Compound ammonium fluoroborate, nonlinear optical crystal of ammonium fluoroborate, and preparation method and use thereof

A method for preparing a nonlinear optical crystal of ammonium fluoroborate, wherein a chemical formula of the nonlinear optical crystal is NH4B4O6F and a molecular weight of the nonlinear optical crystal is 176.28;

• the nonlinear optical crystal is an orthorhombic crystal, a space group of the nonlinear optical crystal is Pna21, and the nonlinear optical crystal has the following cell parameters:
• a=7.615(3) Å, b=11.207(4) Å, c=6.604(3) Å, Z=4, V=563.6 Å3;
• the nonlinear optical crystal grown by a flux method, a Bridgman-Stockbarger method, a room temperature solution method or a solvothermal method;
• the room temperature solution method for growing the nonlinear optical crystal of ammonium fluoroborate comprises the following steps:
• a. mixing an NH4-containing compound, a Boron-containing compound, and a Flurine-containing compound evenly at a molar ratio of NH4:B:F=(0.5-2):(3-5):(0.5-2) to obtain a mixture, sealing the mixture in a hydrothermal reactor or a quartz tube, placing the hydrothermal reactor or the quartz tube into a muffle furnace or a drying oven, raising a first temperature to 150-580° C. at a rate of 20-40° C./h and keeping the first temperature for 10-48 h, then reducing the first temperature to 30° C. at a rate of 1-10° C./h, and opening the hydrothermal reactor or the quartz tube and removing the mixture to obtain a compound NH4B4O6F;
• a chemical formula of the NH4-containing compound is NH4F, a chemical formula of the Boron-containing compound is H3BO3 or B2O3, and a chemical formula of the Fluorine-containing compound is NH4F or HF;
• b. sealing the compound NH4B4O6F obtained in step a in the hydrothermal reactor or the quartz tube, placing the hydrothermal reactor or the quartz tube into the muffle furnace or the drying oven, raising a second temperature to 200-600° C. at a rate of 20-40° C./h and keeping the second temperature for 10-48 h, then reducing the second temperature to 30° C. at a rate of 1-5° C./h, and opening the hydrothermal reactor or the quartz tube to obtain a seed crystal of the NH4B4O6F;
• c. placing the seed crystal obtained in step b at a bottom of a container, and then placing the compound NH4B4O6F obtained in step a into the container;
• d. sealing the container in step c or sealing the container in step c after an addition of 10-100 mL of a solvent, placing the container into the muffle furnace or the drying oven, raising a third temperature to 150-600° C. at a rate of 20-40° C./h and keeping the third temperature for 10-48 h, then reducing the third temperature to 50° C. at a rate of 1-3° C./day, and then reducing the third temperature to 30° C. at a rate of 1-10° C./h, and opening the container to obtain the nonlinear optical crystal of ammonium fluoroborate, a size of the nonlinear optical crystal is 1-20 mm;
• the solvent is deionized water, anhydrous ethanol, N,N-dimethylformamide, N,N-dimethylacetamide or hydrofluoric acid;
• the flux method for growing the nonlinear optical crystal of ammonium fluoroborate comprises the following steps:
• a. mixing an NH4-containing compound, a Boron-containing compound, and a Fluorine-containing compound evenly at a molar ratio of NH4:B:F=(0.5-2):(3-5):(0.5-2) to obtain a mixture, sealing the mixture in a hydrothermal reactor or a first quartz tube, placing the hydrothermal reactor or the first quartz tube into a muffle furnace or a drying oven, raising a first temperature to 150-580° C. at a rate of 20-40° C./h and keeping the first temperature for 10-48 h, then reducing the first temperature to 30° C. at a rate of 1-10° C./h, and opening the hydrothermal reactor or the first quartz tube to obtain a compound NH4B4O6F;
• a chemical formula of the NH4-containing compound is NH4F, a chemical formula of the Boron-containing compound is H3BO3 or B2O3, and a chemical formula of the Fluorine-containing compound is NH4F or HF;
• b. sealing the compound NH4B4O6F obtained in step a in the hydrothermal reactor or the first quartz tube, placing the hydrothermal reactor or the first quartz tube into the muffle furnace or the drying oven, raising a second temperature to 200-600° C. at a rate of 20-40° C./h and keeping the second temperature for 10-48 h, then reducing the second temperature to 30° C. at a rate of 1-5° C./h, and opening the hydrothermal reactor or the first quartz tube to obtain a seed crystal of the NH4B4O6F;
• c. placing the seed crystal of the NH4B4O6F obtained in step b at a bottom of a second quartz tube, then mixing the compound NH4B4O6F obtained in step a with a flux at a molar ratio of 1:(1-10) to obtain a mix and placing the mix into the second quartz tube, and the second quartz tube was lame-sealed under 10−3 Pa with a flame gun;
• a chemical formula of the flux is NH4F, NH4F:H3BO3, NH4F:B2O3, H3BO3 or B2O3;
• d. sealing the second quartz tube in step c or sealing the second quartz tube in step c after an addition of 10-100 mL of a solvent, placing the second quartz tube into the muffle furnace or the drying oven, raising a third temperature to 150-600° C. at a rate of 20-40° C./h and keeping the third temperature for 10-48 h, then reducing the third temperature to 50° C. at a rate of 1-3° C./day, and then reducing the third temperature to 30° C. at a rate of 1-10° C./h, and opening the second quartz tube and removing a product to obtain the nonlinear optical crystal of ammonium fluoroborate, a size of the nonlinear optical crystal is 1-20 mm;
• the solvent is deionized water, anhydrous ethanol, N,N-dimethylformamide, N,N-dimethylacetamide or hydrofluoric acid;
• the Bridgman-Stockbarger method for growing the nonlinear optical crystal of ammonium fluoroborate comprises the following steps:
• a. mixing an NH4-containing compound, a Boron-containing compound, and a Flurine-containing compound evenly at a molar ratio of NH4:B:F=(0.5-2):(3-5):(0.5-2) to obtain a mixture, sealing the mixture in a hydrothermal reactor or a quartz tube, placing the hydrothermal reactor or the quartz tube into a muffle furnace or a drying oven, raising a first temperature to 150-580° C. at a rate of 20-40° C./h and keeping the first temperature for 10-48 h, then reducing the first temperature to 30° C. at a rate of 1-10° C./h, and opening the hydrothermal reactor or the quartz tube and removing the mixture to obtain a compound NH4B4O6F;
• a chemical formula of the NH4-containing compound is NH4F, a chemical formula of the Boron-containing compound is H3BO3 or B2O3, and a chemical formula of the Fluorine-containing compound is NH4F or HF;
• b. sealing the compound NH4B4O6F obtained in step a in the hydrothermal reactor or the quartz tube, placing the hydrothermal reactor or the quartz tube into the muffle furnace or the drying oven, raising a second temperature to 200-600° C. at a rate of 20-40° C./h and keeping the second temperature for 10-48 h, then reducing the second temperature to 30° C. at a rate of 1-5° C./h, and opening the hydrothermal reactor or the quartz tube to obtain a seed crystal of the NH4B4O6F;
• c. placing the seed crystal obtained in step b at a bottom of a container, and then placing the compound NH4B4O6F obtained in step a into the container;
• d. sealing the container in step c and placing the container into a Bridgman-Stockbarger furnace, raising a third temperature to 300-600° C. and keeping the third temperature for 10-20 h, adjusting a position of the container to allow the compound NH4B4O6F to spontaneously nucleate or inoculate at 350-600° C., then lowering the container at a rate of 0.05-2 mm/h slowly while keeping a growth temperature constant or reducing the growth temperature slowly at a rate of 0-3° C./h, then reducing the third temperature of the Bridgman-Stockbarger furnace to 30° C. after a growth of the nonlinear optical crystal is completed, and removing the container to obtain the nonlinear optical crystal of ammonium fluoroborate, a size of the nonlinear optical crystal is 1-20 mm;
• the solvothermal method for growing the nonlinear optical crystal of ammonium fluoroborate comprises the following steps:
• a. mixing an NH4-containing compound, a Boron-containing compound, and an Fluorine-containing compound evenly at a molar ratio of NH4:B:F=(0.5-2):(3-5):(0.5-2) to obtain a first mixture, sealing the first mixture in a hydrothermal reactor or a quartz tube, placing the hydrothermal reactor or the quartz tube into a muffle furnace or a drying oven, raising a first temperature to 150-580° C. at a rate of 20-40° C./h and keeping the first temperature for 10-48 h, then reducing the first temperature to 30° C. at a rate of 1-10° C./h, and opening the hydrothermal reactor or the quartz tube to obtain a compound NH4B4O6F;
• a chemical formula of the NH4-containing compound is NH4F, a chemical formula of the Boron-containing compound is H3BO3 or B2O3, and a chemical formula of the Fluorine-containing compound is NH4F or HF;
• b. sealing the compound NH4B4O6F obtained in step a in the hydrothermal reactor or the quartz tube, placing the hydrothermal reactor or the quartz tube into the muffle furnace or the drying oven, raising a second temperature to 200-600° C. at a rate of 20-40° C./h and keeping the second temperature for 10-48 h, then reducing the second temperature to 30° C. at a rate of 1-5° C./h, and opening the hydrothermal reactor or the quartz tube to obtain a seed crystal of the NH4B4O6F;
• c. placing the seed crystal obtained in step b at a bottom of a container, and then placing the compound NH4B4O6F obtained in step a into the container;
• d. adding 10-100 mL of a solvent to the container in step c to obtain a second mixture, then subjecting the second mixture to ultrasonication to make the second mixture mix and dissolve thoroughly, adjusting a pH value of the second mixture to pH=1-11, performing a filtration with a qualitative filter paper, then sealing the container with a polyvinyl chloride film, a plurality of small holes are arranged in the polyvinyl chloride film and punched to adjust a volatilization rate of the solvent in the second mixture, and placing the container into a static environment without shaking, pollution and air convection, and leaving the second mixture to stand at room temperature to allow the nonlinear optical crystal to grow, so as to obtain the nonlinear optical crystal of ammonium fluoroborate, a size of the nonlinear optical crystal is 1-20 mm at an end of a crystal growth;
• the solvent is deionized water, anhydrous ethanol, N,N-dimethylformamide, N,N-dimethylacetamide or hydrofluoric acid.

A method of producing a harmonic light, wherein the method comprises:

• using a nonlinear optical crystal of ammonium fluoroborate, wherein a chemical formula of the nonlinear optical crystal is NH4B4O6F and a molecular weight of the nonlinear optical crystal is 176.28;
• the nonlinear optical crystal is an orthorhombic system, a space group of the nonlinear optical crystal is Pna21, and the nonlinear optical crystal has the following cell parameters:
• a=7.615(3) Å, b=11.207(4) Å, c=6.604(3) Å, Z=4, V=563.6 Å3;
• the harmonic light is a frequency-doubled, a frequency-tripled, a frequency-quadrupled, a frequency-quintupled or a frequency-sextupled harmonic light from a 1064 nm fundamental frequency light output from a Nd:YAG laser.