2pm luminescent ytterbium-holmium co-doped bismuth borate glass and preparation method thereof

Abstract

The present application relates to the field of high-power fiber laser, in particular to a kind of 2 μm luminescence aluminum ion regulated ytterbium holmium co-doped bismuth borate glass and preparation method, the molar percentage composition of the glass is: its main component is Bi2O330%, B2O345-55%, ZnO 10%, Yb2O32%, Ho2O30.8%, Al2O32.5-7.5%.The present application is intended to solve the problem of low efficiency of mid-infrared light source, limited tuning range and other pain points.The present application uses ytterbium holmium as rare earth doping ion, designs bismuth borate matrix glass formula, and then introduces Al to regulate the topological structure of the glass, to prepare aluminum ion regulated ytterbium holmium co-doped bismuth borate laser glass material with good laser performance, to realize 2 μm waveband laser output.

Description

Technical Field

[0001] This invention belongs to the field of high-power fiber lasers, specifically relating to a 2μm luminescent aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass and its preparation method. Background Technology

[0002] Fiber lasers can be classified into four types based on their gain medium: nonlinear effect, crystal, plastic, and rare-earth ion-doped fiber lasers. Due to their advantages such as good heat dissipation, compact structure, high output beam quality, low cost, high energy conversion efficiency, simple structure, and good stability, they have been widely used in laser communication, lidar, environmental monitoring, biomedicine, and materials processing. In 2016, Henderson Sapir et al. from the University of Adelaide, Australia, reported a wide-range tunable Er... 3+ ZBLAN fiber laser. This laser has a wavelength tuning range up to 450 nm, with a maximum wavelength of 3.78 μm, and achieves 1.45 W (near diffraction-limited) laser output at 3.47 μm. In 2019, Majewski et al. at Macquarie University, Australia, significantly reduced the quantum defect of the pump light and improved the laser's conversion efficiency by using in-band pumping. (The text then abruptly shifts to a seemingly unrelated topic: "Dy pumped from 800 nm...") 3+ / Tm 3+ The co-doped fluoride fiber achieved a slope efficiency of 91%. In 2021, Guo Chunyu et al. from Shenzhen University reported for the first time in China a 2.8μm laser output with a power of 20W from an all-fiber structure.

[0003] To improve the luminescence performance in the mid-infrared band, current research methods can be mainly divided into two categories. One is to introduce other rare-earth ions into single-doped or co-doped systems for modification, allowing them to undergo cross-relaxation processes with the activating ions or form special clusters, further filling the particle layout of excited-state energy levels and thus enhancing mid-infrared emission. The improvement in luminescence performance by introducing different types of glass modifiers into glass components essentially stems from two mechanisms. One is to alter the glass topological cage mesh structure, reducing the mesh vibration frequency and thus lowering the phonon energy of the glass, reducing the multiphonon relaxation effect, and thereby enhancing the radiative transitions of rare-earth ions, thereby improving mid-infrared luminescence efficiency. The other mechanism originates from changes in the glass mesh structure, harmonizing the ligand field environment around the high-spin rare-earth luminescent ions, further regulating the degree of Stark level splitting of rare-earth ions, and ultimately achieving a wide range of mid-infrared emission. Summary of the Invention

[0004] Based on the current situation, the applicant found that to obtain good fluorescence in the 2 μm band, it is necessary to start with the glass matrix and find a matrix glass composition formulation with excellent properties in order to achieve good luminescence performance. Modulating the topology of the glass mesh to enhance its luminescence performance in the 2 μm band also has high research value. Therefore, the applicant proposed an Al-based... 3+ Regulation of Yb 3+ / Ho 3+ The co-doped bismuth borate glass structure has important theoretical and practical significance for the study of luminescence properties at 2.0 μm.

[0005] The present invention is achieved through the following technical solution.

[0006] The first objective of this invention is to provide an aluminum ion-controlled ytterbium-holmium co-doped bismuth-boron glass, wherein the glass matrix comprises the following molar percentage components: Bi₂O₃ 30-40%, B₂O₃ 45-55%, ZnO 10-15%, Al₂O₃ 2.5-7.5%; and doped with: Ho₂O₃ 0.5-1.% and Yb₂O₃ 2-4%.

[0007] Preferably, the glass matrix comprises the following molar percentage components: Bi₂O₃ 30%, B₂O₃ 45-55%, ZnO 10%, Al₂O₃ 2.5-7.5%; and doped with: Ho₂O₃ 0.75%, Yb₂O₃ 2%.

[0008] The second objective of this invention is to provide a method for preparing the above-mentioned aluminum ion-controlled ytterbium-holmium co-doped bismuth boron glass, comprising the following steps: S1. Weigh each raw material according to the following molar percentages: Bi2O3, B2O3, ZnO, Yb2O3, Ho2O3, Al2O3; S2. Place the raw materials weighed in S1 into a corundum crucible and melt them in a silicon carbide electric furnace. Then clarify and homogenize them. Finally, pour the melted glass into a preheated mold. S3. Quickly and smoothly transfer the glass formed in S2 into a preheated muffle furnace and keep it at a temperature 10-50°C below the glass transition temperature. Then cool the muffle furnace to room temperature and remove the glass sample after it has completely cooled.

[0009] Preferably, in S2, the melting temperature is 1150-1250°C.

[0010] Preferably, in S2, the melting time is 30-50 minutes.

[0011] Preferably, in step S2, the clarification and homogenization temperature is 1050-1100℃.

[0012] Preferably, in step S2, the clarification and homogenization time is 20-30 minutes.

[0013] Preferably, in step S3, the heat preservation time is 2-4 hours.

[0014] Preferably, in S3, the cooling rate is 10°C / h.

[0015] Compared with the prior art, the present invention has the following advantages: (1) The glass prepared by introducing Yb2O3 and Ho2O3 into bismuthate glass in this invention has tunable composition, good glass-forming performance, and thermal stability parameter ΔT greater than 100 °C. The ytterbium-holmium co-doped system has high energy transfer efficiency and low loss.

[0016] (2) Al is carried out in the above glass. 3+ Ion doping can produce 2μm luminescent rare-earth bismuth-ytterbium-holmium doped laser glass, Al 3+ Ion doping makes the energy transfer process between rare earth ions more efficient, thereby improving fluorescence emission in the mid-infrared band, which is of great significance in the field of high-power fiber lasers. Attached Figure Description

[0017] Figure 1 The Raman spectra of aluminum ion-modulated ytterbium-holmium co-doped bismuth borate glasses prepared in Examples 1-4 are shown. Figure 2 The graph shows the refractive index test results of the aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glasses prepared in Examples 1-4. Figure 3 The absorption spectra of aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glasses prepared in Examples 1-4 are shown. Figure 4 The emission spectra of aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glasses prepared in Examples 1-4 are shown. Figure 5 The image shows the DSC curve of the aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass prepared in Example 3. Figure 6 Emission spectra of aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glasses prepared in Examples 1, 5 and 6; Detailed Implementation To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0018] The glass compositions of six specific embodiments of the 2 μm luminescent aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass of the present invention are shown in Table 1: Table 1. Glass matrix composition of Examples 1-6

[0019] Based on the matrix in Table 1, doping was performed, and the specific doping ratios are shown in Table 2 below: Table 2 Doping content of Examples 1-6

[0020] Examples 1-6: The composition is shown in Table 1, Examples 1-6, and the specific preparation process is as follows: The masses of the six compounds were calculated according to the molar percentages of the glass composition in Examples 1-6 in Table 1. 5g of the batch material was accurately weighed and mixed evenly. The batch material was placed in a crucible and melted at 1100-1250℃ (melting temperature of S1 to S3 is 1150℃) for 55-65 minutes (melting time of S1 to S3 is 60 minutes). The molten glass was poured into a preheated mold. After forming, it was quickly transferred to a muffle furnace preheated to 380℃ and held at that temperature for 3 hours. After annealing at a rate of 10℃ / h until the temperature dropped to 200℃, it was cooled to room temperature at a rate of 25.0℃ / h. After complete cooling, the glass sample was removed.

[0021] The test results for this glass sample are as follows: Depend on Figure 1 The prepared samples were then subjected to Raman spectroscopy analysis. The Raman spectra of the aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glasses of Examples 1-4 of this invention are as follows: Figure 1 As shown, the Raman spectra of the BBZA series glasses exhibit three distinct broad scattering peaks, belonging to the low-frequency, mid-frequency, and high-frequency regions, respectively. Furthermore, with increasing Al₂O₃ content in the bismuthate matrix, the Raman spectra of BBZA1~BBZA3 glasses show no significant change. Figure 1 The maximum phonon energy of BBZA2 glass is 1166 cm⁻¹. - ¹.

[0022] The annealed glass sample was cut into 10×10×2mm thin slices, and both sides of the glass slices were polished. The refractive index change curve was measured, and then the absorption and emission spectra of the sample were measured under 980nm laser diode pumping. The refractive index test results of the 2μm luminescent aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass in Examples 1-4 of this invention are as follows: Figure 2 As shown, the nonlinear refractive index of BBZA2 is calculated to be 21.356 × 10⁻⁶. -13 esu. By adding Al2O3, a laser glass with better performance was obtained.

[0023] The absorption spectra of 2μm luminescent aluminum ion-modulated ytterbium-holmium co-doped bismuth borate glasses in Examples 1-4 of this invention are as follows: Figure 3 As shown, the absorption band morphology of the BBZA1-3 series samples is highly similar, and the intensity and position of the characteristic absorption peaks do not change with the Al2O3 doping amount. This indicates that Al³⁺... + Ions can dissolve uniformly in the glass network without ion clustering, and for Yb³ + With Ho³ + The local coordination environment of the ions has a weak influence. The infrared transmission spectrum of sample BBZA2 in the 2400-3200 nm range is as follows: Figure 3 As shown. The α value of the BBZA2 glass sample was calculated using the formula. OH The calculated value is 0.22.

[0024] The emission spectra of the 2μm luminescent aluminum ion-modulated ytterbium-holmium co-doped bismuth borate glasses in Examples 1-4 of this invention are as follows: Figure 4 As shown, the fluorescence intensity in the spectrum exhibits a trend of first increasing and then decreasing, reaching its maximum value at an Al₂O₃ doping concentration of 5 mol%. This phenomenon can be attributed to the fact that the introduction of Al₂O₃ as a network modifier into the glass network alters its topological cage structure; simultaneously, Al… 3+ Its ionic radius is similar to that of rare earth ions, which can effectively increase the spacing between Ho-Ho and Ho-Yb clusters, thereby reducing the energy loss caused by interionic resonance and achieving enhanced fluorescence emission.

[0025] The DSC test curve of the 2μm luminescent aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass in Example 3 of this invention is as follows: Figure 5 As shown, after Al2O3 incorporation, the glass transition temperature (Tg) jumps from 378 °C to 390 °C, surpassing that of traditional tellurate glass (TeO2-Ga2O3-ZnO, Tg = 369 °C). Simultaneously, the glass ΔT (Tx–Tg) of BBZA2 is 110 °C, superior to the fluoride system InF3-ZnF2-SrF2-BaF2-GaF3-LaF (ΔT = 88 °C) and alumina glass (ΔT = 98 °C), indicating a significant improvement in its resistance to crystallization, fully meeting the requirements for optical fiber drawing.

[0026] By comparing Examples 1, 5, and 6, the optimal holmium-ytterbium doping ratio was determined by varying the proportion of holmium ions. Figure 6 The data shows that, with Ho 3+ As the doping concentration increased from 0.5 mol% to 1 mol%, the fluorescence intensity showed a trend of first increasing and then decreasing, and at Ho 3+ The peak value was reached at a concentration of 0.75 mol%. The performance of Examples 5 and 6 was not as good as that of Example 1, therefore Example 1 is the optimal ratio for holmium-ytterbium doping.

[0027] Experiments show that the glass sample obtained in Example 3 of this invention can achieve 2μm fluorescence output, and the glass has a high refractive index and high luminescence intensity (due to...). Figure 3 The effect of Al2O3 content on the luminescence intensity of Yb / Ho doped materials can be obtained. The thermal stability parameter is greater than 100℃ (from...). Figure 5 It can be seen that the thermal stability parameter of Example 3 in the bismuth boron aluminum laser glass system is ΔT = 110℃ (greater than 100℃), the energy level lifetime of the sample in the 2μm band is 2.97 ms, and the maximum emission cross section is 14.72 × 10⁻⁶. - 21 cm 2 It significantly improves both the energy transfer coefficient and energy transfer rate, while suppressing rare-earth ion interactions and reducing the maximum phonon energy to 1166 cm⁻¹, effectively enhancing mid-infrared emission characteristics. It is highly suitable for fiber drawing and possesses a relatively high transition temperature (387℃).

[0028] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. An aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass, characterized in that, The glass matrix comprises the following components in molar percentage: Bi₂O₃ 30-40%, B₂O₃ 45-55%, ZnO 10-15%, Al₂O₃ 2.5-7.5%; and is doped with: Ho₂O₃ 0.5-1%, Yb₂O₃ 2-4%.

2. The aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 1, characterized in that, The glass matrix comprises the following components in molar percentage: Bi₂O₃ 30%, B₂O₃ 45-55%, ZnO 10%, Al₂O₃ 2.5-7.5%; and doped with: Ho₂O₃ 0.75%, Yb₂O₃ 2%.

3. The method for preparing aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 1 or 2, characterized in that, Includes the following steps: S1. Weigh each raw material according to the following molar percentages; S2. Place the raw materials weighed in S1 into a corundum crucible and melt them in a silicon carbide electric furnace. Then clarify and homogenize them. Finally, pour the melted glass into a preheated mold. S3. Quickly and smoothly transfer the glass formed in S2 into a preheated muffle furnace and keep it at that temperature. Then cool the muffle furnace to room temperature and remove the glass sample after it has completely cooled.

4. The method for preparing aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 3, characterized in that, In S2, the melting temperature is 1150-1250℃.

5. The method for preparing aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 3, characterized in that, In S2, the melting time is 30-50 minutes.

6. The method for preparing aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 3, characterized in that, In S2, the clarification and homogenization temperature is 1050-1100℃.

7. The method for preparing aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 3, characterized in that, In S2, the clarification and homogenization time is 20-30 minutes.

8. The method for preparing aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 3, characterized in that, In S3, the temperature of the muffle furnace is 10-50°C below the glass transition temperature.

9. The method for preparing aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 3, characterized in that, In S3, the heat preservation time is 2-4 hours.

10. The method for preparing aluminum ion-controlled ytterbium-holmium co-doped bismuth borate glass according to claim 3, characterized in that, In S3, the cooling rate is 10-15°C / h.

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