0.9 mu m light-emitting neodymium-doped fluorophosphate laser glass, its preparation method and application

Abstract

This invention belongs to the field of laser glass and discloses a 0.9 μm luminescent neodymium fluoride phosphate laser glass, its preparation method, and its applications. The molar percentage composition of the neodymium fluoride phosphate laser glass is: 10–80% Sr(PO3)2, 10–80% Ba(PO3)2, 2–10% MgF2, and 2–10% AlF3, with the sum of the above components being 100%. NdF3 is externally doped at a weight ratio of 0.5–4 wt%. The neodymium fluoride phosphate laser glass exhibits excellent thermal stability (ΔT > 100℃) and can achieve ~0.9 μm luminescence under 808 nm laser diode pumping. Direct monitoring shows a lifetime of 333–388.4 μs in this wavelength band, comparable to the lifetime of the 1.06 μm band. The gain cross-section at 902 nm is 2.07–2.40 × 10⁻⁶. ‑20 cm 2 It is suitable for the fabrication and application of 0.9μm laser glass fiber and fiber laser.

Description

Technical Field

[0001] This invention belongs to the field of laser glass, specifically relating to a 0.9μm luminescent neodymium fluoride phosphate laser glass, its preparation method, and its application. Background Technology

[0002] Nd doping 3+ While research on glass fiber lasers in the 1.06 μm band is relatively mature, the development of high-performance fiber lasers and corresponding special fibers in the ~0.9 μm band has attracted much attention from researchers in recent years. Lasers in this band can be directly used to pump Yb 3+ Laser materials are being used in atmospheric detection and image-guided surgery. Furthermore, ~900nm lasers combined with frequency doubling techniques can generate deep blue lasers around ~450nm. Numerous experiments have shown that blue-green light has a significant window for propagation in seawater, which can be used for underwater target measurement and communication. Currently, several methods have been employed to obtain ~900nm high-power lasers, including semiconductor, solid-state, and Nd: 3+ Doped fiber (NDF) lasers. NDF lasers not only have the advantages of wide tunability, compactness, ease of integration, and good beam quality, but also have the advantage of high rare earth doping. This is more conducive to the operation of quasi-three-level ~0.9μm laser systems that require high particle numbers. Therefore, the development of high-efficiency light-emitting NDF lasers has attracted much attention from researchers.

[0003] But due to Nd 3+ : 4 F 3 / 2 → 4 F 11 / 2 (~1060nm) energy level and 4 F 3 / 2 → 4 F 9 / 2 The intense competition for energy level transitions in the ~900nm range leads to a significant increase in emission at ~1060nm compared to ~900nm. Methods such as using bandpass filters near ~900nm, special fiber waveguide designs (e.g., W-type refractive index distribution fiber, photonic bandgap fiber, high core-to-closing ratio fiber), and liquid nitrogen-cooled fiber are all ways to address the gain gap between the two bands. However, passively suppressing ~1060nm to overcome transition competition does not fundamentally solve the problem of weak emission at ~0.9μm. Therefore, designing a suitable matrix glass material for emission in this band is crucial. (2021 Shanghai Institute of Optics and Fine Mechanics (Y.Chen, Z.Lin, H.Sun, Y.Wang, H.Dong, M.Wang, L.Zhang, G.Dong, X.Liu, F.Yu, S.Wang, C.Yu, L.Hu, High-power lasing at ~900nm Nd...) 3+-Doped fiber: a direct coordination engineering approach to enhance fluorescence, Optica. 10 (2023) 905. https: / / doi.org / 10.1364 / OPTICA.494868.) It was previously reported that a sol-gel method combined with dehydration and decarburization processes was used to achieve a significant increase in spectral intensity at 900 nm by doping with NdI3. However, this preparation method also has limitations such as a complex and long preparation period, unstable control effect due to the easy decomposition of NdI3, and low doping concentration in quartz glass. Compared with quartz optical fiber, it has a higher rare earth ion doping concentration (10... 21 ions / cm 3 Phosphate glasses are more conducive to the operation of quasi-three-level laser systems requiring high population inversion, i.e., 0.9 μm laser systems. In recent years, achieving 0.9 μm band laser output in multi-component phosphates has attracted more attention. For example, in 2021, Xiushan Zhu et al. (S. Fu, X. Zhu, J. Zong, M. Li, I. Zavala, V. Temyanko, A. Chavez-Pirson, R. Arnorwood, N. Peyghambarian, Single-Frequency Nd) of the University of Arizona, USA, achieved this. 3+ -Doped Phosphate Fiber Laser at 915nm, J. Lightwave Technol. 39(2021) 1808-1813. https: / / doi.org / 10.1109 / JLT.2020.3043166.) A Nd-doped Fiber Laser was developed. 3+ Phosphate-doped optical fibers, with a maximum pump power of 445 mW, exhibit a 915 nm laser power of 13.5 mW. However, phosphate fibers still suffer from drawbacks such as high phonon energy and easy binding with hydroxyl groups, which hinder further improvement in the luminescence efficiency of rare-earth ions. Therefore, this study aims to design an excellent matrix material suitable for efficient luminescence in the 0.9 μm wavelength band, enhancing the radiative transition performance and luminescence efficiency of rare-earth ions, and achieving Nd-doped fiber luminescence. 3+ The transformation of glass into laser output with strong light emission in the ~0.9μm wavelength band is of great significance. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the primary objective of this invention is to provide a 0.9μm luminescent neodymium fluoride phosphate laser glass.

[0005] Another object of the present invention is to provide a method for preparing 0.9 μm luminescent neodymium fluoride phosphate laser glass.

[0006] Another object of the present invention is to provide the application of the above-mentioned 0.9μm luminescent neodymium fluoride phosphate laser glass.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A 0.9 μm luminescent neodymium fluoride phosphate laser glass, with the following molar percentage composition:

[0009]

[0010]

[0011] The sum of the molar percentages of the above components is 100%;

[0012] NdF3 is added externally at a weight ratio of 0.5–4 wt%.

[0013] Preferably, the molar percentage composition of the 0.9μm luminescent neodymium fluoride phosphate laser glass is as follows:

[0014]

[0015] The sum of the molar percentages of the above components is 100%;

[0016] NdF3 is added externally at a ratio of 1-2 wt%.

[0017] Preferably, the molar percentage composition of the 0.9μm luminescent neodymium fluoride phosphate laser glass is as follows:

[0018]

[0019] The sum of the molar percentages of the above components is 100%;

[0020] NdF3 was added at a weight ratio of 1 wt%.

[0021] A method for preparing 0.9 μm luminescent neodymium fluoride phosphate laser glass includes the following steps:

[0022] (1) Weigh the raw materials according to the composition and proportions, mix and grind them to obtain the compound material;

[0023] (2) The batch material is transferred into a platinum crucible and placed in a high-temperature furnace for melting to obtain a transparent and uniform glass melt;

[0024] (3) Pour the molten glass onto a stainless steel plate to form a transparent glass block;

[0025] (4) Anneal the glass block, keep it warm, and cool it to obtain 0.9μm light-emitting neodymium fluoride phosphate laser glass.

[0026] Preferably, the melting temperature in step (2) is 1250-1350℃ and the melting time is 20-40min.

[0027] Preferably, the annealing temperature in step (4) is 450-580°C, and the holding time is 4-8 hours.

[0028] Preferably, the cooling rate in the step is 10-20℃ / h.

[0029] The above-mentioned 0.9μm luminescent neodymium fluoride phosphate laser glass is used in laser glass optical fibers.

[0030] The above-mentioned 0.9μm luminescent neodymium fluoride phosphate laser glass is used in fiber lasers.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] (1) This invention provides a 0.9μm luminescent neodymium fluoride phosphate laser glass, which is simple and easy to prepare.

[0033] (2) The neodymium-doped fluorine phosphate laser glass of the present invention has excellent thermal stability, with ΔT > 100℃, which is beneficial for fiber drawing.

[0034] (3) The neodymium-doped fluorine phosphate laser glass of this invention can achieve a emission wavelength of ~0.9 μm under 808 nm laser diode pumping, and the lifetime in this band can be directly monitored, reaching 333–388.4 μs, comparable to the lifetime in the 1.06 μm band. The gain cross-section at 902 nm is 2.07–2.40 × 10⁻⁶. -20 cm 2 The spectral quality factor is 7.68–8.03 × 10⁻⁶. -24 cm 2 s, suitable for the fabrication and application of 0.9μm laser glass fiber and fiber laser.

[0035] (4) Nd in the glass of the example 3+ : 4 F 3 / 2 → 4 I 9 / 2 The effective linewidth Δλ of the transition eff Its wavelength ranges from 44.64 to 45.39 nm, which is greater than the effective linewidth (31.3 to 32 nm) of commercial fluorophosphate glasses such as LG-810, LHG10, and NF1. Attached Figure Description

[0036] Figure 1 The following are DSC curves of the neodymium fluoride phosphate laser glasses obtained in Examples 1-5;

[0037] Figure 2The emission spectra of the neodymium-doped fluorine phosphate laser glasses obtained in Examples 1-5 are shown in the ~0.9 μm band.

[0038] Figure 3 The lifetime decay curves for Examples 1-5 are shown, with an excitation wavelength of 808 nm and a monitoring wavelength of 902 nm.

[0039] Figure 4 The gain curves are for Examples 1 and 3-5. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0041] Examples 1-5

[0042] The glass compositions of five specific embodiments of the 0.9 μm luminescent neodymium fluoride phosphate laser glass of the present invention are shown in Table 1, wherein NdF3 is introduced into the glass composition by external doping. Examples 1 to 5 are denoted as x = 0.18, 0.36, 0.45, 0.54, and 0.72 respectively in the figure, where x is the molar ratio of Sr(PO3)2.

[0043] Table 1

[0044]

[0045] The preparation steps of the neodymium-doped fluorine phosphate laser glass in Examples 1-5 are as follows:

[0046] (1) Weigh 10g of raw materials Sr(PO3)2, Ba(PO3)2, MgF2 and AlF3 according to their composition and proportions, and weigh 0.1g of NdF3. All raw materials are high-purity raw materials (>99.99%).

[0047] (2) Mix and grind the raw materials obtained in step (1) in an agate mortar to form a compound;

[0048] (3) Transfer the uniformly ground batch material from step (2) into a platinum crucible, place it in a high-temperature furnace and heat it to 1300°C. After melting for 30 minutes, a bubble-free, stone-free, transparent and uniform glass liquid is obtained. Place it in the furnace and let it stand and homogenize.

[0049] (4) The clarified and homogenized molten glass is poured onto a stainless steel plate to form a transparent glass block without the need for plate pressing.

[0050] (5) The formed transparent glass is transferred to a muffle furnace and annealed at 550°C for 4 hours to remove the internal stress of the glass. Then, it is cooled to room temperature with the furnace at a cooling rate of 15°C / hour to obtain neodymium-doped fluorine phosphate laser glass.

[0051] The DSC curves, emission spectra, and lifetime decay curves of neodymium-doped fluorine sulfophosphate laser glass were tested, and the gain curve and effective linewidth were calculated.

[0052] Figure 1 The DSC curve results show that the anti-crystallization stability ΔT of the samples in Examples 1 to 5 is all >100℃, where ΔT = Tx - Tg, Tx is the initial crystallization temperature, and Tg is the glass transition temperature. This indicates that the samples have excellent thermal stability, which is beneficial for optical fiber drawing. The larger the ΔT, the better the thermal stability of the glass. Figure 2 The fluorescence spectrum of the neodymium-doped fluorinated phosphate glass in the ~900nm band of the example shows that the fluorescence in the ~900nm band first increases and then decreases with the increase of Ba(PO3)2 content. Figure 3 The lifetime decay curves for samples in Examples 1-5 are shown, with excitation wavelength λ. ex The wavelength is 808nm, and the monitoring wavelength is λ. em 902nm, Nd 3+ ion 4 I 9 / 2 The single-exponential fitted lifetime of the energy level is 331–388.4 μs, which is similar to that of Nd. 3+ The lifetimes in the 1.06μm band are comparable, but directly monitoring the lifetime curve of the 902nm band is more difficult than monitoring the lifetime of the 1060nm band. Figure 4 The gain cross-sectional diagrams for Examples 1 and 3-5 show that the calculated gain cross-section at 902 nm is 2.07-2.40 × 10⁻⁶. -20 cm 2 The maximum gain was observed in Example 4 (x = 0.54), and positive gain was achieved only when P = 0.2 in the SrBaFP glass, indicating a low pump threshold and strong 0.9 μm band gain under 808 nm laser diode (LD) pumping. The effective linewidth Δλ was calculated. eff And the spectral quality factor (FOM), the calculation formulas are shown in equations (1) and (2), Nd in the glass of the example 3+ : 4 F 3 / 2 → 4 I 9 / 2 Δλ of the transition eff Its wavelength ranges from 44.64 to 45.39 nm, which is greater than the effective linewidth (31.3 to 32 nm) of commercially available fluorophosphate glasses such as LG-810, LHG10, and NF1. Its form factor (FOM) is 7.68 to 8.03 × 10⁻⁶. -24 cm 2 s.

[0053] △λ eff =(∫I(λ)dλ) / I max Equation (1)

[0054] In equation (1), I(λ) is the emission intensity, I max It is the peak emission intensity.

[0055] FOM = σ e (λ e )×τ exp Equation (2)

[0056] In equation (2), σ e For the stimulated emission cross section, λ e τ is the peak emission wavelength. exp This refers to the experimental lifespan.

[0057] The SrBaFP laser glass of this invention combines excellent stability with ~0.9 micrometer spectral characteristics, and has important application prospects in ~0.9 micrometer band laser glass, active optical fiber, and fiber laser and amplifier.

[0058] Comparative Example 1

[0059] When the concentration of externally doped NdF3 is less than 1 wt%, the luminescence intensity will be weaker, and the emission cross section and gain cross section will decrease accordingly. Especially when measuring lifetime, it will be difficult to monitor the lifetime in the 0.9 μm band due to the weak luminescence signal.

[0060] Comparative Example 2

[0061] Unlike Examples 1-5, glass could not be formed when the temperature was raised to 1200°C in step (3).

[0062] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A 0.9 μm luminescent neodymium fluoride phosphate laser glass, characterized in that, The molar percentage composition is as follows: Sr(PO3)2: 10~80 mol %, Ba(PO3)2: 10~80 mol %, MgF2: 2~10 mol % AlF3: 2~10 mol % The sum of the molar percentages of the above components is 100%; NdF3 is added at a ratio of 1~4 wt%.

2. The 0.9μm luminescent neodymium-doped fluorine phosphate laser glass according to claim 1, characterized in that, The molar percentage composition of the neodymium-doped fluorine phosphate laser glass is as follows: Sr(PO3)2: 18~72 mol %, Ba(PO3)2: 18~72 mol %, MgF2: 5~10 mol% AlF3: 5~10 mol % The sum of the molar percentages of the above components is 100%; NdF3 is added at a ratio of 1~2 wt%.

3. The 0.9μm luminescent neodymium-doped fluorine phosphate laser glass according to claim 2, characterized in that, The molar percentage composition of the neodymium-doped fluorine phosphate laser glass is as follows: Sr(PO3)2: 18~72 mol%. Ba(PO3)2: 18~72 mol%. MgF2: 5 mol% AlF3: 5 mol % The sum of the molar percentages of the above components is 100%; NdF3 was added at a weight ratio of 1 wt%.

4. A method for preparing the 0.9 μm luminescent neodymium fluoride phosphate laser glass according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Weigh the raw materials according to the composition and proportions, mix and grind them to obtain the compound; (2) The batch material is transferred into a platinum crucible and placed in a high-temperature furnace for melting to obtain a transparent and uniform glass melt; (3) The molten glass is poured into a mold to obtain a transparent glass block; (4) Anneal the glass block, keep it warm, and cool it to obtain 0.9μm light-emitting neodymium fluoride phosphate laser glass.

5. The method for preparing 0.9 μm luminescent neodymium fluoride phosphate laser glass according to claim 4, characterized in that, The melting temperature in step (2) is 1250~1350℃ and the melting time is 20-40min.

6. The method for preparing 0.9 μm luminescent neodymium fluoride phosphate laser glass according to claim 4, characterized in that, The annealing temperature in step (4) is 450~580℃, and the holding time is 4~8h.

7. The method for preparing 0.9 μm luminescent neodymium fluoride phosphate laser glass according to claim 4, characterized in that, The cooling rate in step (4) is 10-20℃ / h.

8. The application of the 0.9μm luminescent neodymium fluoride phosphate laser glass according to any one of claims 1 to 3 in laser glass optical fibers.

9. The application of the 0.9μm luminescent neodymium fluoride phosphate laser glass according to any one of claims 1 to 3 in fiber lasers.

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