An optical crystal, its preparation method and its application

Abstract

This application discloses an optical crystal, its preparation method, and its application. The inorganic multifunctional crystal has the chemical formula AgVSeO5. The inorganic nonlinear optical crystal belongs to an orthorhombic crystal system; its space group is Pca21. This AgVSeO5 exhibits excellent infrared nonlinear optical properties; experimental measurements show that its nonlinear effect is 0.5 to 5 times that of commercial AgGaS2, and it can achieve phase matching. Therefore, this AgVSeO5 crystal has significant potential application value as a nonlinear optical material.

Description

Technical Field

[0001] This application relates to an optical crystal, its preparation method, and its application, and belongs to the field of inorganic materials. Background Technology

[0002] Nonlinear optical crystals are functional materials exhibiting nonlinear optical effects (SHG effect), enabling functions such as laser frequency conversion, laser intensity and phase modulation, and holographic storage of laser signals. They have wide applications in military and civilian high-tech optoelectronic materials. Currently, practically used nonlinear optical crystals include AgGaS2 (AGS), LiB3O5 (LBO), β-BaB2O4 (BBO), KH2PO4 (KDP), KTiOPO4 (KTP), and α-LiIO3. With the development of laser technology and the emergence of tunable lasers, nonlinear optical devices have developed rapidly, with laser frequency doubling, mixing, parametric oscillation and amplification; electro-optic modulation, deflection, Q-switching, and photorefractive devices appearing successively. These researches and applications have placed higher demands on the physical and chemical properties of nonlinear optical materials, further promoting their rapid development. Second-order nonlinear optical crystal materials must possess a non-centrosymmetric structure. Summary of the Invention

[0003] This application aims to provide an inorganic compound nonlinear optical crystal that exhibits a strong frequency doubling effect, with its powder SHG coefficient being 0.5 to 5 times that of AGS, and it can achieve phase matching, making it a nonlinear optical material with potential application value.

[0004] According to one aspect of this application, an optical crystal is provided, the optical crystal having the chemical formula AgVSeO5;

[0005] The optical crystal belongs to an orthorhombic crystal system;

[0006] The space group of the optical crystal is Pca21.

[0007] Optionally, the cell parameters of the optical crystal are: α=β=γ=90°, Z=8.

[0008] Optionally, the cell parameters of the optical crystal are: α=β=γ=90°, Z=8.

[0009] Optionally, the cell parameters of the optical crystal are: α=β=γ=90°, Z=8.

[0010] Optionally, in the optical crystal, V includes V1 and V2 sites, both of which are coordinated with six O to form VO6-I octahedrons and VO6-II octahedrons.

[0011] Optionally, the VO6-I octahedron and VO6-II octahedron share a common vertex O to form a "V-shaped" zigzag chain. Three adjacent parallel V-shaped zigzag chains are connected by triangular pyramidal SeO3 to form a "W-shaped" chain. Ag ions are connected to the O on the "W-shaped" chain through electrostatic interaction to form a three-dimensional structure.

[0012] Optionally, in AgVSeO5, V has two sites, V1 and V2. Both V1 and V2 coordinate with six O to form VO6-I octahedrons and VO6-II octahedrons. The VO6-I octahedrons and VO6-II octahedrons are connected by O at common vertices to form an infinitely long V-shaped zigzag chain. Three adjacent parallel "V-shaped" chains are connected by trigonal pyramidal SeO3 to form an infinitely long "W-shaped" chain. Ag ions are connected with O on the "W-shaped" chains through electrostatic interactions to form a three-dimensional structure.

[0013] Optionally, the ultraviolet absorption cutoff wavelength of the optical crystal is 620–660 nm.

[0014] Optionally, the ultraviolet absorption cutoff wavelength of the optical crystal is selected from any value of 620nm, 625nm, 630nm, 640nm, 650nm, 660nm or a range between any two of the above points.

[0015] Optionally, the frequency doubling effect of the optical crystal under 1910nm laser irradiation is 0.5 to 5 times that of AgGaS2.

[0016] Optionally, the optical crystal exhibits a second-order nonlinear optical SHG effect.

[0017] Optionally, the optical crystal has a transmittance of ≥83% in the wavelength range of 1000–4000 nm.

[0018] According to another aspect of this application, a method for preparing the above-described optical crystal is provided, the method comprising:

[0019] In a sealed container, a mixture containing Ag source, V source, Se source and water is reacted and cooled to obtain an optical crystal.

[0020] Optionally, the Ag source is selected from at least one of Ag oxides, Ag halides, silver salts, and silver ion standard solutions.

[0021] Optionally, the Ag source is selected from at least one of silver oxide, silver fluoride, silver chloride, silver bromide, silver iodide, silver carbonate, silver acetate, silver phosphate, silver tetrafluoroborate, silver perchlorate, silver benzoate, silver iodate, silver nitrate, silver metavanadate, silver perchlorate hydrate, silver chromate, silver tungstate, silver trifluoroacetate, silver selenide, silver telluride, silver hexafluorophosphate, concentrated silver nitrate solution, silver sulfate, and silver ion standard solution.

[0022] Optionally, the V source is selected from at least one of V oxides, vanadium powder, vanadium halides, and vanadates.

[0023] Optionally, the V source is selected from vanadium oxide (V₂O₄), vanadium oxide (V₂O₃), and vanadium oxide (V₆O₄). 13 Vanadium pentoxide, vanadium powder, vanadium oxychloride, vanadium chloride, vanadium fluoride (F3OV), vanadium fluoride (VF3), vanadium boride, vanadium sulfide, gallium vanadium vanadate, vanadium oxysulfate, sodium orthovanadate, sodium metavanadate, sodium metavanadate hydrate, ammonium metavanadate, potassium metavanadate, silver metavanadate, potassium orthovanadate, cesium orthovanadate, cesium metavanadate, lead metavanadate, bismuth vanadate.

[0024] Optionally, the Se source is selected from at least one of selenium dioxide, selenium disulfide, selenide, selenite, selenite salt, selenite hydrate, and selenium standard solution.

[0025] Optionally, the Se source is selected from at least one of selenium dioxide, selenium disulfide, nickel selenide, zinc selenide, molybdenum selenide, gallium selenide, iron selenide, copper selenide, cadmium selenide, aluminum selenide, tungsten selenide, indium selenide, sodium selenide, selenium tetrachloride, selenium chloride (Cl2Se2), selenium bromide (SeBr4), tin dichloride oxide, potassium selenite, selenite, sodium selenite, zinc selenite, selenite, selenite hydrate, and selenium standard solution.

[0026] Optionally, the pH adjuster is selected from at least one of the following: strong base-weak acid salt, strong acid-weak base salt, strong acid solution, medium-strong acid solution, weak acid solution, strong base and its solution, and weak base and its solution.

[0027] Optionally, the pH adjuster is selected from at least one of ammonium carbonate, ammonium bicarbonate, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, acetic acid solution, potassium acetate, sodium acetate, hydrochloric acid, ammonium chloride, phosphoric acid, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, potassium phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, nitric acid, ammonium nitrate, sulfuric acid, ammonium sulfate, ammonium dihydrogen sulfate, ammonium bisulfate, ammonia solution, potassium hydroxide, and sodium hydroxide.

[0028] Optionally, the molar ratio of Ag source:V source:Se source:pH adjuster:water is 1:0.01~200:0.01~600:0.01~500:1~2000;

[0029] The number of moles of Ag source is calculated based on the number of moles of Ag element contained therein, the number of moles of V source is calculated based on the number of moles of V element contained therein, the number of moles of Se source is calculated based on the number of moles of Se element contained therein, and the pH adjuster is calculated based on the number of moles of the active ingredient.

[0030] Optionally, the molar ratio of Ag source:V source:Se source:pH adjuster:water is 1:0.01~100:0.1~400:0.01~300:10~1500;

[0031] The number of moles of Ag source is calculated based on the number of moles of Ag element contained therein, the number of moles of V source is calculated based on the number of moles of V element contained therein, the number of moles of Se source is calculated based on the number of moles of Se element contained therein, and the pH adjuster is calculated based on the number of moles of the active ingredient.

[0032] Optionally, the molar ratio of Ag source:V source:Se source:pH adjuster:water is 1:0.05~80:0.1~300:0.1~100:20~1000;

[0033] The number of moles of Ag source is calculated based on the number of moles of Ag element contained therein, the number of moles of V source is calculated based on the number of moles of V element contained therein, the number of moles of Se source is calculated based on the number of moles of Se element contained therein, and the pH adjuster is calculated based on the number of moles of the active ingredient.

[0034] Optionally, in the mixture, the silver ions are derived from silver nitrate, the vanadium is derived from vanadium trioxide, and the selenium is derived from selenium dioxide; the pH adjuster is an aqueous ammonia solution.

[0035] Optionally, the ammonia solution is selected from a 22-25 wt% ammonia solution.

[0036] Optionally, in the mixture, the silver ions are derived from silver nitrate, the vanadium element is derived from vanadium trioxide, the selenium element is derived from selenium dioxide, and the pH adjuster is an ammonia solution. The water in this case is derived from the ammonia solution and added deionized water.

[0037] Optionally, the reaction temperature is 100℃~320℃, and the reaction time is 4h~1000h.

[0038] Optionally, the temperature of the reaction is independently selected from any value or a range between any two of 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, and 320°C.

[0039] Optionally, the reaction time is independently selected from any value or a range between any two of the following: 4h, 6h, 12h, 24h, 30h, 40h, 50h, 62h, 72h, 80h, 100h, 120h, 140h, 160h, 180h, 210h, 240h, 260h, 280h, 300h, 320h, 340h, 360h, 380h, 400h, 420h, 440h, 460h, 480h, 500h, 520h, 540h, 560h, 580h, 600h, 620h, 640h, 660h, 680h, 700h, 720h, 740h, 760h, 780h, 800h, and 1000h.

[0040] Optionally, the reaction temperature is 150℃~300℃, and the reaction time is 6h~800h.

[0041] Optionally, the cooling rate is 0.01℃ / h to 20℃ / h.

[0042] Optionally, the cooling rate is independently selected from any value or a range between 0.01℃ / h, 0.05℃ / h, 0.1℃ / h, 1℃ / h, 2℃ / h, 3℃ / h, 4℃ / h, 6℃ / h, 8℃ / h, 10℃ / h, 13℃ / h, 15℃ / h, 18℃ / h, and 20℃ / h.

[0043] Optionally, the cooling rate is 0.01℃ / h to 15℃ / h.

[0044] Optionally, the cooling rate is 0.01℃ / h to 10℃ / h.

[0045] According to another aspect of this application, an application is provided of the optical crystal described above and the optical crystal prepared by the preparation method described above in a laser frequency converter.

[0046] This application provides a method for preparing optical crystals, employing a hydrothermal crystallization method to grow red, elongated AgVSeO5 crystals. The method is simple and yields high-purity, highly crystalline inorganic compound AgVSeO5 crystal materials.

[0047] As one embodiment of this application, the method for preparing inorganic compound crystals includes the following steps:

[0048] Raw materials containing silver, vanadium, selenium, pH adjuster, and water are mixed and placed in a reaction vessel lined with polytetrafluoroethylene. After sealing, the mixture is crystallized at a crystallization temperature of 100℃ to 320℃ for more than 4 hours. After crystallization, the system is cooled to room temperature at a rate not exceeding 20℃ per hour. The solid sample obtained after separation, washing, and drying is the inorganic compound crystal.

[0049] The inorganic compound crystals prepared by the hydrothermal method are red, elongated crystals.

[0050] The beneficial effects that this application can produce include:

[0051] 1) This application provides an inorganic nonlinear optical crystal, AgVSeO5, which exhibits a powder frequency doubling effect 0.5 to 5 times that of AGS under 1910nm laser irradiation and can achieve phase matching. Therefore, AgVSeO5 crystal has great potential application value as a nonlinear optical material.

[0052] 2) The inorganic compound crystal AgVSeO5 provided in this application has a high transmittance in the spectral range of 1000 to 4000 nm and its ultraviolet absorption cutoff wavelength is about 644 nm. It is a high-performance potential infrared nonlinear optical material.

[0053] 3) The method for preparing an inorganic nonlinear optical crystal provided in this application employs a hydrothermal crystallization method to grow red, elongated AgVSeO5 crystals. The method is simple and yields high-purity, highly crystalline inorganic compound AgVSeO5 crystal material. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the crystal structure of the inorganic compound crystal AgVSeO5 in Example 1 of this application.

[0055] Figure 2 The X-ray diffraction pattern of sample 1# obtained by fitting the crystal structure obtained by single-crystal X-ray diffraction analysis is compared with the X-ray diffraction pattern obtained after the sample is ground into powder.

[0056] Figure 3 The infrared spectrum of sample 1# in this application.

[0057] Figure 4 This is the ultraviolet spectrum of sample 1# of this application.

[0058] Figure 5 This is a comparison diagram of the frequency doubling effect of sample 1# in this application and the frequency doubling effect of AGS. Detailed Implementation

[0059] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0060] Unless otherwise specified, the raw materials used in the embodiments of this application are all purchased commercially and used directly without processing, and the instruments and equipment used adopt the schemes and parameters recommended by the manufacturers.

[0061] In this application, "room temperature" means 30±5℃.

[0062] In this application, single-crystal X-ray diffraction was performed using an Agilent Technologies SuperNova CCD X-ray single-crystal diffractometer.

[0063] Powder X-ray diffraction was performed using a Miniflex II X-ray powder diffractometer from Rigaku Corporation of Japan.

[0064] A Perkin-Elmer Lambda-950 UV-Vis-NIR spectrophotometer was used.

[0065] Example 1: Hydrothermal Synthesis of AgVSeO5 Sample

[0066] Raw materials containing silver, vanadium, selenium, pH adjuster, and water were mixed and placed in a reaction vessel lined with polytetrafluoroethylene. After sealing, the mixture was crystallized at a temperature of 100℃–320℃ for at least 4 hours. After crystallization, the system was cooled to room temperature at a rate not exceeding 20℃. After separation, washing, and drying, a red, elongated solid sample was obtained, which is the sample of the inorganic compound crystal. The crystal structure of AgVSeO5 is as follows: Figure 1 As shown, in AgVSeO5, V has two sites, V1 and V2. Both V1 and V2 coordinate with six O to form VO6-I octahedrons and VO6-II octahedrons. The VO6-I octahedrons and VO6-II octahedrons are connected by O at common vertices to form an infinitely long "V-shaped" zigzag chain. Three adjacent parallel "V-shaped" chains are connected by trigonal pyramidal SeO3 to form an infinitely long "W-shaped" chain. Ag ions are connected with O on the "W-shaped" chains through electrostatic interactions to form a three-dimensional structure.

[0067] The sample number, raw material type and amount, crystallization temperature and holding time, and cooling rate are shown in Table 1. Among them, NH3·H2O (22-25wt%) refers to an ammonia aqueous solution with a mass fraction of 22-25%.

[0068] Table 1

[0069]

[0070] Example 2 Crystal Structure Analysis

[0071] The structure of samples 1# to 3# was analyzed by single-crystal X-ray diffraction.

[0072] Single-crystal X-ray diffraction was performed using an Agilent Technologies SuperNova CCD single-crystal X-ray diffractometer. Data was collected at 293 K, and the diffraction source was graphite-monochromatic Mo-Kα rays. The scanning mode was ω-2θ; the data underwent absorption correction using the Multi-Scan method. Structural analysis was performed using the SHELXTL-2014 package; the positions of heavy atoms were determined using a direct method, and the coordinates of the remaining atoms were obtained using difference Fourier synthesis; F-based... 2 The full matrix least squares method is used to refine the coordinates and anisotropic thermal parameters of all atoms.

[0073] Powder X-ray diffraction was performed on a Miniflex II X-ray powder diffractometer from Rigaku Corporation, Japan. The test conditions were a fixed target, a monochromatic Cu-Kα light source, and a wavelength of [missing information]. The voltage and current are 30kV / 15A, the scanning range is 10~60°, and the scanning step is 0.02°.

[0074] The results showed that samples 1# to 3# were all pure phases. Taking sample 1# as an example, the single-crystal X-ray diffraction pattern obtained by fitting the crystal structure resolved by single-crystal X-ray diffraction was compared with the diffraction pattern obtained by X-ray diffraction after the sample was ground into powder. Figure 2 As shown, single-crystal X-ray diffraction results indicate that samples 1# to 3# all have the chemical formula AgVSeO5, belong to the orthorhombic crystal system, have the space group Pca21, and have the cell parameters [missing information]. α=β=γ=90°, Z=8.

[0075] Taking sample 1# as a typical example, Table 2 shows the single-crystal X-ray diffraction results. It can be seen that sample 1# belongs to the orthorhombic crystal system, with space group Pca21 and cell parameters of [missing information]. α=γ=β=90°, Z=8.

[0076] Table 2 Crystal parameters of AgVSeO5

[0077]

[0078] Taking sample 1# as a typical example, such as Figure 2 As shown, based on the crystal structure resolved by single-crystal X-ray diffraction, the fitted X-ray diffraction pattern is consistent with the pattern obtained by X-ray diffraction testing of sample 1# after it has been ground into powder, showing consistent peak positions and intensities. This indicates that the obtained samples all have high purity.

[0079] Example 3: Diffuse Reflectance Absorption Spectroscopy Test

[0080] like Figure 3 As shown, using sample 1# as an example, diffuse reflectance absorption spectroscopy of AgVSeO5 was performed on a PerkinElmer Lambda-950 UV-Vis-NIR spectrophotometer. The crystalline sample was ground into powder, with BaSO4 used as the reference substrate. The test results are as follows. Figure 3 and Figure 4 As shown, the crystals of the compound AgVSeO5 have a wide transmission range, with high transmittance in the 1000–4000 nm spectral range, and transmittance of not less than 83% in the 1000–4000 nm spectral range. The ultraviolet absorption cutoff wavelength is about 640 nm.

[0081] The diffuse reflectance absorption spectrum test results of samples 2# and 3# are consistent with those of sample 1#.

[0082] Example 4: Frequency doubling test experiment and results

[0083] like Figure 5 As shown, taking sample 1# as a typical example, frequency doubling tests were performed on the inorganic compound crystal AgVSeO5. The specific steps are as follows: A Q-switched Nd:YAG solid-state laser with a frequency converter was used to generate a 1910nm wavelength laser as the fundamental frequency light to irradiate the tested crystal powder. The generated second harmonic was detected using a photomultiplier tube, and the harmonic intensity was displayed on an oscilloscope. The test results show that the SHG coefficient of the AgVSeO5 powder under 1910nm laser irradiation is 0.5 to 3 times that of AGS.

[0084] The frequency doubling test results of samples 2# and 3# are consistent with those of sample 1#.

[0085] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An optical crystal, characterized in that, The chemical formula of the optical crystal is AgVSeO5; The optical crystal belongs to an orthorhombic crystal system; The space group of the optical crystal is Pca21; The unit cell parameters of the optical crystal are a = 10.9897 (3) Å, b = 10.3985 (3) Å, c = 7.4402 (2) Å, α = γ = β = 90°, and Z = 8.

2. The optical crystal according to claim 1, characterized in that, The ultraviolet absorption cutoff wavelength of the optical crystal is 620~660 nm; The frequency doubling effect of the optical crystal under 1910 nm laser irradiation is 0.5 to 5 times that of AgGaS2; The optical crystal exhibits a second-order nonlinear optical SHG effect. The optical crystal has a transmittance of ≥83% in the wavelength range of 1000~4000 nm.

3. The method for preparing the optical crystal according to any one of claims 1 to 2, characterized in that, The preparation method includes: In a closed container, a mixture containing Ag source, V source, Se source, pH adjuster and water is reacted and cooled to obtain an optical crystal. The pH adjuster is an aqueous ammonia solution; The ammonia solution is selected from a 22-25 wt% ammonia solution.

4. The preparation method according to claim 3, characterized in that, The Ag source is selected from at least one of Ag oxides and Ag halides; The V source is selected from at least one of V oxides, vanadium powder, vanadium halides, and vanadates; The Se source is selected from at least one of selenium dioxide, selenium disulfide, selenite, and selenite.

5. The preparation method according to claim 3, characterized in that, The reaction temperature is 100℃~320℃, and the reaction time is 4h~1000h.

6. The preparation method according to claim 3, characterized in that, The reaction temperature is 150℃~300℃, and the reaction time is 6h~800h.

7. The preparation method according to claim 3, characterized in that, The cooling rate is 0.01℃ / h ~ 20℃ / h.

8. The preparation method according to claim 3, characterized in that, The cooling rate is 0.01℃ / h to 15℃ / h.

9. The preparation method according to claim 3, characterized in that, The cooling rate is 0.01℃ / h to 10℃ / h.

10. The application of the optical crystal according to any one of claims 1 to 2, or the optical crystal prepared by the preparation method according to any one of claims 3 to 9, in a laser frequency converter.

Images