A method for loading fiber end faces with single rare-earth ion-doped β-NaYF4 microcrystalline materials and its application in polarization detection systems
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-18
- Publication Date
- 2026-08-14
AI Technical Summary
但近红外光并不在人眼可见波段，因此，对于近红外光偏振信息的变化通常需要搭建复杂的光路，需配备滤波片、半透半反片、偏振片等多种光学元件，同时使用前需要进行光路准直、杂光滤除与激发光汇聚等复杂步骤，不仅导致系统体积庞大、操作繁琐、成本高昂，还存在光能损耗显著、稳定性差等问题，难以满足小型化、集成化、高便捷性的实际应用需求
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Figure CN122563590A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of near-infrared polarization detection technology, specifically a method for loading the end face of an optical fiber with a single rare-earth ion-doped β-NaYF4 microcrystal and its application in a polarization detection system. Background Technology
[0002] Near-infrared light exhibits strong penetration, low transmission loss, strong anti-interference ability, and high recognition accuracy during polarization information transmission. It maintains good transmission efficiency even in harsh environments and can effectively detect microscopic structures and anisotropic temperature and pressure changes in targets that are undetectable by traditional light intensity methods. However, near-infrared light is not in the visible wavelength range. Therefore, detecting changes in near-infrared light polarization information typically requires complex optical paths, necessitating various optical components such as filters, transflectors, and polarizers. Furthermore, complex steps such as optical path collimation, stray light filtering, and excitation light focusing are required before use. This not only results in large system size, cumbersome operation, and high cost but also significant light energy loss and poor stability, making it difficult to meet the practical application requirements of miniaturization, integration, and high convenience. Therefore, research on efficient detection of near-infrared light polarization information has significant scientific value and broad application prospects in fields such as precision sensing, biomedical imaging, target structure recognition, and optical communication.
[0003] In view of the above-mentioned technical problems, this invention is proposed. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a polarization detection system based on a single rare-earth ion-doped β-NaYF4 microcrystal with excellent excitation polarization characteristics loaded on the end face of an optical fiber. This eliminates the need for polarization detection optical path setup, removes stray light interference, and reduces the loss of the detected light. It also eliminates the need for pre-detection optical path collimation and excitation light focusing procedures, thus improving detection efficiency and stability.
[0005] The first objective of this invention is to provide a method for loading the end face of a fiber with a single rare-earth ion-doped β-NaYF4 microcrystalline material, comprising the following steps:
[0006] S1: Preparation of β-NaYF4 microcrystals
[0007] Er was synthesized via a hydrothermal method using disodium ethylenediaminetetraacetate as a chelating agent. 3+ ,Sc 3+ Yb 3+ Co-doped β-NaYF4 fluoride microcrystals;
[0008] S2: Loading a single β-NaYF4 microcrystal onto the fiber end face
[0009] S21: Disperse β-NaYF4 microcrystalline powder;
[0010] S22: Load the uniformly dispersed sample solution obtained in step S21 onto the end face of the optical fiber.
[0011] Preferably, step S1 specifically includes:
[0012] S11: Preparation of solution A
[0013] Dissolve 0.676 g Na2EDTA and 10 mL of 0.2 mol / L mixed rare earth nitrate solution in 30 mL of deionized water, and stir magnetically for 20 min at room temperature to obtain solution A;
[0014] S12: Preparation of solution B
[0015] Take 24 mL of deionized water and add it to 24 mL of 1.0 mol / L sodium fluoride solution. Stir magnetically for 30 min at room temperature to obtain solution B.
[0016] S13: Slowly add solution B dropwise to solution A under continuous stirring, mix, and continue stirring for 60 min to obtain a homogeneous mixture;
[0017] S14: The homogeneous mixture is heated at high temperature, and after heating, it is naturally cooled to room temperature. The solid product is collected by centrifugation, washed, and dried to obtain a white powdery microcrystalline sample.
[0018] Preferably, the rare earth elements RE in step S11 are Y, Er, Sc, and Yb.
[0019] Preferably, step S14 specifically involves: transferring the homogeneous mixture to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, placing it in a forced-air drying oven and heating it at 200°C for 24 h; after heating, removing it and allowing it to cool naturally to room temperature, transferring the solution in the autoclave to a centrifuge tube and centrifuging it in a high-speed centrifuge to collect the solid product, washing it several times alternately with deionized water and ethanol, and finally placing it in a forced-air drying oven to dry at 60°C for 12 h to collect a white powdery microcrystalline sample.
[0020] Preferably, the white powdery microcrystalline sample is β-NaYF4:10%Sc 3+ ,x%Yb 3+ 10%Er 3+ (x=1, 10, 20, 40, 60, 80) microcrystals.
[0021] Preferably, step S21 specifically involves: weighing 0.1 g of β-NaYF4 microcrystalline powder, adding it to 5 mL of ethanol, stirring magnetically for 10 min, and then ultrasonically dispersing it for 10 min to ensure that the particles are uniformly suspended and dispersed in the ethanol solution.
[0022] Preferably, step S22 specifically involves: flattening the fiber core to obtain a smooth fiber core end face, which serves as the loading substrate for the microcrystalline particles; before performing single-particle loading and spectral testing, the uniformly dispersed sample solution obtained in step S21 is added to the fiber core end face through a capillary tube, and the distribution of particles in the droplet is adjusted until only a single microcrystal remains on the end face.
[0023] The second objective of this invention is to provide an application of the optical fiber prepared by the above method in a polarization detection system. The optical fiber is directly connected to a marine spectrometer, and a 980 nm high-performance single-mode polarization-maintaining fiber laser is used as the excitation source to perform polarization spectral testing on a single-particle microcrystal loaded on the end face of the fiber core. By rotating the polarization direction of the excitation light, the upconversion emission spectrum at different polarization angles is recorded, thereby obtaining the polarization response characteristics of the single particle.
[0024] The beneficial effects of this invention are:
[0025] This invention utilizes β-NaYF4:10%Sc, which exhibits good upconversion luminescence intensity and high polarization response. 3+ , x%Yb 3+ ,10%Er 3+ (x=1, 10, 20, 40, 60, 80) Microcrystals are loaded onto the fiber core to achieve highly sensitive near-infrared polarization detection with a single microcrystal loaded on the fiber. Light is transmitted via total internal reflection in the fiber, resulting in low loss and convenient operation. Furthermore, fiber transmission optimizes the complex optical device setup of the optical polarization detection system. Only an optical fiber and a single microcrystal particle with high polarization degree are needed to detect near-infrared light polarization information. Changes in near-infrared polarization information can be converted into changes in light intensity in the visible band, providing a direct and convenient way to detect near-infrared light polarization information. Attached Figure Description
[0026] Figure 1 A schematic diagram of a polarization detection system for an existing fiber-optic load containing a single β-NaYF4 microcrystal.
[0027] Figure 2 This is a schematic diagram of the polarization detection system of the present invention.
[0028] Figure 3 In Figure a: a single β-NaYF4:10%Sc 3+ ,10%Er 3+ Schematic diagram of the core layer end face of microcrystalline loaded fiber. The inset shows a micrograph captured by a CCD on the fiber end face under a 50x objective lens with a single particle. Figure b shows a test pattern of a single-particle loaded fiber. Figure c shows a single β-NaYF4:10%Sc fiber. 3+ ,10%Er 3+The polarization spectrum of the microcrystalline fiber transmission is shown in the inset, which is a fluorescence micrograph of a single microcrystal in the excited state. The scale bar is 10 μm. Figure d is a comparison of the polarization spectra of the fiber polarization detection system and the traditional polarization detection system.
[0029] Figure 4 Figure a shows a test image of a single-particle loaded fiber without an objective lens. Figure b shows a single β-NaYF4:10%Sc fiber. 3+ 60%Yb 3+ ,10%Er 3+ Image of the inner end face of the microcrystalline loaded fiber and fluorescence image under large optical flakes.
[0030] Figure 5 In Figure a, β-NaYF4:x%Yb is excited at 980 nm. 3+ ,10%Er 3+ (x=1, 10, 20, 40, 60, 90) Upconversion spectra of microcrystalline powders. Figure b shows the upconversion spectra of β-NaYF4:10%Sc under 980 nm excitation. 3+ ,x%Yb 3+ ,10%Er 3+ Upconversion spectra of microcrystalline powders (x=1, 10, 20, 40, 60, 80).
[0031] Figure 6 In the middle: Figures a-f show the single β-NaYF4:10%Sc excitation under 980 nm linearly polarized light excitation. 3+ ,x%Yb 3+ ,10%Er 3+ (x=1, 10, 20, 40, 60, 80) Upconversion fluorescence spectra of microcrystals under fiber optic detection with excitation polarization directions from 0° to 360°. Figure f shows the upconversion fluorescence spectrum of a single β-NaYF4:10%Sc microcrystal. 3+ ,x%Yb 3+ ,10%Er 3+ Polar coordinate plot of upconversion emission intensity and excitation polarization angle of microcrystals excited by 980 nm linear polarized light and detected by fiber optics (x=1, 10, 20, 40, 60, 80). Detailed Implementation
[0032] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.
[0033] The technical solution of this invention is as follows:
[0034] A method for loading an end face of a fiber optic cable with a single rare-earth ion-doped β-NaYF4 microcrystalline material includes the following steps:
[0035] S1: Preparation of β-NaYF4 microcrystals
[0036] Er was synthesized via a hydrothermal method using disodium ethylenediaminetetraacetate as a chelating agent. 3+ ,Sc 3+ Yb 3+ Co-doped β-NaYF4 fluoride microcrystals;
[0037] S2: Loading a single β-NaYF4 microcrystal onto the fiber end face
[0038] S21: Disperse β-NaYF4 microcrystalline powder;
[0039] S22: Load the uniformly dispersed sample solution obtained in step S21 onto the end face of the optical fiber.
[0040] In some embodiments, step S1 specifically includes:
[0041] S11: Preparation of solution A
[0042] Dissolve 0.676 g Na2EDTA and 10 mL of 0.2 mol / L mixed rare earth nitrate solution in 30 mL of deionized water, and stir magnetically for 20 min at room temperature to obtain solution A;
[0043] S12: Preparation of solution B
[0044] Take 24 mL of deionized water and add it to 24 mL of 1.0 mol / L sodium fluoride solution. Stir magnetically for 30 min at room temperature to obtain solution B.
[0045] S13: Slowly add solution B dropwise to solution A under continuous stirring, mix, and continue stirring for 60 min to obtain a homogeneous mixture;
[0046] S14: The homogeneous mixture is heated at high temperature, and after heating, it is naturally cooled to room temperature. The solid product is collected by centrifugation, washed, and dried to obtain a white powdery microcrystalline sample.
[0047] In some embodiments, the rare earth elements RE in step S11 are Y, Er, Sc, and Yb.
[0048] In some embodiments, step S14 specifically involves: transferring the homogeneous mixture to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, placing it in a forced-air drying oven and heating it at 200°C for 24 h; after heating, removing it and allowing it to cool naturally to room temperature, transferring the solution in the autoclave to a centrifuge tube and centrifuging it in a high-speed centrifuge to collect the solid product, washing it several times alternately with deionized water and ethanol, and finally placing it in a forced-air drying oven to dry at 60°C for 12 h to collect a white powdery microcrystalline sample.
[0049] In some embodiments, the white powdery microcrystalline sample is β-NaYF4:10%Sc 3+ ,x%Yb 3+ 10%Er 3+ (x=1, 10, 20, 40, 60, 80) microcrystals.
[0050] In some embodiments, step S21 specifically involves: weighing 0.1 g of β-NaYF4 microcrystalline powder, adding it to 5 mL of ethanol, stirring magnetically for 10 min, and then ultrasonically dispersing it for 10 min to ensure that the particles are uniformly suspended and dispersed in the ethanol solution.
[0051] In some embodiments, step S22 specifically involves: flattening the fiber core to obtain a smooth fiber core end face, which serves as the loading substrate for microcrystalline particles; before performing single-particle loading and spectral testing, the uniformly dispersed sample solution obtained in step S21 is added to the fiber core end face through a capillary tube, and the distribution of particles in the droplet is adjusted until only a single microcrystal remains on the end face.
[0052] The optical fiber prepared by the above method is used in a polarization detection system. The optical fiber is directly connected to a marine spectrometer. A 980 nm high-performance single-mode polarization-maintaining fiber laser is used as the excitation source to perform polarization spectral testing on a single-particle microcrystal loaded on the end face of the fiber core. By rotating the polarization direction of the excitation light, the upconversion emission spectrum at different polarization angles is recorded, thereby obtaining the polarization response characteristics of the single particle.
[0053] Example 1
[0054] A single β-NaYF4 microcrystal loaded with an optical fiber is directly connected to a spectrometer for signal acquisition, and the optical fiber is used to achieve low-loss transmission of excitation and emission light. Figure 1 This is a schematic diagram of an existing polarization detection system for a single β-NaYF4 microcrystal loaded on an optical fiber. In this system, 980 nm near-infrared excitation light is focused by a 50x objective lens to excite a single microcrystal located on the sample stage. The emitted light from the single microcrystal passes through optical components such as the objective lens, a semi-transparent and semi-reflective film, and a filter before being collected by the blue optical fiber (highlighted in red) and transmitted to a spectrometer for detection. By rotating the polarization direction of the excitation light, the polarization response of a single particle can be detected. Based on the above system, the optical path has been further simplified, such as... Figure 2 As shown. With Figure 1Unlike other optical systems, one end of the fiber is directly connected to the detector fiber head of the spectrometer via a converter, while the other end is loaded with a single microcrystal. This system eliminates the need for a 50x objective lens to focus the excitation light; instead, it directly illuminates the single particle on the fiber end face with the raw polarized beam of the 980 nm near-infrared laser. This improvement allows the system to more directly detect the upconversion emission response caused by changes in the polarization angle of the raw near-infrared laser, reducing interference from optical components in the optical path on polarization information.
[0055] Figure 1 and Figure 2 The specific differences are: Figure 1 The optical components such as filters and transflective films (highlighted in red) are... Figure 2 The simple single-particle loaded fiber (red box part) is replaced. Figure 1 The testing system also requires steps such as optical path collimation and excitation light focusing during operation. Figure 2 All you need to do is align the fiber optic head with the light source being detected. Figure 1 and Figure 2 The specific difference lies in the optical path of the detection system, such as... Figure 1 and Figure 2 The annotation in the text is omitted after single-particle load fiber. Figure 1 The optical path setup section within the red box in the middle. Figure 1 The detector single particle is on the sample stage. Figure 2 The optical fibers used to connect to the spectrometer are all the same, with the fiber core directly inside. Figure 2 The load is directly placed in the inner layer of the optical fiber, eliminating the need for operations such as searching for single particles on the sample stage, adjusting the emitted light from the sample, and filtering out stray light.
[0056] Specifically, by directly loading a single microcrystal onto the end face of an optical fiber, the advantages of low transmission loss and high stability due to total internal reflection in optical fibers can be leveraged. Compared to traditional polarization testing systems, this eliminates the need for complex optical components such as optical path collimation, stray light filtering, and excitation light focusing, significantly simplifying the near-infrared polarization detection device while maintaining high polarization response. Furthermore, by adjusting Yb... 3+ The doping concentration can significantly improve the upconversion luminescence intensity, enabling the system to achieve stable and intuitive near-infrared polarization angle detection even without objective lens focusing excitation light, proving the feasibility and superiority of the fiber-to-particle integrated structure in near-infrared polarization sensing.
[0057] Example 2
[0058] like Figure 3 As shown, firstly, a single β-NaYF4:10%Sc 3+ ,10%Er 3+ Microcrystals are loaded onto the end face of the fiber core. Figure 3Image a is an optical image captured by a CCD under a 50x objective lens. It can be seen that the fiber end face is flat and smooth, with a single micron-sized rod-shaped microcrystal loaded on the fiber core end face, exhibiting green upconversion emission under 980 nm excitation light. The specific experimental device structure is as follows... Figure 3 As shown in b, while observing the fiber end face with a 50x objective lens, the objective lens also focuses the excitation light, thereby improving the excitation efficiency of the excitation light on a single particle. Figure 3 c shows the polarization detection spectrum measured via fiber optic transmission under this excitation condition, with the inset showing a CCD image of a single microcrystal under excitation. To quantitatively assess the impact of fiber optic transmission on the degree of polarization, the polarization response measured by the fiber optic polarization detection system is compared with that of a traditional space polarization detection system. Figure 3 As shown in d, the results indicate that transmission through optical fiber does not significantly affect the polarization degree of a single particle, and the sample still maintains a highly sensitive polarization response to changes in the polarization angle of the excitation light.
[0059] Compared with conventional polarization detection systems, the fiber optic detection method of this invention has significant advantages: because the fiber end face is in close contact with the single particle, the detected spectrum is the single microcrystalline Er 3+ The characteristic emission band of optical fiber eliminates the need for complex optical paths constructed with filters, semi-transparent mirrors, and other optical components to filter out stray light. Furthermore, the total internal reflection transmission characteristic of optical fiber avoids the cumbersome collimation and angle adjustment processes found in free-space optical paths, making the entire detection system simpler and more efficient.
[0060] Example 3
[0061] like Figure 4 As shown, a single β-NaYF4:10%Sc 3+ 60%Yb 3+ ,10%Er 3+ Microcrystalline loads are applied to the end face of the optical fiber core. In Yb 3+ With doping, individual microcrystals exhibit significant emission enhancement through energy transfer upconversion. Figure 4 a is a schematic diagram of the test without an objective lens. Figure 4 Image b is a CCD image of the inner layer end face of the optical fiber. It shows that even without an objective lens to focus the excitation light spot, a single particle in the sample still maintains good luminescence intensity. Because Yb 3+ After doping with Er 3+ The energy transfer increases the proportion of red light in the sample, making it appear bright yellow under direct human observation. Simultaneously... Figure 4 The test diagram below also shows that the sample was tested under a large aperture without objective lens focusing.
[0062] Analysis shows that removing the objective lens results in a loss of focusing effect on the emitted light, which requires samples with higher excitation power or higher upconversion luminescence efficiency.
[0063] Example 4
[0064] To address the issue of insufficient excitation efficiency without an objective lens, Yb was doped... 3+ Energy transfer upconversion was achieved, thereby improving the luminescence intensity and upconversion luminescence efficiency of the particles.
[0065] By doping with different concentrations of Yb 3+ It effectively improves the upconversion luminescence efficiency, thereby enhancing the emission intensity of a single particle.
[0066] Different Yb 3+ The luminescence intensity of the powder sample at a given concentration, such as Figure 5 As shown. With Yb 3+ As the doping concentration increases, the overall luminescence intensity shows an increasing trend, while the red light intensity increases significantly. This is due to the increased Yb content. 3+ With Er 3+ Energy transfer leads to 4 F 9 / 2 This is due to the increase in the population at different energy levels.
[0067] At the same time, different Yb were tested 3+ Doping concentration of β-NaYF4:10%Sc 3+ , x%Yb 3+ , 10%Er 3+ The polarization response of microcrystals (x = 1, 10, 20, 40, 60, 80) in a lensless fiber optic detection system is shown in the following results. Figure 6 As shown in the figure. It can be seen that fiber optic transmission and Yb 3+ The doping reduced the polarization degree of the sample to some extent, but the overall trend was consistent with that when an objective lens was present. Microcrystals of different concentrations still exhibited good anisotropic polarization response to changes in the polarization angle of the 980 nm near-infrared excitation light, indicating that this simplified system is feasible for practical polarization detection.
[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
[0069] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A method for loading the end face of an optical fiber with a single rare-earth ion-doped β-NaYF4 microcrystalline material, characterized in that, Includes the following steps: S1: Preparation of β-NaYF4 microcrystals Er was synthesized via a hydrothermal method using disodium ethylenediaminetetraacetate as a chelating agent. 3+ ,Sc 3+ Yb 3+ Co-doped β-NaYF4 fluoride microcrystals; S2: Loading a single β-NaYF4 microcrystal onto the fiber end face S21: Disperse β-NaYF4 microcrystalline powder; S22: Load the uniformly dispersed sample solution obtained in step S21 onto the end face of the optical fiber.
2. The method for loading an optical fiber end face with a single rare-earth ion-doped β-NaYF4 microcrystalline material as described in claim 1, characterized in that, Step S1 is as follows: S11: Preparation of solution A Dissolve 0.676 g Na2EDTA and 10 mL of 0.2 mol / L mixed rare earth nitrate solution in 30 mL of deionized water, and stir magnetically for 20 min at room temperature to obtain solution A; S12: Preparation of solution B Take 24 mL of deionized water and add it to 24 mL of 1.0 mol / L sodium fluoride solution. Stir magnetically for 30 min at room temperature to obtain solution B. S13: Slowly add solution B dropwise to solution A under continuous stirring, mix, and continue stirring for 60 min to obtain a homogeneous mixture; S14: The homogeneous mixture is heated at high temperature, and after heating, it is naturally cooled to room temperature. The solid product is collected by centrifugation, washed, and dried to obtain a white powdery microcrystalline sample.
3. The method for loading an optical fiber end face with a single rare-earth ion-doped β-NaYF4 microcrystalline material as described in claim 2, characterized in that, In step S11, the rare earth elements RE = Y, Er, Sc, Yb.
4. The method for loading an optical fiber end face with a single rare-earth ion-doped β-NaYF4 microcrystalline material as described in claim 2, characterized in that, Step S14 specifically involves: transferring the homogeneous mixture to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave, placing it in a forced-air drying oven and heating it at 200°C for 24 h; after heating, removing it and allowing it to cool naturally to room temperature, transferring the solution in the autoclave to a centrifuge tube and centrifuging it in a high-speed centrifuge to collect the solid product, washing it several times alternately with deionized water and ethanol, and finally placing it in a forced-air drying oven to dry at 60°C for 12 h, and collecting a white powdery microcrystalline sample.
5. The method for loading an optical fiber end face with a single rare-earth ion-doped β-NaYF4 microcrystalline material as described in claim 4, characterized in that, The white powdery microcrystalline sample was β-NaYF4:10%Sc 3+ ,x%Yb 3+ 10%Er 3+ (x=1, 10, 20, 40, 60, 80) microcrystals.
6. The method for loading an optical fiber end face with a single rare-earth ion-doped β-NaYF4 microcrystalline material as described in claim 1, characterized in that, Step S21 is as follows: Weigh 0.1 g of β-NaYF4 microcrystalline powder, add it to 5 mL of ethanol, stir magnetically for 10 min, and then ultrasonically disperse for 10 min to make the particles uniformly suspended and dispersed in the ethanol solution.
7. The method for loading an optical fiber end face with a single rare-earth ion-doped β-NaYF4 microcrystalline material as described in claim 1, characterized in that, Step S22 specifically involves: flattening the fiber core to obtain a smooth fiber core end face, which serves as the loading substrate for the microcrystalline particles; before performing single-particle loading and spectral testing, the uniformly dispersed sample solution obtained in step S21 is added to the fiber core end face through a capillary tube, and the distribution of particles in the droplet is adjusted until only a single microcrystalline particle remains on the end face.
8. The application of the optical fiber prepared by any one of the methods described in claims 1-7 in a polarization detection system, characterized in that, The optical fiber was directly connected to a marine spectrometer, and a 980 nm high-performance single-mode polarization-maintaining fiber laser was used as the excitation source to perform polarization spectral testing on a single-particle microcrystal loaded on the end face of the fiber core. By rotating the polarization direction of the excitation light, the upconversion emission spectrum at different polarization angles was recorded, thereby obtaining the polarization response characteristics of the single particle.