Growth method of crystal doped in guided mode period

Abstract

The invention discloses a growth method of a crystal doped in a guided mode period. The growth method comprises the following steps: S1, putting a growth raw material into a container; one ends of a plurality of molds are placed in a growth table, the seed crystals are located over the molds, and the molds are provided with channels; the container comprises a plurality of crucibles, and the channels are communicated with inner cavities of the crucibles; s2, the hearth is vacuumized and filled with inert gas; s3, performing exhaust treatment; s4, melting the growth raw materials in the crucible; s5, enabling the seed crystal to be in contact with the upper surface of the mold, and pulling up the seed crystal; s6, cooling; s7, separating the whole crystal from the mold; and S8, annealing treatment is conducted after cooling. Different channels are respectively communicated with different crucibles, periodic doping of the laser crystal is realized under rotation of the turntable, optical characteristics of the laser crystal can be optimized, fine regulation and control of spectral characteristics of the laser crystal are realized, requirements of different application scenes are met, thermal stability of the laser crystal is improved, and damage resistance of the laser crystal is enhanced. The service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of crystal growth, and more particularly to a method for growing a guided-mode periodically doped crystal. Background Art

[0002] Laser technology is regarded as one of the four major inventions in the 20th century. Laser and laser application technologies are high-techs with extremely rapid development. As a new type of light source, lasers have the characteristics of good directivity, high brightness, good monochromaticity, and high energy density;

[0003] Laser crystals are the core components of solid-state lasers. As the working substance for generating stimulated emission transitions, the energy level structure of doped ions in laser crystals determines the wavelength of the laser, and the lattice structure of the matrix and its macroscopic physical and chemical properties determine the output performance of the laser. Therefore, laser crystals greatly influence the development of solid-state lasers and are also the core and foundation of the development of laser technology. Since the lasers generated by solid-state lasers have a large wavelength range, covering wavelengths from 200 nm ultraviolet to 3 μm, can achieve high energy, high power, and high repetition rate operation, have a high peak power, and low usage cost, solid-state laser technology is widely used in material processing such as cutting, welding, marking, and engraving, medical beauty, military, and scientific research fields, and is currently the laser technology with the widest application range and the most mature technology;

[0004] The main crystal growth methods are the Cz method (Czochralski method) and the EFG method (edge-defined film-fed growth method); in the fields of medical diagnosis, optical communication, etc., when applying specific wavelength light sources, it is necessary to achieve efficient laser output. In high-power and harsh working environments, it is particularly important to increase the thermal stability of the laser and enhance the anti-damage ability of the laser crystal. Therefore, it is necessary to prepare laser crystals that can meet the requirements of different application scenarios. Summary of the Invention

[0005] In view of the above problems, the present invention designs a method for growing a guided-mode periodically doped crystal, including S1: placing the growth raw materials in a container; placing one end of a plurality of molds in a growth stage, placing the other end of the molds in the container, and connecting the growth stage, the container to a turntable; fixing a seed crystal at one end of a seed crystal rod, and connecting the seed crystal rod to a lifting mechanism; placing the seed crystal 10-30 mm directly above the mold through the seed crystal rod, and a channel is provided on the mold;

[0006] The container includes a plurality of crucibles, and the channel communicates with the inner cavity of the crucible;

[0007] S2: evacuating the furnace chamber and then filling it with an inert gas;

[0008] S3: performing an exhaust treatment;

[0009] S4: Raise the temperature inside the crucible to the first temperature to melt the growth raw materials inside the crucible;

[0010] S5: After lowering the seed crystal to contact the channel on the upper surface of the mold through the seed crystal rod, raise the temperature inside the crucible to the second temperature again, and then lift the seed crystal through the seed crystal rod;

[0011] S6: Start a primary temperature reduction. Stop the temperature reduction when the width of the grown crystal is the same as the width of the mold, and record the temperature T1 inside the mold;

[0012] S7: The crystal continues to grow. The temperature control after equal diameter is adjusted based on the data feedback by the sensor on the basis of the temperature T1. After the crystal growth is completed, the temperature is T2. At this time, wait for 10 - 20 minutes after T2 + 10 °C, and then separate the whole crystal from the mold;

[0013] S8: Perform annealing treatment after temperature reduction.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: By placing the growth raw materials into a container and putting several molds into the growth table, the molds are provided with channels, and different channels are respectively connected to the inside of different crucibles. Under the rotation of the turntable, periodic doping of the laser crystal can be realized, which can optimize the optical properties of the laser crystal, improve the gain, reduce the threshold, etc. By precisely controlling the doping period and concentration, fine regulation of the spectral properties of the laser crystal can be achieved, so as to meet the requirements of different application scenarios. Periodic doping helps to improve the thermal stability of the laser crystal during high-power output, reduce the performance fluctuations caused by temperature changes, and reduce the performance fluctuations caused by temperature changes; in high-power or harsh working environments, periodic doping can enhance the anti-damage ability of the laser crystal and extend its service life; through periodic doping, high-efficiency laser output can be achieved within a specific wavelength range; through temperature control in the furnace chamber, combined with a reasonable pulling speed, periodic doping with different concentrations, and the cooperation between the mold and the growth table, the preparation of periodic doping of the laser crystal can be realized, and high-efficiency laser output of the crystal under different application fields can be achieved.

[0015] Further, a main heating device is arranged on the outer side of the crucible, and a post-heating device is arranged on the outer side of the crystal;

[0016] The growth table is provided with an annular groove, and several clamping holes are arranged in the annular groove. The upper end of the mold is arranged in the clamping holes, the channel is communicated with the inner cavity of the annular groove, and the seed crystal is arranged above the annular groove;

[0017] The growth table is connected to the turntable through a lifting device II;

[0018] The turntable is connected to the driving device, and the turntable is connected to the base through a bearing.

[0019] The beneficial effects of adopting the above further technical solutions are as follows: The main heating device and the post-heating device provide heat for the crucible and crystal growth. The main heating device can heat the growth raw materials in the crucible, and the post-heating device enables in-situ annealing after crystal growth to reduce the stress distribution inside the crystal. The growth table is provided with an annular groove, and molds are arranged in several clamping holes of the annular groove, so that different molds introduce the growth raw materials in different crucibles onto the upper surface of the mold to contact the seed crystal. The driving device drives the turntable to rotate, the turntable drives the crucible to rotate, and at the same time drives the growth table to rotate. During the rotation of the growth table, the seed crystal can contact different clamping holes in the annular groove, so that the seed crystal can contact different molds in different clamping holes during the crystal growth process of pulling the crystal, thereby preparing a crystal with different concentrations of doping stacked layer by layer, which has strong thermal stability and a long service life in high-power or harsh working environments, and realizes efficient laser output of the crystal in different application fields. The growth table is connected to the turntable through the second lifting device, and the distance between the growth table and the crucible can be adjusted, so as to adjust the depth of the mold in the crucible.

[0020] Further, a partition groove with a gradually decreasing depth from both sides to the middle is arranged between two adjacent clamping holes; the upper surface of the mold is flush with the clamping hole, and the seed crystal contacts the upper surfaces of the molds in different clamping holes.

[0021] The beneficial effects of adopting the above further technical solutions are as follows: By arranging a partition groove between two adjacent clamping holes, it can ensure that the seed crystal is always in contact with the melted growth raw materials during the crystal growth process of pulling the crystal, and at the same time can prevent the solution from mixing between the spaced clamping holes. Since the upper surface of the mold is flush with the clamping hole, the seed crystal contacts the upper surfaces of the molds in different clamping holes, thereby preparing a periodically doped crystal.

[0022] Further, a crucible support is arranged on the crucible, and a first lifting device is arranged on the crucible support; preferably, the gaps of the several channels are all 0.1 - 1 mm.

[0023] The beneficial effects of adopting the above further technical solutions are as follows: By arranging a first lifting device on the crucible support, the crucible can be driven to move up and down, which is convenient for replacing the growth raw materials. Since the gap of the channel is less than 1 mm, a siphon phenomenon can be formed by the gap, and continuous feeding is provided to the top of the guiding mold during crystal growth, thereby forming a periodically doped crystal.

[0024] Further, the preparation process of the crystal in S1 includes: S11: putting the seed crystal growth raw material into a crucible for heating and melting treatment, and at the same time, carrying out refining treatment; S12: contacting the seed crystal with a specific crystal orientation with the growth raw material melt, and during the cooling process, the melt with disordered atoms becomes a crystal with orderly arranged atoms; S13: pulling up the crystal; S14: carrying out equal-diameter growth, after the equal-diameter growth is completed, reducing the pulling speed and temperature for finishing treatment, and after the finishing treatment is completed, carrying out cooling and annealing treatment.

[0025] Further, the temperature of the heating treatment in S11 is 1850°C - 1970°C;

[0026] The temperature of the cooling in S12 is 5°C - 30°C;

[0027] The pulling speed in S13 is 0.1 - 30 mm / h;

[0028] The temperature of the equal-diameter growth in S14 is 1830°C - 1950°C, the growth speed of the equal-diameter growth is 0.1 - 30 mm / h, the pulling speed of the finishing treatment is 100 - 1000 mm / h, the temperature of the finishing treatment is the crystal growth end temperature + 10°C, the temperature of the cooling treatment is 1630°C - 1720°C, the cooling and annealing time is 5 - 10 h, and the cooling rate is 300 - 100°C / h.

[0029] The beneficial effects of adopting the above further technical solutions are as follows: By putting the growth raw material into the crucible for heating treatment, the growth raw material is melted; using the seed crystal with a specific crystal orientation to contact the melt, and crystals are precipitated during the cooling process. During the pulling process, by controlling the pulling rate, a slender narrow neck is formed, which can effectively intercept the dislocations in the seed crystal and reduce the defects in the crystal; in the equal-diameter growth stage, the growth speed and temperature gradient of the crystal are kept stable to ensure the uniformity of the crystal diameter; when the crystal growth is approaching completion, a finishing operation is required to gradually reduce the pulling rate and temperature gradient to avoid cracks or dislocations at the tail of the crystal; after the growth is completed, the crystal is slowly cooled to room temperature to avoid crystal cracking or internal stress caused by too rapid temperature change; by strictly controlling the parameters and conditions of each link, high-quality seed crystals can be prepared, providing a strong guarantee for subsequent crystal growth.

[0030] Further, the growth raw material in S1 is alumina; in S2, the vacuum is pumped to within 10 Pa, the inert gas is argon and nitrogen, and the flow rate of the inert gas is 0.5 - 5 L / min;

[0031] When the air pressure for exhaust treatment in S3 is lower than 1 kPa - 100 kPa, stop the exhaust treatment; heat the temperature inside the crucible to 2050 - 2200 °C through a heating device and maintain it at a constant temperature of 2050 - 2200 °C for 25 - 35 min.

[0032] The beneficial effects of adopting the above further technical solutions are as follows: by filling argon and nitrogen below 10 Pa, the oxidation and volatilization of the crystal after heating are effectively inhibited, avoiding the pollution of the growth raw materials by oxidation and volatilization, avoiding the generation of impurities inside the crystal, and improving the smoothness of the crystal surface; by exhausting during high temperature to remove the impurities volatilized during crystal growth, the quality of the crystal is further improved.

[0033] Further, in S4, the temperature rising time to the first temperature is 4 - 10 h, the temperature rising rate is 80 - 300 °C / h, and the first temperature is 2050 - 2200 °C;

[0034] In S5, the second temperature is 20 - 150 °C higher than the first temperature. After reaching the second temperature, keep it warm for 5 - 60 min and then lift the seed crystal through the seed crystal rod, and the lifting speed is 5 - 100 mm / h.

[0035] The beneficial effects of adopting the above further technical solutions are as follows: when the temperature reaches 2050 - 2200 °C, heat convection melts the alumina raw materials in the crucible into a melt; by lifting the seed crystal, the bubbles in the crystal are initially released, avoiding the phenomenon of bubbling in the crystal finished product, improving the growth quality of the crystal, and improving the smoothness of the surface of the crystal finished product.

[0036] Further, in S6, the temperature decreasing rate for the first - stage temperature decrease is 1 - 50 °C / h; record the temperature T1 inside the mold;

[0037] In S7, after the crystal growth is completed, wait for 10 - 20 min at a temperature of T2 + 10 °C, and then separate the whole crystal from the mold; after the crystal growth is completed in S7, raise the temperature inside the crucible by 9 - 11 °C, and then lift the crystal through the seed crystal rod at a lifting speed of 950 - 1100 mm / h and separate it from the mold;

[0038] In S8, after the crystal is separated from the mold, cool it through a post - heating device, and cool it by 180 - 220 °C based on the temperature when the crystal is separated from the mold;

[0039] After cooling and keeping it warm for 1 - 4 h, complete the annealing; after the annealing treatment, cool it through the post - heating device at a temperature decreasing rate of 100 - 400 °C / h respectively, and then take it out after placing it for 10 - 24 h.

[0040] The beneficial effects of adopting the above further technical solution are as follows: After entering the equal-diameter stage, the growth rate of the crystal is judged by the weight sensor, and the crystal growth process is completed by controlling the magnitude of the growth rate, which is beneficial to the perfect development of the crystal; when the temperature T inside the mold makes the crystal break away from the mold at a pulling speed of 1000 mm / h, the crystal growth is completed; after pulling away from the mold, the crystal growth is completed and then starts to cool down. After cooling, the crystal enters the annealing state, and after cooling, the crystal is taken out, realizing the optimization of the laser beam quality, helping to improve the stability of the laser system. Especially under high-power operating conditions, it can reduce the performance fluctuations caused by thermal effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 FIG. is a schematic structural view of the growth table and the mold in cooperation Figure 1 ;

[0042] Figure 2 FIG. is a schematic structural view of the growth table and the mold in cooperation Figure 2 ;

[0043] Figure 3 FIG. is a schematic structural view of the growth table;

[0044] Wherein: 1, crucible; 11, crucible support; 12, lifting device I; 2, mold; 21, channel; 3, growth table; 31, annular groove; 32, clamping hole; 33, partition groove; 34, lifting device II; 4, turntable; 41, driving device; 5, seed crystal; 6, seed crystal rod; 7, main heating device; 8, post heating device; 9, crystal. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0046] This embodiment provides a method for growing a guided-mode periodically doped crystal,

[0047] Example 1: It includes S1: putting the growth raw materials into a container; putting one end of several molds 2 into a growth table 3, placing the other end of the mold 2 in the container, and connecting the growth table 3, the container and a turntable 4; fixing a seed crystal 5 at one end of a seed crystal rod 6, and connecting the seed crystal rod 6 with a lifting mechanism; placing the seed crystal 5 20 mm directly above the mold 2 through the seed crystal rod 6, and a channel 21 is provided on the mold 2; the container includes several crucibles 1, and the channel 21 communicates with the inner cavity of the crucible 1; S2: evacuating the furnace chamber and then filling it with an inert gas; S3: performing an exhaust treatment; S4: raising the temperature in the crucible 1 to a first temperature to melt the growth raw materials in the crucible 1; S5: lowering the seed crystal 5 through the seed crystal rod 6 until it contacts the channel 21 on the upper surface of the mold 2, then raising the temperature again to raise the temperature in the crucible 1 to a second temperature, and then pulling up the seed crystal 5 through the seed crystal rod 6; S6: starting a first cooling, stopping the cooling when the width of the grown crystal 9 is the same as the width of the mold 2, and recording the temperature T1 inside the mold 2; S7: continuing to grow the crystal 9, controlling the temperature after isodiametric growth according to the data fed back by the sensor and adjusting it based on the temperature T1, the temperature is T2 when the crystal 9 growth ends, wait for 15 min after T2 + 10 °C, and separating the whole crystal 9 from the mold 2; S8: performing an annealing treatment after cooling. By placing the growth raw materials into the container, putting several molds 2 into the growth table 3, with channels 21 provided on the molds 2, different channels 21 respectively communicating with the interiors of different crucibles 1, periodic doping of the laser crystal 9 can be achieved under the rotation of the turntable 4, which can optimize the optical properties of the laser crystal 9, improve the gain, reduce the threshold, etc. By precisely controlling the doping period and concentration, fine regulation of the spectral properties of the laser crystal 9 can be realized, so as to meet the requirements of different application scenarios. Periodic doping helps to improve the thermal stability of the laser crystal 9 during high-power output, reduce the performance fluctuations caused by temperature changes, and reduce the performance fluctuations caused by temperature changes; in high-power or harsh working environments, periodic doping can enhance the anti-damage ability of the laser crystal 9 and extend its service life; through periodic doping, high-efficiency laser output can be achieved within a specific wavelength range; through temperature control in the furnace chamber, combined with a reasonable pulling speed, periodic doping with different concentrations and the cooperation between the mold 2 and the growth table 3, the preparation of periodic doping of the laser crystal 9 can be realized, and high-efficiency laser output of the crystal 9 under different application fields can be achieved.

[0048] A main heating device 7 is arranged on the outer side of the crucible 1, and a post-heating device 8 is arranged on the outer side of the crystal 9; the growth table 3 is provided with an annular groove 31, and a number of clamping holes 32 are arranged in the annular groove 31. The upper end of the mold 2 is arranged in the clamping hole 32, and the channel 21 is communicated with the inner cavity of the annular groove 31. The seed crystal 5 is arranged above the annular groove 31; the growth table 3 is connected to the turntable 4 through a second lifting device 34; the turntable 4 is connected to a driving device 41, and the turntable 4 is connected to the base through a bearing. Heat is provided for the growth of the crucible 1 and the crystal 9 by the main heating device 7 and the post-heating device 8. The growth raw material in the crucible 1 can be heated by the main heating device 7, and the in-situ annealing after the growth of the crystal 9 is carried out by the post-heating device 8 to reduce the stress distribution inside the crystal 9; since the growth table 3 is provided with the annular groove 31 and the number of clamping holes 32 in the annular groove 31 are provided with the mold 2, different molds 2 introduce the growth raw materials in different crucibles 1 onto the upper surface of the mold 2 to contact the seed crystal 5. The turntable 4 is driven to rotate by the driving device 41, the turntable 4 drives the crucible 1 to rotate, and at the same time drives the growth table 3 to rotate. During the rotation of the growth table 3, the seed crystal 5 can contact different clamping holes 32 in the annular groove 31, so that the seed crystal 5 can contact different molds 2 in different clamping holes 32 during the growth of pulling the crystal 9, thereby preparing a crystal 9 with different concentrations of doping stacked layer by layer, which has strong thermal stability and long service life in high-power or harsh working environments, and realizes efficient laser output of the crystal 9 under different application fields; the growth table 3 is connected to the turntable 4 through a second lifting device 34, and the distance between the growth table 3 and the crucible 1 can be adjusted, so as to adjust the depth of the mold 2 in the crucible 1.

[0049] A partition groove 33 with gradually decreasing equal depth from both sides to the middle is arranged between two adjacent clamping holes 32; the upper surface of the mold 2 is flush with the clamping hole 32, and the seed crystal 5 contacts the upper surfaces of the molds 2 in different clamping holes 32. By arranging the partition groove 33 between two adjacent clamping holes 32, the mixing of the solutions between the spaced clamping holes 32 can be avoided. Since the upper surface of the mold 2 is flush with the clamping hole 32, the seed crystal 5 contacts the upper surfaces of the molds 2 in different clamping holes 32, thereby preparing a periodically doped crystal 9.

[0050] A crucible support 11 is arranged on the crucible 1, and a first lifting device 12 is arranged on the crucible support 11; preferably, the gaps of the number of channels 21 are all 0.6 mm. By arranging the first lifting device 12 on the crucible support 11, the crucible 1 can be driven to move up and down, so as to facilitate the replacement of the growth raw material. Since the gap of the channel 21 is less than 1 mm, a siphon phenomenon can be formed by the gap, and the top of the guiding mold 2 is continuously supplied with materials during the growth of the crystal 9, thereby forming a periodically doped crystal 9.

[0051] The preparation process of crystal 9 in S1 includes: S11: putting the growth raw material into crucible 1 for heating and melting; S12: making a seed crystal 5 with a specific crystal orientation contact with the growth raw material melt, and changing the melt with disordered atoms into a crystal 9 with ordered atomic arrangement during the cooling process; S13: pulling up crystal 9; S14: carrying out equal-diameter growth. After the equal-diameter growth is completed, the pulling rate and temperature are reduced for finishing treatment. After the finishing treatment is completed, cooling and annealing treatment is carried out. The heating temperature in S11 is 1920 °C; the cooling temperature in S12 is 20 °C. The pulling rate in S13 is 20 mm / h, the growth rate of equal-diameter growth in S14 is 1900 °C, the pulling rate of the finishing treatment is 20 mm / h, the temperature of the finishing treatment is 600 mm / h, the temperature of the cooling treatment is the crystal 9 growth end temperature + 10 °C, the temperature of the cooling and annealing treatment is 1680 °C, the cooling and annealing time is 7 h, and the cooling rate is 200 °C / h. By putting the growth raw material into crucible 1 for heating treatment, the growth raw material is melted; by using a seed crystal 5 with a specific crystal orientation to contact with the melt, crystal 9 is precipitated during the cooling process. During the pulling process, by controlling the pulling rate, a slender narrow neck can be formed to effectively intercept the dislocations in the seed crystal 5 and reduce the defects in crystal 9; during the equal-diameter growth stage, the growth rate and temperature gradient of crystal 9 remain stable to ensure the uniformity of the diameter of crystal 9; when the growth of crystal 9 is nearly completed, a finishing operation is required to gradually reduce the pulling rate and temperature gradient to avoid cracks or dislocations at the tail of crystal 9; after the growth is completed, crystal 9 is slowly cooled to room temperature to avoid cracking or generating internal stress due to too rapid temperature change; by strictly controlling the parameters and conditions of each link, high-quality seeds can be prepared, providing a strong guarantee for the subsequent growth of crystal 9.

[0052] The growth raw material in S1 is alumina; in S2, the vacuum is pumped to within 10 Pa, the inert gas is argon and nitrogen, and the flow rate of the inert gas is 2.5 L / min; in S3, when the air pressure of the exhaust treatment is lower than 50 kPa, the exhaust treatment is stopped; the temperature in crucible 1 is heated to 2100 °C by a heating device, maintained at 2100 °C for 30 min, and then the furnace chamber is evacuated. When the air pressure is lower than 50 kPa, the evacuation is stopped. By filling argon and nitrogen below 6 Pa, the oxidation and volatilization of crystal 9 after heating are effectively inhibited, avoiding the pollution of the growth raw material by oxidation and volatilization, avoiding the generation of impurities inside crystal 9, and improving the smoothness of the surface of crystal 9; by the exhaust treatment, the impurities volatilized during the growth of crystal 9 are removed at high temperature, thereby improving the quality of crystal 9.

[0053] In S4, the heating time to the first temperature is 7 h, and the heating rate is 200 °C / h. The first temperature is 2100 °C. In S5, the second temperature is 100 °C higher than the first temperature. After reaching the second temperature, it is held for 30 min, and then the seed crystal 5 is lifted by the seed crystal rod 6 at a lifting speed of 50 mm / h. When the temperature reaches 2100 °C, heat convection melts the alumina raw material in the crucible 1 into a melt. By lifting the seed crystal 5, the crystal 9 is pulled up, and the bubbles in the crystal 9 are initially released, avoiding the phenomenon of bubbling in the finished crystal 9, improving the growth quality of the crystal 9, and improving the surface smoothness of the finished crystal 9.

[0054] In S6, the cooling rate during the first cooling is 25 °C / h; the temperature T1 inside the mold 2 is recorded. In S7, after the crystal 9 finishes growing and the temperature is at T2 + 10 °C, wait for 15 min, and then the whole crystal 9 is separated from the mold 2. After the crystal 9 finishes growing in S7, the temperature in the crucible 1 is increased by 10 °C, and then the crystal 9 is lifted and separated from the mold 2 through the seed crystal rod 6 at a lifting speed of 1000 mm / h. In S8, after the crystal 9 is separated from the mold 2, it is cooled by the post-heating device 8, and the temperature is reduced by 200 °C based on the temperature when the crystal 9 is separated from the mold 2. After cooling and holding for 2.5 h, annealing is completed. After the annealing treatment, the temperature is reduced by the post-heating device 8 at a cooling rate of 300 °C / h respectively, and then taken out after being placed for 18 h. After entering the isodiametric stage, the growth rate of the crystal 9 is judged by the weight sensor, and the growth process of the crystal 9 is completed by controlling the magnitude of the growth rate, which is beneficial to the perfect development of the crystal 9; when the temperature inside the mold 2 is at a lifting speed of 1000 mm / h, the crystal 9 is separated from the mold 2 to complete the growth of the crystal 9. After being lifted and separated from the mold 2, the crystal 9 starts to cool after the growth is completed. After cooling, the crystal 9 enters the annealing state, and after cooling, the crystal 9 is taken out, realizing the optimization of the laser beam quality, helping to improve the stability of the laser system, especially under high-power operating conditions, and being able to reduce the performance fluctuations caused by thermal effects.

[0055] The same content as in Embodiment 1 will not be elaborated here; the different solutions from Embodiment 1 are as follows:

[0056] This embodiment provides a method for growing a guided-mode periodically doped crystal 9.

[0057] Embodiment 2: The seed crystal 5 is located 12 mm directly above the mold 2 through the seed crystal rod 6. S6: Start the first cooling, and the cooling rate is 5 °C / h. S7: After the crystal 9 finishes growing, the temperature is T2. At this time, wait for 12 min at T2 + 10 °C, and then the whole crystal 9 is separated from the mold 2.

[0058] The gaps of the several channels 21 are all 0.2 mm. The temperature of the heat treatment in S11 is 1860 °C; the temperature of the temperature reduction in S12 is 7 °C. The pulling speed in S13 is 5 mm / h, the temperature of the equal-diameter growth in S15 is 1850 °C, the growth speed of the equal-diameter growth is 5 mm / h, the pulling speed of the finishing treatment is 150 mm / h, the temperature of the finishing treatment is the crystal 9 growth end temperature + 10 °C, the temperature of the cooling and annealing treatment is 1650 °C, the cooling and annealing time is 6 h, and the cooling rate is 120 °C / h.

[0059] The growth raw material in S1 is alumina; in S2, the vacuum is pumped to within 3 Pa, the inert gas is argon and nitrogen, and the flow rate of the inert gas is 0.6 L / min; in S3, when the air pressure of the exhaust treatment is lower than 5 kPa, the exhaust treatment is stopped; the temperature in the crucible 1 is heated to 2060 °C by a heating device, and it is kept at a constant temperature of 2060 °C for 27 min, and then the inside of the furnace chamber is evacuated. When the air pressure is lower than 5 kPa, the evacuation is stopped. By filling argon and nitrogen below 3 Pa, the oxidation and volatilization of the crystal 9 after heating are effectively inhibited, the growth raw material is prevented from being polluted by oxidation and volatilization, impurities are prevented from being generated inside the crystal 9, and the smoothness of the surface of the crystal 9 is improved; through the exhaust treatment, the impurities volatilized during the growth of the crystal 9 are removed at high temperature, thereby improving the quality of the crystal 9.

[0060] In S4, the temperature is raised to the first temperature, the temperature rise time is 5 h, and the temperature rise rate is 90 °C / h. The first temperature is 2060 °C; in S5, the second temperature is 30 °C higher than the first temperature. After reaching the second temperature and keeping it warm for 8 min, the seed crystal 5 is pulled up by the seed crystal rod 6, and the pulling speed is 8 mm / h. When the temperature reaches 2060 °C, the heat convection melts the alumina raw material in the crucible 1 into a melt; by pulling up the seed crystal 5 and pulling the crystal 9, the bubbles in the crystal 9 are initially released, avoiding the phenomenon of bubbling in the finished crystal 9, improving the growth quality of the crystal 9, and improving the smoothness of the surface of the finished crystal 9.

[0061] In S6, the cooling rate during the first cooling is 10 °C / h; record the temperature T inside the mold 2. After the crystal 9 growth in S7 ends and the temperature is at T2 + 10 °C, wait for 12 min and then separate the whole crystal 9 from the mold 2. After the crystal 9 growth in S7 ends, raise the temperature inside the crucible 1 by 10 °C, and then pull the crystal 9 at a pulling speed of 960 mm / h through the seed rod 6 to separate it from the mold 2. In S8, after the crystal 9 is separated from the mold 2, cool it through the post-heating device 8, and cool it by 190 °C based on the temperature when the crystal 9 is separated from the mold 2. After cooling, keep it warm for 2 h to complete annealing. After the annealing treatment, cool it through the post-heating device 8 at a cooling rate of 120 °C / h respectively, and then take it out after placing it for 11 h. After entering the equal-diameter stage, judge the growth rate of the crystal 9 through the weight sensor, and complete the crystal 9 growth process by controlling the magnitude of the growth rate, which is beneficial to the perfect development of the crystal 9. When the temperature inside the mold 2 is at a pulling speed of 960 mm / h, separate the crystal 9 from the mold 2 to complete the crystal 9 growth. After pulling and separating from the mold 2, the crystal 9 growth is completed and starts to cool. After cooling, the crystal 9 enters the annealing state. After cooling, take out the crystal 9 to optimize the quality of the laser beam, which helps to improve the stability of the laser system. Especially under high-power operating conditions, it can reduce the performance fluctuations caused by the thermal effect.

[0062] The same content as in Embodiment 2 will not be elaborated here; the different solutions of this embodiment from Embodiment 2 are as follows:

[0063] This embodiment provides a method for growing a guided-mode periodically doped crystal 9.

[0064] Embodiment 3: It includes S2: Place the seed crystal 5 20 mm directly above the mold 2 through the seed rod 6. In S7, after the crystal 9 growth ends and the temperature is T2, wait for 15 min at T2 + 10 °C and then separate the whole crystal 9 from the mold 2.

[0065] The gaps of the several channels 21 are all 0.6 mm.

[0066] The temperature of the heat treatment in S11 is 1960 °C; the temperature of the cooling in S12 is 28 °C. The pulling speed in S13 is 28 mm / h, the temperature of the equal-diameter growth in S15 is 1930 °C, the growth speed of the equal-diameter growth is 28 mm / h, the pulling speed of the finishing treatment is 900 mm / h, the temperature of the finishing treatment is the crystal 9 growth end temperature + 10 °C, the temperature of the cooling and annealing treatment is 1710 °C, the cooling and annealing time is 9 h, and the cooling rate is 280 °C / h.

[0067] In S2, evacuate to within 8 Pa, and the inert gas is argon and nitrogen, with the flow rate of the inert gas being 4 L / min; in S3, stop the exhaust treatment when the air pressure of the exhaust treatment is lower than 95 kPa; heat the temperature in crucible 1 to 2170 °C through a heating device, maintain it at 2170 °C for 34 min, and then evacuate the furnace chamber. When the air pressure is lower than 95 kPa, stop the evacuation. By filling argon and nitrogen below 8 Pa, the oxidation and volatilization of crystal 9 after heating are effectively inhibited, preventing oxidation and volatilization from contaminating the growth raw materials, avoiding the generation of impurities inside crystal 9, and improving the smoothness of the surface of crystal 9; through the exhaust treatment, the impurities volatilized during the growth of crystal 9 are removed at high temperatures, thereby improving the quality of crystal 9.

[0068] In S4, the temperature is raised to the first temperature, the temperature-raising time is 8 h, and the temperature-raising rate is 280 °C / h. The first temperature is 2150 °C;

[0069] In S5, the second temperature is 140 °C higher than the first temperature. After maintaining the temperature for 55 min when reaching the second temperature, pull up seed crystal 5 through seed crystal rod 6, and the pulling-up speed is 95 mm / h. When the temperature reaches 2150 °C, heat convection melts the alumina raw materials in crucible 1 into a melt; by pulling up seed crystal 5, the bubbles in crystal 9 are initially released, avoiding the phenomenon of bubbling in the finished product of crystal 9, improving the growth quality of crystal 9, and enhancing the smoothness of the surface of the finished product of crystal 9.

[0070] In S6, the cooling rate for the first cooling is 45 °C / h; record the internal temperature T1 of mold 2; in S7, after crystal 9 finishes growing and the temperature is at T2 + 10 °C, wait for 18 min and then separate the whole crystal 9 from mold 2; after crystal 9 finishes growing in S7, raise the temperature in crucible 1 by 10 °C, and then pull up crystal 9 through seed crystal rod 6 at a pulling-up speed of 1060 mm / h and separate it from mold 2; in S8, after crystal 9 is separated from mold 2, cool it through post-heating device 8, and cool it by 210 °C based on the temperature when crystal 9 is separated from mold 2;

[0071] After cooling and maintaining for 3 h, annealing is completed; after the annealing treatment, cool it through post-heating device 8 at a cooling rate of 350 °C / h respectively, and then take it out after placing it for 23 h.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A guided-mode periodically doped crystal growth method, characterized in that: The method comprises S1: placing a growing material into a container; placing one end of a plurality of molds (2) into a growth platform (3), placing the other end of the mold (2) into the container, wherein the growth platform (3), the container and a turntable (4) are connected; fixing a seed crystal on one end of a seed crystal rod, wherein the seed crystal rod is connected to a lifting mechanism; placing the seed crystal 10-30 mm above the mold (2) through the seed crystal rod, wherein a channel (21) is provided on the mold (2); The container comprises a plurality of crucibles (1), and the channel (21) is connected to the inner cavity of the crucible (1); S2: Evacuate the furnace and then fill it with inert gas; S3: perform exhaust treatment; S4: raising the temperature in the crucible (1) to a first temperature to melt the growth raw material in the crucible (1); S5: after the seed crystal is lowered by the seed crystal rod until it contacts the channel (21) on the upper surface of the mold (2), the temperature in the crucible (1) is raised to a second temperature again, and then the seed crystal is pulled up by the seed crystal rod; S6: Start cooling once until the width of the growing crystal (9) is the same as the width of the mold (2), then stop cooling, and record the internal temperature T1 of the mold (2); S7: The crystal (9) continues to grow, and the temperature control after equalization is adjusted based on the temperature of T1 according to the data fed back by the sensor. After the growth of the crystal (9) is completed, the temperature is T2. At this time, after waiting for 10-20 minutes at T2+10°C, the whole crystal (9) is separated from the mold (2); S8: After cooling, annealing is performed.

2. A guided-mode periodically doped crystal growth method according to claim 1, characterized in that: A main heating device (7) is provided on the outer side of the crucible (1), and a post-heating device (8) is provided on the outer side of the crystal (9); The growth platform (3) is provided with an annular groove (31), a plurality of holding holes (32) are provided in the annular groove (31), the upper end of the mold (2) is arranged in the holding hole (32), the channel (21) is communicated with the inner cavity of the annular groove (31), and the seed crystal is arranged above the annular groove (31); The growth platform (3) is connected to the turntable (4) via a second lifting device (34); The turntable (4) is connected to a driving device (41), and the turntable (4) is connected to a base via a bearing.

3. A guided-mode periodically doped crystal growth method according to claim 2, characterized in that: A partition groove (33) with a gradually changing depth from both sides to the middle is provided between the two adjacent holding holes (32); The upper surface of the mold (2) is flush with the holding hole (32), and the seed crystal contacts the upper surface of the mold (2) in different holding holes (32).

4. A guided-mode periodically doped crystal growth method according to claim 2, characterized in that: A crucible support (11) is arranged on the crucible (1), and a lifting device (12) is arranged on the crucible support (11); Preferably, the gaps of the plurality of channels (21) are all 0.1-1 mm.

5. The method for growing a guided-mode periodically doped crystal according to claim 1, characterized in that: The preparation process of the crystal in S1 comprises: S11: placing the growth material into a crucible (1) for heating and melting treatment; S12: using a seed crystal with a specific crystal orientation to contact the growth material melt, and transforming it into a crystal (9) with orderly atomic arrangement during the cooling process; S13: pulling the crystal (9); S14: performing isodiametric growth, and after the isodiametric growth is completed, reducing the pulling speed and temperature for finishing treatment, and performing cooling annealing treatment after the finishing treatment is completed.

6. A guided-mode periodically doped crystal growth method according to claim 5, characterized in that: The temperature of the heating treatment in S11 is 1850°C-1970°C; The temperature of the cooling step in S12 is 5°C-30°C; The pulling speed in S13 is 0.1-30 mm / h; The temperature of the isodiametric growth in the S15 is 1830°C-1950°C, the growth rate of the isodiametric growth is 0.1-30mm / h, the pulling speed of the finishing treatment is 100-1000mm / h, the temperature of the finishing treatment is the crystal growth end temperature + 10°C, the temperature of the cooling annealing treatment is 1630°C-1720°C, the cooling annealing time is 5-10h, and the cooling rate is 300-100°C / h.

7. The guided-mode periodically doped crystal growth method according to claim 1, characterized in that: The growth raw material in S1 is alumina; S2 is evacuated to a vacuum level of less than 10 Pa, the inert gas is nitrogen, and the inert gas flow rate is 0.5-5 L / min; When the gas pressure of the exhaust treatment in S3 is lower than 1 kPa-100 kPa, the exhaust treatment is stopped; the temperature in the crucible (1) is heated to 2050-2200° C. by a heating device, and maintained at a constant temperature of 2050-2200° C. for 25-35 minutes.

8. The guided-mode periodically doped crystal growth method according to claim 1, characterized in that: The heating time of heating to the first temperature in S4 is 4-10 hours, the heating rate is 80-300°C / h, and the first temperature is 2050-2200°C; The second temperature in S5 is 20-150° C. higher than the first temperature. After reaching the second temperature, the temperature is kept for 5-60 minutes and then the seed crystal is pulled up by the seed crystal rod. The pulling speed is 5-100 mm / h.

9. The guided-mode periodically doped crystal growth method according to claim 1, characterized in that: The cooling rate of the first cooling in S6 is 1-50°C / h; recording the internal temperature T1 of the mold (2); In the step S7, the internal temperature of the mold (2) is fixed at T1 until the crystal (9) is completed, and the entire crystal (9) is separated from the mold (2); After the growth of the crystal (9) in S7 is completed, the temperature is kept at T2+10° C. for 10-20 minutes, and then the whole crystal is separated from the mold (2); After the crystal (9) in S7 is finished, the temperature in the crucible (1) is increased by 9-11° C., and then the crystal (9) is pulled up by the seed crystal rod at a pulling speed of 950-1100 mm / h and separated from the mold (2); After the crystal (9) is separated from the mold (2) in S8, the temperature is lowered by a post-heating device, and the temperature is lowered by 180-220° C. based on the temperature when the crystal (9) is separated from the mold (2); After cooling, the temperature is kept for 1-4 hours to complete annealing; after annealing, the temperature is cooled at a cooling rate of 100-400°C / h through a heating device, and then it is placed for 10-24 hours before being taken out.

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