereof. The chemical formula of the crystal is [C(NH2)3]B6O9F, the molecular weight is 287.95, the crystal belongs to an orthorhombic system, the space group is Pnma, Pna 21, the cell parameter is a=7.8420(11) Å, b=15.1862(19) Å, c=8.5762(9) Å, α =90°, β =90°, γ =90°, the unit cell volume is 1021.3(2) ų, the crystal is grown by a high-temperature solution method or a flux method, the frequency doubling effect of the crystal is 0.4 times of that of KH2PO4 (KDP), the ultraviolet cutoff edge is 190 nm, the birefringence is large, the birefringence is 0.133 @ 1064 nm, and the deep ultraviolet phase matching capability is deep, the shortest matching wavelength is 196 nm, and the crystal can be applied to deep ultraviolet nonlinear optical crystals in a full solid-state laser.

Description

Technical Field

[0001] This invention relates to a guanidine fluoride borate salt [C(NH2)3]B6O9F nonlinear optical crystal, its preparation method, and its uses. Background Technology

[0002] Deep ultraviolet (wavelength < 200 nm) lasers, with their high photon energy, short wavelength, and excellent resolution, play an irreplaceable and crucial role in fields such as semiconductor lithography, high-resolution spectroscopy, laser micro-nano fabrication, and cutting-edge scientific research. Currently, the most practical and efficient technical approach to obtaining deep ultraviolet laser sources is to down-convert the frequency of infrared or visible lasers using nonlinear optical crystals.

[0003] Finding high-performance deep-ultraviolet nonlinear optical crystals is one of the major challenges in the field of optoelectronic functional materials. Such crystals must simultaneously meet three demanding and mutually restrictive performance indicators: (1) a sufficiently wide bandgap (typically >6.2 eV) to achieve high transmittance in the deep-ultraviolet band; (2) a moderate birefringence to achieve phase matching in the deep-ultraviolet band; and (3) a sufficiently large second-order nonlinear optical coefficient to ensure high frequency conversion efficiency. Traditional commercial crystals, such as KBe2BO3F2 (KBBF), can achieve deep-ultraviolet laser output, but their severe layered growth habit makes it difficult to peel off the crystal and grow it in large sizes, which limits its practical application. Therefore, developing new deep-ultraviolet nonlinear optical crystal materials that have both excellent comprehensive performance and are easy to grow is an urgent need to break through the current technical bottlenecks and promote the development of related fields.

[0004] Previous research has yielded inventions regarding guanidine tetrafluoroborate nonlinear optical crystals, their preparation methods, and applications (Patent Publication No.: CN112760717A), and compounds guanidine fluoroborate and guanidine fluoroborate nonlinear optical crystals, their preparation methods, and applications (Patent Publication No.: CN119824547A). The main difference between this invention and the aforementioned two patents is that the space group of the [C(NH2)3]B6O9F nonlinear optical crystal is... Pna 21 belongs to the orthorhombic crystal system. Furthermore, its growth habits, key growth process parameters, and linear and nonlinear optical properties differ from the former. Summary of the Invention

[0005] The purpose of this invention is to provide a guanidine fluoride borate salt nonlinear optical crystal. The crystal has the chemical formula [C(NH₂)₃]B₆O₹F, a molecular weight of 287.95, belongs to the orthorhombic crystal system, and has a space group of [missing information]. Pna21 (No. 33) does not have a center of symmetry. Its unit cell parameters are: a = 7.8420(11) Å, b = 15.1862(19) Å, c = 8.5762(9) Å, α = β = γ = 90°, and the unit cell volume is 1021.3(2) ų.

[0006] Another objective of this invention is to provide a method for preparing guanidine fluoride borate nonlinear optical crystals. This method employs a high-temperature solution method or a flux-based crystal growth method. By precisely controlling the raw material ratio, reaction temperature, holding time, and cooling procedure, single crystals with high optical quality and suitable size can be grown, with stable process and good repeatability.

[0007] One object of the present invention is to provide the use of guanidine fluoride borate salt nonlinear optical crystals.

[0008] The present invention discloses a guanidine fluoride borate salt nonlinear optical crystal with the chemical formula [C(NH2)3]B6O9F, a molecular weight of 287.95, belonging to the orthorhombic crystal system, and a space group of [missing information]. Pna 21, the unit cell parameters are: a = 7.8420(11) Å, b = 15.1862(19) Å, c = 8.5762(9) Å, α = 90°, β = 90°, γ = 90°, and the unit cell volume is 1021.3(2)ų.

[0009] The preparation method of the guanidinium fluoride nonlinear optical crystal involves growing the crystal using a high-temperature solution method or a flux method, and the specific operation is carried out according to the following steps: The high-temperature solution method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Add the aqueous solutions of [C(NH2)3]2CO3 and HBF4 to a polytetrafluoroethylene beaker at a molar ratio of 1:2 and mix. Keep the mixture at 80 ℃ for 2-3 days to obtain solid powder of [C(NH2)3]BF4. b. Mix the [C(NH2)3]BF4 solid powder obtained in step a with B2O3 at a molar ratio of 1:3, pack it into a quartz tube, evacuate to 10⁻³ Pa, seal the quartz tube, and then place the quartz tube in a muffle furnace with programmed temperature rise, heat to 280-300℃, and hold for 48-120 h. c. Cool to 30℃ to obtain a guanidine fluoride borate nonlinear optical crystal; The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Mix [C(NH2)3]2CO3 and HBF4 aqueous solution in a polytetrafluoroethylene beaker at a molar ratio of 1:2, and keep warm at 80 ℃ for 2-3 days to obtain [C(NH2)3]BF4 solid powder; b. Mix the [C(NH2)3]BF4 solid powder obtained in step a with B2O3 or H3BO3 at a molar ratio of 1:3 or 1:6, load the mixture into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and hold at 230 ℃ for 48 h to obtain [C(NH2)3]B6O9F polycrystalline powder. c. Mix the [C(NH2)3]B6O9F polycrystalline powder obtained in step b with a flux at a molar ratio of 1:1-4, load the mixture into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and heat to 240-300 ℃ and hold for 48 h. The flux is [C(NH2)3]BF4, B2O3 or H3BO3. d. Slowly cool to 30℃ to obtain a guanidine fluoride borate nonlinear optical crystal.

[0010] The guanidine fluoride borate salt nonlinear optical crystal is used in the fabrication of second, third, or fourth harmonic outputs of the 1064 nm fundamental frequency light from an Nd:YAG laser in nonlinear optical devices.

[0011] The guanidine fluoride borate salt nonlinear optical crystal is used in the fabrication of frequency multiplier generators, up / down frequency converters, or optical parametric oscillators.

[0012] Application of the guanidine fluoride borate salt nonlinear optical crystal in deep ultraviolet laser frequency conversion devices.

[0013] The method for preparing the guanidine fluoride borate nonlinear optical crystal of this invention involves obtaining a large-size guanidine fluoride borate nonlinear optical crystal. Based on the crystallographic data, the crystal blank is oriented, cut to the required angle, thickness, and cross-sectional dimensions, and the light-transmitting surface is polished, making it suitable for use as a nonlinear optical device. This crystal has a wide deep ultraviolet transmission window with an ultraviolet absorption cutoff edge of approximately 190 nm; it exhibits a high birefringence of 0.133 at a wavelength of 1064 nm; theoretical calculations show that its shortest phase-matching wavelength can reach 196 nm, and it possesses Type I phase-matching capability; its powder frequency doubling effect is approximately 0.4 times that of KH₂PO₄ (KDP). Based on these excellent properties, this crystal is suitable for converting the 1064 nm fundamental frequency light output from an Nd:YAG laser into second (532 nm), third (355 nm), or fourth (266 nm) harmonic laser light, and has clear application value in the preparation of frequency doubling generators, up / down frequency converters, optical parametric oscillators, and other deep ultraviolet band laser frequency conversion devices. Attached Figure Description

[0014] Figure 1 The experimental X-ray diffraction (XRD) pattern of the [C(NH2)3]B6O9F polycrystalline powder of this invention; Figure 2 This is a schematic diagram of the crystal structure of the guanidine fluoride borate salt nonlinear optical crystal [C(NH2)3]B6O9F of the present invention; Figure 3 This is a schematic diagram of the working principle of the nonlinear optical device made of the [C(NH2)3]B6O9F crystal of the present invention, wherein 1 is a laser, 2 is the emitted beam, 3 is the [C(NH2)3]B6O9F crystal, 4 is the emitted beam, and 5 is a filter. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to the embodiments. The following embodiments are intended to illustrate the technical solutions and effects of the present invention, and not to limit the scope of protection of the present invention. Unless otherwise specified, the raw materials and equipment used in the present invention are commercially available products. Example 1

[0016] The high-temperature solution method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 10.0 g (about 0.056 mol) of [C(NH2)3]2CO3, add 20 mL of 40% HBF4 aqueous solution, mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2-3 days to obtain [C(NH2)3]BF4 solid powder; b. Weigh 0.495 g (3 mmol) of [C(NH2)3]BF4 solid powder and 0.630 g (9 mmol) of B2O3 obtained in step a, in a molar ratio of 1:3. Mix them and place them into a clean 10×100 mm quartz tube. Evacuate the tube to 10⁻³ Pa and seal it. Place the quartz tube in a muffle furnace with a programmed temperature rise, raise the temperature to 280℃ in 12 h, and hold for 48 h. c. Cooling to 30℃ at a rate of 1.5℃ / h yields a guanidine fluoride salt nonlinear optical crystal with dimensions of 3.0 mm × 2.0 mm × 0.5 mm. Example 2

[0017] The high-temperature solution method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 10.0 g (about 0.056 mol) of [C(NH2)3]2CO3, add 20 mL of 40% HBF4 aqueous solution, mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2-3 days to obtain [C(NH2)3]BF4 solid powder; b. Weigh 4.95 g (30 mmol) of [C(NH2)3]BF4 solid powder and 6.30 g (90 mmol) of B2O3 obtained in step a, according to a molar ratio of 1:3. Mix them and put them into a clean quartz tube with a diameter of 20×150 mm. Evacuate to 10⁻³ Pa, seal the quartz tube, and then place the quartz tube in a muffle furnace with a programmed temperature rise. Heat the tube to 300 ℃ at a rate of 50 ℃ / h and hold for 120 h. c. Then, the temperature is lowered to 100℃ at a rate of 0.5℃ / h, and then lowered to room temperature at a rate of 10℃ / h to obtain a guanidine fluoride nonlinear optical crystal with dimensions of 10.0×8.0×3.0 mm³. Example 3

[0018] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 18.0 g (0.1 mol) of guanidine carbonate, add 44.0 g of 40% HBF4 solution (containing 17.6 g, 0.2 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2 days to obtain 29.6 g (0.2 mol) of [C(NH2)3]BF4 solid powder. b. Take 29.6 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 42.0 g (0.6 mol) of B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 57.8 g (0.2 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 57.8 g of the polycrystalline powder [C(NH2)3]B6O9F obtained in step b, mix it with 29.6 g (0.2 mol) of flux [C(NH2)3]BF4, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 260℃ and hold it for 48 h; d. The temperature was reduced to 30℃ at a cooling rate of 0.5℃ / h to obtain a colorless and transparent guanidine fluoride borate nonlinear optical crystal with dimensions of 5 mm × 4 mm × 2 mm. Example 4

[0019] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 9.0 g (0.05 mol) of guanidine carbonate, add 22.0 g of 40% HBF4 solution (containing 8.8 g, 0.1 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 3 days to obtain 14.8 g (0.1 mol) of [C(NH2)3]BF4 solid powder. b. Take 14.8 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 37.2 g (0.6 mol) of H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 28.9 g (0.1 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 28.9 g of the [C(NH2)3]B6O9F polycrystalline powder obtained in step b, mix it with 14.0 g (0.2 mol) of flux B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 240℃ and hold it for 48 h; d. Cooling to 30℃ at a rate of 1℃ / h, a guanidine fluoride salt nonlinear optical crystal with dimensions of 3 mm × 2 mm × 1 mm was obtained. Example 5

[0020] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 36.0 g (0.2 mol) of guanidine carbonate, add 88.0 g of 40% HBF4 solution (containing 35.2 g, 0.4 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2 days to obtain 59.2 g (0.4 mol) of [C(NH2)3]BF4 solid powder. b. Take 59.2 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 84.0 g (1.2 mol) of B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 115.6 g (0.4 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 115.6 g of the [C(NH2)3]B6O9F polycrystalline powder obtained in step b, mix it with 99.2 g (1.6 mol) of flux H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 300℃ and hold it for 48 h. d. The temperature was reduced to 30℃ at a cooling rate of 0.2℃ / h to obtain a guanidine fluoride salt nonlinear optical crystal with dimensions of 8 mm × 6 mm × 3 mm. Example 6

[0021] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 18.0 g (0.1 mol) of guanidine carbonate, add 44.0 g of 40% HBF4 solution (containing 17.6 g, 0.2 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2 days to obtain 29.6 g (0.2 mol) of [C(NH2)3]BF4 solid powder. b. Take 29.6 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 37.2 g (0.6 mol) of H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 57.8 g (0.2 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 57.8 g of the polycrystalline powder [C(NH2)3]B6O9F obtained in step b, mix it with 59.2 g (0.4 mol) of flux [C(NH2)3]BF4, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 250℃ and hold it for 48 h; d. The temperature was reduced to 30℃ at a cooling rate of 1.5℃ / h to obtain a guanidine fluoride salt nonlinear optical crystal with dimensions of 4 mm × 3 mm × 2 mm. Example 7

[0022] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 9.0 g (0.05 mol) of guanidine carbonate, add 22.0 g of 40% HBF4 solution (containing 8.8 g, 0.1 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 3 days to obtain 14.8 g (0.1 mol) of [C(NH2)3]BF4 solid powder. b. Take 14.8 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 42.0 g (0.6 mol) of B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 28.9 g (0.1 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 28.9 g of the [C(NH2)3]B6O9F polycrystalline powder obtained in step b, mix it with 7.0 g (0.1 mol) of flux B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 280℃ and hold it for 48 h. d. The temperature was reduced to 30℃ at a cooling rate of 0.8℃ / h to obtain a guanidine fluoride salt nonlinear optical crystal with dimensions of 2 mm × 2 mm × 1 mm. Example 8

[0023] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 27.0 g (0.15 mol) of guanidine carbonate, add 66.0 g of 40% HBF4 solution (containing 26.4 g, 0.3 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2 days to obtain 44.4 g (0.3 mol) of [C(NH2)3]BF4 solid powder. b. Take 44.4 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 55.8 g (0.9 mol) of H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 86.7 g (0.3 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 86.7 g of the polycrystalline powder [C(NH2)3]B6O9F obtained in step b, mix it with 133.2 g (0.9 mol) of flux [C(NH2)3]BF4, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 260℃ and hold it for 48 h; d. The temperature was reduced to 30℃ at a cooling rate of 0.3℃ / h to obtain a guanidine fluoride salt nonlinear optical crystal with dimensions of 7 mm × 5 mm × 4 mm. Example 9

[0024] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 18.0 g (0.1 mol) of guanidine carbonate, add 44.0 g of 40% HBF4 solution (containing 17.6 g, 0.2 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2 days to obtain 29.6 g (0.2 mol) of [C(NH2)3]BF4 solid powder. b. Take 29.6 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 42.0 g (0.6 mol) of B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 57.8 g (0.2 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 57.8 g of the [C(NH2)3]B6O9F polycrystalline powder obtained in step b, mix it with 24.8 g (0.4 mol) of flux H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 270℃ and hold it for 48 h. d. Cooling to 30℃ at a rate of 2℃ / h, a guanidine fluoride salt nonlinear optical crystal with dimensions of 3 mm × 2 mm × 1 mm was obtained. Example 10

[0025] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 9.0 g (0.05 mol) of guanidine carbonate, add 22.0 g of 40% HBF4 solution (containing 8.8 g, 0.1 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 3 days to obtain 14.8 g (0.1 mol) of [C(NH2)3]BF4 solid powder. b. Take 14.8 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 37.2 g (0.6 mol) of H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 28.9 g (0.1 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 28.9 g of the polycrystalline powder [C(NH2)3]B6O9F obtained in step b, mix it with 59.2 g (0.4 mol) of flux [C(NH2)3]BF4, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 240℃ and hold it for 48 h; d. Cooling to 30℃ at a rate of 0.5℃ / h, a guanidine fluoride salt nonlinear optical crystal with dimensions of 5 mm × 4 mm × 3 mm was obtained. Example 11

[0026] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 45.0 g (0.25 mol) of guanidine carbonate, add 110.0 g of 40% HBF4 solution (containing 44.0 g, 0.5 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2 days to obtain 74.0 g (0.5 mol) of [C(NH2)3]BF4 solid powder. b. Take 74.0 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 210.0 g (3.0 mol) of B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 144.5 g (0.5 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 144.5 g of the [C(NH2)3]B6O9F polycrystalline powder obtained in step b, mix it with 105.0 g (1.5 mol) of flux B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 290℃ and hold it for 48 h. d. Cooling to 30℃ at a rate of 1℃ / h, a guanidine fluoride salt nonlinear optical crystal with dimensions of 6 mm × 5 mm × 2 mm was obtained. Example 12

[0027] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 18.0 g (0.1 mol) of guanidine carbonate, add 44.0 g of 40% HBF4 solution (containing 17.6 g, 0.2 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2 days to obtain 29.6 g (0.2 mol) of [C(NH2)3]BF4 solid powder. b. Take 29.6 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 37.2 g (0.6 mol) of H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 57.8 g (0.2 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 57.8 g of the [C(NH2)3]B6O9F polycrystalline powder obtained in step b, mix it with 12.4 g (0.2 mol) of flux H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 250℃ and hold it for 48 h. d. The temperature was reduced to 30℃ at a cooling rate of 0.2℃ / h to obtain a guanidine fluoride salt nonlinear optical crystal with dimensions of 10 mm × 8 mm × 5 mm. Example 13

[0028] The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Weigh 18.0 g (0.1 mol) of guanidine carbonate, add 44.0 g of 40% HBF4 solution (containing 17.6 g, 0.2 mol of HBF4), mix in a polytetrafluoroethylene beaker, and keep warm at 80℃ for 2 days to obtain 29.6 g (0.2 mol) of [C(NH2)3]BF4 solid powder. b. Take 29.6 g of [C(NH2)3]BF4 powder obtained in step a, mix it with 42.0 g (0.6 mol) of B2O3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and keep it at 230℃ for 48 h to obtain 57.8 g (0.2 mol) of [C(NH2)3]B6O9F polycrystalline powder. c. Take 57.8 g of the [C(NH2)3]B6O9F polycrystalline powder obtained in step b, mix it with 18.6 g (0.3 mol) of flux H3BO3, put it into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat it to 265℃ and hold it for 48 h. d. The temperature was reduced to 30℃ at a cooling rate of 0.4℃ / h to obtain a guanidine fluoride salt nonlinear optical crystal with dimensions of 7 mm × 6 mm × 4 mm. Example 14

[0029] The arbitrary [C(NH2)3]B6O9F nonlinear optical crystals obtained in Examples 1-13 are processed according to matching directions, and then... Figure 3 As shown, the [C(NH2)3]B6O9F single crystal 3 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 is emitted from the Q-switched Nd:YAG laser 1 and enters the [C(NH2)3]B6O9F single crystal 3, producing green frequency-doubled light with a wavelength of 532 nm. The output intensity is approximately 0.4 times that of KDP under the same conditions.

Claims

1. A guanidine fluoride borate salt nonlinear optical crystal, characterized in that, The crystal has the chemical formula [C(NH2)3]B6O9F, a molecular weight of 287.95, belongs to the orthorhombic crystal system, and its space group is [C(NH2)3]B6O9F. Pna 21, the unit cell parameters are: a = 7.8420(11) Å, b = 15.1862(19) Å, c = 8.5762(9) Å, α = 90°, β = 90°, γ = 90°, and the unit cell volume is 1021.3(2) ų.

2. The method for preparing the guanidine fluoride borate nonlinear optical crystal as described in claim 1, characterized in that, Crystal growth is performed using the high-temperature solution method, and the specific steps are as follows: The high-temperature solution method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Add the aqueous solutions of [C(NH2)3]2CO3 and HBF4 to a polytetrafluoroethylene beaker at a molar ratio of 1:2 and mix. Keep the mixture at 80℃ for 2-3 days to obtain solid powder of [C(NH2)3]BF4. b. Mix the [C(NH2)3]BF4 solid powder obtained in step a with B2O3 or H3BO3 at a molar ratio of 1:3 or 1:6, pack the mixture into a quartz tube, evacuate to 10⁻³ Pa, seal the quartz tube, and then place the quartz tube in a muffle furnace with programmed temperature rise, raise the temperature to 280 ℃ in 12 h, and hold for 48 h. c. Then slowly cool down to 30℃ to obtain the guanidine fluoride borate salt nonlinear optical crystal; The flux method is used to prepare guanidinium fluoride nonlinear optical crystals. a. Mix [C(NH2)3]2CO3 and HBF4 aqueous solution in a polytetrafluoroethylene beaker at a molar ratio of 1:2 and keep warm at 80 ℃ for 2-3 days to obtain [C(NH2)3]BF4 solid powder; b. Mix the [C(NH2)3]BF4 solid powder obtained in step a with B2O3 or H3BO3 at a molar ratio of 1:3 or 1:6, load the mixture into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, and hold at 230 ℃ for 48 h to obtain [C(NH2)3]B6O9F polycrystalline powder. c. Mix the [C(NH2)3]B6O9F polycrystalline powder obtained in step b with a flux at a molar ratio of 1:1-4, load the mixture into a platinum crucible, place the platinum crucible in a muffle furnace with programmed temperature rise, heat to 280-300 ℃ and hold for 48 h, wherein the flux is [C(NH2)3]BF4, B2O3 or H3BO3; d. Then slowly cool down to 30℃ to obtain a guanidine fluoride borate nonlinear optical crystal.

3. The application of the guanidine fluoride borate salt nonlinear optical crystal as described in claim 1 in the fabrication of second, third, or fourth harmonic outputs of the 1064 nm fundamental frequency light from an Nd:YAG laser in nonlinear optical devices.

4. The use of the guanidine fluoride borate salt nonlinear optical crystal as described in claim 1 in the fabrication of frequency multiplier generators, up / down frequency converters, or optical parametric oscillators.

5. The use of the guanidine fluoride borate salt nonlinear optical crystal as described in claim 1 in deep ultraviolet laser frequency conversion devices.

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