A slow-release device, a rubidium-titanium potassium phosphate oxide crystal and a preparation method thereof

Abstract

The application provides a slow-release device, a rubidium-titanium potassium phosphate oxide crystal and a preparation method thereof, and belongs to the technical field of electro-optic crystals and nonlinear optical crystals. The application provides a slow-release device, which comprises a hollow inner tube and a hollow outer tube sleeved outside the hollow inner tube; the hollow inner tube and the hollow outer tube are both closed structures provided with slow-release holes at the top; the diameter of the slow-release hole is 0.3-3 mm. The slow-release device provided by the application can avoid crystal cracking, and the prepared rubidium-titanium potassium phosphate oxide crystal has the advantages of high resistivity and uniform resistivity distribution.

Description

Technical Field

[0001] This invention belongs to the field of electro-optic crystal and nonlinear optical crystal technology, specifically relating to a slow-release device, a rubidium (Rb)-potassium titanium oxyphosphate (KTiOPO4, abbreviated as KTP) crystal, namely Rb:KTiOPO4 crystal (abbreviated as Rb:KTP) and its preparation method. Background Technology

[0002] Potassium titanate phosphate crystals grown via hydrothermal method possess excellent nonlinear optical and electro-optic properties, but they suffer from problems such as small crystal size, high cost, and difficulty in widespread application. Furthermore, the resistivity of KTP crystals grown via hydrothermal method can only reach 10 Ω·cm at room temperature. 10 The resistivity is on the order of Ω·cm, which cannot fully meet the requirements of electro-optical applications. The flux method (also known as the molten salt method) can mass-produce large-size, high-quality, and low-cost KTP crystals, enabling their nonlinear optical properties to be widely applied. However, KTP crystals grown by the flux method suffer from gray spots, and especially from low resistivity (10 Ω·cm at room temperature). 6-7 Two major problems (on the order of Ω·cm) hinder its application in the electro-optical field. Because KTP crystals decompose at high temperatures and lack a uniform eutectic point, currently only two methods exist for growing KTP crystals: the hydrothermal method and the flux method.

[0003] The biggest obstacle restricting the electro-optical applications of KTP crystals is their excessively low resistivity, which makes them prone to electrochemical damage and blackening under an applied electric field. In the KTP crystal structure, there are tunnels with a large radius along its Z-axis (see schematic diagram of the KTP crystal structure). Figure 4 ), K + Vacancies migrate along tunnels under the influence of an applied electric field. Therefore, KTP crystals are generally considered to be quasi-one-dimensional ionic conductive materials, and their resistivity along the Z-axis is about three orders of magnitude lower than that in the other two directions.

[0004] By introducing appropriate impurities to block the conductive tunnels along the Z-axis of the KTP crystal, K... + Vacancies are difficult to migrate, which can greatly increase the resistivity of KTP crystals. Rb and K belong to the same group, and Rb has a larger ionic radius than K. + (K + Radius: 0.138nm, Rb + With a radius of 0.152 nm, its electronegativity is similar to that of K ions, making it a suitable choice.

[0005] Existing techniques typically involve mechanically mixing the solid Rb salt required for growing Rb:KTP crystals with other solid raw materials, followed by crystal growth using fluxing or hydrothermal methods. However, due to the infinite solid solubility of K and Rb ions in KTP crystals, only a trace amount of Rb ions can be uniformly incorporated into the entire KTP crystal to avoid excessive lattice distortion, thus preventing crystal cracking or the formation of internal cloud-like structures.

[0006] However, even if the amount of Rb added during the growth of Rb:KTP crystal is very small in proportion to the total amount of raw materials and is mixed evenly, it will still cause excessive local Rb ion doping in the early stage, resulting in problems such as crystal cracking or cloud formation inside, making it unusable; and in the later stage, due to the excessive consumption of Rb ions in the early stage and the inability to replenish them, the doping amount is insufficient, the resistivity cannot be effectively improved, and at the same time, it leads to uneven resistivity distribution in the entire crystal. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a slow-release device, a rubidium-titanium phosphate potassium crystal, and a method for preparing the same. Using the slow-release device provided by this invention to prepare rubidium-titanium phosphate potassium crystal can avoid crystal cracking, and the prepared rubidium-titanium phosphate potassium crystal has the advantage of high resistivity and uniform resistivity distribution.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] The present invention provides a slow-release device, comprising a hollow inner tube and a hollow outer tube sleeved outside the hollow inner tube; both the hollow inner tube and the hollow outer tube are closed structures with a slow-release hole at the top; the diameter of the slow-release hole is 0.3-3 mm.

[0010] Preferably, the volume of the hollow outer tube not occupied by the hollow inner tube is 50-70% of the volume of the hollow inner tube.

[0011] Preferably, the outer diameter of the hollow outer tube is 6-15 mm and the height is 5-40 mm; the wall thickness of the hollow outer tube and the hollow inner tube are independently 0.5-0.8 mm.

[0012] Preferably, the sustained-release device is in the shape of a cylindrical tube, a capsule, a sphere, or a square column.

[0013] Preferably, the material of the sustained-release device includes one or more of gold, silver, platinum, palladium, iridium and rhodium.

[0014] This invention provides a method for preparing rubidium-titanium oxyphosphate potassium crystals using the slow-release device described above, comprising the following steps:

[0015] A soluble solid Rb salt is placed into the hollow inner tube of a slow-release device to obtain a slow-release device containing Rb salt; the slow-release device is the slow-release device described in the above scheme.

[0016] The rubidium-titanium phosphate crystals were obtained by placing potassium oxytitanium phosphate fragments, seed crystals, mineralizing agent solution and slow release device containing Rb salt in a closed container. The crystal growth was carried out by hydrothermal method.

[0017] Preferably, the crystal growth temperature is 480–550°C, the time is 30–120 days, and the pressure is 140–170 MPa.

[0018] Preferably, the solute in the mineralizing agent solution includes K2HPO4, KH2PO4, and H2O2; in the mineralizing agent solution, the concentration of K2HPO4 is 2-6.5 mol / L, the concentration of KH2PO4 is 0.1-0.5 mol / L, and the concentration of H2O2 is 1-5 wt.%.

[0019] Preferably, the mass ratio of the potassium oxytitanium phosphate crystal culture medium to the volume ratio of the mineralizing agent solution is 260g:450mL; the mass ratio of the soluble solid Rb salt to the potassium oxytitanium phosphate crystal culture medium is 1.2:260.

[0020] This invention provides a rubidium-titanium oxyphosphate potassium crystal prepared by the method described above, comprising a rubidium oxyphosphate potassium crystal and Rb doped into the rubidium oxyphosphate potassium crystal. + The Rb + The doping amount is 0.15–0.25 wt.% of potassium titanium phosphate crystals.

[0021] This invention provides a slow-release device, comprising a hollow inner tube and a hollow outer tube sleeved around the inner tube; both the inner and outer tubes are sealed structures with a slow-release hole at the top; the diameter of the slow-release hole is 0.3–3 mm. In this invention, a mineralizing agent solution that enters and fills the inner layer (hollow inner tube) of the "slow-release device" through the slow-release hole dissolves part of the soluble solid Rb salt. The resulting saturated solution is then released and diffused to the outer layer (outer tube) through the slow-release hole in the inner layer, releasing Rb ions (Rb... +The concentration of Rb ions is diluted; the diluted solution in the outer layer is then released and diffused into the mineralizer solution for crystal growth through the slow-release pores in the outer layer, resulting in further dilution. This two-stage diffusion dilution ensures that the Rb ion concentration in the mineralizer solution remains between 0.02 and 0.06 mol / L throughout the entire hydrothermal crystal growth process, which lasts 30–120 days. The Rb ions consumed in the mineralizer solution during Rb:KTP crystal growth are replenished by dissolving soluble solid Rb salts in the inner layer. This avoids the problems associated with directly mixing the soluble solid Rb salts required for doping with the KTP fragments needed for Rb:KTP crystal growth. In the early stages of crystal growth, all the soluble solid Rb salts would dissolve, leading to an excessively high initial Rb ion concentration and excessive doping in the crystal. Later, when Rb ions are consumed and cannot be replenished, problems such as crystal cracking, clouding, and uneven resistivity distribution can occur.

[0022] This invention provides a method for preparing rubidium-titanium oxyphosphate (KTP) crystals using the slow-release device described above. In the Rb ion doping process, this invention uses a slow-release device to hold soluble solid Rb salt, allowing for real-time control of the Rb ion doping amount during crystal growth. This is achieved by directly mixing the soluble solid Rb salt into the fragmented crystal material required for KTP crystal growth (directly mixing the soluble solid Rb salt into the fragmented crystal material leads to the following: in the early stages of crystal growth, the concentration of the Rb compound is high, resulting in a high concentration incorporated into the KTP crystal; in the later stages, the Rb compound mass decreases, leading to a lower content incorporated into the KTP crystal. As a result, while the resistivity of KTP is improved in the early stages, crystal uniformity and optical quality are affected, and in the later stages, due to the decreased Rb ion concentration, the resistivity of the KTP crystal is not effectively improved).

[0023] Using the method of this invention, Rb ions are slowly released into the solution through slow-release pores throughout the crystal growth process, ensuring a uniform distribution of Rb ions in the crystal. This improves the resistivity consistency of the crystal and effectively increases the crystal yield. Furthermore, KTP electro-optic devices typically require two paired crystals for use, necessitating very high uniformity between the two crystals. The Rb:KTP crystal prepared using this invention also exhibits significantly improved optical uniformity, thereby enhancing the performance of the fabricated KTP electro-optic device.

[0024] The method provided by this invention utilizes a "large ion micro-doped sustained release" technique. The core of this technique is to encapsulate a doped soluble solid Rb salt within a pore-filled "sustaining device," allowing the Rb... + Continuously and slowly released into the mineralizing agent solution, maintaining the Rb content in the mineralizing agent solution. + The concentration remains essentially constant, thus ensuring that Rb in the KTP crystal remains relatively constant. +The content of [agent] is maintained at 0.15–0.25 wt.%, and its distribution is uniform, ensuring consistent resistivity throughout the KTP crystal, thus achieving high uniformity and high resistivity (10). 13 Batch, repeatable growth of Rb:KTP crystals using hydrothermal method (Ω·cm scale).

[0025] This invention provides rubidium-titanium oxyphosphate potassium crystals prepared by the method described above. The rubidium-titanium oxyphosphate potassium crystals provided by this invention not only possess high resistance to laser damage (>1GW / cm²), but also exhibit high resistance to laser damage. 2 @1064nm, 10ns, 10Hz, AR-Coated), high anti-smudge performance (at 10kW / cm²). 2 The increase in absorbance at 1064 nm under green light induction was <1.5 × 10⁻⁶ per minute. -4 / cm), suitable for nonlinear frequency conversion of lasers, and the resistivity of the crystal at room temperature is increased to 10. 13 It has a strength in the Ω·cm range and can maintain 10 at 80℃. 11 With a strength on the order of Ω·cm, it better meets the requirements for fabricating electro-optic devices (it is a key material for realizing electro-optic modulation). Under the action of a high-voltage electric field, the crystal will not suffer electro-induced damage and failure, thus meeting the needs of wide-temperature-spectrum electro-optic devices. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a cross-sectional view of the "slow-release device";

[0028] Figure 2 A cross-sectional view of a "slow-release device" filled with soluble solid Rb salt;

[0029] Figure 3 This is a schematic diagram of crystal growth in Embodiment 1 of the present invention;

[0030] Figure 4 This is a schematic diagram of the KTP crystal structure in the background art. Detailed Implementation

[0031] The present invention provides a slow-release device, comprising a hollow inner tube and a hollow outer tube sleeved outside the hollow inner tube; both the hollow inner tube and the hollow outer tube are sealed structures with a slow-release hole at the top.

[0032] Unless otherwise specified, all materials and equipment used in this invention are commercially available products.

[0033] In this invention, the diameter of the slow-release hole is 0.3–3 mm. In specific embodiments of this invention, it can be 0.3 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.5 mm, or 3 mm. Preferably, one slow-release hole is provided at the center of the top of both the hollow inner tube and the hollow outer tube.

[0034] This invention sets the diameter of the slow-release pores to 0.3–3 mm, which can regulate the release amount of soluble solid Rb salt in a certain amount of mineralizing agent solution per unit time, ensuring consistent resistivity throughout the KTP crystal. This achieves high uniformity and high resistivity without causing crystal cracking or clouding. If the pore size is too small, the Rb salt release will be insufficient, and the resistivity of the crystal cannot be effectively improved; if the pore size is too large, it will cause crystal cracking or clouding.

[0035] In this invention, the volume of the hollow outer tube not occupied by the hollow inner tube is preferably 50% to 70% of the volume of the hollow inner tube. In the embodiments of this invention, it can be 50%, 60% or 70%.

[0036] In this invention, the outer diameter of the hollow outer tube is preferably 6-15 mm, and in specific embodiments, it can be 6 mm, 8 mm, 10 mm, 12 mm, 13 mm, or 15 mm; the height is preferably 5-40 mm, and in specific embodiments, it can be 5 mm, 10 mm, 15 mm, 18 mm, 20 mm, 25 mm, 30 mm, 35 mm, or 40 mm. This invention does not have particular requirements for the outer diameter, inner diameter, and height of the hollow inner tube, as long as the volume not occupied by the hollow inner tube in the hollow outer tube is 50-70% of the volume of the hollow inner tube. In specific embodiments, the outer diameter of the hollow inner tube is preferably the same as the inner diameter of the hollow outer tube, that is, the bottoms and walls of the hollow inner tube and the hollow outer tube are placed tightly together (simply by fitting the hollow inner tube and the hollow outer tube together). In specific embodiments, the height of the hollow inner tube can be 12 mm.

[0037] In this invention, the wall thickness of the hollow outer tube and the hollow inner tube is independently 0.5 to 0.8 mm. In the embodiments of this invention, it can specifically be 0.5 mm, 0.6 mm, 0.7 mm or 0.8 mm.

[0038] In this invention, the shape of the sustained-release device preferably includes a cylindrical tubular shape (e.g., Figure 1 a) Colloidal (e.g.) Figure 1 b) Spherical (e.g.) Figure 1c) or square columnar shape. In this invention, the hollow inner tube and hollow outer tube of the slow-release device can have the same or different shapes, as long as the volume of the hollow outer tube not occupied by the hollow inner tube is 50-70% of the volume of the hollow inner tube. For example, the inner layer is cylindrical and the outer layer is square columnar. In an embodiment of this invention, it is preferable that the hollow inner tube and hollow outer tube of the slow-release device have the same shape, such as... Figure 1 .

[0039] In this invention, the sustained-release device preferably has at least two layers (e.g., Figure 1 The structure shown is a two-layer structure. In the embodiments of the present invention, it can be a two-layer, three-layer, or four-layer structure to slow down the release of dopant ions.

[0040] When the slow-release device has a three- or four-layer structure, the present invention preferably adds one or two more hollow tubes outside the hollow outer tube to form a three- or four-layer slow-release device.

[0041] In this invention, the material of the slow-release device preferably includes materials resistant to high temperatures (≥400℃) and acid and alkali corrosion. In this invention, the material of the slow-release device preferably includes precious metals that are resistant to high temperatures and corrosion; the material of the slow-release device preferably includes one or more of gold, silver, platinum, palladium, iridium, and rhodium; the gold preferably includes gold; the platinum preferably includes platinum; and the silver preferably includes silver.

[0042] In this invention, a mineralizing agent solution, entering the inner layer (hollow inner tube) of the "slow-release device" through a slow-release pore, dissolves a portion of the soluble solid Rb salt. The resulting saturated solution then diffuses outward through the slow-release pore of the inner layer to the outer layer (central control outer tube), releasing Rb ions (Rb... + The concentration of Rb ions is diluted; the diluted solution in the outer layer is then released and diffused into the mineralizer solution for crystal growth through the slow-release pores in the outer layer, resulting in further dilution. This two-stage diffusion dilution ensures that the Rb ion concentration in the mineralizer solution remains between 0.02 and 0.06 mol / L throughout the entire hydrothermal crystal growth process, which lasts 30–120 days. The Rb ions consumed in the mineralizer solution during Rb:KTP crystal growth are replenished by dissolving soluble solid Rb salts in the inner layer. This avoids the problems associated with directly mixing the soluble solid Rb salts required for doping with the KTP fragments needed for Rb:KTP crystal growth. In the early stages of crystal growth, all the soluble solid Rb salts would dissolve, leading to an excessively high initial Rb ion concentration and excessive doping in the crystal. Later, when Rb ions are consumed and cannot be replenished, problems such as crystal cracking, clouding, and uneven resistivity distribution can occur.

[0043] This invention provides a method for preparing rubidium-titanium oxyphosphate potassium crystals using the slow-release device described above, comprising the following steps:

[0044] A soluble solid Rb salt is placed into the hollow inner tube of a slow-release device to obtain a slow-release device containing Rb salt; the slow-release device is the slow-release device described in the above scheme.

[0045] The rubidium-titanium phosphate crystals were obtained by placing potassium oxytitanium phosphate fragments, seed crystals, mineralizing agent solution and slow release device containing Rb salt in a closed container. The crystal growth was carried out by hydrothermal method.

[0046] The present invention places a soluble solid Rb salt into the hollow inner tube of a slow-release device to obtain a slow-release device containing Rb salt; the slow-release device is the slow-release device described in the above scheme.

[0047] In this invention, the soluble solid Rb salt preferably comprises a soluble solid Rb salt; the soluble solid Rb salt preferably comprises one or more of Rb₂O, Rb₂CO₃, RbNO₃, RbCl, Rb₂SO₄, Rb₃PO₄, Rb₂HPO₄, and RbH₂PO₄; the filling volume of the soluble solid Rb salt is 60-80% of the volume of the hollow inner tube of the "slow-release device" (e.g., ...). Figure 2 As shown, the dotted shaded areas represent the soluble solid Rb salt of the filler, which in embodiments of the present invention can specifically be 60%, 70%, or 80%. In the present invention, the bulk density of the Rb₂CO₃ is preferably 2.7 g / cm³. 3 .

[0048] After obtaining the slow-release device containing Rb salt, the present invention places potassium oxytitanium phosphate fragments, seed crystals, mineralizing agent solution and slow-release device containing Rb salt in a sealed container for crystal growth to obtain the rubidium-potassium oxytitanium phosphate crystals.

[0049] This invention does not impose any particular requirements on the crystal growth method; any method well-known in the art can be used. In this invention, the sealed container preferably includes an autoclave.

[0050] In this invention, the potassium oxytitanium phosphate crystal culture medium, seed crystals, mineralizing agent solution, and slow release device containing Rb salt are preferably sealed in the gold bushing of the autoclave to avoid corrosion of the autoclave by the mineralizing agent solution.

[0051] In this invention, the inner cavity size of the gold bushing tube is preferably Φ38×750mm, and the tube wall thickness is preferably 0.8mm.

[0052] In this invention, the solute in the mineralizing agent solution preferably includes K₂HPO₄, KH₂PO₄, and H₂O₂; the concentration of K₂HPO₄ in the mineralizing agent solution is preferably 2–6.5 mol / L, and in the embodiments of this invention, it can specifically be 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, or 6.5 mol / L; the concentration of KH₂PO₄ is preferably 0.1–0.5 mol / L, and in the embodiments of this invention, it can specifically be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, or 0.5 mol / L; the concentration of H₂O₂ is preferably 1–5 wt.%, and in the embodiments of this invention, it can specifically be 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, or 5 wt.%. In this invention, the preferred mass ratio of the potassium oxytitanium phosphate crystal culture medium to the mineralizing agent solution is 260g:450mL; the preferred mass ratio of the soluble solid Rb salt to the potassium oxytitanium phosphate crystal culture medium is 1.2:260.

[0053] This invention preferably uses a porous baffle to divide the gold bushing tube inside the autoclave into upper and lower parts, with the upper part being the crystal growth zone and the lower part being the dissolution zone. Preferably, the potassium oxytitanium phosphate (KTP) crystal fragment culture medium, the mineralizing agent solution, and the slow-release device containing Rb₂CO₃ are placed in the dissolution zone, with the Rb₂CO₃ slow-release device placed on top of the culture medium at the bottom of the gold bushing tube (to prevent the KTP crystal fragment culture medium from clogging the slow-release pores of the "slow-release device"); the seed crystal is placed in the crystal growth zone and fixed to the top of the gold bushing tube.

[0054] In this invention, the porosity of the porous baffle is preferably 6-12%. This invention does not have any particular requirements on the pore size of the porous baffle; any pore size known in the art can be used to achieve this invention.

[0055] In this invention, the seed crystal preferably includes a seed wafer; the seed wafer is preferably cut in a certain direction; the cutting direction of the seed wafer preferably includes (011), (210), (001) or (010), and in the embodiment of this invention, it is specifically (011).

[0056] In this invention, the crystal growth temperature is preferably 480–550°C. In an embodiment of this invention, the temperature of the crystal growth region can specifically be 480°C, and the temperature of the dissolution region can specifically be 550°C. In this invention, the crystal growth direction is preferably (011).

[0057] In this invention, the crystal growth time is preferably 30 to 120 days, and in specific embodiments of this invention, it can be 30 days, 40 days, 50 days, 60 days, 70 days, 80 days, 90 days, 100 days, 110 days, or 120 days; the crystal growth pressure is preferably 140 to 170 MPa.

[0058] In this invention, during Rb ion doping, a slow-release device is used to hold soluble solid Rb salt, allowing for real-time control of the Rb ion doping amount during crystal growth. This is achieved instead of directly mixing the soluble solid Rb salt into the fragmented crystal material required for KTP crystal growth. (Directly mixing the soluble solid Rb salt into the fragmented crystal material leads to the following: in the early stages of crystal growth, the concentration of the Rb compound is high, resulting in a high concentration incorporated into the KTP crystal; later, due to the decrease in the mass of the Rb compound, the content incorporated into the KTP crystal decreases. As a result, although the resistivity of KTP is improved in the early stages, crystal uniformity and optical quality are affected, while in the later stages, due to the decrease in Rb ion concentration, the resistivity of the KTP crystal is not effectively improved.)

[0059] Using the method of this invention, Rb ions are slowly released into the solution through slow-release pores throughout the crystal growth process, ensuring a uniform distribution of Rb ions in the crystal. This improves the resistivity consistency of the crystal and effectively increases the crystal yield. Furthermore, KTP electro-optic devices typically require two paired crystals for use, necessitating very high uniformity between the two crystals. The Rb:KTP crystal prepared using this invention also exhibits significantly improved optical uniformity, thereby enhancing the performance of the fabricated KTP electro-optic device.

[0060] The method provided by this invention utilizes a "large ion micro-doped sustained release" technique. The core of this technique is to encapsulate a doped soluble solid Rb salt within a pore-filled "sustaining device," allowing the Rb... + Continuously and slowly released into the mineralizing agent solution, maintaining the Rb content in the mineralizing agent solution. + The concentration remains essentially constant, thus ensuring that Rb in the KTP crystal remains relatively constant. + The content of [agent] is maintained at 0.15–0.25 wt.%, and its distribution is uniform, ensuring consistent resistivity throughout the KTP crystal, thus achieving high uniformity and high resistivity (10). 13 Batch, repeatable growth of Rb:KTP crystals using hydrothermal method (Ω·cm scale).

[0061] This invention provides a rubidium-titanium oxyphosphate potassium crystal prepared by the method described above, comprising a rubidium oxyphosphate potassium crystal and Rb doped into the rubidium oxyphosphate potassium crystal. + .

[0062] In this invention, the Rb+ The doping amount is 0.15 to 0.25 wt.% of potassium titanium phosphate crystals, and in the embodiments of the present invention, it can be 0.15%, 0.2%, or 0.25%.

[0063] The rubidium-titanium oxyphosphate potassium crystal provided by this invention not only has high resistance to laser damage (>1GW / cm) 2 @1064nm, 10ns, 10Hz, AR-Coated), high anti-smudge performance (at 10kW / cm²). 2 The increase in absorbance at 1064 nm under green light induction was <1.5 × 10⁻⁶ per minute. -4 / cm), suitable for nonlinear frequency conversion of lasers, and the resistivity of the crystal at room temperature is increased to 10. 13 It has a strength in the Ω·cm range and can maintain 10 at 80℃. 11 With a strength on the order of Ω·cm, it better meets the requirements for fabricating electro-optic devices (it is a key material for realizing electro-optic modulation). Under the action of a high-voltage electric field, the crystal will not suffer electro-induced damage and failure, thus meeting the needs of wide-temperature-spectrum electro-optic devices.

[0064] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes a slow-release device, a rubidium-titanium oxyphosphate potassium crystal, and a method for preparing the same, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] Adopting such Figure 1 The "slow-release device" shown in Figure a is made of gold and consists of a hollow inner tube and a hollow outer tube fitted outside the hollow inner tube (i.e., the slow-release device in this embodiment has a two-layer structure of a hollow inner tube and a hollow outer tube); both the hollow inner tube and the hollow outer tube are closed cylinders with a slow-release hole at the top.

[0067] The outer diameter of the hollow inner tube is 8mm (the bottom and wall of the hollow inner tube and the hollow outer tube are in close contact, that is, the inner diameter of the hollow outer tube is 8mm), the wall thickness of the hollow outer tube and the hollow inner tube is 0.6mm, the height of the hollow inner tube is 12mm, and the height of the hollow outer tube is 18mm; a slow-release hole with a diameter of 1.5mm is opened at the center of the top of the hollow inner tube and the hollow outer tube.

[0068] 1.2 g of solid Rb₂CO₃ was placed into the hollow inner tube of the "slow-release device" to obtain a slow-release device containing Rb₂CO₃; the bulk density of the solid Rb₂CO₃ was 2.7 g / cm³. 3 Rubidium carbonate occupies 70% of the volume of the hollow inner tube;

[0069] like Figure 3As shown, 260g of KTP fragment culture medium, seed crystals, 450mL of mineralizing agent solution (composition: 2mol / L K2HPO4 + 0.1mol / L KH2PO4 + 1wt.% H2O2), and a slow-release device containing Rb2CO3 were sealed in a gold-lined tube of an autoclave (to prevent corrosion of the autoclave by the mineralizing agent solution) for crystal growth (hydrothermal method) to obtain rubidium-titanium oxyphosphate crystals, i.e., Rb:KTP crystals; the inner cavity of the gold-lined tube has a diameter of Φ38×750mm and a wall thickness of 0.8mm;

[0070] A porous baffle divides the gold bushing tube inside the autoclave into upper and lower parts. The upper part is the crystal growth zone, and the lower part is the dissolution zone. 260g of KTP crushed crystal culture medium, 450mL of mineralizing agent solution, and a slow release device containing Rb2CO3 are placed in the dissolution zone. The slow release device containing Rb2CO3 is placed on top of the culture medium in the lower part of the gold bushing tube (to prevent the KTP crushed crystal culture medium from clogging the slow release pores of the "slow release device"). The seed crystal (cut in the 011 direction) is placed in the crystal growth zone and fixed to the top of the gold bushing tube.

[0071] The temperature of the dissolution zone is 550℃, the temperature of the crystal growth zone is 480℃, and throughout the entire crystal growth process (crystals are anisotropic, so crystal growth needs to be directional to control the speed and quality of crystal growth; in this embodiment, the direction of crystal growth is 011), the working pressure is maintained at 140-170MPa, and the crystal growth time is 30 days.

[0072] Performance testing

[0073] The Rb:KTP crystal grown in Example 1 was sequentially cut into wafers with a thickness of 1 mm along the (001) plane for resistivity testing.

[0074] The test electrode diameter was 3 mm, and a test point was placed every 5 mm. The test temperature was 25℃. The results showed that the resistivity of all wafers was 10. 13 The resistivity is on the order of Ω·cm, indicating that the resistivity distribution is uniform.

[0075] According to the embodiments of the present invention, the problem of non-uniform resistivity distribution of KTP crystals during Rb ion doping can be solved. This not only solves the problem of electro-induced damage to KTP crystals, but also meets the optical compensation requirements of the two crystals when KTP electro-optic devices are used in pairs, effectively improving the yield and performance of KTP electro-optic devices.

[0076] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing rubidium-titanium oxyphosphate potassium crystals using a slow-release device, characterized in that, The slow-release device includes a hollow inner tube and a hollow outer tube sleeved outside the hollow inner tube; both the hollow inner tube and the hollow outer tube are sealed structures with a slow-release hole at the top; the diameter of the slow-release hole is 0.3~3mm; the method includes the following steps: Soluble solid Rb salt is placed in the hollow inner tube of a slow-release device to obtain a slow-release device containing Rb salt; potassium oxytitanium phosphate crystal culture medium, seed crystals, mineralizing agent solution and slow-release device containing Rb salt are placed in a sealed container for crystal growth to obtain the rubidium-potassium oxytitanium phosphate crystal; the crystal growth is carried out by hydrothermal method.

2. The method according to claim 1, characterized in that, The volume of the hollow outer tube that is not occupied by the hollow inner tube is 50-70% of the volume of the hollow inner tube.

3. The method according to claim 1 or 2, characterized in that, The outer diameter of the hollow outer tube is 6~15mm, and the height is 5~40mm; the wall thickness of the hollow outer tube and the hollow inner tube are independently 0.5~0.8mm.

4. The method according to claim 1, characterized in that, The sustained-release device may be cylindrical, tubular, spherical, or square-shaped.

5. The method according to claim 1, 2 or 4, characterized in that, The material of the sustained-release device includes one or more of gold, silver, platinum, palladium, iridium, and rhodium.

6. The method according to claim 1, characterized in that, The crystal growth temperature is 480~550℃, the time is 30~120 days, and the pressure is 140~170MPa.

7. The method according to claim 1 or 6, characterized in that, The solutes in the mineralizing agent solution include K2HPO4, KH2PO4, and H2O2; in the mineralizing agent solution, the concentration of K2HPO4 is 2~6.5 mol / L, the concentration of KH2PO4 is 0.1~0.5 mol / L, and the concentration of H2O2 is 1~5 wt.%.

8. The method according to claim 7, characterized in that, The mass ratio of the potassium oxytitanium phosphate crystal culture medium to the volume ratio of the mineralizing agent solution is 260g:450mL; the mass ratio of the soluble solid Rb salt to the potassium oxytitanium phosphate crystal culture medium is 1.2:

260.

9. The rubidium-titanium oxyphosphate potassium crystal prepared by the method according to any one of claims 1 to 8 comprises a rubidium oxyphosphate potassium crystal and Rb doped into the rubidium oxyphosphate potassium crystal. + The Rb + The doping amount is 0.15~0.25 wt.% of potassium titanium phosphate crystals.

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