Preparation method of large-size nonlinear optical crystal NaI3O8
By controlling the raw material ratio and cooling rate through the hydrothermal synthesis method, large-sized nonlinear optical crystal NaI3O8 was prepared, which solved the problem of high risk in the preparation process and achieved safe and simple crystal growth and the acquisition of high-purity crystal materials.
Patent Information
- Application Number
- CN202410493018.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-23
- Publication Date
- 2025-10-24
AI Technical Summary
In the existing technology, the preparation process of iodate nonlinear optical crystal material NaI3O8 is highly dangerous, difficult to achieve large-scale industrialization, and the preparation process is complex and has low safety.
The large-sized nonlinear optical crystal NaI3O8 was prepared by hydrothermal synthesis method using iodine pentoxide and sodium nitrate as raw materials, controlling the raw material ratio and cooling rate, avoiding the use of hazardous substances such as concentrated nitric acid and simplifying the preparation process.
Large-sized, high-purity NaI3O8 crystals with strong frequency doubling effect were successfully prepared. They have a short growth cycle, high safety, simplified preparation process and reduced environmental pollution risks.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of nonlinear optical crystal preparation, and particularly relates to a preparation method of large-size nonlinear optical crystal NaI3O8. BACKGROUND
[0002] The information disclosed in this Background section is for the purpose of generally presenting the context of the application. The information disclosed in this Background section is not to be necessarily taken as an acknowledgement or any form of suggestion that this information forms part of the prior art already known to a person skilled in the art.
[0003] Nonlinear optical crystal material is a kind of material with special optical properties. They can produce nonlinear optical effects under the action of external light field, realize the conversion of laser frequency, including frequency multiplication, sum frequency, difference frequency, optical parametric oscillation and phase modulation of light waves. These effects make the wavelength of laser can be expanded to new bands, especially in the infrared and ultraviolet regions, greatly enriching the available spectral resources, and providing new laser wavelengths for scientific research and industrial applications. It has wide application prospects in military and civilian fields, such as laser weapons, nuclear fusion laser drive, laser communication, optical storage and measurement, etc.
[0004] At present, the nonlinear optical crystal materials that have realized industrialization and application mainly include potassium dihydrogen phosphate (KDP), potassium titanyl phosphate (KTP), lithium niobate (LiNbO3) and barium borate (BBO) etc. However, compared with iodate nonlinear optical crystal materials, there is still a big gap in their second-order nonlinear optical coefficients. Therefore, in recent years, the development and research of new iodate nonlinear optical crystal materials has become a hot spot. The macroscopic nonlinear optical performance of iodate crystal is mainly the geometric superposition effect of the micro nonlinear optical coefficient of IO3 - group. Due to the different arrangement ways of IO3 - group in the crystal structure and the synergistic effect of the oxygen octahedron distortion of transition metal ions, the nonlinear optical performance of iodate crystal is significantly improved, and many strong frequency doubling effect composite iodate crystal materials are reported. For example, Isabelle et al. prepared a nonlinear optical crystal material NaI3O8 with a new structure by a volatilization method, which has a size of 2*2*5mm 3 , belongs to tetragonal system, and the space group is The structure contains [I3O8] - group. [I3O8] -And four sodium ions are connected to form a complex three-dimensional network structure, has strong powder frequency doubling effect, high laser damage threshold and very wide light transmission range. However, its preparation process adds concentrated nitric acid and volatilizes at 60 DEG C, because concentrated nitric acid has strong corrosive property, the requirement to equipment is relatively high, slight carelessness, easy to cause more serious harm to the staff, the production safety is low, which limits its industrialization.
[0005] Therefore, it is of great significance to prepare a new iodate nonlinear optical crystal material NaI3O8 with large size and strong frequency doubling effect by a simple method. SUMMARY
[0006] In order to solve the problems of the prior art, the purpose of the present application is to provide a preparation method of large-size nonlinear optical crystal NaI3O8, the present application uses diiodine pentoxide and sodium nitrate as raw materials, adopts hydrothermal synthesis method to grow crystal, and realizes the preparation of large-size nonlinear optical crystal NaI3O8 by controlling the proportion of raw materials and the cooling rate, the preparation method is simple, and the crystal growth period is short.
[0007] In order to achieve the above purpose, the technical scheme of the present application is:
[0008] The first aspect of the present application provides a preparation method of large-size nonlinear optical crystal NaI3O8, which adopts hydrothermal synthesis method to grow crystal, and includes the following steps:
[0009] The diiodine pentoxide, sodium nitrate and water are mixed and sealed in a hydrothermal reaction kettle for hydrothermal reaction, heated to 170-190 DEG C, constant temperature, and then cooled to room temperature at a cooling rate of ≤6 DEG C / h, to obtain large-size nonlinear optical crystal NaI3O8.
[0010] The advantage of using hydrothermal synthesis method to explore new materials mainly lies in that the crystal surface characteristics of the synthesized crystal are obvious, the crystal defects are less, and the thermal stress is small. However, there is no specific reaction path for synthesizing nonlinear optical crystal NaI3O8 by hydrothermal method at present, and it is still in the state of groping. Therefore, the final product of hydrothermal synthesis method may not be consistent with the expectation, and various factors affecting the reaction need to be considered and analyzed, such as reasonable use of raw material ratio, solvent type and reaction temperature.
[0011] The application designs a simple preparation technique of NaI3O8, uses diiodine pentoxide and sodium nitrate as raw materials, adopts a hydrothermal synthesis method, successfully obtains large-size nonlinear optical crystal NaI3O8 by controlling raw material ratio and cooling rate, and has the advantages of simple preparation method, short crystal growth period, large size and high purity.
[0012] In some embodiments of the application, the molar ratio of diiodine pentoxide, sodium nitrate and water is 1:(0.5-1):(15-15.5). In the application, the amount of water needs to be strictly controlled, and exceeding the ratio will affect crystallization.
[0013] Preferably, the molar ratio of diiodine pentoxide, sodium nitrate and water is 1:1:(15-15.5). Under this ratio, large-size nonlinear optical crystal NaI3O8 can be further obtained.
[0014] The application does not have strict requirements for the heating and constant temperature stages of the hydrothermal reaction, and full dissolution of diiodine pentoxide and sodium nitrate can be achieved. For example, the hydrothermal reaction is preferably: heating to 170-190 DEG C for 0.5-2h, constant temperature for 1-2h, and then cooling to room temperature at a cooling rate of ≤6 DEG C / h.
[0015] In the application, the cooling rate during the hydrothermal reaction is very critical. If the cooling rate is too fast, the growth of the crystal will be affected, and large-size nonlinear optical crystal NaI3O8 cannot be prepared. Therefore, the application limits the maximum limit of the heating rate, which is 6 DEG C / h. The lower the cooling rate, the slower the cooling, and the more conducive to obtaining larger-size nonlinear optical crystal NaI3O8, but the crystal growth period is relatively long. To balance the crystal size and growth period, the cooling rate is preferably 5 DEG C / h.
[0016] In some embodiments of the application, the hydrothermal reaction is: heating to 180 DEG C for 2h, constant temperature for 2h, and then cooling to room temperature at a cooling rate of ≤6 DEG C / h.
[0017] In some embodiments of the application, the hydrothermal reaction is: heating to 180 DEG C for 2h, constant temperature for 2h, and then cooling to room temperature at a cooling rate of 5 DEG C / h.
[0018] In some embodiments of the application, the room temperature is ≤40 DEG C.
[0019] In some embodiments of the application, the large-size nonlinear optical crystal NaI3O8 prepared by the hydrothermal synthesis method has a size of 4*4*3mm 3 -6*4*3mm 3 ;
[0020] The crystal structure of the large-size nonlinear optical crystal NaI3O8 belongs to a tetragonal system, and a point group is The space group is Without a center of symmetry; the cell parameters thereof are Alpha = beta = gamma = 90 degrees, Z = 2, and the cell volume is
[0021] The crystal structure of the large-size nonlinear optical crystal NaI3O8 obtained in the application is jointly constituted by Na + and [I3O8] - groups, and the [I3O8] - group is formed by one IO4 3- group and two IO3 - groups sharing O atoms as vertices, wherein the Na atom is connected with 8 O atoms around the Na atom, and the 8 O atoms belong to 4 IO3 - groups around the Na atom, as shown in the formula (I). Figure 1
[0022] The nonlinear optical crystal NaI3O8 obtained by the hydrothermal synthesis method in the application is millimeter level, large in size, simple in preparation method, short in crystal growth period, and has a strong frequency doubling effect.
[0023] In a second aspect of the application, a laser frequency conversion device is provided, and the optical crystal in the laser frequency conversion device is the large-size nonlinear optical crystal NaI3O8 obtained by the preparation method in the first aspect.
[0024] In some embodiments of the application, the laser frequency conversion device is a harmonic generator in a middle and far infrared region or an optical parametric device in a middle and far infrared region.
[0025] In some embodiments of the application, the laser frequency conversion device is a frequency doubling laser frequency conversion device, a three-fold frequency laser frequency conversion device, a four-fold frequency laser frequency conversion device, a five-fold frequency laser frequency conversion device or a six-fold frequency laser frequency conversion device.
[0026] Compared with the prior art, the application has the following beneficial effects:
[0027] The application provides a preparation method of a large-size nonlinear optical crystal NaI3O8, and the large-size nonlinear optical crystal NaI3O8 is successfully obtained by using diiodine pentoxide and sodium nitrate as raw materials, adopting a hydrothermal synthesis method, and controlling the raw material ratio and the cooling rate, the preparation method is simple, the crystal growth period is short, and the size is large (up to 6*4*3mm 3 The prepared NaI3O8 has high purity, and no dangerous substance such as nitric acid is used, so that the preparation process is safe. Meanwhile, the method does not increase the structural and process complexity, and is convenient to prepare and does not increase environmental pollution. The obtained NaI3O8 crystal material is subjected to powder frequency doubling test by using a Q-switched Nd:YAG laser with a wavelength of 1064 nm as the fundamental light, and the result shows that the crystal material has strong frequency doubling effect. BRIEF DESCRIPTION OF DRAWINGS
[0028] The accompanying drawings, which form a part of the specification, are included to provide a further understanding of the application and are incorporated herein in conjunction with the description of the application. The embodiments of the present application, together with its advantages, can best be understood by referring to the following description taken in conjunction with the accompanying drawings in which:
[0029] Figure 1 The crystal structure schematic diagram of the large-size nonlinear optical crystal NaI3O8 prepared in the embodiment of the present application, wherein (a) is a schematic diagram obtained by projecting along the a-axis direction, and (b) is a schematic diagram obtained by projecting along the c-axis direction;
[0030] Figure 2 The X-ray diffraction pattern of the large-size nonlinear optical crystal NaI3O8 prepared in the embodiment 1 of the present application, wherein Powder represents the X-ray diffraction pattern measured after the crystal is ground into powder, and Crystal represents the X-ray diffraction pattern obtained by fitting the single crystal structure;
[0031] Figure 3 The actual object diagram of the large-size nonlinear optical crystal NaI3O8 prepared in the embodiment 1 of the present application. DETAILED DESCRIPTION
[0032] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below with specific embodiments.
[0033] In the following examples, the experimental methods are conventional methods unless otherwise specified; and the reagents and materials, etc. are commercially available unless otherwise specified.
[0034] Embodiment 1
[0035] A preparation method of a large-size nonlinear optical crystal NaI3O8, comprising the steps of: weighing I2O5 6g (18mmol) and NaNO3 1.53g (18mmol) and loading into a reaction kettle with a polytetrafluoroethylene lining, adding 5mL ultrapure water and stirring uniformly, sealing, and placing in a program-controlled temperature oven, and setting the temperature rising and falling program as follows: rising from room temperature to 180℃ for 2 hours, keeping constant temperature for 2 hours, and then falling to 40℃ at a rate of 5℃ per hour, to obtain colorless block-shaped NaI3O8 crystal.
[0036] The obtained growth results show that the size of the obtained colorless block NaI3O8 crystal is 6*4*3mm 3 , and the yield is high, up to 85%.
[0037] Example 2
[0038] A preparation method of a large-size nonlinear optical crystal NaI3O8, comprising the steps of: weighing I2O5 6g (18mmol) and NaNO3 0.765g (9mmol) and loading into a reaction kettle with a polytetrafluoroethylene lining, adding 5mL of ultrapure water and stirring uniformly, sealing, and placing in a program-controlled temperature oven, and setting the temperature rising and falling program as: rising from room temperature to 180℃ for 2 hours, keeping constant temperature for 2 hours, and then falling to 40℃ at a rate of 5℃ per hour, to obtain colorless block NaI3O8 crystal.
[0039] The obtained growth results show that the size of the obtained colorless block NaI3O8 crystal is 5*4*3mm 3 .
[0040] Example 3
[0041] A preparation method of a large-size nonlinear optical crystal NaI3O8, comprising the steps of: weighing I2O5 3g (9mmol) and NaNO3 0.765g (9mmol) and loading into a reaction kettle with a polytetrafluoroethylene lining, adding 2.5mL of ultrapure water and stirring uniformly, sealing, and placing in a program-controlled temperature oven, and setting the temperature rising and falling program as: rising from room temperature to 180℃ for 2 hours, keeping constant temperature for 2 hours, and then falling to 40℃ at a rate of 5℃ per hour, to obtain colorless block NaI3O8 crystal.
[0042] The obtained growth results show that the size of the obtained colorless block NaI3O8 crystal is 4*4*3mm 3 .
[0043] Example 4
[0044] A preparation method of a large-size nonlinear optical crystal NaI3O8, which is different from example 1 in that the falling rate is 3℃ per hour, and the remaining steps are the same as those of example 1. Colorless block NaI3O8 crystal is obtained.
[0045] The obtained growth results show that the size of the obtained colorless block NaI3O8 crystal is similar to that of example 1.
[0046] Comparative Example 1
[0047] A preparation method of a large-size nonlinear optical crystal NaI3O8, which is different from example 1 in that the cooling rate is 7 ℃ per hour, and the remaining steps are consistent with those of example 1. Small-size colorless block-shaped NaI3O8 polycrystal is obtained, and no large-size single crystal is obtained.
[0048] It can be seen that the cooling rate will affect the crystal size and growth, and will have an impact on the preparation result. Slow cooling is beneficial to the growth of large-size single crystal, and rapid cooling is easy to cause burst nucleation, forming small-size crystal or polycrystal.
[0049] Comparative example 2
[0050] A preparation method of a large-size nonlinear optical crystal NaI3O8, which is different from example 3 in that 3g (9mmol) of I2O5 and 0.765g (9mmol) of NaNO3 are weighed, and 3mL of ultrapure water is added to stir uniformly and then loaded into a reaction kettle with a polytetrafluoroethylene lining. The remaining steps are consistent with those of example 3. Colorless block-shaped NaI3O8 crystal cannot be obtained.
[0051] It can be seen that the amount of water needs to be strictly controlled, and exceeding the ratio defined in the application will affect crystallization.
[0052] Comparative example 3
[0053] A preparation method of a large-size nonlinear optical crystal NaI3O8, which comprises the steps of weighing 3g (9mmol) of I2O5 and 1.35g (9mmol) of NaI and loading them into a reaction kettle with a polytetrafluoroethylene lining, adding 2mL of ultrapure water to stir uniformly, sealing, and placing in a program-controlled oven, and setting the temperature rising and falling program as follows: rising from room temperature to 180℃ for 2 hours, keeping constant temperature for 2 hours, and then cooling to 30℃ at a rate of 5℃ per hour. Colorless block-shaped NaI3O8 crystal cannot be obtained.
[0054] It can be seen that the amount of water needs to be strictly controlled, and less than the ratio defined in the application will also affect crystallization.
[0055] Comparative example 4
[0056] A preparation method of a large-size nonlinear optical crystal NaI3O8, which is different from example 1 in that sodium iodide is used instead of sodium nitrate, and the amount of sodium iodide is 2.7g (18mmol), and the remaining steps are consistent with those of example 1. Small-size colorless block-shaped NaI3O8 polycrystal is obtained, and no large-size single crystal is obtained.
[0057] It can be seen that the type of sodium salt will have an impact on the preparation result. Using sodium nitrate is beneficial to the preparation of large-size nonlinear optical crystal NaI3O8.
[0058] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.
Claims
1. A method for preparing a large-size nonlinear optical crystal NaI3O8, characterized in that, The crystal is grown by a hydrothermal synthesis method, comprising the following steps: The diiodine pentoxide, sodium nitrate and water are mixed and sealed in a hydrothermal reactor, and then hydrothermal reaction is carried out, the temperature is raised to 170-190 DEG C, and then the temperature is kept constant, and then the temperature is reduced to room temperature at a rate of ≤6 DEG C / h, to obtain the large-size nonlinear optical crystal NaI3O8.
2. The method for preparing a large-scale nonlinear optical crystal NaI3O8 according to claim 1, characterized in that: The molar ratio of the diiodine pentoxide, sodium nitrate and water is 1:(0.5-1):(15-15.5).
3. The method for preparing a large-scale nonlinear optical crystal NaI3O8 according to claim 1, characterized in that: The molar ratio of the diiodine pentoxide, sodium nitrate and water is 1:1:(15-15.5).
4. The method for preparing a large-scale nonlinear optical crystal NaI3O8 according to claim 1, characterized in that: The hydrothermal reaction is that the temperature is raised to 170-190 DEG C at a rate of 0.5-2 h, the temperature is kept constant for 1-2 h, and then the temperature is reduced to room temperature at a rate of ≤6 DEG C / h.
5. The method of claim 4, wherein the large size nonlinear optical crystal NaI308 is prepared by the method, characterized in that, The hydrothermal reaction is that the temperature is raised to 180 DEG C at a rate of 2 h, the temperature is kept constant for 2 h, and then the temperature is reduced to room temperature at a rate of ≤6 DEG C / h.
6. The method of claim 1, wherein the large size nonlinear optical crystal NaI308 is prepared by the method, characterized in that, The room temperature is ≤40 DEG C.
7. The method of claim 1, wherein the large size nonlinear optical crystal NaI308 is prepared by the method, characterized in that, The size of the large-size nonlinear optical crystal NaI308 prepared by a hydrothermal synthesis method is 4*4*3mm 3 -6*4*3mm 3 ; The crystal structure of the large-size nonlinear optical crystal NaI3O8 belongs to a tetragonal system, and a point group is The space group is Without a center of symmetry; the cell parameters of the crystal are α = β = γ = 90°, Z = 2, the cell volume is 8. A laser frequency conversion device, characterized by, The optical crystal in the laser frequency conversion device is the large-size nonlinear optical crystal NaI3O8 prepared by the preparation method of any one of claims 1-7.
9. The laser frequency conversion device of claim 8, wherein, The laser frequency conversion device is a harmonic generator in a middle and far infrared region or an optical parametric device in a middle and far infrared region.
10. The laser frequency conversion device of claim 8, wherein, The laser frequency conversion device is a frequency doubling laser frequency conversion device, a frequency tripling laser frequency conversion device, a frequency quadrupling laser frequency conversion device, a frequency quintupling laser frequency conversion device or a frequency sextupling laser frequency conversion device.