A boron-doped zinc oxide single crystal and a method for growing the same, and a laser crystal

Abstract

The application provides a borate-doped zinc single crystal and a growth method and a laser crystal thereof. The method comprises the following steps: mixing raw materials containing manganese, zinc and boron, stirring after being heated to a first temperature, cooling to a second temperature to obtain a melt; immersing a platinum wire below the liquid level of the melt, slowly cooling, and taking out the platinum wire with the grown crystal from the melt to perform first cooling; taking all or part of the obtained crystal as a seed crystal, immersing the seed crystal below the liquid level of the melt, setting a seed crystal rotating speed, slowly cooling, taking out the crystal from the melt to perform second cooling; and taking all or part of the obtained crystal as a seed crystal, repeating the crystal growth process at least once. The borate-doped zinc single crystal prepared by the method has low thermal expansion coefficient (isotropic), high thermal conductivity, long fluorescence lifetime, excellent absorption cross section and emission cross section, excellent optical performance and thermophysical performance, can significantly improve the thermal stability and output laser performance of a laser, and has a good application prospect in laser technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser crystals, in particular to a doped zinc borate single crystal and a growth method thereof and a laser crystal. BACKGROUND

[0002] Laser crystals, as laser generation and amplification media, are key basic materials for all-solid-state lasers. In the process of laser generation and amplification, residual heat inevitably occurs in the laser crystal, which will lead to unnecessary thermal effects, such as thermal lens, thermal distortion and thermal diffraction loss, etc., and seriously affect the quality and power of the generated laser. Commonly used laser crystals are mainly oxides and fluorides, which strongly depend on heat management equipment to offset thermal effects, so as to ensure the quality of the generated laser. However, the considerable thermal expansion and low thermal conductivity of these crystals restrict the output laser quality limit that can be achieved by heat management, which is increasingly unable to meet the growing requirements of laser technology for laser quality and power. Exploring laser crystals with as low as possible (preferably isotropic) thermal expansion and as high as possible thermal conductivity is an urgent need for the development of laser technology. SUMMARY

[0003] In order to solve the above technical problems, the present application provides a doped zinc borate single crystal and a growth method thereof and a laser crystal.

[0004] In a first aspect, the present application provides a growth method of a doped zinc borate single crystal, comprising:

[0005] 1) preparing a melt of ZBO:Mn 2+ : mixing raw materials containing manganese, zinc and boron, stirring after being heated to a first temperature, and cooling to a second temperature to obtain a melt;

[0006] 2) crystal growth: immersing a platinum-gold wire below the liquid level of the melt and slowly cooling, and then performing first cooling after taking out the platinum-gold wire with the grown crystal from the melt;

[0007] 3) secondary crystal growth: immersing the crystal obtained in step 2) below the liquid level of the melt as a seed crystal, setting a seed crystal rotation speed and slowly cooling, and then performing second cooling after taking out the crystal from the melt;

[0008] 4) repeated crystal growth: taking the crystal obtained in step 3) as a seed crystal, repeating the crystal growth process of step 3) at least once.

[0009] The present application provides a growth method of a doped zinc borate single crystal with excellent performance, which can grow a large-size and high-quality ZBO:Mn 2+ single crystal. ZBO:Mn 2+The single crystal has green light emission under ultraviolet light irradiation, and has low, isotropic thermal expansion coefficient, high thermal conductivity, long fluorescent lifetime, excellent absorption cross section and emission cross section, which significantly improves the thermal stability of the laser. ZBO:Mn 2+ The single crystal has excellent optical and thermal physical properties, which can effectively improve the power and quality of the output laser, prolong the service life of the laser, and is suitable for high-power laser and high-optical-quality laser technology applications.

[0010] As preferred, in step 1), the first temperature is 1000-1100℃; preferably, the temperature is raised to 1000-1100℃ at a rate of 0.5-5℃ / min, and the platinum gold stirring paddle is stirred at a stirring rate of 5-50rpm for 2-10 days.

[0011] Further preferably, in step 1), the second temperature is 900-1000℃; preferably, the temperature is lowered to 900-1000℃ at a rate of 0.1-20℃ / h.

[0012] Further preferably, in step 1), in the raw materials, the manganese source is MnCO3 and / or MnO, the zinc source is ZnO, Zn2(OH)2CO3 and / or Zn2(CH3COO)2·2H2O, and the boron source is B2O3 and / or H3BO3; the ZBO:Mn 2+ is Zn4B6O 13 :Mn 2+ , Mn 2+ The doping concentration of ions is 0.1%-30%, preferably 1%-10%. According to the present application, in the doped zinc borate single crystal, the doping concentration is the molar percentage of the amount of manganese element doped in zinc in the zinc borate.

[0013] According to the present application, the purity of the raw materials is 99.99%. The raw materials are thoroughly ground and mixed and filled into a platinum crucible, and then subjected to subsequent treatment in a programmed crystal growth furnace.

[0014] Further preferably, in step 2), the platinum wire is immersed below the liquid level of the melt by 1-5mm.

[0015] Further preferably, in step 2), the slow cooling is at a rate of 0.1-1℃ / day for 3-20 days.

[0016] Further preferably, in step 2), the platinum wire with the grown crystal is lifted above the liquid level of the melt by 1-5cm.

[0017] Further preferably, in step 2), the first cooling is at a rate of 1-20℃ / h to room temperature.

[0018] Further preferably, it is to be noted that the single crystal of ZBO:Mn 2+ may be directly taken as the seed crystal, and the scheme and its extension are also within the protection scope of the present application.

[0019] The ZBO:Mn 2+ single crystal obtained by the present application has low, isotropic thermal expansion coefficient, high thermal conductivity, excellent optical properties and high optical stability at temperature change, and can quickly dissipate heat and reduce optical distortion caused by thermal expansion in laser technology. In particular, the specific growth method, growth temperature, growth time and rotation speed of the crystal growth, secondary growth and repeated growth, as well as the specific cooling rate and time are further optimized, which further ensures the purity and quality of the crystal and significantly improves the performance of the laser crystal.

[0020] As preferred, in step 3), the seed crystal is immersed below the liquid level of the melt by 1-5 mm.

[0021] Further preferably, in step 3), the rotation speed of the seed crystal is 1-30 rpm, and the slow cooling is at a rate of 0.1-1 ℃ / day for 3-20 days.

[0022] Further preferably, in step 3), the crystal is taken out of the melt, and the grown crystal is taken to above the liquid level of the melt by 1-5 cm.

[0023] Further preferably, in step 3), the second cooling is to room temperature at a rate of 1-20 ℃ / h.

[0024] Further preferably, in step 3), the raw reagent after cooling in step 2) is re-heated to the first temperature, then stirred, cooled to the second temperature, and the melt is obtained again; preferably, the temperature is increased to 1000-1100 ℃ at a rate of 0.5-5 ℃ / min, and the platinum gold stirring paddle is stirred at a stirring speed of 5-50 rpm for 2-10 days; then decreased to 900-1000 ℃ at a rate of 0.1-20 ℃ / h to obtain the melt.

[0025] Further preferably, in step 3) and / or step 4), the transparent and uniform part of the grown crystal is taken as the seed crystal. In the present application, the transparent and uniform part refers to the part of the crystal that is transparent and uniform in color.

[0026] Further preferably, in step 4), the crystal growth process is repeated 1-10 times, preferably 3-10 times.

[0027] The present invention processes raw materials and grows crystals under optimal conditions, then performs secondary crystal growth on the resulting seed crystals. The transparent, uniform portion is then used as a seed crystal for repeated growth. By optimizing the process and process parameters, higher-quality doped crystals are obtained. The preparation process of the present invention is simple to operate, and by optimizing process parameters, crystal quality can be significantly improved. Through process and parameter optimization, the optical and thermophysical properties of the doped zinc borate single crystals are further enhanced.

[0028] In a second aspect, the present invention provides a doped zinc borate single crystal, which is obtained by the above-mentioned growth method of the doped zinc borate single crystal.

[0029] Further preferably, the doped zinc borate single crystal has green light emission under ultraviolet light irradiation; preferably, the luminescence properties of the doped zinc borate single crystal are: emission peak central wavelength: 530-550nm, emission peak half-maximum width: 30-50nm, excitation band: 200-500nm, fluorescence lifetime at 300K: 10-20ms, emission cross section: 10 -25 ~10 -21 cm -2 , absorption cross section: 10 -24 ~10 -20 cm -2 .

[0030] Further preferably, the thermal expansion coefficient of the doped zinc borate single crystal at 300K is lower than 4.0 / MK, preferably 2.5-3.5 / MK; the doped zinc borate single crystal has an isotropic thermal expansion coefficient; and / or the thermal conductivity of the doped zinc borate single crystal at 300K is higher than 20 W / m·K, preferably 25-35 W / m·K.

[0031] In the present invention, Mn 2+ Ions were introduced into the zinc borate lattice by the method of the present invention, and large-scale high-quality ZBO:Mn 2+ Single crystal, fluorescence test shows that the ZBO:Mn obtained by the method of the present invention 2+ The single crystal has optical properties superior to those of traditional laser crystals and a longer fluorescence lifetime than most other laser crystals (usually less than ~1ms), reaching 10-20ms at an emission wavelength of ~539nm at room temperature, which is very beneficial for lowering the pump threshold of laser generation. It is worth noting that thermal physical measurements show that at room temperature, the ZBO:Mn 2+ The single crystal has the lowest thermal expansion coefficient and the highest thermal conductivity of all isotropic laser crystals reported so far ( Figure 1 ) and has an isotropic thermal expansion coefficient. Using this crystal can significantly improve the overall performance of lasers, effectively increasing the power and quality of output lasers, making it suitable for high-power lasers and high-optical-quality laser technology applications.

[0032] In a third aspect, the present invention provides a doped zinc borate single crystal obtained by the above-mentioned growth method of a doped zinc borate single crystal, or the use of the above-mentioned doped zinc borate single crystal in a green high-power laser device. The doped zinc borate single crystal provided by the present invention has excellent optical properties and can be well used as a laser crystal in the laser field. It has low thermal expansion (isotropy) and high thermal conductivity, which can reduce the thermal effects of laser crystals in high-power laser technology and achieve high-power, high-quality laser output. It is a laser crystal with excellent overall performance.

[0033] In a fourth aspect, the present invention provides a laser crystal, wherein the laser crystal is a doped zinc borate single crystal obtained using the above-described method for growing a doped zinc borate single crystal, or the above-described doped zinc borate single crystal. The doped zinc borate single crystal grown by the present method exhibits significant advantages over the thermal expansion coefficient and thermal conductivity of previously reported isotropic oxide and fluoride laser crystals, exhibiting a higher thermal conductivity and a lower thermal expansion coefficient, and the thermal expansion coefficient is isotropic.

[0034] In a fifth aspect, the present invention provides a green high-power laser device comprising the aforementioned laser crystal. The doped zinc borate single crystal grown using the present invention can be better used as a high-performance green laser crystal and is suitable for various high-power laser devices.

[0035] The beneficial effects of the present invention are at least as follows: the Mn 2+ Doped zinc borate crystals, with optimized preparation conditions, exhibit the lowest thermal expansion coefficient (isotropic) and highest thermal conductivity of all reported isotropic laser crystals to date. This significantly enhances the thermal stability of the laser and provides excellent optical and thermophysical properties, effectively increasing the power and quality of the output laser. This makes them suitable for high-power lasers and high-optical-quality laser applications. The method provided by this invention addresses the problem of laser power and quality degradation caused by thermal effects of laser crystals in high-power laser technology without requiring any complex processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A comparison of the thermal expansion coefficient and thermal conductivity of the provided doped zinc borate single crystal with those of reported isotropic oxide and fluoride laser crystals.

[0038] Figure 2 A crystal schematic diagram of the doped zinc borate single crystal provided in the embodiments of the present application.

[0039] Figure 3 A fluorescence emission spectrum of the doped zinc borate single crystal provided in the embodiments of the present application.

[0040] Figure 4 A fluorescence lifetime diagram of the doped zinc borate single crystal provided in the embodiments of the present application.

[0041] Figure 5 A fluorescence excitation spectrum of the doped zinc borate single crystal provided in the embodiments of the present application.

[0042] Figure 6 A thermal expansion curve of the doped zinc borate single crystal provided in the embodiments of the present application.

[0043] Figure 7 A thermal conductivity diagram of the doped zinc borate single crystal provided in the embodiments of the present application. DETAILED DESCRIPTION

[0044] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0045] The specific techniques or conditions not mentioned in the embodiments of the present application are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. The devices, instruments, reagents, etc. not mentioned by the manufacturer are all conventional products that can be purchased through a regular channel. The raw materials used in the present application can be easily bought on the domestic product market.

[0046] Embodiment 1

[0047] The present embodiment provides a Mn 2+ doped zinc borate single crystal (ZBO:Mn 2+ ), and the doping concentration of Mn 2+ is 3%.

[0048] The present embodiment provides a growth method of the above-mentioned Mn 2+ doped zinc borate single crystal, and the steps are as follows:

[0049] 1) MnCO3, ZnO and B2O3 raw materials with a purity of 99.99% are mixed according to a ratio of (ZBO:Mn 2+The mixture (doped with 3% MgCl2) was thoroughly ground and mixed in a molar ratio. The mixture was then placed in a 100 mm diameter platinum crucible in a programmed crystal growth furnace. The temperature was raised to 1050°C at a rate of 1°C / min to melt the reagents. The melt was stirred at 25 rpm using a platinum stirring paddle for 7 days. The temperature was then lowered to 955°C at a rate of 1°C / h.

[0050] 2) Immerse the platinum wire 2 mm below the melt surface. During crystal growth, cool the wire at a rate of 0.1°C / day. After 10 days of crystal growth, raise the wire containing the crystal to 2 cm above the melt surface and cool it to room temperature at a rate of 5°C / hour.

[0051] 3) A transparent, uniform portion of the grown crystal was cut and used as a seed crystal. The temperature was raised back to 1050°C at a rate of 1°C / min to melt the reagents. The melt was stirred at 25 rpm with a platinum stirring paddle for 7 days. The melt temperature was then lowered to 955°C at a rate of 1°C / h, and the seed crystal was immersed 2 mm below the melt surface. During crystal growth, the cooling rate was set at 0.1°C / day and the seed crystal rotation speed was set at 10 rpm. After 10 days of crystal growth, the grown crystal was raised to 2 cm above the melt surface and the temperature was lowered to room temperature at a rate of 5°C / h.

[0052] 4) By repeating step 3) for 7 times, ZBO:Mn 2+ Light green crystals ( Figure 2 ), size 44×41×18mm 3 .

[0053] The 3% doping concentration ZBO:Mn prepared in this example 2+ The single crystal was tested for performance, and the test results are as follows:

[0054] 1) Emission spectrum: such as Figure 3 As shown, the emission peak center wavelength is 539nm, the emission peak half-maximum width is 40nm, and the emission cross section is 4.54×10 -23 cm -2 ;like Figure 4 As shown, fluorescence lifetime: 16.66ms.

[0055] 2) Excitation spectrum: such as Figure 5 As shown, the excitation peaks are: 421nm, 427nm, 445nm, and the absorption cross sections corresponding to the three peaks are: 3.34×10 -22 cm -2 , 4.16×10 -22 cm -2 , 2.73×10 -22 cm -2 .

[0056] 3)Thermophysical properties: as shown, at 300 K: thermal expansion coefficient 3.01 / MK, isotropic; as shown, at 300 K: thermal conductivity 28.80 W / (m-K). Figure 6 Figure 7

[0057] Example 2

[0058] This example provides a Mn 2+ doped zinc borate single crystal, the specific steps of the growth method are as follows:

[0059] 1) The raw materials of MnCO3, ZnO and B2O3 with a purity of 99.99% are fully ground and mixed according to the molar ratio of (ZBO:Mn 2+ , doping concentration 1%), then filled into a platinum crucible with a diameter of 100 mm and placed in a programmed crystal growth furnace. The temperature is raised to 1080°C at a rate of 2°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 20 rpm for 6 days. Then the temperature is reduced to 954°C at a rate of 2°C / h.

[0060] 2) The platinum wire is immersed 1 mm below the melt surface, and the cooling rate is set to 0.2°C / day during crystal growth. After 7 days of crystal growth, the platinum wire with the grown crystal is lifted 1 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 12°C / h.

[0061] 3) The grown crystal is cut off from the transparent and uniform part and used as a seed crystal, and the temperature is raised to 1080°C at a rate of 2°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 20 rpm for 6 days. Then the melt temperature is reduced to 954°C at a rate of 2°C / h, the seed crystal is immersed 1 mm below the melt surface, and the cooling rate is set to 0.2°C / day during crystal growth. The seed crystal rotation speed is set to 15 rpm. After 7 days of crystal growth, the grown crystal is lifted 1 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 12°C / h.

[0062] 4) By repeating step 3) for 4 times of crystal growth, a light green crystal of ZBO:Mn 2+ is obtained, with a size of 40x40x16mm 3 .

[0063] The test results of this example are as follows: 1) emission spectrum: emission peak center wavelength: 539 nm, emission peak half-width: 41 nm, emission cross-section: 6.53x10 -23 cm -2 , fluorescence lifetime: 15.22 ms. 2) excitation spectrum: excitation peaks: 421 nm, 427 nm, 445 nm, absorption cross-section corresponding to the three peaks:​​

[0064] 4.34 x 10 -22 cm -2 , 4.36 x 10 -22 cm -2 , 2.67 x 10 -22 cm -2 . 3) Thermal physical properties: at 300 K: thermal expansion coefficient 3.14 / MK, isotropic; at 300 K: thermal conductivity 28.56 W / (m-K).

[0065] Example 3

[0066] This example provides a Mn 2+ doped zinc borate single crystal, the specific steps of the growth method are as follows:

[0067] 1) The raw materials of MnC03, ZnO and B203 with a purity of 99.99% are fully ground and mixed according to the molar ratio of (ZBO:Mn 2+ , doping concentration 5%), then filled into a platinum crucible with a diameter of 100 mm and placed in a programmed crystal growth furnace. The temperature is raised to 1070°C at a rate of 1.5°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 18 rpm for 5 days. Then the temperature is reduced to 956°C at a rate of 3°C / h.

[0068] 2) The platinum wire is immersed 3 mm below the melt surface, and during the crystal growth process, the cooling rate is set to 0.3°C / day. After 8 days of crystal growth, the platinum wire with the grown crystal is lifted 2 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 15°C / h.

[0069] 3) The grown crystal is cut off and used as a seed crystal, and the temperature is raised to 1070°C at a rate of 1.5°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 18 rpm for 5 days. Then the melt temperature is reduced to 956°C at a rate of 3°C / h, the seed crystal is immersed 3 mm below the melt surface, and during the crystal growth process, the cooling rate is set to 0.3°C / day, and the seed crystal rotation speed is set to 15 rpm. After 8 days of crystal growth, the grown crystal is lifted 2 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 15°C / h.

[0070] 4) By repeating step 3) for 4 times of crystal growth, a light green crystal of ZBO:Mn 2+ with a size of 38 x 35 x 14 mm 3 is obtained.

[0071] The test results of this example are as follows: 1) emission spectrum: emission peak center wavelength: 539 nm, emission peak half-peak width: 38 nm, emission cross section: 3.45 x 10 -23 cm -2 , fluorescence lifetime: 15.67 ms. 2) excitation spectrum: excitation peaks: 421 nm, 427 nm, 445 nm, absorption cross sections corresponding to the three peaks: 3.74 x 10 -22 cm -2 , 5.35 x 10 -22 cm -2 , 2.67 x 10 -22 cm -2 . 3) thermal physical properties: at 300 K: thermal expansion coefficient 3.34 / MK, isotropic; at 300 K: thermal conductivity 29.44 W / (m K).

[0072] Example 4

[0073] This example provides a Mn 2+ doped zinc borate single crystal, and the specific steps of the growth method are as follows:

[0074] 1) The raw materials of MnCO3, ZnO and B2O3 with a purity of 99.99% are fully ground and mixed according to the molar ratio (ZBO:Mn 2+ , doping concentration 6%), then filled into a platinum crucible with a diameter of 100 mm and placed in a programmed crystal growth furnace. The temperature is raised to 1040°C at a rate of 2°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 34 rpm for 5 days. Then the temperature is reduced to 955°C at a rate of 5°C / h.

[0075] 2) The platinum wire is immersed 1 mm below the melt surface, and during the crystal growth process, the cooling rate is set to 0.2°C / day. After 6 days of crystal growth, the platinum wire with the grown crystal is lifted to 4 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 6°C / h.

[0076] 3) The grown crystal is cut off from the transparent and uniform part and used as a seed crystal. The temperature is raised to 1040°C at a rate of 2°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 34 rpm for 5 days. Then the melt temperature is reduced to 955°C at a rate of 5°C / h, the seed crystal is immersed 1 mm below the melt surface, and during the crystal growth process, the cooling rate is set to 0.2°C / day, and the seed crystal rotation speed is set to 15 rpm. After 6 days of crystal growth, the grown crystal is lifted to 4 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 6°C / h.

[0077] 4) By repeating step 3) for 5 times of crystal growth, a ZBO:Mn 2+light green crystal, size 38 x 41 x 17 mm 3 .

[0078] The test results of this example are as follows: 1) emission spectrum: emission peak center wavelength: 539 nm, emission peak half-peak width: 40 nm, emission cross section: 7.56 x 10 -23 cm -2 , fluorescence lifetime: 15.84 ms. 2) excitation spectrum: excitation peaks: 421 nm, 427 nm, 445 nm, absorption cross sections corresponding to the three peaks: 5.67 x 10 -22 cm -2 , 4.89 x 10 -22 cm -2 , 6.61 x 10 -22 cm -2 . 3) thermal physical properties: at 300 K: thermal expansion coefficient 3.03 / MK, isotropic; at 300 K: thermal conductivity 29.89 W / (m K).

[0079] Example 5

[0080] This example provides a Mn 2+ doped zinc borate single crystal, and the specific steps of the growth method are as follows:

[0081] 1) The raw materials of MnCO3, ZnO and B2O3 with a purity of 99.99% are fully ground and mixed according to the molar ratio (ZBO:Mn 2+ , doping concentration 0.5%), then filled into a platinum crucible with a diameter of 100 mm and placed in a programmed crystal growth furnace. The temperature is raised to 1090°C at a rate of 1°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 30 rpm for 4 days. Then the temperature is reduced to 955°C at a rate of 2°C / h.

[0082] 2) The platinum wire is immersed 3 mm below the melt surface, and during the crystal growth process, the cooling rate is set to 0.1°C / day. After 10 days of crystal growth, the platinum wire with the grown crystal is lifted 1 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 8°C / h.

[0083] 3) The grown crystal is cut off from the transparent and uniform part and used as a seed crystal. The temperature is raised to 1090°C at a rate of 1°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 30 rpm for 4 days. Then the melt temperature is reduced to 955°C at a rate of 2°C / h, the seed crystal is immersed 3 mm below the melt surface, and during the crystal growth process, the cooling rate is set to 0.1°C / day and the seed crystal rotation speed is set to 8 rpm. After 10 days of crystal growth, the grown crystal is lifted 1 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 8°C / h.

[0084] 4) By repeating step 3) for 3 times, ZBO:Mn 2+ green crystals with size of 44x43x21mm 3 were obtained.

[0085] The results of this example are as follows: 1) Emission spectrum: center wavelength of emission peak: 539 nm, half-peak width of emission peak: 41 nm, emission cross section: 9.51x10 -23 cm -2 , fluorescence lifetime: 18.25 ms. 2) Excitation spectrum: excitation peaks: 421 nm, 427 nm, 445 nm, absorption cross sections corresponding to the three peaks:

[0086] 5.64x10 -22 cm -2 , 4.31x10 -22 cm -2 , 3.33x10 -22 cm -2 . 3) Thermophysical properties: at 300 K: thermal expansion coefficient 3.22 / MK, isotropic; at 300 K: thermal conductivity 30.77 W / (mK).

[0087] Example 6

[0088] This example provides a Mn 2+ doped zinc borate single crystal, and the specific steps of the growth method are as follows:

[0089] 1) The raw materials of MnCO3, ZnO and B2O3 with a purity of 99.99% are fully ground and mixed according to the molar ratio (ZBO:Mn 2+ , doping concentration 0.8%), then filled into a platinum crucible with a diameter of 100 mm and placed in a programmed crystal growth furnace. The temperature is raised to 1030°C at a rate of 1°C / min to melt the reagents, and the melt is stirred with a platinum stirring paddle at a stirring rate of 20 rpm for 4 days. Then the temperature is reduced to 957°C at a rate of 2°C / h.

[0090] 2) The platinum wire is immersed 2 mm below the melt surface, and during the crystal growth process, the cooling rate is set to 0.5°C / day. After the crystal growth continues for 6 days, the platinum wire with the grown crystal is lifted to 4 cm above the melt surface, and the temperature is reduced to room temperature at a rate of 9°C / h.

[0091] 3) The grown crystal was cut to take a transparent and uniform part and used as a seed crystal. The temperature was raised to 1030 °C at a rate of 1 °C / min to melt the reagent, and the melt was stirred with a platinum stirrer at a stirring rate of 20 rpm for 4 days. Then the temperature of the melt was decreased to 957 °C at a rate of 2 °C / h, and the seed crystal was immersed 2 mm below the melt surface. During the crystal growth, the temperature decreasing rate was set to 0.5 °C / day, and the rotation rate of the seed crystal was set to 15 rpm. After the crystal growth continued for 6 days, the grown crystal was lifted 4 cm above the melt surface, and the temperature was decreased to room temperature at a rate of 9 °C / h.

[0092] 4) By repeating step 3) for 4 times, the ZBO:Mn 2+ crystals with a size of 38 x 41 x 15 mm 3 in light green were obtained.

[0093] The test results of this example are as follows: 1) Emission spectrum: center wavelength of emission peak: 539 nm, half-peak width of emission peak: 40 nm, emission cross section: 7.56 x 10 -23 cm -2 , fluorescence lifetime: 19.54 ms. 2) Excitation spectrum: excitation peaks: 421 nm, 427 nm, 445 nm, absorption cross sections corresponding to the three peaks: 5.44 x 10 -22 cm -2 , 3.45 x 10 -22 cm -2 , 6.78 x 10 -22 cm -2 . 3) Thermophysical properties: thermal expansion coefficient: 3.31 / MK, isotropic, at 300 K; thermal conductivity: 29.78 W / (m·K), at 300 K.

[0094] Example 7

[0095] This example provides a Mn 2+ doped zinc borate single crystal, and the specific steps of the growth method are as follows:

[0096] 1) MnCO3, Zn2(OH)2CO3 and H3BO3 raw materials with a purity of 99.99% were fully ground and mixed according to a molar ratio of (ZBO:Mn 2+ , doping concentration 3%), and then filled into a platinum crucible with a diameter of 100 mm and placed in a programmed crystal growth furnace. The temperature was raised to 1050 °C at a rate of 1 °C / min to melt the reagent, and the melt was stirred with a platinum stirrer at a stirring rate of 35 rpm for 7 days. Then the temperature was decreased to 955 °C at a rate of 1 °C / h.

[0097] 2) The Pt wire is immersed 1 mm below the liquid surface of the melt. During the crystal growth, the temperature is decreased at a rate of 0.1 °C / day. After the crystal growth is continued for 10 days, the Pt wire with the grown crystal is lifted 1 cm above the liquid surface of the melt. The temperature is decreased to room temperature at a rate of 6 °C / h.

[0098] 3) The grown crystal is cut to take a transparent and uniform part as seed crystal. The temperature is increased to 1050 °C at a rate of 1 °C / min. The reagent is melted and stirred by a Pt stirrer at a stirring rate of 35 rpm for 7 days. Then the temperature of the melt is decreased to 955 °C at a rate of 1 °C / h. The seed crystal is immersed 1 mm below the liquid surface of the melt. During the crystal growth, the temperature is decreased at a rate of 0.1 °C / day and the rotation rate of the seed crystal is set to 8 rpm. After the crystal growth is continued for 10 days, the grown crystal is lifted 1 cm above the liquid surface of the melt. The temperature is decreased to room temperature at a rate of 6 °C / h.

[0099] 4) The ZBO:Mn 2+ light green crystal with a size of 38 x 38 x 15 mm 3 is obtained by repeating the crystal growth of step 3) for 4 times.

[0100] The test results of this example are as follows: 1) Emission spectrum: center wavelength of emission peak: 539 nm, half peak width of emission peak: 38 nm, emission cross section: 9.77 x 10 -24 cm -2 , fluorescence lifetime: 16.78 ms. 2) Excitation spectrum: excitation peaks: 421 nm, 427 nm, 445 nm, absorption cross sections corresponding to the three peaks: 8.56 x 10 -23 cm -2 , 7.78 x 10 -23 cm -2 , 4.55 x 10 -23 cm -2 . 3) Thermophysical properties: thermal expansion coefficient: 3.24 / MK, isotropic at 300 K; thermal conductivity: 29.67 W / (m·K) at 300 K.

[0101] Example 8

[0102] This example provides a Mn 2+ doped zinc borate single crystal, and the specific steps of the growth method are as follows:

[0103] 1) The raw materials of MnO, Zn2(OH)2CO3 and H3BO3 with a purity of 99.99% are mixed according to the formula (ZBO:Mn 2+, doping concentration 3%) were thoroughly ground and mixed, then filled into a platinum crucible with a diameter of 100 mm and placed in a programmed crystal growth furnace. The temperature was raised to 1050°C at a rate of 1°C / min to melt the reagents, and the melt was stirred with a platinum stirring paddle at a stirring rate of 40 rpm for 7 days. Then the temperature was decreased to 955°C at a rate of 1°C / h.

[0104] 2) A platinum wire was immersed 1 mm below the melt surface, and during the crystal growth process, the cooling rate was set to 0.1°C / day. After the crystal growth lasted for 10 days, the platinum wire with the grown crystal was lifted 2 cm above the melt surface, and the temperature was decreased to room temperature at a rate of 6°C / h.

[0105] 3) A transparent and uniform part of the grown crystal was cut off and used as a seed crystal, the temperature was raised to 1050°C at a rate of 1°C / min to melt the reagents, and the melt was stirred with a platinum stirring paddle at a stirring rate of 40 rpm for 7 days, then the melt temperature was decreased to 955°C at a rate of 1°C / h, the seed crystal was immersed 1 mm below the melt surface, and during the crystal growth process, the cooling rate was set to 0.1°C / day, and the rotation speed of the seed crystal was set to 18 rpm. After the crystal growth lasted for 10 days, the grown crystal was lifted 2 cm above the melt surface, and the temperature was decreased to room temperature at a rate of 6°C / h.

[0106] 4) By repeating step 3) for 4 times, a light green crystal of ZBO:Mn 2+ with a size of 41 x 41 x 19 mm 3 was obtained.

[0107] The test results of this example are as follows: 1) Emission spectrum: center wavelength of emission peak: 539 nm, half-width of emission peak: 40 nm, emission cross section: 1.53 x 10 -21 cm -2 , fluorescence lifetime: 16.31 ms. 2) Excitation spectrum: excitation peaks: 421 nm, 427 nm, 445 nm, absorption cross sections corresponding to the three peaks: 5.77 x 10 -20 cm -2 , 7.33 x 10 -21 cm -2 , 1.63 x 10 -20 cm -2 . 3) Thermophysical properties: thermal expansion coefficient: 3.21 / MK, isotropic, at 300 K; thermal conductivity: 29.98 W / (m·K), at 300 K.

[0108] Example 9

[0109] This example provides a Mn 2+ doped zinc borate single crystal, and the specific steps of the growth method are as follows:

[0110] 1) MnCO3, Zn2(CH3COO)2.2H2O and B2O3 raw materials with purity of 99.99% were mixed in the molar ratio of (ZBO:Mn 2+ :Bi = 0.99:0.01:0.001, doping concentration 3%) and then filled into a platinum crucible with a diameter of 100 mm and placed in a programmed crystal growth furnace. The temperature was raised to 1050°C at a rate of 1°C / min to melt the reagents, and the melt was stirred with a platinum stirring paddle at a stirring rate of 25 rpm for 7 days. Then the temperature was reduced to 955°C at a rate of 1°C / h.

[0111] 2) The platinum wire was immersed 3 mm below the melt surface, and the cooling rate was set to 0.1°C / day during the crystal growth process. After the crystal growth lasted for 10 days, the platinum wire with the grown crystal was lifted to 3 cm above the melt surface, and the temperature was reduced to room temperature at a rate of 6°C / h.

[0112] 3) The grown crystal was cut to take a transparent and uniform part and used as a seed crystal. The temperature was raised to 1050°C at a rate of 1°C / min to melt the reagents, and the melt was stirred with a platinum stirring paddle at a stirring rate of 25 rpm for 7 days. Then the melt temperature was reduced to 955°C at a rate of 1°C / h, and the seed crystal was immersed 3 mm below the melt surface. The cooling rate was set to 0.1°C / day during the crystal growth process, and the rotation speed of the seed crystal was set to 16 rpm. After the crystal growth lasted for 10 days, the grown crystal was lifted to 3 cm above the melt surface, and the temperature was reduced to room temperature at a rate of 6°C / h.

[0113] 4) By repeating step 3) for 5 times, a light green crystal of ZBO:Mn 2+ :Bi = 0.99:0.01:0.001 was obtained, with a size of 42x42x18 mm 3 .

[0114] The test results of this example are as follows: 1) Emission spectrum: emission peak center wavelength: 539 nm, emission peak half-width: 39 nm, emission cross-section: 4.13x10 -23 cm -2 , fluorescence lifetime: 18.67 ms. 2) Excitation spectrum: excitation peaks: 421 nm, 427 nm, 445 nm, absorption cross-sections corresponding to the three peaks: 5.54x10 -22 cm -2 , 3.21x10 -22 cm -2 , 5.68x10 -22 cm -2 . 3) Thermophysical properties: thermal expansion coefficient 3.43 / MK at 300K, isotropic; thermal conductivity 32.98 W / (m·K) at 300K.

[0115] Comparative Example 1

[0116] The present comparative example provides a borate zinc-doped glass, which is prepared by the method of the invention CN1785865A. The manganese-doped long afterglow glass provided by Comparative Example 1 is prepared by a melt-quenching method (the raw materials are accurately weighed according to the proportion, finely ground and uniformly mixed, melted in a high-temperature furnace, elemental zinc is added as a reducing agent or a reducing atmosphere is formed in the furnace, the glass is poured into a mold after being discharged from the furnace, annealed and naturally cooled), which is different from the slow cooling crystallization method of the present invention. From the perspective of microstructure, the glass only has a short program, without a long program; while the crystal has both a short program and a long program. Due to the difference in microstructure, the manganese-doped borate zinc single crystal provided by the present invention emits green light (center wavelength ~ 539 nm), while the manganese-doped borate zinc glass provided in Comparative Example 1 emits red light (center wavelength ~ 600 nm). Meanwhile, Comparative Example 1 does not involve the thermal conductivity data of manganese-doped borate zinc glass, but from the structure-performance relationship of thermal conductivity, the structural disorder in the glass will strongly scatter the phonons, which are the carriers of heat propagation, and the thermal conductivity of the glass will be lower than that of the crystal. The manganese-doped borate zinc glass given in Comparative Example 1 does not have the high thermal conductivity performance of the manganese-doped borate zinc single crystal provided by the present invention, and cannot be used as a working medium for high-power and high-quality laser generation.

[0117] Comparative Example 2

[0118] The present comparative example provides an application of borate zinc crystal in laser crystals (CN 107740179A). The doping ion (i.e. the active ion) used in the present invention is manganese ion, while the active ion used in Comparative Example 2 is neodymium ion, thulium ion, ytterbium ion, erbium ion or titanium ion. Due to the difference in doping ions, the luminescence characteristics of the crystal provided by Comparative Example 2 are different from those of the crystal provided by the present invention, and the crystal provided by Comparative Example 2 does not have the optical parameter indicators of the manganese-doped borate zinc single crystal provided by the present invention as a laser crystal application. In addition, the present invention uses a crystal growth method of directly mixing and melting the raw materials, while Comparative Example 2 uses a crystal growth method of “first solid-phase synthesis, then melt growth”. The crystal growth method of the present invention is simpler than that of Comparative Example 2.

[0119] Comparative Example 3

[0120] The present comparative example provides a growth method of Zn4B6O 13 single crystal (CN 114457423 A). The Zn4B6O 13 single crystal provided by Comparative Example 3 does not have doping ions and does not have the performance as a laser crystal application. In addition, the crystal growth method provided by the present invention does not provide the ZBO:Mn 2+Aside from the necessary manganese, zinc, and boron sources for the single crystal, no other reagents are required. Comparative Example 3, however, employs a co-solvent growth method that, in addition to the necessary zinc and boron sources, also requires the addition of one or more co-solvents: LiF, NaF, KF, RbF, CsF, or ZnF2. Compared to Comparative Example 3, the present invention eliminates the need for additional reagents, resulting in a simpler crystal growth method. Furthermore, the resulting crystals contain no impurity atoms and exhibit superior performance.

[0121] Comparative Example 4

[0122] This comparative example provides a method for preparing large-sized Zn4B6O 13 Single crystal method (CN 108221052A). Comparative Example 4 provides Zn4B6O 13 The single crystal has no doping ions and does not have the performance required for use as a laser crystal. Furthermore, the present invention employs a crystal growth method that directly mixes and melts the raw materials, while Comparative Example 4 employs a crystal growth method that follows the steps of "precursor I - precursor II - polycrystalline material - single crystal growth." The present invention is simpler than the crystal growth method of Comparative Example 4.

[0123] Comparative Example 5

[0124] This comparative example provides a method for preparing large-sized Zn4B6O 13 Single crystal method (Xingxing Jiang et alNear-Zero Thermal Expansion and High Ultraviolet Transparency in a BorateCrystal of Zn4B6O 13 Advanced Materials, 2016, Vol. 28, No. 201601816). Comparative Example 5 provides Zn4B6O 13 The single crystal has no doping ions and does not have the performance required for use as a laser crystal. Furthermore, the present invention uses a crystal growth method that directly mixes and melts the raw materials, while Comparative Example 5 uses a "solid-phase synthesis-single crystal growth" method. Compared to the crystal growth method of Comparative Example 5, the present invention is simpler and produces crystals with superior performance.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for growing a doped zinc borate single crystal, characterized in that: Here are the steps: 1) Preparation of Zn4B6O 13 :Mn 2+ Melt: Mix raw materials containing manganese, zinc and boron, grind and mix the raw materials thoroughly and fill them into a platinum crucible, then heat them to a first temperature in a programmed crystal growth furnace, stir them, and cool them to a second temperature to obtain a melt. Mn 2+ Ion doping concentration is 0.1%~30%; 2) Crystal growth: immersing a platinum wire below the liquid surface of the melt and then slowly cooling it, removing the platinum wire with the crystal grown thereon from the melt and then performing a first cooling step; 3) Secondary crystal growth: the raw material reagents cooled in step 2) are heated again to the first temperature and stirred, then cooled to the second temperature to obtain a melt again, all or part of the crystals obtained in step 2) are used as seed crystals and immersed below the liquid surface of the melt, the seed crystal rotation speed is set and the temperature is slowly reduced, and the crystals are removed from the melt and then subjected to a second cooling step; 4) Repeated crystal growth: using all or part of the crystal obtained in step 3) as a seed crystal, repeat the crystal growth process of step 3) 3 to 10 times; The doped zinc borate single crystal has green light emission under ultraviolet light irradiation; the luminescence properties of the doped zinc borate single crystal are: emission peak center wavelength: 530~550nm, emission peak half-maximum width: 30~50nm, excitation band: 200~500nm, fluorescence lifetime at 300K: 10~20ms, emission cross section: 10 -25 ~10 -21 cm -2 , absorption cross section: 10 -24 ~10 -20 cm -2 ; The thermal expansion coefficient of the doped zinc borate single crystal at 300K is lower than 4.0 / MK; the doped zinc borate single crystal has an isotropic thermal expansion coefficient; the thermal conductivity of the doped zinc borate single crystal at 300K is higher than 20W / m·K.

2. The method for growing a doped zinc borate single crystal according to claim 1, wherein: In step 1), the first temperature is 1000-1100° C.; the temperature is raised to 1000-1100° C. at a rate of 0.5-5° C. / min, and stirred at a stirring rate of 5-50 rpm with a platinum stirring paddle for 2-10 days; And / or, in step 1), the second temperature is 900-1000° C.; the temperature is reduced to 900-1000° C. at a rate of 0.1-20° C. / h; And / or, in step 1), in the raw materials, the manganese source is MnCO3 and / or MnO, and the zinc source is ZnO, Zn2(OH)2 CO3 and / or Zn2(CH3COO)2·2H2O, and the boron source is B2O3 and / or H3BO3.

3. The method for growing a doped zinc borate single crystal according to claim 1, wherein: In step 2), the mixture is immersed 1 to 5 mm below the liquid surface of the melt; And / or, in step 2), the slow cooling is performed at a rate of 0.1-1°C / day for 3-20 days; and / or, in step 2), taking out the platinum wire with the crystals grown thereon from the melt, and raising the platinum wire with the crystals grown thereon to 1 to 5 cm above the melt surface; And / or, in step 2), the first cooling is to cool to room temperature at a rate of 1-20°C / h.

4. The method for growing a doped zinc borate single crystal according to any one of claims 1 to 3, characterized in that: In step 3), the mixture is immersed 1 to 5 mm below the liquid surface of the melt; And / or, in step 3), the rotation speed of the seed crystal is 1-30 rpm, and the slow cooling is performed at a rate of 0.1-1°C / day for 3-20 days; and / or, in step 3), extracting crystals from the melt, and raising the grown crystals to 1 to 5 cm above the melt surface; And / or, in step 3), the second cooling is to cool to room temperature at a rate of 1-20°C / h; And / or, in step 3) and / or step 4), a transparent and uniform portion of the grown crystal is used as a seed crystal.

5. A doped zinc borate single crystal, characterized in that: The zinc borate-doped single crystal is obtained by the growth method of any one of claims 1 to 4.

6. The doped zinc borate single crystal according to claim 5, characterized in that The doped zinc borate single crystal has green light emission under ultraviolet light irradiation; the luminescence properties of the doped zinc borate single crystal are: emission peak center wavelength: 530~550nm, emission peak half-maximum width: 30~50nm, excitation band: 200~500nm, fluorescence lifetime at 300K: 10~20ms, emission cross section: 10 -25 ~10 - 21 cm -2 , absorption cross section: 10 -24 ~10 -20 cm -2 .

7. The doped zinc borate single crystal according to claim 5 or 6, characterized in that The thermal expansion coefficient of the doped zinc borate single crystal at 300K is lower than 4.0 / MK; the doped zinc borate single crystal has an isotropic thermal expansion coefficient; and the thermal conductivity of the doped zinc borate single crystal at 300K is higher than 20W / m·K.

8. Use of the doped zinc borate single crystal obtained by the growth method of the doped zinc borate single crystal according to any one of claims 1 to 4 or the doped zinc borate single crystal according to any one of claims 5 to 7 in a green high-power laser device.

9. A laser crystal, characterized in that: The laser crystal is a doped zinc borate single crystal obtained by the growth method of the doped zinc borate single crystal according to any one of claims 1 to 4 or the doped zinc borate single crystal according to any one of claims 5 to 7.

10. A green high-power laser device, characterized in that: The laser crystal according to claim 9 is included.

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