Compound guanidine difluorophosphate and guanidine difluorophosphate nonlinear optical crystal as well as preparation method and use thereof

Abstract

The present invention provides a compound guanidine difluorophosphate and a guanidine difluorophosphate nonlinear optical crystal, as well as a preparation method and use thereof. The chemical formula of the compound is C(NH2)3PO2F2, the molecular weight is 161.06, and the crystal is prepared by a room temperature solution method. The chemical formula of the crystal is C(NH2)3PO2F2, the molecular weight is 161.06, and the crystal belongs to the orthorhombic system with a space group of P mn21, the unit cell parameters are a=8.159(3), b=4.9477(17), c=7.945(3), α=90°, β=90°, γ=90°, and the unit cell volume is 315.35 Å 3 The crystal is grown by room temperature solution method or hydrothermal method. The crystal has good chemical stability and can be used as a short-wavelength nonlinear optical crystal in all-solid-state lasers.

Description

Technical Field

[0001] The present invention relates to a compound guanidine difluorophosphate C(NH2)3PO2F2 and a nonlinear optical crystal of guanidine difluorophosphate C(NH2)3PO2F2, as well as a preparation method and application thereof. Background Art

[0002] Ultraviolet lasers, due to their high energy and beam quality, have important applications in lithography, micromachining, optoelectronics, and many other fields. Frequency conversion via nonlinear optical crystals is one of the most effective methods for generating ultraviolet laser light. To date, the only practical short-wavelength nonlinear optical crystals developed by Chinese scientists are β-BaB2O4, LiB3O5, and KBe2BO3F2. However, due to limitations in their crystal structure and other properties, they remain elusive for industrialization to meet the demands of scientific and technological development. β-BaB2O4 crystals have a high birefringence, resulting in a small acceptance angle for phase matching and a large walk-off angle, leading to low frequency-doubled conversion efficiency and poor spot quality when generating laser output. LiB3O5 crystals have a low birefringence, resulting in a minimum phase-matching wavelength of only 276 nm, making direct frequency-doubled generation of 266 nm or shorter wavelengths impossible. KBe2BO3F2 crystals, constrained by intrinsic defects (weak interlayer forces), exhibit a severe layered growth habit, making large-scale crystal growth difficult. Therefore, the preparation and synthesis of new short-wavelength nonlinear optical crystal materials with excellent comprehensive performance is of great significance and practical value. Summary of the Invention

[0003] The present invention aims to provide a compound guanidine difluorophosphate, the chemical formula of the compound is C(NH2)3PO2F2, the molecular weight is 161.06, and the compound is prepared by a room temperature solution method.

[0004] Another object of the present invention is to provide a nonlinear optical crystal of difluoroguanidine phosphate C(NH2)3PO2F2, which has a molecular weight of 161.06, belongs to the orthorhombic system, has a space group of Pmn21, and has unit cell parameters of =8.159(3), b=4.9477(17), c=7.945(3), α=90°, β=90°, γ=90°, and a unit cell volume of Another object of the present invention is to provide a method for preparing difluoroguanidine phosphate C(NH2)3PO2F2 nonlinear optical crystals, using a room temperature solution method or a hydrothermal method to grow the crystals.

[0005] Another object of the present invention is to provide a use of guanidine difluorophosphate C(NH2)3PO2F2 nonlinear optical crystal.

[0006] The compound of the present invention, guanidine difluorophosphate, has a chemical formula of C(NH2)3PO2F2, a molecular weight of 161.06, and is prepared by a room temperature solution method.

[0007] The preparation method of the compound guanidine difluorophosphate adopts a room temperature solution method, and the specific operation is carried out according to the following steps:

[0008] A C(NH2)3 compound and a P-containing compound are uniformly mixed in a molar ratio of C(NH2)3:P=1:1, placed in a clean plastic container, added with 20-100 mL of deionized water, and then ultrasonically treated to fully mix and dissolve, filtered to obtain a mixed solution, and then sealed with plastic wrap, pierced the seal with several small holes, and allowed to stand at a temperature of 40-50°C for 5-20 days to obtain a compound C(NH2)3PO2F2, wherein the C(NH2)3 compound is C(NH2)3HF2, C(NH2)3Cl, C(NH2)3F, [C(NH2)3]2CO3, and C(NH2)3HCO3; and the P-containing compound is HPO2F2, LiPO2F2, and KPO2F2.

[0009] A nonlinear optical crystal of guanidine difluorophosphate, having a chemical formula of C(NH2)3PO2F2, a molecular weight of 161.06, belongs to the orthorhombic crystal system, has a space group of Pmn21, unit cell parameters of =8.159(3), b=4.9477(17), c=7.945(3), α=90°, β=90°, γ=90°, and a unit cell volume of

[0010] The method for preparing the guanidine difluorophosphate nonlinear optical crystal adopts a room temperature solution method or a hydrothermal method to grow the crystal;

[0011] The room temperature solution method for growing guanidine difluorophosphate nonlinear optical crystals is specifically performed in the following steps:

[0012] a. Mix the C(NH2)3 compound and the P-containing compound in a molar ratio of C(NH2)3:P=1:1, put them into a clean plastic container, add 20-100 mL of deionized water, and then ultrasonicate them to fully mix and dissolve them. Filter and obtain a mixed solution, wherein the C(NH2)3 compound is C(NH2)3HF2, C(NH2)3Cl, C(NH2)3F, [C(NH2)3]2CO3, and C(NH2)3HCO3; the P-containing compound is HPO2F2, LiPO2F2, and KPO2F2.

[0013] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 40-50°C for 5-20 days;

[0014] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0015] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it stand and grow at a temperature of 40-50°C for 10-30 days to obtain C(NH2)3PO2F2 nonlinear optical crystal.

[0016] The hydrothermal method for growing guanidine difluorophosphate nonlinear optical crystals is specifically performed in the following steps:

[0017] a. Place a C(NH2)3 compound and a P-containing compound in a polytetrafluoroethylene beaker at a molar ratio of C(NH2)3:P=1:1, mix them evenly, put them in a clean plastic container, add 20-65 mL of water, stir and mix evenly, filter to obtain a mixed solution, wherein the C(NH2)3 compound is C(NH2)3HF2, C(NH2)3Cl, C(NH2)3F, [C(NH2)3]2CO3, C(NH2)3HCO3; and the P-containing compound is HPO2F2, LiPO2F2, or KPO2F2;

[0018] b. Transfer the mixed solution obtained in step a into the polytetrafluoroethylene liner of a 23 ml autoclave, add deionized water as the solvent, and tighten and seal the opening of the autoclave;

[0019] c. Place the autoclave in step b in a thermostat and heat the temperature to 220°C at a rate of 20°C / h, maintain the temperature for 24 hours, and then cool it down to room temperature at a rate of 2°C / h;

[0020] d. Open the high-pressure reactor and obtain millimeter-sized C(NH2)3PO2F2 nonlinear optical crystals in a colorless clear solution.

[0021] The difluoroguanidine diphosphate nonlinear optical crystal is used in preparing 1064nm fundamental frequency light output by an Nd:YAG laser for frequency doubling and frequency tripling harmonic light output.

[0022] The difluoroguanidine phosphate nonlinear optical crystal is used in preparing short-wavelength frequency-doubled light outputs of 266 nm and 355 nm.

[0023] The guanidine difluorophosphate nonlinear optical crystal is used in preparing a frequency doubling generator, an up- or down-frequency converter or an optical parametric oscillator.

[0024] The present invention discloses a method for preparing guanidine difluorophosphate nonlinear optical crystals. The container used in the preparation process is a plastic cup lined with a polytetrafluoroethylene (PTFE) liner or a stainless steel-lined hydrothermal autoclave equipped with a platinum sleeve. When using a plastic cup, the container must first be cleaned with acid, rinsed with deionized water, and air-dried.

[0025] The preparation method of the guanidine difluorophosphate nonlinear optical crystal described in the present invention is adopted to obtain a C(NH2)3PO2F2 nonlinear optical crystal with a size of millimeter level. By using a large-sized container and extending the growth period of the crystal, a corresponding large-sized nonlinear optical crystal C(NH2)3PO2F2 can be obtained. During the growth of the C(NH2)3PO2F2 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.

[0026] The large-sized C(NH2)3PO2F2 nonlinear optical crystal obtained by the preparation method of the difluoroguanidine phosphate nonlinear optical crystal of the present invention can be used as a nonlinear optical device by orienting the crystal blank according to the crystallographic data of the crystal, cutting the crystal according to the required angle, thickness and cross-sectional size, and polishing the light-transmitting surface of the crystal. 2非 Linear optical crystals have the advantages of stable physical and chemical properties, not easy to deliquesce, easy to process and store, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the XRD spectrum of the compound C(NH2)3PO2F2 powder of the present invention;

[0028] Figure 2 This is a structural diagram of the C(NH2)3PO2F2 crystal of the present invention;

[0029] Figure 3 This is a working principle diagram of the nonlinear optical device made of C(NH2)3PO2F2 crystal of the present invention, where 1 is the laser, 2 is the emitted light beam, 3 is the C(NH2)3PO2F2 crystal, 4 is the output light beam, and 5 is the filter. DETAILED DESCRIPTION

[0030] The present invention is further described below with reference to the following examples. It should be noted that the examples given 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. The raw materials and equipment used in the present invention, unless otherwise specified, are commercially available.

[0031] Example 1

[0032] According to the reaction formula: C(NH2)3F+LiPO2F2→C(NH2)3PO2F2+LiF, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0033] C(NH2)3F and LiPO2F2 were mixed evenly in a molar ratio of 1:1 and placed in a clean plastic container. 80 mL of deionized water was added, followed by ultrasonic treatment to fully mix and dissolve the mixture. The mixture was filtered to obtain a mixed solution, and then sealed with plastic wrap. Several small holes were pierced in the seal, and the mixture was allowed to stand at 45°C for 15 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0034] Example 2

[0035] According to the reaction formula: C(NH2)3HF2+LiPO2F2→C(NH2)3PO2F2+LiHF2, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0036] C(NH2)3HF2 and LiPO2F2 were mixed evenly in a molar ratio of 1:1 and placed in a clean plastic container. 60 mL of deionized water was added, followed by ultrasonic treatment for thorough mixing and dissolution. The mixed solution was filtered to obtain a mixed solution. The container was then sealed with plastic wrap, and several small holes were pierced in the seal. The container was allowed to stand at 40°C for 20 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0037] Example 3

[0038] According to the reaction formula: C(NH2)3HF2+HPO2F2→C(NH2)3PO2F2+2HF, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0039] C(NH2)3HF2 and HPO2F2 were mixed evenly in a molar ratio of 1:1 and placed in a clean plastic container. 50 mL of deionized water was added, followed by ultrasonic treatment to fully mix and dissolve the mixture. The mixture was filtered to obtain a mixed solution, and the container was sealed with plastic wrap. Several small holes were pierced in the seal, and the container was allowed to stand at 42°C for 10 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0040] Example 4

[0041] According to the reaction formula: C(NH2)3F+HPO2F2→C(NH2)3PO2F2+HF, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0042] C(NH2)3F and HPO2F2 were mixed evenly in a molar ratio of 1:1 and placed in a clean plastic container. 20 mL of deionized water was added, followed by ultrasonic treatment to fully mix and dissolve the mixture. The mixture was filtered to obtain a mixed solution, which was then sealed with plastic wrap. Several small holes were pierced in the seal, and the mixture was allowed to stand at 50°C for 5 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0043] Example 5

[0044] According to the reaction formula: C(NH2)3Cl+LiPO2F2→C(NH2)3PO2F2+LiCl, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0045] C(NH2)3Cl and LiPO2F2 were mixed evenly in a molar ratio of 1:1 in a clean plastic container, 50 mL of deionized water was added, and then ultrasonic treatment was performed to fully mix and dissolve the mixture. The mixture was filtered to obtain a mixed solution, and the container was sealed with plastic wrap. Several small holes were pierced in the seal, and the container was allowed to stand at 44°C for 13 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0046] Example 6

[0047] According to the reaction formula: C(NH2)3Cl+HPO2F2→C(NH2)3PO2F2+HCl, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0048] C(NH2)3Cl and HPO2F2 were mixed evenly in a molar ratio of 1:1, placed in a clean plastic container, and 20 mL of deionized water was added. The mixture was then ultrasonically treated to fully mix and dissolve. The mixture was filtered to obtain a mixed solution. The container was then sealed with plastic wrap, and several small holes were pierced in the seal. The container was allowed to stand at 50°C for 5 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0049] Example 7

[0050] According to the reaction formula: C(NH2)3F+HPO2F2+→C(NH2)3PO2F2+HF, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0051] C(NH2)3F and HPO2F2 were mixed evenly in a molar ratio of 1:1, placed in a clean plastic container, and 50 mL of deionized water was added. The mixture was then ultrasonically treated to fully mix and dissolve. The mixture was filtered to obtain a mixed solution. The container was then sealed with plastic wrap, and several small holes were pierced in the seal. The container was allowed to stand at 40°C for 10 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0052] Example 8

[0053] According to the reaction formula: [C(NH2)3]2CO3+2LiPO2F2+2HF→2C(NH2)3PO2F2+2LiF+H2O+CO2, the compound 2C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0054] [C(NH2)3]2CO3, LiPO2F2, and HF were mixed evenly in a molar ratio of 1:2:2, placed in a clean plastic container, and 80 mL of deionized water was added. The mixture was then ultrasonically treated to ensure thorough mixing and dissolution. The mixture was filtered to obtain a mixed solution, and then sealed with plastic wrap. Several small holes were pierced in the seal, and the mixture was allowed to stand at 45°C for 20 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0055] Example 9

[0056] According to the reaction formula: [C(NH2)3]2CO3+2HPO2F2→2C(NH2)3PO2F2+H2O+CO2, the compound C(NH2)3PO2F2 was synthesized by the room temperature solution method:

[0057] [C(NH2)3]2CO3 and HPO2F2 were mixed evenly in a molar ratio of 1:2, placed in a clean plastic container, and 100 mL of deionized water was added. The mixture was then ultrasonically treated to fully mix and dissolve, and filtered to obtain a mixed solution. The container was then sealed with plastic wrap, and several small holes were pierced in the seal. The container was allowed to stand at 40°C for 20 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0058] Example 10

[0059] According to the reaction formula: C(NH2)3HCO3+HPO2F2→C(NH2)3PO2F2+H2O+CO2, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0060] C(NH2)3HCO3 and HPO2F2 were mixed evenly in a molar ratio of 1:1, placed in a clean plastic container, added with 70 mL of deionized water, and then ultrasonicated to fully mix and dissolve. The mixture was filtered to obtain a mixed solution, and then sealed with plastic wrap, pierced with several small holes in the seal, and allowed to stand at 41°C for 18 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0061] Example 11

[0062] According to the reaction formula: C(NH2)3HCO3+LiPO2F2+HF→C(NH2)3PO2F2+LiF+H2O+CO2, the compound C(NH2)3PO2F2 was synthesized by room temperature solution method:

[0063] C(NH2)3HCO3, HPO2F2, and HF were mixed evenly in a molar ratio of 1:1:1, placed in a clean plastic container, and 70 mL of deionized water was added. The mixture was then ultrasonically treated to allow for thorough mixing and dissolution. The mixture was filtered to obtain a mixed solution, which was then sealed with plastic wrap. Several small holes were pierced in the seal, and the solution was allowed to stand at 43°C for 18 days to obtain a polycrystalline powder of the compound C(NH2)3PO2F2.

[0064] Example 12

[0065] According to the reaction formula: C(NH2)3HF2+LiPO2F2→C(NH2)3PO2F2+LiHF2, the room temperature aqueous solution method was used to grow C(NH2)3PO2F2 nonlinear optical crystals:

[0066] a. Mix C(NH2)3HF2 and LiPO2F2 in a molar ratio of 1:1, place in a clean plastic container, add 60 mL of deionized water, and then ultrasonicate to fully mix and dissolve, and filter to obtain a mixed solution;

[0067] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 40°C for 20 days;

[0068] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0069] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it stand and grow at 40°C for 30 days to obtain a 4mm×3mm×1mm C(NH2)3PO2F2 nonlinear optical crystal.

[0070] Example 13

[0071] According to the reaction formula: C(NH2)3F+LiPO2F2→C(NH2)3PO2F2+LiF, the room temperature aqueous solution method was used to grow C(NH2)3PO2F2 nonlinear optical crystals:

[0072] a. Mix C(NH2)3F and LiPO2F2 in a molar ratio of 1:1, place in a clean plastic container, add 80 mL of deionized water, and then ultrasonicate to fully mix and dissolve, and filter with filter paper to obtain a mixed solution;

[0073] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 45°C for 15 days;

[0074] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0075] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it grow at 45°C for 12 days to obtain a 4mm×2mm×2mm C(NH2)3PO2F2 nonlinear optical crystal.

[0076] Example 14

[0077] According to the reaction formula: C(NH2)3HF2+HPO2F2→C(NH2)3PO2F2+2HF, the room temperature aqueous solution method was used to grow C(NH2)3PO2F2 nonlinear optical crystals:

[0078] a. Mix C(NH2)3HF2 and HPO2F2 in a molar ratio of 1:1, place in a clean plastic container, add 50 mL of deionized water, and then ultrasonicate to fully mix and dissolve, and filter to obtain a mixed solution;

[0079] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 40°C for 10 days;

[0080] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0081] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it stand and grow at a temperature of 45°C for 20 days to obtain a 3mm×2mm×1mm C(NH2)3PO2F2 nonlinear optical crystal.

[0082] Example 15

[0083] According to the reaction formula: C(NH2)3F+HPO2F2→C(NH2)3PO2F2+HF, the room temperature aqueous solution method was used to grow C(NH2)3PO2F2 nonlinear optical crystals:

[0084] a. Mix C(NH2)3F and HPO2F2 in a molar ratio of 1:1, place in a clean plastic container, add 20 mL of deionized water, and then ultrasonicate to fully mix and dissolve, filter to obtain a mixed solution.

[0085] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 50°C for 5 days;

[0086] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0087] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it stand and grow at a temperature of 50°C for 10 days to obtain a 4mm×3mm×3mm C(NH2)3PO2F2 nonlinear optical crystal.

[0088] Example 16

[0089] According to the reaction formula: C(NH2)3Cl+HPO2F2→C(NH2)3PO2F2+HCl, the room temperature solution method is used to grow C(NH2)3PO2F2 nonlinear optical crystal:

[0090] a. Mix C(NH2)3Cl and HPO2F2 in a molar ratio of 1:1, place in a clean plastic container, add 20 mL of deionized water, and then ultrasonicate to fully mix and dissolve, and filter to obtain a mixed solution;

[0091] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 50°C for 5 days;

[0092] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0093] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it stand for 10 days at a temperature of 50°C to obtain a 3mm×2mm×1mm C(NH2)3PO2F2 nonlinear optical crystal.

[0094] Example 17

[0095] According to the reaction formula: [C(NH2)3]2CO3+2LiPO2F2+2HF→2C(NH2)3PO2F2+2LiF+H2O+CO2, the C(NH2)3PO2F2 nonlinear optical crystal was grown by room temperature solution method:

[0096] a. Mix [C(NH2)3]2CO3, LiPO2F2, and HF in a molar ratio of 1:2:2, place in a clean plastic container, add 80 mL of deionized water, and then ultrasonicate to fully mix and dissolve, and filter to obtain a mixed solution;

[0097] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 45°C for 20 days;

[0098] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0099] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it stand and grow at a temperature of 45°C for 20 days to obtain a 4mm×2mm×2mm C(NH2)3PO2F2 nonlinear optical crystal.

[0100] Example 18

[0101] According to the reaction formula: [C(NH2)3]2CO3+2HPO2F2→2C(NH2)3PO2F2+H2O+CO2, the C(NH2)3PO2F2 nonlinear optical crystal was grown by room temperature solution method:

[0102] a. Mix [C(NH2)3]2CO3 and HPO2F2 in a molar ratio of 1:2, place in a clean plastic container, add 100 mL of deionized water, and then ultrasonicate to fully mix and dissolve, filter to obtain a mixed solution;

[0103] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 40°C for 20 days;

[0104] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0105] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it stand and grow at 40°C for 30 days to obtain a 3mm×2mm×2mm C(NH2)3PO2F2 nonlinear optical crystal.

[0106] Example 19

[0107] According to the reaction formula: C(NH2)3HCO3+HPO2F2+→C(NH2)3PO2F2+H2O+CO2, the C(NH2)3PO2F2 nonlinear optical crystal was grown by room temperature solution method:

[0108] a. Mix C(NH2)3HCO3 and HPO2F2 in a molar ratio of 1:1, place in a clean plastic container, add 70 mL of deionized water, and then ultrasonicate to fully mix and dissolve, and filter to obtain a mixed solution;

[0109] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 41°C for 18 days;

[0110] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0111] d. Select the seed crystal with better quality from step c, suspend it in the mixed solution prepared in step b, and let it grow at 41°C for 18 days to obtain a 4 mm × 3 mm × 3 mm C(NH2)3PO2F2 nonlinear optical crystal.

[0112] Example 20

[0113] According to the reaction formula: C(NH2)3HCO3+LiPO2F2+HF→C(NH2)3PO2F2+LiF+H2O+CO2, the C(NH2)3PO2F2 nonlinear optical crystal was grown by room temperature solution method:

[0114] a. Mix C(NH2)3HCO3, LiPO2F2, and HF in a molar ratio of 1:1:1, place in a clean plastic container, add 80 mL of deionized water, and then ultrasonicate to fully mix and dissolve, and filter to obtain a mixed solution;

[0115] b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 43°C for 16 days;

[0116] c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals;

[0117] d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it grow at 43°C for 16 days to obtain a 3 mm × 2 mm × 2 mm C(NH2)3PO2F2 nonlinear optical crystal.

[0118] Example 21

[0119] According to the reaction formula: C(NH2)3HF2+LiPO2F2→C(NH2)3PO2F2+LiHF2, the C(NH2)3PO2F2 nonlinear optical crystal is grown by hydrothermal method:

[0120] a. Place C(NH2)3HF2 and LiPO2F2 in a polytetrafluoroethylene beaker at a molar ratio of 1:1 and mix well. Place the mixture in a clean plastic container, add 20 mL of water, stir and mix well, and filter to obtain a mixed solution.

[0121] b. Transfer the mixed solution obtained in step a into the polytetrafluoroethylene liner of a 23 ml autoclave, add deionized water as the solvent, and tighten and seal the opening of the autoclave;

[0122] c. Place the autoclave in step b in a thermostat and heat the temperature to 220°C at a rate of 20°C / h, maintain the temperature for 24 hours, and then cool it down to room temperature at a rate of 2°C / h;

[0123] d. Open the high-pressure reactor and obtain a 0.7 mm × 0.4 mm × 0.3 mm C(NH2)3PO2F2 nonlinear optical crystal in a colorless clear solution.

[0124] Example 22

[0125] According to the reaction formula: C(NH2)3HF2+LiPO2F2→C(NH2)3PO2F2+LiHF2, the C(NH2)3PO2F2 nonlinear optical crystal is grown by hydrothermal method:

[0126] a. Place C(NH2)3HF2 and LiPO2F2 in a polytetrafluoroethylene beaker at a molar ratio of 1:1 and mix well. Place the mixture in a clean plastic container, add 30 mL of water, stir and mix well, and filter to obtain a mixed solution.

[0127] b, the mixed solution obtained in step a was transferred to a 23ml polytetrafluoroethylene-lined autoclave, deionized water was added as a solvent, and the mouth of the reactor was tightly sealed.

[0128] c. Place the autoclave in step b in a thermostat and heat the temperature to 220°C at a rate of 20°C / h, maintain the temperature for 24 hours, and then cool it down to room temperature at a rate of 2°C / h;

[0129] d. Open the high-pressure reactor and obtain a 0.9 mm × 0.5 mm × 0.4 mm C(NH2)3PO2F2 nonlinear optical crystal in a colorless clear solution.

[0130] Example 23

[0131] According to the reaction formula: [C(NH2)3]2CO3+2HPO2F2→2C(NH2)3PO2F2+H2O+CO2, the C(NH2)3PO2F2 nonlinear optical crystal is grown by hydrothermal method:

[0132] a. Mix [C(NH2)3]2CO3 and HPO2F2 in a PTFE beaker at a molar ratio of 1:2, place in a clean plastic container, add 40 mL of water, stir and mix, and filter to obtain a mixed solution;

[0133] b. Transfer the mixed solution obtained in step a into the polytetrafluoroethylene liner of a 23 ml autoclave, add deionized water as the solvent, and tighten and seal the opening of the autoclave;

[0134] c. Place the autoclave in step b in a thermostat and heat the temperature to 220°C at a rate of 20°C / h, maintain the temperature for 24 hours, and then cool it down to room temperature at a rate of 2°C / h;

[0135] d. Open the high-pressure reactor and obtain a 1 mm × 0.7 mm × 0.5 mm C(NH2)3PO2F2 nonlinear optical crystal in a colorless clear solution.

[0136] Example 24

[0137] According to the reaction formula: C(NH2)3HCO3+LiPO2F2+HF→C(NH2)3PO2F2+LiF+H2O+CO2, the C(NH2)3PO2F2 nonlinear optical crystal is grown by hydrothermal method:

[0138] a. Place C(NH2)3HCO3, LiPO2F2, and HF in a polytetrafluoroethylene beaker at a molar ratio of 1:1:1 and mix well. Place the mixture in a clean plastic container, add 65 mL of water, stir to mix well, and filter to obtain a mixed solution.

[0139] b. Transfer the mixed solution obtained in step a into the polytetrafluoroethylene liner of a 23 ml autoclave, add deionized water as the solvent, and tighten and seal the opening of the autoclave;

[0140] c. Place the autoclave in step b in a thermostat and heat the temperature to 220°C at a rate of 20°C / h, maintain the temperature for 24 hours, and then cool it down to room temperature at a rate of 2°C / h;

[0141] d. Open the high-pressure reactor and obtain a 1 mm × 0.7 mm × 0.6 mm C(NH2)3PO2F2 nonlinear optical crystal in a colorless clear solution.

[0142] Example 25

[0143] According to the reaction formula: C(NH2)3Cl+HPO2F2→C(NH2)3PO2F2+HCl, the C(NH2)3PO2F2 nonlinear optical crystal is grown by hydrothermal method:

[0144] a. Mix C(NH2)3Cl and HPO2F2 in a molar ratio of 1:1, place in a polytetrafluoroethylene beaker and mix evenly, put into a clean plastic container, add 20 mL of water, stir and mix evenly, and filter to obtain a mixed solution;

[0145] b. Transfer the mixed solution obtained in step a into the polytetrafluoroethylene liner of a 23 ml autoclave, add deionized water as the solvent, and tighten and seal the opening of the autoclave;

[0146] c. Place the autoclave in step b in a thermostat and heat the temperature to 220°C at a rate of 20°C / h, maintain the temperature for 24 hours, and then cool it down to room temperature at a rate of 2°C / h;

[0147] d. Open the high-pressure reactor and obtain a 3 mm × 1.2 mm × 5 mm C(NH2)3PO2F2 nonlinear optical crystal in a colorless clear solution.

[0148] Example 26

[0149] According to the reaction formula: C(NH2)3F+HPO2F2→C(NH2)3PO2F2+HF, the C(NH2)3PO2F2 nonlinear optical crystal is grown by hydrothermal method:

[0150] a. Mix C(NH2)3F and HPO2F2 in a molar ratio of 1:1, place in a polytetrafluoroethylene beaker and mix evenly, put into a clean plastic container, add 50 mL of water, stir and mix evenly, and filter to obtain a mixed solution;

[0151] b. Transfer the mixed solution obtained in step a into the polytetrafluoroethylene liner of a 23 ml autoclave, add deionized water as the solvent, and tighten and seal the opening of the autoclave;

[0152] c. Place the autoclave in step b in a thermostat and heat the temperature to 220°C at a rate of 20°C / h, maintain the temperature for 24 hours, and then cool it down to room temperature at a rate of 2°C / h;

[0153] d. Open the high-pressure reactor and obtain a 5 mm × 4 mm × 6 mm C(NH2)3PO2F2 nonlinear optical crystal in a colorless clear solution.

[0154] Example 27

[0155] Any C(NH2)3PO2F2 crystal obtained in Examples 12-26 is processed in a 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 C(NH2)3PO2F2 single crystal 3, generating green frequency-doubled light with a wavelength of 532nm. The output intensity is about 1.5 times that of KDP under the same conditions.

Claims

1. A guanidine difluorophosphate nonlinear optical crystal, characterized in that The chemical formula of the crystal is C(NH2)3PO2F2, the molecular weight is 161.06, it belongs to the orthorhombic system, and the space group is P mn21, unit cell parameters are a = 8.159(3), b = 4.9477(17), c = 7.945(3), α = 90°, β = 90°, γ = 90°, and unit cell volume is 315.35Å 3 .

2. The method for preparing the guanidine difluorophosphate nonlinear optical crystal according to claim 1, wherein Crystals are grown using a room temperature solution method or a hydrothermal method; The specific operation of growing guanidine difluorophosphate nonlinear optical crystal by room temperature solution method is carried out in the following steps: a. Mix a C(NH2)3 compound and a P-containing compound in a molar ratio of C(NH2)3:P=1:1, place the mixture in a clean plastic container, add 20-100 mL of deionized water, and then ultrasonicate to fully mix and dissolve the mixture, and filter to obtain a mixed solution, wherein the C(NH2)3 compound is C(NH2)3HF2, C(NH2)3Cl, C(NH2)3F, [C(NH2)3]2CO3, or C(NH2)3HCO3; and the P-containing compound is HPO2F2, LiPO2F2, or KPO2F2; b. Place the mixed solution obtained in step a in a clean plastic container, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, poke several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at 40-50°C for 5-20 days; c. Waiting for the solution in step b to grow crystal particles at the bottom of the container until the crystal particle size no longer changes significantly, thereby obtaining seed crystals; d. Select the seed crystal with better quality in step c, suspend it in the mixed solution prepared in step b, and let it stand and grow at a temperature of 40-50° C. for 10-30 days to obtain a C(NH2)3PO2F2 nonlinear optical crystal; The hydrothermal method for growing guanidine difluorophosphate nonlinear optical crystals is specifically performed in the following steps: a. Place a C(NH2)3 compound and a P-containing compound in a polytetrafluoroethylene beaker at a molar ratio of C(NH2)3:P=1:1, mix them evenly, put them in a clean plastic container, add 20-65 mL of water, stir and mix evenly, filter to obtain a mixed solution, wherein the C(NH2)3 compound is C(NH2)3HF2, C(NH2)3Cl, C(NH2)3F, [C(NH2)3]2CO3, C(NH2)3HCO3; and the P-containing compound is HPO2F2, LiPO2F2, or KPO2F2; b. Transfer the mixed solution obtained in step a into the polytetrafluoroethylene liner of a 23 ml autoclave, add deionized water as the solvent, and tighten and seal the opening of the autoclave; c. Place the autoclave in step b in a thermostat and heat it to 220°C at a rate of 20°C / h, keep the temperature constant for 24 hours, and then cool it down to room temperature at a rate of 2°C / h; d. Open the high-pressure reactor and obtain millimeter-sized C(NH2)3PO2F2 nonlinear optical crystals in a colorless clear solution.

3. A use of the guanidine difluorophosphate nonlinear optical crystal as claimed in claim 1 in preparing a second harmonic light output of the fundamental frequency light of 1064 nm output by an Nd:YAG laser.

4. Use of the guanidine difluorophosphate nonlinear optical crystal according to claim 1 in preparing a frequency doubling generator, an up- or down-frequency converter, or an optical parametric oscillator.

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