Aminomethylphosphonic acid aminoguanidine nonlinear optical crystal, preparation method and use thereof

Abstract

This invention relates to an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal, its preparation method, and its uses. The crystal has the molecular formula (CN4OH7)(CH2NH3PO3), a molecular weight of 203.15, belongs to the orthorhombic crystal system, and has a space group of [missing information]. P 212121, cell parameters are a =6.276(2)Å, b =10.239(4)Å, c =13.868(4)Å, α =90.00° β =90.00° c =90.00° Z =4, V =891.2(5)Å 3 Centimeter-sized crystals were grown using evaporation, aqueous solution cooling, or hydrothermal methods. The ultraviolet absorption edge of these crystals is shorter than 200 nm, and the experimental birefringence is approximately 0.15 at 546 nm. This crystal preparation method is simple and low-cost, exhibiting significant nonlinear optical effects, a large birefringence, a wide transmission range, and ease of growth and processing. It can be used as an ultraviolet nonlinear optical crystal and a birefringent crystal.

Description

Technical Field

[0001] This invention relates to the field of nonlinear optical crystal materials technology, specifically to an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal, its preparation method, and its applications. Background Technology

[0002] Nonlinear optical crystals are important functional materials for frequency conversion, such as laser frequency doubling, sum frequency, difference frequency, and optical parametric oscillation, and have wide applications in laser technology, precision machining, information technology, medicine, and defense. With the increasing demand for ultraviolet and deep ultraviolet coherent light sources, higher requirements are being placed on the nonlinear optical effects, birefringence, transmission range, crystal growth performance, and processing performance of nonlinear optical crystals.

[0003] Currently, inorganic crystal systems are the most studied among crystal materials used for ultraviolet and deep ultraviolet optical frequency conversion. However, some materials still suffer from problems such as demanding preparation conditions, long growth cycles, and high equipment requirements. In contrast, certain organic or organic salt crystals are easier to crystallize under mild conditions and have certain advantages in molecular structure design and birefringence control. Therefore, developing novel nonlinear optical crystals that can be grown under milder conditions and simultaneously possess large nonlinear optical responses and large birefringences is of great significance.

[0004] Both aminomethylphosphonic acid and aminoguanidine compounds contain functional groups that facilitate the formation of hydrogen bond networks and polar stacking. Under appropriate conditions, they can form non-centrosymmetric crystal structures, thus exhibiting excellent nonlinear optical properties. Therefore, developing aminomethylphosphonic acid-aminoguanidine nonlinear optical crystals and establishing their growth processes using evaporation, aqueous solution cooling, and hydrothermal methods are of great value for expanding the range of ultraviolet nonlinear optical crystal materials. Summary of the Invention

[0005] One of the objectives of this invention is to provide an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal.

[0006] The second objective of this invention is to provide a method for preparing an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal.

[0007] The third objective of this invention is to provide an application of aminomethylphosphonic acid aminoguanidine nonlinear optical crystal.

[0008] The present invention discloses an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with the molecular formula (CN4OH7)(CH2NH3PO3), a molecular weight of 203.15, belonging to the orthorhombic crystal system, and a space group of [missing information]. P 212121, cell parameters are a =6.276(2)Å, b =10.239(4)Å, c=13.868(4)Å, α =90.00° β =90.00° γ =90.00° Z =4, V =891.2(5)Å 3 The crystal has an ultraviolet absorption edge shorter than 200 nm and an experimental birefringence of approximately 0.15 at 546 nm.

[0009] The method for preparing the aminoguanidine nonlinear optical crystal of aminomethylphosphonic acid uses aminoguanidine carbonate (hydrogen) and aminomethylphosphonic acid as the main raw materials, and grows the crystal by evaporation, aqueous solution cooling or hydrothermal method. The crystal growth method using evaporation is specifically performed according to the following steps: a. Mix aminoguanidine carbonate (or aminoguanidine bicarbonate) or aminoguanidine carbonate with aminomethylphosphonic acid at a molar ratio of 1:1-2, place the mixture in a polytetrafluoroethylene beaker, plastic beaker, or glass beaker, add 20-100 mL of deionized water, stir or sonicate for 5-30 minutes to allow it to react fully and form a clear solution. b. After filtering the solution obtained in step a, transfer it into a crystallization container, seal it with plastic wrap, and then poke several small holes at the seal to adjust the evaporation rate. c. Place the crystallization container from step b at a temperature of 20-30℃ and allow it to evaporate. Once the size of the precipitated crystal no longer changes, remove the crystal and dry it to obtain the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal. The crystal growth method using aqueous solution cooling is performed according to the following steps: a. Mix aminoguanidine carbonate (bicarbonate) or aminoguanidine carbonate with aminomethylphosphonic acid at a molar ratio of 1:1-2, place in a polytetrafluoroethylene beaker, plastic beaker or glass beaker, add 20-100mL of deionized water, heat to 40-80℃, stir until the raw materials are fully reacted and dissolved to obtain a saturated or near-saturated solution. b. Filter the solution obtained in step a while hot and transfer it into a crystallization container. Slowly cool the temperature from 40-80℃ to 20-30℃ and allow crystals to grow during the cooling process. c. After the crystal grows to the target size, remove the crystal and dry it to obtain the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal; The hydrothermal crystal growth method is specifically performed according to the following steps: a. Mix aminoguanidine carbonate (or aminoguanidine bicarbonate) or aminoguanidine carbonate with aminomethylphosphonic acid at a molar ratio of 1:1-2. Transfer the mixture into a clean, uncontaminated 23-100mL high-temperature and high-pressure reactor liner. Add 0.5-6mL of deionized water and tighten the reactor to seal it. b. Place the high-temperature and high-pressure reactor from step a into a constant temperature chamber, raise the temperature to 100-180℃ at a rate of 10-30℃ / h, keep it at the constant temperature for 3-7 days, and then lower it to room temperature at a rate of 0.1-2℃ / day. c. Open the reaction vessel, take out the crystal and dry it to obtain the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal.

[0010] The aminomethylphosphonic acid aminoguanidine nonlinear optical crystal is used in the preparation of second, third, or fourth harmonic output of the 1064nm fundamental frequency light from an Nd:YAG laser.

[0011] The aminomethylphosphonic acid aminoguanidine nonlinear optical crystal is used in the preparation of frequency multiplier generators, up-frequency converters, down-frequency converters, optical parametric oscillators, ultraviolet nonlinear optical devices, or birefringent optical devices.

[0012] The present invention relates to an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal, its preparation method, and its uses. The glass beakers, polytetrafluoroethylene beakers, plastic beakers, and crystallization containers used are all cleaned with acid before use, then rinsed with deionized water and dried to reduce the influence of impurities on crystal nucleation and growth.

[0013] Using the method described in this invention, centimeter-sized aminomethylphosphonic acid aminoguanidine single crystals can be obtained by increasing the size of the crystallization container, extending the crystal growth cycle, and optimizing the evaporation rate, cooling rate, or hydrothermal conditions. The obtained large-size crystals, after being oriented according to crystallographic data, can be cut and polished for use as nonlinear optical devices or birefringent devices.

[0014] The aminomethylphosphonic acid aminoguanidine nonlinear optical crystal, its preparation method, and its applications described in this invention have the following advantages: (1) The aminomethylphosphonic acid aminoguanidine crystal has a non-centrosymmetric crystal structure and good nonlinear optical effects; (2) Under 1064nm laser irradiation, the powder frequency doubling response of the crystal is equivalent to twice that of KH2PO4 (KDP); (3) The ultraviolet absorption edge of the crystal is shorter than 200 nm, and the experimental birefringence is about 0.15@546 nm; (4) The crystal can be prepared under relatively mild conditions by evaporation, aqueous solution cooling or hydrothermal method, which is simple and low cost; (5) The crystal is easy to grow and process, and centimeter-sized single crystals can be obtained. It can be used as ultraviolet nonlinear optical crystals and birefringent crystals. Attached Figure Description

[0015] Figure 1 The powder X-ray diffraction pattern of the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal of the present invention; Figure 2 This is a schematic diagram of the structure of aminomethylphosphonic acid aminoguanidine crystal of the present invention; Figure 3 This is a schematic diagram of the working principle of the nonlinear optical device fabricated in this invention. The device outputs laser light of the required wavelength using a direct frequency doubling method. Detailed Implementation

[0016] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to the following embodiments. Any equivalent substitutions or improvements made based on the technical solutions of the present invention should fall within the protection scope of the present invention.

[0017] In the following examples, unless otherwise specified, all aminoguanidine carbonates (bicarbonates) used are aminoguanidine bicarbonates; aminoguanidine carbonates can also be used as substitutes. The proportions described in this invention are for illustrating the ingredient relationships and do not limit the actual reaction mechanism. Example 1

[0018] The crystal growth method using evaporation is specifically performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid at a molar ratio of 1:1, place them in a polytetrafluoroethylene beaker, add 20 mL of deionized water, and sonicate for 5 minutes to allow them to react fully and form a clear solution. b. After filtering the solution obtained in step a, transfer it into a crystallization container, seal it with plastic wrap, and then poke several small holes at the seal to adjust the evaporation rate. c. Place the crystallization container from step b at 20°C and allow it to evaporate. Once the size of the precipitated crystal no longer changes, remove the crystal and dry it to obtain an aminoguanidine aminomethylphosphonic acid nonlinear optical crystal with a size of 4mm×4mm×2mm. Example 2

[0019] The crystal growth method using evaporation is specifically performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid at a molar ratio of 1:1.5, place in a glass beaker, add 60 mL of deionized water, and sonicate for 20 minutes to allow them to react fully and form a clear solution. b. After filtering the solution obtained in step a, transfer it into a crystallization container, seal it with plastic wrap, and then poke several small holes at the seal to adjust the evaporation rate. c. Place the crystallization container from step b at 25°C and allow it to evaporate. Once the size of the precipitated crystal no longer changes, remove the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 5mm×3mm×2mm. Example 3

[0020] The crystal growth method using evaporation is specifically performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid at a molar ratio of 1:2, place them in a plastic beaker, add 100mL of deionized water, and stir for 30 minutes to allow them to react fully and form a clear solution. b. After filtering the solution obtained in step a, transfer it into a crystallization container, seal it with plastic wrap, and then poke several small holes at the seal to adjust the evaporation rate. c. Place the crystallization container from step b at 20°C and allow it to evaporate. Once the size of the precipitated crystal no longer changes, remove the crystal and dry it to obtain an aminoguanidine aminomethylphosphonic acid nonlinear optical crystal with a size of 5mm×3mm×1mm. Example 4

[0021] The crystal growth method using evaporation is specifically performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid at a molar ratio of 1:1, place them in a plastic beaker, add 100mL of deionized water, stir for 5 minutes to allow them to react fully and form a clear solution; b. After filtering the solution obtained in step a, transfer it into a crystallization container, seal it with plastic wrap, and then poke several small holes at the seal to adjust the evaporation rate. c. Place the crystallization container from step b at 30°C and allow it to evaporate. Once the size of the precipitated crystal no longer changes, remove the crystal and dry it to obtain an aminoguanidine aminomethylphosphonic acid nonlinear optical crystal with a size of 3mm×2mm×1mm. Example 5

[0022] The crystal growth method using evaporation is specifically performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid at a molar ratio of 1:2, place them in a polytetrafluoroethylene beaker, add 40 mL of deionized water, and sonicate for 5 minutes to allow them to react fully and form a clear solution. b. After filtering the solution obtained in step a, transfer it into a crystallization container, seal it with plastic wrap, and then poke several small holes at the seal to adjust the evaporation rate. c. Place the crystallization container from step b at 30°C and allow it to evaporate. Once the size of the precipitated crystal no longer changes, remove the crystal and dry it to obtain an aminoguanidine aminomethylphosphonic acid nonlinear optical crystal with a size of 5mm×2mm×2mm. Example 6

[0023] The crystal growth method using evaporation is specifically performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid at a molar ratio of 1:1.5, place in a glass beaker, add 20 mL of deionized water, and sonicate for 30 minutes to allow them to react fully and form a clear solution. b. After filtering the solution obtained in step a, transfer it into a crystallization container, seal it with plastic wrap, and then poke several small holes at the seal to adjust the evaporation rate. c. Place the crystallization container from step b at 20°C and allow it to evaporate. Once the size of the precipitated crystal no longer changes, remove the crystal and dry it to obtain an aminoguanidine aminomethylphosphonic acid nonlinear optical crystal with a size of 3mm×2mm×1mm. Example 7

[0024] The crystal growth method using aqueous solution cooling is performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid at a molar ratio of 1:1, place them in a polytetrafluoroethylene beaker, add 20 mL of deionized water, heat to 40 °C, and stir until the raw materials have fully reacted and dissolved to obtain a clear saturated solution. b. After filtering the solution obtained in step a while hot, transfer it to a crystallization container and slowly cool it from 40°C to 30°C, allowing crystals to grow during the cooling process. c. After the crystal grows to the target size, remove the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 5mm×3mm×1mm. Example 8

[0025] The crystal growth method using aqueous solution cooling is performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid at a molar ratio of 1:1.5, place them in a plastic beaker, add 60 mL of deionized water, heat to 60 °C, and stir until the raw materials have fully reacted and dissolved to obtain a clear, nearly saturated solution. b. Filter the solution obtained in step a while hot and transfer it into a crystallization container. Slowly cool the temperature from 60°C to 25°C and allow crystals to grow during the cooling process. c. After the crystal grows to the target size, remove the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 4mm×4mm×2mm. Example 9

[0026] The crystal growth method using aqueous solution cooling is performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid at a molar ratio of 1:2, place in a glass beaker, add 80 mL of deionized water, heat to 50 °C, and stir until the raw materials have fully reacted and dissolved to obtain a clear saturated solution; b. Filter the solution obtained in step a while hot and transfer it into a crystallization container. Slowly cool the temperature from 50°C to 20°C and allow crystals to grow during the cooling process. c. After the crystal grows to the target size, remove the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 2mm×2mm×1mm. Example 10

[0027] The crystal growth method using aqueous solution cooling is performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid at a molar ratio of 1:1, place them in a polytetrafluoroethylene beaker, add 40 mL of deionized water, heat to 80 °C, and stir until the raw materials have fully reacted and dissolved to obtain a clear, nearly saturated solution. b. Filter the solution obtained in step a while hot and transfer it into a crystallization container. Slowly cool the temperature from 80°C to 30°C and allow crystals to grow during the cooling process. c. After the crystal grows to the target size, remove the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 5mm×2mm×2mm. Example 11

[0028] The crystal growth method using aqueous solution cooling is performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid at a molar ratio of 1:2, place them in a plastic beaker, add 80 mL of deionized water, heat to 40 °C, and stir until the raw materials have fully reacted and dissolved to obtain a clear saturated solution; b. Filter the solution obtained in step a while hot and transfer it into a crystallization container. Slowly cool the temperature from 40°C to 20°C and allow crystals to grow during the cooling process. c. After the crystal grows to the target size, remove the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 6mm×5mm×2mm. Example 12

[0029] The crystal growth method using aqueous solution cooling is performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid at a molar ratio of 1:1.5, place them in a polytetrafluoroethylene beaker, plastic beaker or glass beaker, add 100mL of deionized water, heat to 40℃, and stir until the raw materials have fully reacted and dissolved to obtain a clear saturated solution; b. Filter the solution obtained in step a while hot and transfer it into a crystallization container. Slowly cool the temperature from 40°C to 20°C and allow crystals to grow during the cooling process. c. After the crystal grows to the target size, remove the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 5mm×5mm×1mm. Example 13

[0030] The hydrothermal crystal growth method is specifically performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid evenly at a molar ratio of 1:1, transfer the mixture into a clean, uncontaminated 23mL high-temperature and high-pressure reactor liner, add 0.5mL of deionized water, and tighten and seal the reactor. b. Place the high-temperature and high-pressure reactor from step a into a constant temperature chamber, raise the temperature to 180°C at a rate of 10°C / h, keep it at the constant temperature for 7 days, and then lower it to room temperature at a rate of 0.1°C / day. c. Open the reaction vessel, take out the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 2mm×2mm×1mm. Example 14

[0031] The hydrothermal crystal growth method is specifically performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid evenly at a molar ratio of 1:1.5, transfer the mixture into a clean, uncontaminated 50mL high-temperature and high-pressure reactor liner, add 2mL of deionized water, and tighten and seal the reactor. b. Place the high-temperature and high-pressure reactor from step a into a constant temperature chamber, raise the temperature to 150°C at a rate of 15°C / h, keep it at the constant temperature for 3 days, and then lower it to room temperature at a rate of 0.5°C / day. c. Open the reaction vessel, take out the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 2mm×2mm×1mm. Example 15

[0032] The hydrothermal crystal growth method is specifically performed according to the following steps: a. Mix aminoguanidine bicarbonate and aminomethylphosphonic acid evenly at a molar ratio of 1:2, transfer the mixture into a clean, uncontaminated 100mL high-temperature and high-pressure reactor liner, add 6mL of deionized water, and tighten and seal the reactor. b. Place the high-temperature and high-pressure reactor from step a in a constant temperature chamber, raise the temperature to 100°C at a rate of 30°C / h, keep it at the constant temperature for 5 days, and then lower it to room temperature at a rate of 2°C / day. c. Open the reaction vessel, take out the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 1mm×1mm×1mm. Example 16

[0033] The hydrothermal crystal growth method is specifically performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid evenly at a molar ratio of 1:1, transfer the mixture into a clean, uncontaminated 100mL high-temperature and high-pressure reactor liner, add 6mL of deionized water, and tighten and seal the reactor. b. Place the high-temperature and high-pressure reactor from step a into a constant temperature chamber, raise the temperature to 100°C at a rate of 10°C / h, keep it at the constant temperature for 3 days, and then lower it to room temperature at a rate of 0.1°C / day. c. Open the reaction vessel, take out the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 3mm×1mm×1mm. Example 17

[0034] The hydrothermal crystal growth method is specifically performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid evenly at a molar ratio of 1:2, transfer the mixture into a clean, uncontaminated 50mL high-temperature and high-pressure reactor liner, add 0.5mL of deionized water, and tighten and seal the reactor. b. Place the high-temperature and high-pressure reactor from step a into a constant temperature chamber, raise the temperature to 140°C at a rate of 20°C / h, keep it at the constant temperature for 5 days, and then lower it to room temperature at a rate of 1°C / day. c. Open the reaction vessel, take out the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 2mm×2mm×1mm. Example 18

[0035] The hydrothermal crystal growth method is specifically performed according to the following steps: a. Mix aminoguanidine carbonate and aminomethylphosphonic acid evenly at a molar ratio of 1:1.5, transfer the mixture into a clean, uncontaminated 23mL high-temperature and high-pressure reactor liner, add 3mL of deionized water, and tighten and seal the reactor. b. Place the high-temperature and high-pressure reactor from step a into a constant temperature chamber, raise the temperature to 180°C at a rate of 30°C / h, keep it at the constant temperature for 7 days, and then lower it to room temperature at a rate of 2°C / day. c. Open the reaction vessel, take out the crystal and dry it to obtain an aminomethylphosphonic acid aminoguanidine nonlinear optical crystal with a size of 3mm×3mm×2mm. Example 19

[0036] Any of the aminomethylphosphonic acid aminoguanidine nonlinear optical crystals obtained in Examples 1-18 are processed in matching directions. At room temperature, using a Q-switched Nd:YAG laser as the light source with an incident wavelength of 1064 nm, a frequency-doubled output of 532 nm can be obtained. Example 20

[0037] Any of the aminomethylphosphonic acid aminoguanidine nonlinear optical crystals obtained in Examples 1-18 are processed in matching directions. At room temperature, using a Q-switched Nd:YAG laser as the light source with an incident wavelength of 532nm, a 266nm frequency-doubled output can be obtained. Example 21

[0038] After processing any of the aminomethylphosphonic acid aminoguanidine nonlinear optical crystals obtained in Examples 1-18 in matching directions, they can be used to prepare frequency multipliers, up-frequency converters, down-frequency converters, optical parametric oscillators, ultraviolet nonlinear optical devices, or birefringent devices.

Claims

1. An aminomethylphosphonic acid aminoguanidine nonlinear optical crystal, characterized in that: The crystal has the molecular formula (CN4OH7)(CH2NH3PO3), a molecular weight of 203.15, belongs to the orthorhombic crystal system, and has the space group [missing information]. P 212121, cell parameters are a =6.276(2)Å, b =10.239(4)Å, c =13.868(4)Å, α =90.00° β =90.00° γ =90.00° Z =4, V =891.2(5)Å 3 The crystal has an ultraviolet absorption edge shorter than 200 nm and an experimental birefringence of 0.15@546 nm.

2. The method for preparing the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal according to claim 1, characterized in that: Crystals were grown using aminoguanidine carbonate (bicarbonate) and aminomethylphosphonic acid as the main raw materials, employing evaporation, aqueous solution cooling, or hydrothermal methods. The crystal growth method using evaporation is specifically performed according to the following steps: a. Mix aminoguanidine carbonate (or aminoguanidine bicarbonate) or aminoguanidine carbonate with aminomethylphosphonic acid at a molar ratio of 1:1-2, place the mixture in a polytetrafluoroethylene beaker, plastic beaker, or glass beaker, add 20-100 mL of deionized water, stir or sonicate for 5-30 minutes to allow it to react fully and form a clear solution. b. After filtering the solution obtained in step a, transfer it into a crystallization container, seal it with plastic wrap, and then poke several small holes at the seal to adjust the evaporation rate. c. Place the crystallization container from step b at a temperature of 20-30℃ and allow it to evaporate. Once the size of the precipitated crystal no longer changes, remove the crystal and dry it to obtain the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal. The crystal growth method using aqueous solution cooling is performed according to the following steps: a. Mix aminoguanidine carbonate (bicarbonate) or aminoguanidine carbonate with aminomethylphosphonic acid at a molar ratio of 1:1-2, place in a polytetrafluoroethylene beaker, plastic beaker or glass beaker, add 20-100mL of deionized water, heat to 40-80℃, stir until the raw materials are fully reacted and dissolved to obtain a saturated or near-saturated solution. b. Filter the solution obtained in step a while hot and transfer it into a crystallization container. Slowly cool the temperature from 40-80℃ to 20-30℃ and allow crystals to grow during the cooling process. c. After the crystal grows to the target size, remove the crystal and dry it to obtain the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal; The hydrothermal crystal growth method is specifically performed according to the following steps: a. Mix aminoguanidine carbonate (or aminoguanidine bicarbonate) or aminoguanidine carbonate with aminomethylphosphonic acid at a molar ratio of 1:1-2. Transfer the mixture into a clean, uncontaminated 23-100mL high-temperature and high-pressure reactor liner. Add 0.5-6mL of deionized water and tighten the reactor to seal it. b. Place the high-temperature and high-pressure reactor from step a into a constant temperature chamber, raise the temperature to 100-180℃ at a rate of 10-30℃ / h, keep it at the constant temperature for 3-7 days, and then lower it to room temperature at a rate of 0.1-2℃ / day. c. Open the reaction vessel, take out the crystal and dry it to obtain the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal.

3. The use of the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal according to claim 1 in preparing second, third, or fourth harmonic outputs of the 1064nm fundamental frequency light output from an Nd:YAG laser.

4. The use of the aminomethylphosphonic acid aminoguanidine nonlinear optical crystal according to claim 1 in the preparation of frequency doubling generators, up-frequency converters, down-frequency converters, optical parametric oscillators, ultraviolet nonlinear optical devices or birefringent optical devices.

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