Lithium hydrated succinate and lithium hydrated succinate birefringent crystals, their preparation methods and applications

Abstract

This invention provides a compound, lithium hydrated succinate, and a birefringent crystal of lithium hydrated succinate, along with their preparation method and applications. The compound has the chemical formula LiHC4O4H2O and a molecular weight of 138.00, and is prepared using a hydrothermal method. The crystal also has the chemical formula LiHC4O4H2O and a molecular weight of 138.00, belongs to the monoclinic crystal system, and has a space group of [space group missing]. C 2 / c The unit cell parameters are a =13.6014(9)Å, b =7.7711(4)Å, c =10.8202(12)Å, α =90°, β =120.269(2)°, c =90°, unit cell volume is 987.75(14) Å 3 Its light transmission range is 330-2000 nm, and its birefringence is between 0.354 (2000 nm) and 0.605 (330 nm). The lithium hydrated squaric acid birefringent crystal described in this invention has moderate mechanical hardness, is easy to cut, polish, and store; it has a large birefringence; and it has important applications in the fields of optics and communications, and can be used to fabricate polarizing beam splitters, phase delay devices, and electro-optic modulation devices, etc.

Description

Technical Field

[0001] This invention provides a compound lithium hydrated squartz acid and a lithium hydrated squartz acid birefringent crystal, as well as their preparation methods and uses, particularly an application of a lithium hydrated squartz acid birefringent crystal with the molecular formula LiHC4O4·H2O for the short wavelength-visible-infrared band. Background Technology

[0002] Birefringence refers to the phenomenon where a beam of light incident on a crystal surface produces two refracted beams. The fundamental reason for this phenomenon lies in the anisotropy of the crystal material. When light propagates in an optically anisotropic homogeneous material (such as crystals other than cubic systems), except in a few specific directions (along the optical axis), its vibrational characteristics change, decomposing into two polarized beams with mutually perpendicular electric field vector vibrations, different propagation speeds, and unequal refractive indices. This phenomenon is called birefringence, and such crystals are called birefringent crystals. The birefringence property of crystals is an important optical performance parameter for optoelectronic functional materials. Utilizing the properties of birefringent crystals, the polarization state of light can be modulated and detected to obtain linearly polarized light, and beam displacement can be achieved. Therefore, birefringent crystals are key materials for fabricating optical components such as optical isolators, circulators, beam shifters, phase retarders, optical polarizers, and optical modulators.

[0003] Commonly used birefringent materials include rutile TiO2 crystals, LiNbO3 crystals, calcite CaCO3 crystals, YVO4 crystals, α-BaB2O4 crystals, and MgF2 crystals. Taking MgF2 as an example, its transmission range is 110-8500 nm, making it a birefringent crystal used in deep ultraviolet light. However, its birefringence is too low, making it unsuitable for manufacturing Glan prisms; it can only be used for Rohung prisms. Furthermore, its small beam separation angle results in large device sizes and inconvenience. YVO4 crystal is an artificially prepared birefringent crystal. Due to its high melting point, it must be grown using an iridium crucible in a weak oxygen atmosphere. This leads to yttrium valence changes during growth, reducing crystal quality and making it difficult to obtain high-quality crystals. Rutile TiO2 crystal is a birefringent material with a high birefringence, but it is difficult to grow large crystals, and its high hardness makes it challenging to process and cut. Several borate birefringent crystals have been reported in recent years: the transmission range of high-temperature phase α-BaB2O4 crystal is 189-3500nm, and the birefringence is 0.120@546nm. However, it is subject to phase transfer and is prone to cracking during crystal growth, which affects the yield and utilization rate of the crystal.

[0004] With societal development, the demand for birefringent crystals is increasing, and the quality requirements are becoming more stringent. Therefore, breaking through and developing new and superior birefringent optical functional crystal materials remains a pressing issue. Based on the current development of inorganic birefringent crystal materials, novel birefringent crystals not only require high birefringence but also excellent overall performance parameters and ease of fabrication into high-quality, large-size bulk crystals. This necessitates extensive, systematic, and in-depth research. Exploring high-performance birefringent crystal materials is a crucial topic in the field of optoelectronic functional materials, and researchers continue to explore ways to discover even better birefringent crystals. Summary of the Invention

[0005] The purpose of this invention is to provide a compound, lithium hydrosquamolate, with the chemical formula LiHC4O4·H2O and a molecular weight of 138.00, which is prepared by a hydrothermal method.

[0006] Another object of the present invention is to provide a birefringent crystal of lithium hydrated squaric acid, wherein the chemical formula of the compound is LiHC4O4·H2O, the molecular weight is 138.00, it belongs to the monoclinic crystal system, the space group is C2 / c, and the cell parameters are as follows. α=90°, β=120.269(2)°, γ=90°, unit cell volume is

[0007] Another objective of this invention is to provide a method for preparing lithium hydrated succinate (LiHC4O4·H2O) birefringent crystals, wherein the crystals are grown using a hydrothermal method, a solvothermal method, or a room temperature solution method.

[0008] Another object of the present invention is to provide the use of lithium hydrated squaric acid lithium (LiHC4O4·H2O) birefringent crystal.

[0009] The present invention discloses a compound, lithium hydrosquamolate, with the chemical formula LiHC4O4·H2O and a molecular weight of 138.00, which is prepared by a hydrothermal method.

[0010] The compound lithium squaric acid hydrate is prepared by a hydrothermal method, and the specific operation is carried out according to the following steps:

[0011] The hydrothermal method was used to prepare the compound lithium hydrated succinate.

[0012] A Li-containing compound and an HC4O4-containing compound were mixed evenly in a molar ratio of Li:HC4O4 = 1:1. Water was added, and the temperature was raised to 40-80℃ at a rate of 3-5℃ / h to prepare a saturated solution at the corresponding temperature. The solution was kept at this temperature for 4 hours and then slowly cooled to crystallize, thus obtaining the compound LiHC4O4·H2O. The Li-containing compound was LiF, LiCl, LiBr, LiI, LiOH, or Li2CO3; the HC4O4-containing compound was H2C4O4.

[0013] A birefringent crystal of lithium hydrated squaric acid, with the chemical formula LiHC4O4·H2O, a molecular weight of 138.00, belonging to the monoclinic crystal system, space group C2 / c, and cell parameters of [missing information]. α=90°, β=120.269(2)°, γ=90°, unit cell volume is

[0014] The preparation method of the hydrated lithium succinate birefringent crystal adopts the hydrothermal method, solvothermal method or room temperature solution method to grow the crystal;

[0015] The hydrothermal growth of lithium hydrated squaric acid birefringent crystals is carried out according to the following steps:

[0016] a. Mix the Li-containing compound and the HC4O4-containing compound evenly in a molar ratio of Li:HC4O4 = 1:1, add water, and heat to 40-80℃ at a rate of 3-5℃ / h to prepare a saturated solution at the corresponding temperature. Maintain this temperature for 4 hours, then slowly cool to crystallize, thus obtaining the compound LiHC4O4·H2O. The Li-containing compound is LiF, LiCl, LiBr, LiI, LiOH, or Li2CO3; the HC4O4-containing compound is H2C4O4.

[0017] b. Mix the polycrystalline powder of LiHC4O4·H2O obtained in step a with distilled water or the organic polar solvent dimethyl sulfoxide and N,N-dimethylformamide in a molar ratio of 0-1:0.3-3. Transfer the mixture into the lining of a clean, uncontaminated 50mL high-pressure reactor, seal the reactor tightly, place it in a constant temperature chamber, heat it to 120-190℃, hold it at that temperature for 12-96 hours, then cool it down to 100℃ at a rate of 0.05-1℃ / h, and then rapidly cool it down to room temperature at a rate of 3-5℃ / h to obtain LiHC4O4·H2O birefringent crystals.

[0018] The solvothermal growth of lithium hydrated squaric acid birefringent crystal is carried out according to the following steps:

[0019] a. Mix the Li-containing compound and the HC4O4-containing compound evenly in a molar ratio of Li:HC4O4 = 1:1, add water, heat to 40-80℃ at a rate of 3-5℃ / h to prepare a saturated solution at the corresponding temperature, and keep at the temperature for 4 hours. Then, slowly cool and crystallize to obtain the compound LiHC4O4·H2O. The Li-containing compound is LiF, LiCl, LiBr, LiI, LiOH, or Li2CO3; the HC4O4-containing compound is H2C4O4.

[0020] b. Mix the polycrystalline powder of LiHC4O4·H2O obtained in step a with the co-solvent boric acid at a molar ratio of 0-1:0.3-3. Transfer the mixture into the lining of a clean, uncontaminated 50mL high-pressure reactor. Tightly seal the reactor and place it in a constant temperature chamber. Heat the mixture to 120-190℃ and hold it at that temperature for 12-96 hours. Then, cool the mixture to 100℃ at a rate of 0.05-1℃ / h, and then rapidly cool it to room temperature at a rate of 3-5℃ / h to obtain LiHC4O4·H2O birefringent crystals.

[0021] The specific steps for growing hydrated lithium succinate birefringent crystals using the room temperature solution method are as follows:

[0022] a. Mix the Li-containing compound and the HC4O4-containing compound evenly in a molar ratio of Li:HC4O4 = 1:1, add water, heat to 40-80℃ at a rate of 3-5℃ / h to prepare a saturated solution at the corresponding temperature, and keep it at the temperature for 4 hours. Then, slowly cool and crystallize to obtain the compound LiHC4O4·H2O. The Li-containing compound is LiF, LiCl, LiBr, LiI, LiOH or Li2CO3; the HC4O4-containing compound is H2C4O4.

[0023] b. Place the polycrystalline powder of compound LiHC4O4·H2O obtained in step a into a clean glass container, add 10-50 mL of deionized water, then stir and heat to fully mix and dissolve. The heating temperature is 40-90℃ to prepare a saturated solution at the corresponding temperature, and keep it at the temperature for 4 hours.

[0024] c. Place the mixed solution obtained in step b in a clean glass container, seal it with weighing paper, and place it in a static environment without shaking, pollution, or air convection. Make several small holes in the seal to adjust the evaporation rate of the water in the aqueous solution. Let it stand at room temperature for 10-60 days.

[0025] d. After the solution in step c grows crystal particles at the bottom of the container until the size of the crystal particles no longer changes significantly, seed crystals are obtained.

[0026] e. Select the seed crystal with better quality from step d, suspend it in the mixed solution prepared in step b, and let it grow at room temperature for 10-30 days to obtain LiHC4O4·H2O birefringent crystal.

[0027] The use of the hydrated lithium squartz birefringent crystal in the fabrication of optical isolators, circulators, beam shifters, optical polarizers, or optical modulators.

[0028] The optical polarizer is a polarizing beam splitter prism.

[0029] The polarizing beam splitter is a Glan prism, a Wollaston prism, or a Lochte prism.

[0030] The preparation method of lithium hydrated squaric acid (LiHC4O4·H2O) birefringent crystal according to the present invention uses conical flasks, beakers, and hydrothermal reactors lined with polytetrafluoroethylene or stainless steel with platinum sleeves. The containers, whether conical flasks or beakers, must first be cleaned with acid, then rinsed with deionized water, and finally dried.

[0031] The method for preparing lithium hydrated succinate (LiHC4O4·H2O) birefringent crystals according to the present invention uses a muffle furnace or a drying oven in the preparation process.

[0032] The hydrated lithium succinate birefringent crystal of the present invention is used in the short wavelength-visible-infrared band. It is a biaxial crystal with a transmission range of 330-2000nm and a birefringence between 0.354 (2000nm) and 0.605 (330nm).

[0033] The lithium hydrated squaric acid (LiHC4O4·H2O) birefringent crystal described in this invention is easy to grow, cut, grind, polish, and store. It can be used to fabricate polarizing beam splitters such as Glan prisms, Wollaston prisms, Lochtein prisms, or beam splitters, and has important applications in optics and communications. Attached Figure Description

[0034] Figure 1 Powder XRD pattern of lithium hydrated succinate (LiHC4O4·H2O) birefringent crystal;

[0035] Figure 2 This is a structural diagram of the birefringent crystal of lithium hydrated squaric acid (LiHC4O4·H2O) of the present invention.

[0036] Figure 3 Birefringence calculation curve of lithium hydrated squaric acid (LiHC4O4·H2O) birefringent crystal;

[0037] Figure 4This is a schematic diagram of a Glan prism for the infrared-visible band made using the crystal obtained in this invention.

[0038] Figure 5 A schematic diagram of a Wollaston prism for the infrared-visible band fabricated using the crystal obtained in this invention;

[0039] Figure 6 A schematic diagram of a wedge-shaped birefringent crystal polarization beam splitter for the infrared-visible band, fabricated using the crystal obtained in this invention;

[0040] Figure 7 This is a schematic diagram of an optical isolator for the infrared-visible band fabricated using the crystal obtained in this invention.

[0041] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0042] Example 1

[0043] Preparation of compounds:

[0044] According to the reaction formula: LiF + H₂C₄O₄ + H₂O → LiHC₄O₄·H₂O + HF, the compound LiHC₄O₄·H₂O was synthesized by hydrothermal method.

[0045] Weigh LiF and H2C4O4 according to their chemical formula ratio, put them into an Erlenmeyer flask, add water, heat to 60℃ at a rate of 3℃ / h to prepare a saturated solution at the corresponding temperature, keep the temperature constant for more than 4 hours, and slowly cool to crystallize to obtain the compound LiHC4O4·H2O.

[0046] Example 2

[0047] Preparation of compounds:

[0048] According to the reaction formula: Li₂CO₃ + 2H₂C₄O₄ → 2LiHC₄O₄·H₂O + CO₂, the compound LiHC₄O₄·H₂O is synthesized by hydrothermal method.

[0049] Mix Li2CO3 and H2C4O4 evenly in a molar ratio of 1:2, put the mixture into an Erlenmeyer flask, add water, and heat to 80°C at a rate of 5°C / h to prepare a saturated solution at the corresponding temperature. Keep the solution at this temperature for more than 4 hours, and then slowly cool to crystallize, thus obtaining the compound LiHC4O4·H2O.

[0050] Example 3

[0051] Preparation of compounds:

[0052] According to the reaction formula: LiCl + H₂C₄O₄ + H₂O → LiHC₄O₄·H₂O + HCl, the compound LiHC₄O₄·H₂O was synthesized by hydrothermal method.

[0053] Mix LiCl and H2C4O4 evenly in a molar ratio of 1:1, put the mixture into an Erlenmeyer flask, add water, and heat to 70°C at a rate of 4°C / h to prepare a saturated solution at the corresponding temperature. Keep the solution at this temperature for more than 4 hours, and then slowly cool to crystallize, thus obtaining the compound LiHC4O4·H2O.

[0054] Example 4

[0055] Preparation of compounds:

[0056] According to the reaction formula: LiBr + H₂C₄O₄ + H₂O → LiHC₄O₄·H₂O + HBr, the compound LiHC₄O₄·H₂O was synthesized by hydrothermal method.

[0057] Mix LiBr and H2C4O4 evenly in a molar ratio of 1:1, put the mixture into an Erlenmeyer flask, add water, and heat to 80°C at a rate of 5°C / h to prepare a saturated solution at the corresponding temperature. Keep the solution at this temperature for more than 4 hours, and then slowly cool to crystallize, thus obtaining the compound LiHC4O4·H2O.

[0058] Example 5

[0059] Preparation of compounds:

[0060] According to the reaction formula: LiI + H₂C₄O₄ + H₂O → LiHC₄O₄·H₂O + HI, the compound LiHC₄O₄·H₂O was synthesized by hydrothermal method.

[0061] Mix Li2CO3 and H2C4O4 evenly in a molar ratio of 1:1, put the mixture into an Erlenmeyer flask, add water, and heat to 80°C at a rate of 4°C / h to prepare a saturated solution at the corresponding temperature. Keep the solution at this temperature for more than 4 hours, and then slowly cool to crystallize, thus obtaining the compound LiHC4O4·H2O.

[0062] Example 6

[0063] Preparation of compounds:

[0064] According to the reaction formula: LiOH + H₂C₄O₄ → LiHC₄O₄·H₂O, the compound LiHC₄O₄·H₂O was synthesized by hydrothermal method.

[0065] Mix LiOH and H2C4O4 evenly in a molar ratio of 1:1, put the mixture into an Erlenmeyer flask, add water, and heat to 40°C at a rate of 5°C / h to prepare a saturated solution at the corresponding temperature. Keep the solution at this temperature for more than 4 hours, and then slowly cool to crystallize, thus obtaining the compound LiHC4O4·H2O.

[0066] Example 7

[0067] Hydrothermal growth of lithium hydrated succinate (LiHC4O4·H2O) birefringent crystals:

[0068] The polycrystalline powder of LiHC4O4·H2O obtained in Example 1 was added to distilled water at a molar ratio of 1:3. The mixture was then transferred into the liner of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 150 °C and held for 12 hours. The temperature was then lowered to 100 °C at a rate of 0.05 °C / h, and then rapidly lowered to room temperature at a rate of 3 °C / h. This yielded a birefringent LiHC4O4·H2O crystal with dimensions of 4 mm × 3 mm × 2 mm.

[0069] Example 8

[0070] The hydrothermal growth of lithium hydrated squaric acid birefringent crystals is carried out according to the following steps:

[0071] The polycrystalline powder of LiHC4O4·H2O obtained in Example 2 was mixed with the organic polar solvents dimethyl sulfoxide and N,N-dimethylformamide at a molar ratio of 0.8:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 120 °C and held for 20 hours. The temperature was then lowered to 100 °C at a rate of 0.10 °C / h, and then rapidly lowered to room temperature at a rate of 4 °C / h. This yielded a birefringent LiHC4O4·H2O crystal with dimensions of 3 mm × 2 mm × 2 mm.

[0072] Example 9

[0073] The hydrothermal growth of lithium hydrated squaric acid birefringent crystals is carried out according to the following steps:

[0074] The polycrystalline powder of LiHC4O4·H2O obtained in Example 5 was mixed with distilled water at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 140 °C and held for 24 hours. The temperature was then lowered to 100 °C at a rate of 0.5 °C / h, and then rapidly lowered to room temperature at a rate of 3 °C / h. This yielded a LiHC4O4·H2O birefringent crystal with dimensions of 6 mm × 5 mm × 3 mm.

[0075] Example 10

[0076] The hydrothermal growth of lithium hydrated squaric acid birefringent crystals is carried out according to the following steps:

[0077] The polycrystalline powder of LiHC4O4·H2O obtained in Example 4 was mixed with the organic polar solvents dimethyl sulfoxide and N,N-dimethylformamide at a molar ratio of 0.5:0.8. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 160 °C and held for 48 hours. The temperature was then lowered to 100 °C at a rate of 0.15 °C / h, and then rapidly lowered to room temperature at a rate of 4 °C / h to obtain a birefringent LiHC4O4·H2O crystal with dimensions of 8 mm × 3 mm × 2 mm.

[0078] Example 11

[0079] The hydrothermal growth of lithium hydrated squaric acid birefringent crystals is carried out according to the following steps:

[0080] The polycrystalline powder of LiHC4O4·H2O obtained in Example 5 was mixed with distilled water at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 170 °C and held for 72 hours. The temperature was then lowered to 100 °C at a rate of 0.5 °C / h, and then rapidly lowered to room temperature at a rate of 5 °C / h. This yielded a LiHC4O4·H2O birefringent crystal with dimensions of 6 mm × 4 mm × 4 mm.

[0081] Example 12

[0082] The hydrothermal growth of lithium hydrated squaric acid birefringent crystals is carried out according to the following steps:

[0083] The polycrystalline powder of LiHC4O4·H2O obtained in Example 3 was mixed with the organic polar solvents dimethyl sulfoxide and N,N-dimethylformamide at a molar ratio of 0.1:0.3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 180 °C and held for 80 hours. The temperature was then lowered to 100 °C at a rate of 1 °C / h, and then rapidly lowered to room temperature at a rate of 3 °C / h to obtain a birefringent LiHC4O4·H2O crystal with dimensions of 5 mm × 5 mm × 3 mm.

[0084] Example 13

[0085] The hydrothermal growth of lithium hydrated squaric acid birefringent crystals is carried out according to the following steps:

[0086] The polycrystalline powder of LiHC4O4·H2O obtained in Example 6 was mixed with distilled water at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 190 °C and held for 96 hours. The temperature was then lowered to 100 °C at a rate of 0.05 °C / h, and then rapidly lowered to room temperature at a rate of 5 °C / h. This yielded a LiHC4O4·H2O birefringent crystal with dimensions of 6 mm × 4 mm × 2 mm.

[0087] Example 14

[0088] Solvothermal growth of birefringent lithium hydrated succinate (LiHC4O4·H2O):

[0089] The polycrystalline powder of LiHC4O4·H2O obtained in Example 2 was mixed with the co-solvent H3BO3 at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 180 °C and held for 24 hours. The temperature was then lowered to 100 °C at a rate of 0.08 °C / h, and then rapidly lowered to room temperature at a rate of 4 °C / h. This yielded a birefringent LiHC4O4·H2O crystal with dimensions of 4 mm × 3 mm × 1 mm.

[0090] Example 15

[0091] The solvothermal growth of lithium hydrated squaric acid birefringent crystal is carried out according to the following steps:

[0092] The polycrystalline powder of LiHC4O4·H2O obtained in Example 1 was mixed with boric acid as a co-solvent at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 120 °C and held for 12 hours. The temperature was then lowered to 100 °C at a rate of 0.05 °C / h, and then rapidly lowered to room temperature at a rate of 3 °C / h. This yielded a birefringent LiHC4O4·H2O crystal with dimensions of 7 mm × 5 mm × 4 mm.

[0093] Example 16

[0094] The solvothermal growth of lithium hydrated squaric acid birefringent crystal is carried out according to the following steps:

[0095] The polycrystalline powder of LiHC4O4·H2O obtained in Example 3 was mixed with boric acid as a co-solvent at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 150 °C and held for 36 hours. The temperature was then lowered to 100 °C at a rate of 0.1 °C / h, and then rapidly lowered to room temperature at a rate of 4 °C / h. This yielded a LiHC4O4·H2O birefringent crystal with dimensions of 6 mm × 5 mm × 3 mm.

[0096] Example 17

[0097] The solvothermal growth of lithium hydrated squaric acid birefringent crystal is carried out according to the following steps:

[0098] The polycrystalline powder of LiHC4O4·H2O obtained in Example 4 was mixed with boric acid as a co-solvent at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 170 °C and held for 72 hours. The temperature was then lowered to 100 °C at a rate of 0.5 °C / h, and then rapidly lowered to room temperature at a rate of 5 °C / h. This yielded a LiHC4O4·H2O birefringent crystal with dimensions of 4 mm × 3 mm × 2 mm.

[0099] Example 18

[0100] The solvothermal growth of lithium hydrated squaric acid birefringent crystal is carried out according to the following steps:

[0101] The polycrystalline powder of LiHC4O4·H2O obtained in Example 5 was mixed with boric acid as a co-solvent at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 180 °C and held for 80 hours. The temperature was then lowered to 100 °C at a rate of 0.8 °C / h, and then rapidly lowered to room temperature at a rate of 3 °C / h. This yielded a birefringent LiHC4O4·H2O crystal with dimensions of 8 mm × 6 mm × 5 mm.

[0102] Example 19

[0103] The solvothermal growth of lithium hydrated squaric acid birefringent crystal is carried out according to the following steps:

[0104] The polycrystalline powder of LiHC4O4·H2O obtained in Example 6 was mixed with boric acid as a co-solvent at a molar ratio of 1:3. The mixture was then transferred into the lining of a clean, uncontaminated 50 mL high-pressure reactor. The reactor was then tightly sealed and placed in a constant temperature chamber. The temperature was raised to 190 °C and held for 96 hours. The temperature was then lowered to 100 °C at a rate of 1 °C / h, and then rapidly lowered to room temperature at a rate of 5 °C / h. This yielded a LiHC4O4·H2O birefringent crystal with dimensions of 5 mm × 3 mm × 2 mm.

[0105] Example 20

[0106] Birefringent crystals of lithium hydrated succinate (LiHC4O4·H2O) grown by room temperature solution method:

[0107] The polycrystalline powder of any compound LiHC4O4·H2O obtained in Example 1 was placed in a clean glass container, 10 mL of distilled water was added, and then the mixture was ultrasonically treated to fully mix and dissolve. The mixture was then filtered through filter paper to obtain a mixed solution.

[0108] Place the obtained mixed solution in a clean Erlenmeyer flask, seal it with weighing paper, and place it in a static environment without shaking, pollution, or air convection. Make several small holes in the seal to adjust the evaporation rate of the water in the aqueous solution, and let it stand at room temperature for 10 days.

[0109] Seed crystals are obtained when crystal particles grow at the bottom of the container and the size of the crystal particles no longer changes significantly.

[0110] Select a high-quality seed crystal, suspend it in the prepared mixed solution, and allow it to grow at room temperature for 30 days to obtain a LiHC4O4·H2O birefringent crystal with dimensions of 10mm×8mm×2mm.

[0111] Example 21

[0112] The specific steps for growing hydrated lithium succinate birefringent crystals using the room temperature solution method are as follows:

[0113] The polycrystalline powder of compound LiHC4O4·H2O obtained in Example 2 was placed in a clean glass container, 20 mL of deionized water was added, and then the mixture was stirred and heated to fully mix and dissolve. The heating temperature was 40°C to prepare a saturated solution at the corresponding temperature, and the solution was kept at the temperature for 4 hours.

[0114] The obtained mixed solution was placed in a clean glass container, sealed with weighing paper, and placed in a static environment without shaking, pollution, or air convection. Several small holes were punched in the seal to adjust the evaporation rate of water in the aqueous solution. The solution was left to stand at room temperature for 20 days.

[0115] Seed crystals are obtained when crystal particles grow at the bottom of the container and the size of the crystal particles no longer changes significantly.

[0116] Select a high-quality seed crystal, suspend it in the prepared mixed solution, and let it grow at room temperature for 10 days to obtain a LiHC4O4·H2O birefringent crystal with dimensions of 5mm×4mm×2mm.

[0117] Example 22

[0118] The specific steps for growing hydrated lithium succinate birefringent crystals using the room temperature solution method are as follows:

[0119] The polycrystalline powder of compound LiHC4O4·H2O obtained in Example 3 was placed in a clean glass container, 30 mL of deionized water was added, and then the mixture was stirred and heated to fully mix and dissolve. The heating temperature was 50°C to prepare a saturated solution at the corresponding temperature, and the solution was kept at the temperature for 4 hours.

[0120] The obtained mixed solution was placed in a clean glass container, sealed with weighing paper, and placed in a static environment without shaking, pollution, or air convection. Several small holes were punched in the seal to adjust the evaporation rate of the water in the aqueous solution. The solution was left to stand at room temperature for 30 days.

[0121] Seed crystals are obtained when crystal particles grow at the bottom of the container and the size of the crystal particles no longer changes significantly.

[0122] Select a high-quality seed crystal, suspend it in the prepared mixed solution, and let it grow at room temperature for 15 days to obtain a LiHC4O4·H2O birefringent crystal with dimensions of 9mm×6mm×4mm.

[0123] Example 23

[0124] The specific steps for growing hydrated lithium succinate birefringent crystals using the room temperature solution method are as follows:

[0125] The polycrystalline powder of compound LiHC4O4·H2O obtained in Example 4 was placed in a clean glass container, 40 mL of deionized water was added, and then the mixture was stirred and heated to fully mix and dissolve. The heating temperature was 60°C to prepare a saturated solution at the corresponding temperature, and the solution was kept at the temperature for 4 hours.

[0126] The obtained mixed solution was placed in a clean glass container, sealed with weighing paper, and placed in a static environment without shaking, pollution, or air convection. Several small holes were punched in the seal to adjust the evaporation rate of the water in the aqueous solution. The solution was left to stand at room temperature for 40 days.

[0127] Seed crystals are obtained when crystal particles grow at the bottom of the container and the size of the crystal particles no longer changes significantly.

[0128] Select high-quality seed crystals, suspend them in the prepared mixed solution, and let them grow at room temperature for 25 days to obtain a LiHC4O4·H2O birefringent crystal with dimensions of 8mm×5mm×3mm.

[0129] Example 24

[0130] The specific steps for growing hydrated lithium succinate birefringent crystals using the room temperature solution method are as follows:

[0131] The polycrystalline powder of compound LiHC4O4·H2O obtained in Example 5 was placed in a clean glass container, 45 mL of deionized water was added, and then the mixture was stirred and heated to fully mix and dissolve. The heating temperature was 80°C to prepare a saturated solution at the corresponding temperature, and the solution was kept at the temperature for 4 hours.

[0132] The obtained mixed solution was placed in a clean glass container, sealed with weighing paper, and placed in a static environment without shaking, pollution, or air convection. Several small holes were punched in the seal to adjust the evaporation rate of the water in the aqueous solution. The solution was left to stand at room temperature for 50 days.

[0133] Seed crystals are obtained when crystal particles grow at the bottom of the container and the size of the crystal particles no longer changes significantly.

[0134] Select a high-quality seed crystal, suspend it in the mixed solution prepared in step b, and let it grow at room temperature for 30 days to obtain a LiHC4O4·H2O birefringent crystal with dimensions of 6mm×5mm×3mm.

[0135] Example 25

[0136] The specific steps for growing hydrated lithium succinate birefringent crystals using the room temperature solution method are as follows:

[0137] The polycrystalline powder of compound LiHC4O4·H2O obtained in Example 6 was placed in a clean glass container, 50 mL of deionized water was added, and then the mixture was stirred and heated to fully mix and dissolve. The heating temperature was 90°C to prepare a saturated solution at the corresponding temperature, and the solution was kept at the temperature for 4 hours.

[0138] The obtained mixed solution was placed in a clean glass container, sealed with weighing paper, and placed in a static environment without shaking, pollution, or air convection. Several small holes were punched in the seal to adjust the evaporation rate of the water in the aqueous solution. The solution was left to stand at room temperature for 60 days.

[0139] Seed crystals are obtained when crystal particles grow at the bottom of the container and the size of the crystal particles no longer changes significantly.

[0140] Select a high-quality seed crystal, suspend it in the prepared mixed solution, and let it grow at room temperature for 30 days to obtain a LiHC4O4·H2O birefringent crystal with a size of 6mm×6mm×5mm.

[0141] Example 26

[0142] A Gland-type prism was fabricated using any of the lithium hydrated succinate LiHC4O4·H2O birefringent crystals obtained in Examples 7-26.

[0143] The lithium hydrated squaric acid birefringent crystal is processed into two identical crystal prisms, such as... Figure 4 As shown, the light is incident perpendicularly along the crystallographic axis of the crystal, and the incident plane contains two other crystallographic axes. Two prisms are connected together along the inclined plane by a thin air layer; or the connecting layer between the two prisms can be replaced with optical adhesive of different refractive indices instead of air, thus obtaining polarizing prisms with different apex angles. By adjusting the apex angle of the prism, prism designs within the 330-2000nm transmission band of the crystal can be achieved. When a beam of light is incident perpendicularly to the incident plane, after passing through the first prism of the Glan prism, the directions of the two beams of light with mutually perpendicular polarization directions are not deflected. The incident angle on the inclined plane is equal to the angle between the inclined plane of the prism and the right-angled plane (i.e., the apex angle of the prism). By selecting a suitable prism apex angle, one beam of polarized light undergoes total internal reflection on the inclined plane, and the other beam of polarized light exits after passing through the connecting layer between the two prisms and the second prism.

[0144] Example 27

[0145] A Wollaston prism was fabricated using the lithium hydrated succinate LiHC4O4·H2O birefringent crystal obtained in any of Examples 7-26.

[0146] Two prisms are fabricated from lithium hydrated succinate birefringent crystals and then bonded together to form a Wollaston prism. Figure 5 As shown, the two prisms have the same apex angle, but the crystallographic axes contained in the incident and exit surfaces are different. The incident light is incident perpendicularly on the end face of the prism. Inside the prism, two beams of polarized light with mutually perpendicular polarization directions travel at different speeds along the same direction. When the light enters the second prism from the first prism, the refractive index changes because the crystallographic axis rotates 90° along the incident direction. The two linearly polarized beams are separated due to birefringence. When the two separated beams of polarized light enter the air from the second prism, they undergo a second birefringence and are further separated. The greater the birefringence of the crystal, the more favorable it is for the separation of the beams.

[0147] Example 28

[0148] A polarization beam splitter was fabricated using any of the lithium hydrated succinate LiHC4O4·H2O birefringent crystals obtained in Examples 7-26.

[0149] Lithium succinate birefringent crystals were used to fabricate wedge-shaped birefringent crystal polarization beam splitters (such as...). Figure 6 As shown, a wedge-shaped birefringent crystal, with the direction of light passing along the y-axis of the crystal, allows a beam of natural light to be incident along the optical principal axis y-axis and then split into two linearly polarized beams after passing through the crystal. The greater the birefringence, the farther the two beams can be separated, which facilitates the separation of the light beams.

[0150] Example 29

[0151] A polarization beam splitter was fabricated using any of the lithium hydrated succinate LiHC4O4·H2O birefringent crystals obtained in Examples 7-26.

[0152] Lithium succinate birefringent crystals are used to fabricate optical isolators. An optical isolator is constructed by placing a Faraday rotator with its incident beam polarization plane rotated by 45° between a pair of birefringent crystal deflectors placed at 45° angles to each other. This isolator allows only forward-propagating beams to pass through the system while blocking backward-propagating beams. Figure 7 'a' indicates that the incident light beam can pass through. Figure 7 b indicates that the reflected light is blocked.

Claims

1. A method for preparing a hydrated lithium squartz birefringent crystal, characterized in that... Crystals are grown using hydrothermal, solvothermal, or room-temperature solution methods. The hydrothermal growth of lithium hydrated squaric acid birefringent crystals is carried out according to the following steps: a. Mix the Li-containing compound and the HC4O4-containing compound evenly in a molar ratio of Li:HC4O4 = 1:1, add water, heat to 40-80℃ at a rate of 3-5℃ / h to prepare a saturated solution at the corresponding temperature, and keep at the temperature for 4 hours. Then, slowly cool and crystallize to obtain the compound LiHC4O4•H2O. The Li-containing compound is LiF, LiCl, LiBr, LiI, LiOH, or Li2CO3; the HC4O4-containing compound is H2C4O4. b. Mix the polycrystalline powder of LiHC4O4•H2O obtained in step a with distilled water or an organic polar solvent, dimethyl sulfoxide, at a molar ratio of 0.1:0.3-3. N , N - Mix dimethylformamide evenly and transfer it into the lining of a clean, uncontaminated 50 mL high-pressure reactor. Tightly seal the reactor and place it in a constant temperature chamber. Heat the mixture to 120-190℃ and hold it at that temperature for 12-96 hours. Then, cool the mixture to 100℃ at a rate of 0.05-1℃ / h, and then rapidly cool it to room temperature at a rate of 3-5℃ / h to obtain LiHC4O4•H2O birefringent crystals. The solvothermal growth of lithium hydrated squaric acid birefringent crystal is carried out according to the following steps: a. Mix the Li-containing compound and the HC4O4-containing compound evenly in a molar ratio of Li:HC4O4 = 1:1, add water, heat to 40-80℃ at a rate of 3-5℃ / h to prepare a saturated solution at the corresponding temperature, and keep at the temperature for 4 hours. Then, slowly cool and crystallize to obtain the compound LiHC4O4•H2O. The Li-containing compound is LiF, LiCl, LiBr, LiI, LiOH, or Li2CO3; the HC4O4-containing compound is H2C4O4. b. Mix the polycrystalline powder of LiHC4O4•H2O obtained in step a with the co-solvent boric acid at a molar ratio of 0-1:0.3-3. Transfer the mixture into the lining of a clean, uncontaminated 50 mL high-pressure reactor. Tightly seal the reactor and place it in a constant temperature chamber. Heat the mixture to 120-190℃ and hold it at that temperature for 12-96 hours. Then, cool the mixture to 100℃ at a rate of 0.05-1℃ / h, and then rapidly cool it to room temperature at a rate of 3-5℃ / h to obtain LiHC4O4•H2O birefringent crystals. The specific steps for growing hydrated lithium succinate birefringent crystals using the room temperature solution method are as follows: a. Mix the Li-containing compound and the HC4O4-containing compound evenly in a molar ratio of Li:HC4O4 = 1:1, add water, heat to 40-80℃ at a rate of 3-5℃ / h to prepare a saturated solution at the corresponding temperature, and keep at the temperature for 4 hours. Then, slowly cool and crystallize to obtain the compound LiHC4O4•H2O. The Li-containing compound is LiF, LiCl, LiBr, LiI, LiOH, or Li2CO3; the HC4O4-containing compound is H2C4O4. b. Place the polycrystalline powder of compound LiHC4O4•H2O obtained in step a into a clean glass container, add 10-50 mL of deionized water, then stir and heat to fully mix and dissolve. The heating temperature is 40-90℃ to prepare a saturated solution at the corresponding temperature, and keep it at the temperature for 4 hours. c. Place the mixed solution obtained in step b in a clean glass container, seal it with weighing paper, and place it in a static environment without shaking, pollution, or air convection. Make several small holes in the seal to adjust the evaporation rate of the water in the aqueous solution. Let it stand at room temperature for 10-60 days. d. After the solution in step c grows crystal particles at the bottom of the container until the size of the crystal particles no longer changes significantly, seed crystals are obtained. e. Select the seed crystal with better quality from step d, suspend it in the mixed solution prepared in step b, and let it grow at room temperature for 10-30 days to obtain LiHC4O4•H2O birefringent crystal.

2. The use of the lithium hydrated squaric acid birefringent crystal obtained by the method according to claim 1 in the preparation of optical isolators, circulators, beam shifters, optical polarizers or optical modulators.

3. The use according to claim 2, characterized in that... The optical polarizer is a polarizing beam splitter prism.

4. The use according to claim 3, characterized in that... The polarizing beam splitter is a Glan prism, a Wollaston prism, or a Lochte prism.

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