A method for preparing a transparent ceramic for a sunlight-pumped solid-state laser

Abstract

The application discloses a preparation method of transparent ceramic for a sunlight-pumped solid laser, adds SrCO3 and MgO as co-sintering aids, and prepares the transparent ceramic by using a solid-phase reaction method in combination with vacuum sintering, and components of the transparent ceramic satisfy the following formula (Ce x Nd y M 1‑x‑y )3Al5O 12 , wherein x is a molar ratio of Ce 3+ doping M 3+ , y is a molar ratio of Nd 3+ doping M 3+ , wherein 0.001<=x<=0.005, 0.005<=y<=0.03, and M is one of Y and Lu. The ceramic prepared by the method has high sunlight absorption, high light-light conversion and strong emission optical performance, the light-light conversion rate can reach 75%-85%, the optical quality is excellent, the preparation time is short, high energy consumption and high equipment requirement of high-pressure sintering are avoided.

Description

Technical Field

[0001] This invention relates to the field of advanced ceramic preparation technology, specifically to a method for preparing transparent ceramics for solar-pumped solid-state lasers. Background Technology

[0002] The gain medium is the core of a solid-state laser, determining the laser output wavelength and optical conversion efficiency. Compared to single-crystal materials, transparent ceramics, as a new generation of solid-state laser gain media, can achieve material densification simply by high-temperature sintering of raw material powders. The preparation temperature is far below the material's melting point, and the preparation cycle is only one week. Furthermore, ceramic materials, with their inherent polycrystalline properties, are easily capable of achieving high-concentration, homogeneous ion doping. Transparent ceramics are currently a hot topic and focus of solid-state laser material research, and are considered "the most promising laser material."

[0003] Gain media possess both high absorption and high conversion efficiency for sunlight, a prerequisite for achieving high-quality laser output in solar-pumped solid-state lasers. Compared to Cr... 3+ Ce 3+ Because it has strong absorption in the visible light range and can react with Nd... 3+ Effective energy transfer has been achieved and is currently used in the gain medium of solar-pumped solid-state lasers, but its energy transfer is not ideal. Zhou et al. prepared different Nd... 3+ Ion-doped Cr,Nd:YAG transparent ceramics exhibited energy transfer efficiencies of 14.9%, 26.0%, and 36.9%, respectively. Lupei et al. prepared 1.0 at.% Cr, 1.0 at.% Nd:YAG transparent ceramics with an energy transfer efficiency of 52%, while Honda et al. prepared 2.0 at.% Cr, 1.0 at.% Nd:YAG transparent ceramics with an energy transfer efficiency of 58%.

[0004] Therefore, there is an urgent need in this field to develop a method for preparing transparent ceramic materials for solar pumping that possess high solar absorption, high light-to-light conversion efficiency, and strong emission. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing transparent ceramics for solar-pumped solid-state lasers, by adding SrCO3 and MgO as co-sintering aids, and by destroying Nd... 3+ The local crystal field symmetry around the ions breaks the Nd ion's symmetry. 3+ The forbidden 4f-4f transition effectively improves its launch performance, and utilizes Sr 2+ With Mg 2+The oxygen vacancy electron sensitization effect generated by co-doping substitution achieves high energy transfer efficiency of Ce-Nd and greatly enhances its emission intensity. The prepared ceramics not only have high absorption, high conversion and strong emission optical properties, but also excellent optical quality. Moreover, the preparation time is short, avoiding the high energy consumption and high equipment requirements of high-pressure sintering (which is beneficial for reducing grain size).

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing transparent ceramic for a solar-pumped solid-state laser, comprising the following steps:

[0007] (1) Slurry preparation: according to the chemical formula (Ce x Nd y M 1-x-y )3Al5O 12 The stoichiometric ratios of each element in the formula are determined by weighing M2O3 powder, α-Al2O3 powder, CeO2 powder, and Nd2O3 powder with a purity of ≥99.99%, placing them in a ball mill jar, adding sintering aids, dispersants, and anhydrous ethanol to prepare a slurry; where x represents Ce. 3+ Doped M 3+ The molar ratio, y is Nd 3+ Doped M 3+ The molar ratio is 0.001≤x≤0.005, 0.005≤y≤0.03, and M is one of Y and Lu; the sintering aid is a co-sintering aid of SrCO3 and MgO, the amount of SrCO3 added accounts for 0.10-0.30% of the total mass of the raw material powder, and the mass ratio of SrCO3 to MgO is 10:2-5;

[0008] (2) Ball milling and powder treatment: Place the ball mill jar containing slurry and grinding balls in the ball mill, ball mill to obtain mixed slurry, dry the mixed slurry and grind and sieve to obtain mixed powder;

[0009] (3) Powder forming: The mixed powder is placed in a mold and dry-pressed to obtain a green body. The green body is then cold isostatically pressed. The green body is then placed in a muffle furnace for calcination and naturally cooled to obtain a ceramic body.

[0010] (4) Sintering and annealing: The ceramic blank is placed in a vacuum furnace for vacuum sintering, and then annealed in a muffle furnace to eliminate oxygen vacancies.

[0011] (5) Polishing: Polish the annealed ceramic to obtain transparent ceramic.

[0012] Preferably, in step (1), the dispersant is DS005, a strong polymerizing dispersant from Polymer Innovations, Inc., USA, and the amount of dispersant added is 0.03-0.06% of the total mass of M2O3 powder and α-Al2O3 powder; the liquid-solid ratio of the amount of anhydrous ethanol added to the total mass of the raw material powder is 3-5 mL: 3 g.

[0013] Preferably, in step (2), the ball milling speed is 180-250 r / min and the ball milling time is 8-15 h.

[0014] Preferably, in step (2), the drying temperature is 60-100℃, the drying time is 8-24h, and the mesh size of the sieve is 80-300 mesh.

[0015] Preferably, in step (3), the dry pressing pressure is 20-90 MPa, the pressure holding time is 10-50 s, the cold isostatic pressing pressure is 120-300 MPa, and the cold isostatic pressing holding time is 5-40 min.

[0016] Preferably, in step (3), the calcination temperature in the muffle furnace is 300-1100℃, the calcination time is 3-15h, and the temperature is naturally cooled to 20-60℃.

[0017] Preferably, in step (4), the vacuum sintering temperature is 1740-1800℃ and the holding time is 6h-20h.

[0018] Preferably, in step (4), the annealing temperature is 900-1300℃ and the holding time is 10h-18h.

[0019] High absorption, high conversion, and strong emission performance are essential for solar-pumped solid-state lasers. However, under traditional fabrication processes, transparent ceramics exhibit low optical conversion efficiency, and improvements in their emission performance rely entirely on increasing and optimizing ion doping concentration. However, relying solely on optimizing doping concentration to achieve high concentrations can easily lead to ion segregation and concentration quenching, resulting in a decrease in the optical quality of the gain medium and fluorescence quenching, ultimately affecting laser performance.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The ceramic prepared by the present invention has optical properties of high solar light absorption, high light-to-light conversion and strong emission, with a light-to-light conversion rate of 75%-85%.

[0022] (2) The solar-pumped transparent ceramic gain medium prepared in this invention breaks with traditional concepts by adding Sr 2+ Destroyed Nd 3+ The local crystal field symmetry around the ions leads to Nd 3+The high electronic configuration of the ion's f state breaks the forbidden 4f-4f transition, effectively improving the Nd... 3+ Ion emission performance;

[0023] (3) The ceramic preparation method provided by the present invention uses Sr 2+ With Mg 2+ The oxygen vacancies generated by co-doping not only trap electrons in Ce 3+ The higher energy level, therefore more electrons in Ce 3+ The upper energy level is used to achieve higher energy transfer efficiency in Ce-Nd; at the same time, oxygen vacancies can trap Nd. 3+ With the aid of phonons, the electrons in the ionized state of the ion relax to Nd ions at the oxygen vacancy ionized state. 3+ The excited state energy levels further enhance Nd 3+ Increase emission intensity to improve its laser emission performance;

[0024] (4) The ceramic preparation method provided by this invention uses Sr 2+ With Mg 2+ As a co-sintering aid, the prepared ceramics have excellent optical quality and high transmittance;

[0025] (5) The ceramic preparation method provided by the present invention avoids the high energy consumption and high equipment requirements of ultra-high pressure sintering and has the prospect of industrial application. Attached Figure Description

[0026] Figure 1 The transmittance curve of Ce,Nd:YAG transparent ceramic prepared in Example 1 of this invention;

[0027] Figure 2 The PL emission spectrum curves at 1064 nm are shown for Ce,Nd:YAG transparent ceramic prepared in Example 1 of this invention and conventional transparent ceramic.

[0028] Figure 3 This is a photograph of the Ce,Nd:YAG transparent ceramic prepared in Example 1 of the present invention.

[0029] Figure 4 This is a comparison of the light-to-light conversion efficiency of Ce,Nd:YAG transparent ceramics prepared in Examples 1, 2, and 3 of this invention. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0031] The purpose of this invention is to provide a method for preparing transparent ceramics for solar-pumped solid-state lasers with high conversion and strong emission. This method involves adding SrCO3 and MgO as co-sintering aids and destroying Nd... 3+The local crystal field symmetry around the ions breaks the Nd ion's symmetry. 3+ The forbidden 4f-4f transition effectively improves its launch performance, and utilizes Sr 2+ With Mg 2+ The oxygen vacancy electron sensitization effect generated by co-doping substitution achieves high energy transfer efficiency of Ce-Nd and greatly enhances its emission intensity. The prepared ceramics not only have high absorption, high conversion and strong emission optical properties, but also excellent optical quality. Moreover, the preparation time is short, avoiding the high energy consumption and high equipment requirements of high-pressure sintering (which is beneficial for reducing grain size).

[0032] The powders, reagents and other raw materials used in the following examples are all commercially available products, and the purity of the α-Al2O3 powder is above 99.99%.

[0033] Example 1

[0034] ①According to (Ce 0.001 Nd 0.005 Y 0.994 )3Al5O 12 The stoichiometric ratios of each element were determined by weighing 60g of powder and placing it in a ball mill jar. 0.06g of SrCO3, 0.012g of MgO, and 0.018g of dispersant were added, and 60mL of anhydrous ethanol was added to prepare a slurry.

[0035] ② Place the ball mill jar containing the slurry obtained in step ① and high-purity alumina grinding balls in a planetary ball mill and ball mill for 8 hours at a speed of 180 r / min. Place the resulting mixed slurry in an oven to dry at a temperature of 60℃ for 8 hours, and then sieve it through an 80-mesh sieve.

[0036] ③ Place the sieved powder obtained in step ② into a stainless steel mold and dry press it. Place the obtained green blank into a sealed bag and cold isostatically press it at 120 MPa for 5 minutes. Place the green blank in a muffle furnace and calcine it at 300℃ for 3 hours, and then let it cool naturally to 20℃.

[0037] ④ Place the calcined green blank from step ③ into a vacuum sintering furnace. The vacuum sintering temperature is 1740℃ and the holding time is 6h.

[0038] ⑤ The ceramic obtained in step ④ is annealed in air at 900℃ for 10 hours, and finally polished to make its thickness 2mm.

[0039] Figure 1 The transmittance curve of the Ce,Nd:YAG transparent ceramic prepared in this embodiment shows that the ceramic has a transmittance of 82.3% at 1064 nm, indicating that the ceramic has a high transmittance.

[0040] Figure 2The PL emission intensity curves at 1064 nm for the Ce,Nd:YAG transparent ceramic prepared in this embodiment and the traditional transparent ceramic show that this embodiment has a stronger emission intensity.

[0041] Figure 3 This is a physical image of the Ce,Nd:YAG transparent ceramic prepared in this embodiment. The ceramic sample has excellent light transmittance, and the image underneath the ceramic can be clearly seen.

[0042] Depend on Figure 4 It can be seen that the light-to-light conversion efficiency of the Ce,Nd:YAG transparent ceramic prepared in this embodiment is 75%.

[0043] Example 2

[0044] ①According to (Ce 0.003 Nd 0.015 Y 0.982 )3Al5O 12 The stoichiometric ratios of each element were determined by weighing 60g of powder and placing it in a ball mill jar. 0.12g of SrCO3, 0.036g of MgO, and 0.024g of dispersant were added, and 80mL of anhydrous ethanol was added to prepare a slurry.

[0045] ② Place the ball mill jar containing the slurry obtained in step ① and high-purity alumina grinding balls in a planetary ball mill and ball mill for 12 hours at a speed of 220 r / min. Place the resulting mixed slurry in an oven to dry at a temperature of 80℃ for 15 hours, and then sieve it through a 150-mesh sieve.

[0046] ③ Place the sieved powder obtained in step ② into a stainless steel mold and dry press it. Place the obtained green blank into a sealed bag and cold isostatically press it at 200 MPa for 25 minutes. Place the green blank in a muffle furnace and calcine it at 800℃ for 8 hours, and then let it cool naturally to 40℃.

[0047] ④ Place the calcined green blank from step ③ into a vacuum sintering furnace. The vacuum sintering temperature is 1780℃ and the holding time is 15h.

[0048] ⑤ The ceramic obtained in step ④ is annealed in air at 1100℃ for 14 hours, and finally polished to make its thickness 2mm.

[0049] The transmittance curve, PL spectrum, and physical image of the Ce,Nd:YAG transparent ceramic prepared in this embodiment are similar to those in Example 1. Figure 4 It can be seen that the light-to-light conversion efficiency of the Ce,Nd:YAG transparent ceramic prepared in this embodiment is 85%.

[0050] Example 3

[0051] ①According to (Ce0.005 Nd 0.030 Y 0.965 )3Al5O 12 Weigh 60g of powder into a ball mill jar, add 0.18g of SrCO3, 0.09g of MgO, 0.036g of dispersant, and 100mL of anhydrous ethanol to prepare a slurry.

[0052] ② Place the ball mill jar containing the slurry obtained in step ① and high-purity alumina grinding balls in a planetary ball mill and ball mill for 15 hours at a speed of 250 r / min. Place the resulting mixed slurry in an oven to dry at a temperature of 100℃ for 24 hours, and then sieve it through a 300-mesh sieve.

[0053] ③ Place the sieved powder obtained in step ② into a stainless steel mold and dry press it. Place the obtained green blank into a sealed bag and cold isostatically press it at 300 MPa for 40 minutes. Place the green blank in a muffle furnace and calcine it at 1100℃ for 15 hours, and then let it cool naturally to 60℃.

[0054] ④ Place the calcined green blank from step ③ into a vacuum sintering furnace. The vacuum sintering temperature is 1800℃ and the holding time is 20h.

[0055] ⑤ The ceramic obtained in step ④ is annealed in air at 1300℃ for 18 hours, and finally polished to make its thickness 2mm.

[0056] The transmittance curve, PL spectrum, and physical image of the Ce,Nd:YAG transparent ceramic prepared in this embodiment are similar to those in Example 1. Figure 4 It can be seen that the light-to-light conversion efficiency of the Ce,Nd:YAG transparent ceramic prepared in this embodiment is 79%.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing transparent ceramic for a solar-pumped solid-state laser, characterized in that, Includes the following steps: (1) Slurry preparation: according to the chemical formula (Ce x Nd y M 1-x-y )3Al5O 12 The stoichiometric ratios of each element in the formula are determined by weighing M2O3 powder, α-Al2O3 powder, CeO2 powder, and Nd2O3 powder with a purity of ≥99.99%, placing them in a ball mill jar, adding sintering aids, dispersants, and anhydrous ethanol to prepare a slurry; where x represents Ce. 3+ Doped M 3+ The molar ratio, y is Nd 3+ Doped M 3+ The molar ratio is 0.001≤x≤0.005, 0.005≤y≤0.03, and M is one of Y and Lu; the sintering aid is a co-sintering aid of SrCO3 and MgO, the amount of SrCO3 added accounts for 0.10-0.30% of the total mass of the raw material powder, and the mass ratio of SrCO3 to MgO is 10:2-5; (2) Ball milling and powder treatment: Place the ball mill jar containing slurry and grinding balls in the ball mill, and ball mill to obtain a mixed slurry. After drying the mixed slurry, grind and sieve it to obtain a mixed powder. (3) Powder forming: The mixed powder is placed in a mold and dry-pressed to obtain a green body. The green body is then cold isostatically pressed. The green body is then placed in a muffle furnace for calcination and naturally cooled to obtain a ceramic body. (4) Sintering and annealing: The ceramic blank is placed in a vacuum furnace for vacuum sintering, and then annealed in a muffle furnace to eliminate oxygen vacancies. (5) Polishing: Polish the annealed ceramic to obtain transparent ceramic.

2. The method for preparing transparent ceramic for a solar-pumped solid-state laser according to claim 1, characterized in that, In step (1), the dispersant is DS005, a strong polymerizing dispersant from Polymer Innovations, Inc., USA. The amount of dispersant added is 0.03-0.06% of the total mass of M2O3 powder and α-Al2O3 powder. The liquid-solid ratio of the amount of anhydrous ethanol added to the total mass of the raw material powder is 3-5 mL: 3 g.

3. The method for preparing transparent ceramic for a solar-pumped solid-state laser according to claim 1, characterized in that, In step (2), the ball milling speed is 180-250 r / min and the ball milling time is 8-15 h.

4. The method for preparing transparent ceramic for a solar-pumped solid-state laser according to claim 1, characterized in that, In step (2), the drying temperature is 60-100℃, the drying time is 8-24h, and the mesh size of the sieve is 80-300 mesh.

5. The method for preparing transparent ceramic for a solar-pumped solid-state laser according to claim 1, characterized in that, In step (3), the dry pressing pressure is 20-90 MPa and the pressure holding time is 10-50 s. The cold isostatic pressing pressure is 120-300 MPa and the cold isostatic pressing holding time is 5-40 min.

6. The method for preparing transparent ceramic for a solar-pumped solid-state laser according to claim 1, characterized in that, In step (3), the calcination temperature in the muffle furnace is 300-1100℃ and the calcination time is 3-15h; then the temperature is naturally cooled to 20-60℃.

7. The method for preparing transparent ceramic for a solar-pumped solid-state laser according to claim 1, characterized in that, In step (4), the vacuum sintering temperature is 1740-1800℃ and the holding time is 6h-20h.

8. The method for preparing transparent ceramic for a solar-pumped solid-state laser according to claim 1, characterized in that, In step (4), the annealing temperature is 900-1300℃ and the holding time is 10h-18h.

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