LiNbO3 glass-ceramics, a preparation method and application thereof

Abstract

The application belongs to the technical field of glass ceramics, and discloses a LiNbO3 glass ceramic and a preparation method and application thereof. The LiNbO3 glass ceramic comprises the following components in terms of mole percentage: Li2CO3: 10-50%, SiO2: 10-40%, Al2O3: 5-30%, Nb2O5: 5-40%, R2CO3: 0-20%, wherein R is one of K, Rb or Cs. The application can obtain the precursor glass by introducing large-radius alkali metal ions into the glass component and then performing heat treatment. The method is simple, and the prepared LiNbO3 glass ceramic has the highest frequency doubling response strength of 1.99 times of the original system, the shortest ultraviolet cutoff edge of 356 nm, a blue shift of 10 nm compared with the original system, and the highest frequency doubling response strength of 6.9 times of the original system to 800 nm femtosecond laser.

Description

Technical Field

[0001] This invention belongs to the technical field of microcrystalline glass, specifically relating to a LiNbO3 microcrystalline glass, its preparation method, and its application. Background Technology

[0002] LiNbO3 microcrystalline glass materials, which are randomly composed of glass phase and lithium niobate (LiNbO3) microcrystalline phase, have special nonlinear optical responses and are currently of great application potential in fields such as ultrashort optical pulse detection, optical communication, and optical frequency conversion.

[0003] An excellent nonlinear optical material needs to possess high frequency doubling conversion efficiency and a wide transparency range. Feng Xu achieved in-situ growth of highly crystalline, nanoscale LiNbO3 crystals within a glass with compositions of 34Li2O-24Nb2O5-24SiO2-18Al2O3 and 34Li2O-24Nb2O5-24SiO2-18Ga2O3 (mol%). The high crystallinity of LiNbO3 ensures high frequency doubling conversion efficiency, while the nanoscale grains effectively avoid scattering effects. Therefore, efficient output of frequency-doubled blue, green, yellow, and red light in the visible band (>435nm) was achieved in the above material (Feng Xu. Domain Structure Regulation and Nonlinear Optical Response of Nonlinear Microcrystalline Glass. South China University of Technology, 2022). However, microscopic defects (such as Vc) are easily generated during the in-situ growth of LiNbO3 crystals in the above system. Li - and Nb Li 4+ (K. Chen, et al. Microstructure and defect characteristics of lithium niobate with different Li concentrations. Inorg. Chem. Front. 2021, 8, 4006). The aforementioned defects will lead to a redshift of the ultraviolet cutoff edge of LiNbO3 crystals and a decrease in frequency doubling conversion efficiency. Due to the relatively long ultraviolet cutoff edge of the material, frequency-doubled light below 435nm cannot be effectively output due to the material's self-absorption, making it difficult to apply to frequency doubling conversion of common Ti:sapphire femtosecond laser 800nm ​​and shorter wavelength femtosecond fundamental frequency pulses. Therefore, it is urgent to prepare a LiNbO3 glass-ceramic with a short ultraviolet cutoff edge and high frequency doubling responsivity. Summary of the Invention

[0004] In order to overcome the shortcomings of existing microcrystalline glass materials where the ultraviolet cutoff wavelength of LiNbO3 crystal is too long and cannot achieve effective output of frequency doubling light in the band below 435nm, the primary objective of this invention is to provide a LiNbO3 microcrystalline glass that simultaneously possesses (1) high crystallinity and nano-sized LiNbO3; and (2) low Li defect content in the LiNbO3 crystal, resulting in a short ultraviolet cutoff edge and higher frequency doubling response.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned LiNbO3 microcrystalline glass, which can be obtained by introducing large-radius alkali metal ions into the glass composition and then heat-treating the precursor glass.

[0006] Another object of the present invention is to provide applications of the above-mentioned LiNbO3 microcrystalline glass.

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

[0008] A LiNbO3 microcrystalline glass comprises the following components in molar percentage:

[0009]

[0010] Where R is one of K, Rb, or Cs.

[0011] Preferably, the LiNbO3 microcrystalline glass comprises the following components in molar percentage:

[0012]

[0013]

[0014] Preferably, the ultraviolet cutoff edge of the LiNbO3 microcrystalline glass is 356nm to 366nm.

[0015] The above-mentioned method for preparing LiNbO3 microcrystalline glass includes the following steps:

[0016] (1) Weigh Li2CO3, SiO2, Al2O3, Nb2O3 and R2CO3 according to their components and molar percentages, grind them thoroughly, and then melt them to obtain glass melt;

[0017] (2) Cool and press the molten glass into shape to obtain the precursor glass;

[0018] (3) Heat-treat the precursor glass and cool it to room temperature to obtain LiNbO3 microcrystalline glass.

[0019] Preferably, the melting conditions in step (1) are: holding at 1300℃~1700℃ for 0.5h~2h.

[0020] Preferably, the heat treatment conditions in step (3) are: heat treatment at 700-900℃ for 1-4 hours.

[0021] The above-mentioned applications of LiNbO3 microcrystalline glass in the field of optical frequency conversion.

[0022] The above-mentioned LiNbO3 microcrystalline glass is used in the field of ultrashort pulse measurement.

[0023] The above-mentioned applications of LiNbO3 microcrystalline glass in the field of optical communication.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] (1) The method of the present invention is simple and can efficiently prepare LiNbO3 microcrystalline glass material with short ultraviolet cutoff edge and high frequency response;

[0026] (2) The LiNbO3 microcrystalline glass material of the present invention has high optical transparency, high crystallinity and nano-sized grains, with an average grain size of 10.6 nm to 12.5 nm;

[0027] (3) The LiNbO3 microcrystalline glass material with short ultraviolet cutoff edge and high frequency doubling response proposed in this invention has fewer internal Li defects in the in-situ grown LiNbO3, thus having a shorter ultraviolet cutoff edge and enabling frequency doubling light output below 435nm.

[0028] (4) The LiNbO3 grown in situ has fewer Li defects, and the grown grains have a higher nonlinear response. Therefore, the LiNbO3 microcrystalline glass material with a short ultraviolet cutoff edge and high frequency doubling response proposed in this invention also has a higher frequency doubling conversion efficiency, which can be as short as 356nm. The ultraviolet cutoff edge is blue-shifted by 1 to 10nm compared with the original system, and the frequency doubling response intensity is 1.03 to 1.99 times that of the original system.

[0029] (5) The LiNbO3 microcrystalline glass with a short ultraviolet cutoff edge and high frequency doubling response intensity under 800nm ​​femtosecond laser has a frequency doubling response intensity that is 5.3 to 6.9 times that of the original system. Attached Figure Description

[0030] Figure 1 The image shows a photograph of the LiNbO3 microcrystalline glass prepared in Comparative Example 1.

[0031] Figure 2 The XRD pattern of the LiNbO3 microcrystalline glass prepared in Comparative Example 1 is shown.

[0032] Figure 3The XRD pattern of the LiNbO3 microcrystalline glass sample prepared in Comparative Example 1 is obtained by fine scanning of the diffraction peak at approximately 23.7°.

[0033] Figure 4 This is a transmission electron microscope image of the LiNbO3 microcrystalline glass sample prepared in Comparative Example 1, with the grain size distribution shown in the upper left corner.

[0034] Figure 5 The graph shows the overtone response test results of the LiNbO3 microcrystalline glass sample prepared in Comparative Example 1.

[0035] Figure 6 The diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass prepared in Comparative Example 1 is shown.

[0036] Figure 7 The image shows the frequency doubling response of the LiNbO3 microcrystalline glass prepared in Comparative Example 1 to an 800nm ​​femtosecond laser through a self-built optical path. The upper right corner shows the spatial distribution of the frequency doubling signal.

[0037] Figure 8 These are photographs of the LiNbO3 microcrystalline glass prepared in Example 1;

[0038] Figure 9 The XRD pattern of the LiNbO3 microcrystalline glass prepared in Example 1 is shown.

[0039] Figure 10 The XRD pattern of the LiNbO3 microcrystalline glass sample prepared in Example 1, with a diffraction peak of approximately 23.7°, is obtained through fine scanning.

[0040] Figure 11 The graph shows the octave response test results of the LiNbO3 microcrystalline glass sample prepared in Example 1.

[0041] Figure 12 This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass prepared in Example 1;

[0042] Figure 13 These are photographs of the LiNbO3 microcrystalline glass prepared in Example 2;

[0043] Figure 14 The XRD pattern of the LiNbO3 microcrystalline glass prepared in Example 2 is shown.

[0044] Figure 15 The XRD pattern of the LiNbO3 microcrystalline glass sample prepared in Example 2 is a fine scan of the diffraction peak at approximately 23.7°.

[0045] Figure 16 This is a graph showing the octave response test results of the LiNbO3 microcrystalline glass sample prepared in Example 2;

[0046] Figure 17 This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass prepared in Example 2;

[0047] Figure 18 These are photographs of the LiNbO3 microcrystalline glass prepared in Example 3;

[0048] Figure 19 The XRD pattern of the LiNbO3 microcrystalline glass prepared in Example 3 is shown.

[0049] Figure 20 The XRD pattern of the LiNbO3 microcrystalline glass sample prepared in Example 3 is a fine scan of the diffraction peak at approximately 23.7°.

[0050] Figure 21 The graph shows the octave response test results of the LiNbO3 microcrystalline glass sample prepared in Example 3.

[0051] Figure 22 This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass prepared in Example 3;

[0052] Figure 23 This is the frequency doubling response diagram of the LiNbO3 microcrystalline glass prepared in Example 3 to an 800nm ​​femtosecond laser through a self-built optical path. The upper left corner shows the spatial distribution of the frequency doubling signal.

[0053] Figure 24 These are photographs of the LiNbO3 microcrystalline glass prepared in Example 4;

[0054] Figure 25 The XRD pattern of the LiNbO3 microcrystalline glass prepared in Example 4 is shown.

[0055] Figure 26 The XRD pattern of the LiNbO3 microcrystalline glass sample prepared in Example 4 is a fine scan of the diffraction peak at approximately 23.7°.

[0056] Figure 27 This is a graph showing the octave response test results of the LiNbO3 microcrystalline glass sample prepared in Example 4;

[0057] Figure 28 This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass prepared in Example 4;

[0058] Figure 29 These are photographs of the LiNbO3 microcrystalline glass prepared in Example 5;

[0059] Figure 30 The XRD pattern of the LiNbO3 microcrystalline glass prepared in Example 5 is shown.

[0060] Figure 31The XRD pattern of the LiNbO3 microcrystalline glass sample prepared in Example 5 is a fine scan of the diffraction peak at approximately 23.7°.

[0061] Figure 32 This is a transmission electron microscope (TEM) image of the LiNbO3 microcrystalline glass sample prepared in Example 5, with the grain size distribution shown in the upper left corner.

[0062] Figure 33 The graph shows the octave response test results of the LiNbO3 microcrystalline glass sample prepared in Example 5.

[0063] Figure 34 This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass prepared in Example 5;

[0064] Figure 35 This is the frequency doubling response diagram of the LiNbO3 microcrystalline glass prepared in Example 5 to an 800nm ​​femtosecond laser through a self-built optical path. The upper left corner shows the spatial distribution of the frequency doubling signal.

[0065] Figure 36 The image shows a photograph of the LiNbO3 microcrystalline glass prepared in Comparative Example 2.

[0066] Figure 37 The XRD pattern of the LiNbO3 microcrystalline glass prepared in Comparative Example 2 is shown.

[0067] Figure 38 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in Comparative Example 2, with a diffraction peak at approximately 23.7°. Detailed Implementation

[0068] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto. For process parameters not specifically specified, conventional techniques can be referred to.

[0069] Comparative Example 1:

[0070] The preparation steps of a LiNbO3 microcrystalline glass material are as follows:

[0071] (1) Weigh the raw materials according to the following molar percentages: 24Nb2O5-18Al2O3-24SiO2-34Li2CO3, grind them thoroughly, and then melt them at 1500℃ for 0.5h to obtain glass melt;

[0072] (2) Pour the molten glass from step (1) onto a stainless steel plate and press it into shape with another iron plate to obtain the precursor glass.

[0073] (3) Cut the precursor glass into the required size, place it in a muffle furnace for heat treatment at 780°C for 2 hours, and remove it after natural cooling to room temperature to obtain LiNbO3 microcrystalline glass.

[0074] Figure 1 This is a photograph of the LiNbO3 glass-ceramic obtained in this comparative example. Figure 1 It can be seen that the sample maintains high optical transparency after heat treatment.

[0075] Figure 2 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this comparative example. Figure 2 It can be seen that the sample has high crystallinity, and LiNbO3 is the main crystalline phase.

[0076] Figure 3 This is the fine-scan XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this comparative example, showing a diffraction peak at approximately 23.7°. Analysis of the fine-scan XRD pattern indicates that the diffraction peak of the LiNbO3 microcrystalline glass sample is located at 23.66°.

[0077] Figure 4 This is a transmission electron microscope (TEM) image of the LiNbO3 microcrystalline glass sample prepared in this comparative example. From... Figure 4 It can be seen that the LiNbO3 microcrystals in the sample are uniformly dispersed and have a high grain density. The inset shows that the average grain size of the LiNbO3 microcrystals in the sample is 10.6 nm.

[0078] Figure 5 This is a graph showing the octave response test results of the LiNbO3 microcrystalline glass sample prepared in this comparative example. The octave response intensity of the sample in this comparative example was measured according to the measurement device and method described in the literature (Y.Xie, et al. Strong, anisotropic, layer-independent second harmonic generation in multilayer SnS film, Opt. Express, 2023, 31, 9779).

[0079] Figure 6This is the diffuse reflectance absorption spectrum of the LiNbO3 glass-ceramic sample prepared in this comparative example. Following the reference (K. Yoshimoto, et al. Low phonon energies and wideband optical windows of La2O3-Ga2O3 glasses prepared using an aerodynamic levitation technique. Scientific Reports, 2017, 7, 45600), the UV cutoff edge of the sample was fitted, yielding a UV cutoff edge of 366 nm for the LiNbO3 glass-ceramic sample prepared in this comparative example.

[0080] Figure 7 This is the frequency harmonic response diagram of the LiNbO3 microcrystalline glass prepared in this comparative example under an 800 nm femtosecond laser via a self-built optical path. The upper left corner shows the spatial distribution of the frequency harmonic signal. The frequency harmonic response intensity of the sample in this comparative example under an 800 nm femtosecond laser was measured according to the measurement device and method described in the literature (X. Feng, et al. Manipulating Nonlinear Optical Response via Domain Control in Nanocrystal-in-glass Composites. Advanced Materials, 2021, 33, 2006482).

[0081] Example 1:

[0082] The preparation steps of a LiNbO3 microcrystalline glass material with a short ultraviolet cutoff edge and high octave response are as follows:

[0083] (1) Weigh the raw materials according to the following molar percentages: 24Nb2O5-18Al2O3-24SiO2-32Li2CO3-2K2CO3, grind them thoroughly, and then melt them at 1300℃ for 2 hours to obtain glass melt;

[0084] (2) Pour the molten glass from step (1) onto a stainless steel plate and press it into shape with another iron plate to obtain the precursor glass.

[0085] (3) Cut the precursor glass into the required size, place it in a muffle furnace for heat treatment at 800℃ for 2 hours, and take it out after natural cooling to room temperature to obtain LiNbO3 microcrystalline glass.

[0086] Figure 8 This is a photograph of the LiNbO3 microcrystalline glass obtained in this embodiment. Figure 8It can be seen that the sample maintains high optical transparency after heat treatment.

[0087] Figure 9 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Figure 9 It can be seen that the sample has high crystallinity, and LiNbO3 is the main crystalline phase.

[0088] Figure 10 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this embodiment, obtained through fine scanning at a diffraction peak of approximately 23.7°. Analysis of the fine-scan XRD pattern shows that the LiNbO3 microcrystalline diffraction peak of this sample is located at 23.67°. The XRD diffraction peak shifts to a higher angle, indicating a decrease in the Li defect content in the LiNbO3 microcrystalline phase; conversely, a shift to a lower angle indicates an increase. Compared to the LiNbO3 microcrystalline glass sample prepared in Comparative Example 1, the XRD diffraction peak shifted to a higher angle by 0.01°, demonstrating that the Li defect content in the LiNbO3 microcrystalline phase of the microcrystalline glass material prepared in this embodiment is lower than that in Comparative Example 1.

[0089] Figure 11 This is a graph showing the octave response test results of the LiNbO3 microcrystalline glass sample prepared in this embodiment. The octave response intensity of the sample prepared in this embodiment was measured according to the measurement apparatus and method described in the literature (Y. Xie, et al. Strong, anisotropic, layer-independent secondharmonic generation in multilayer SnS film, Opt. Express, 2023, 31, 9779). The octave response intensity of the sample prepared in this embodiment was measured under the same test conditions. The test results showed that the octave response intensity of this system was 1.03 times that of the sample in Comparative Example 1.

[0090] Figure 12 This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Following the reference (K. Yoshimoto, et al. Low phonon energies and wideband optical windows of La2O3-Ga2O3 glasses prepared using an aerodynamic levitation technique. Scientific Reports, 2017, 7, 45600), the UV cutoff edge of the sample was fitted, yielding a UV cutoff edge of 365 nm for the LiNbO3 microcrystalline glass sample prepared in this embodiment. Compared to the comparative sample, the UV cutoff edge of the LiNbO3 microcrystalline glass sample prepared in this embodiment shows a blue shift of 1 nm.

[0091] Example 2:

[0092] The preparation steps of a LiNbO3 microcrystalline glass material with a short ultraviolet cutoff edge and high octave response are as follows:

[0093] (1) Weigh the raw materials according to the following molar percentages: 10Nb2O5-20Al2O3-24SiO2-40Li2CO3-6K2CO3, grind them thoroughly, and then melt them at 1700℃ for 1 hour to obtain glass melt.

[0094] (2) Pour the molten glass from step (1) onto a stainless steel plate and press it into shape with another iron plate to obtain the precursor glass.

[0095] (3) Cut the precursor glass into the required size, place it in a muffle furnace for heat treatment at 700℃ for 4 hours, and take it out after natural cooling to room temperature to obtain transparent LiNbO3 microcrystalline glass.

[0096] Figure 13 This is a photograph of the LiNbO3 microcrystalline glass obtained in this embodiment. Figure 13 It can be seen that the sample maintains high optical transparency after heat treatment.

[0097] Figure 14 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Figure 14 It can be seen that the sample has high crystallinity, and LiNbO3 is the main crystalline phase.

[0098] Figure 15 The XRD pattern is a fine-scan XRD pattern of the LiNbO3 glass-ceramic sample prepared in this embodiment, showing a diffraction peak at approximately 23.7°. Analysis of the fine-scan XRD pattern reveals that the LiNbO3 microcrystalline diffraction peak of this sample is located at 23.69°. The XRD diffraction peak shifts to higher angles, indicating a decrease in Li defect content in the LiNbO3 microcrystalline phase; conversely, a shift to lower angles indicates an increase. Compared to the LiNbO3 glass-ceramic sample prepared in Comparative Example 1, the XRD diffraction peak shifted to higher angles by 0.03°, demonstrating a decrease in Li defect content in the LiNbO3 microcrystalline phase of the glass-ceramic material prepared in this embodiment compared to Comparative Example 1.

[0099] Figure 16This is a graph showing the octave response test results of the LiNbO3 microcrystalline glass sample prepared in this embodiment. The octave response intensity of the sample prepared in this embodiment was measured according to the measurement apparatus and method described in the literature (Y. Xie, et al. Strong, anisotropic, layer-independent secondharmonic generation in multilayer SnSfilm, Opt. Express, 2023, 31, 9779). The octave response intensity of the sample prepared in this embodiment was measured under the same test conditions. The test results showed that the octave response intensity of this system was 1.06 times that of the sample in Comparative Example 1.

[0100] Figure 17 This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Following the method described in the literature (K. Yoshimoto, et al. Low phonon energies and wideband optical windows of La2O3-Ga2O3 glasses prepared using an aerodynamic levitation technique. Scientific Reports, 2017, 7, 45600), the UV cutoff edge of the sample was fitted, yielding a UV cutoff edge of 361 nm for the LiNbO3 microcrystalline glass sample prepared in this embodiment. Compared to the comparative sample, the UV cutoff edge of the LiNbO3 microcrystalline glass sample prepared in this embodiment shows a blue shift of 5 nm.

[0101] Example 3:

[0102] The preparation steps of a LiNbO3 microcrystalline glass material with a short ultraviolet cutoff edge and high octave response are as follows:

[0103] (1) Weigh the raw materials according to the following molar percentages: 30Nb2O5-10Al2O3-15SiO2-25Li2CO3-10K2CO3, grind them thoroughly, and then melt them at 1500℃ for 0.5h to obtain glass melt;

[0104] (2) Pour the molten glass from step (1) onto a stainless steel plate and press it into shape with another iron plate to obtain the precursor glass.

[0105] (3) Cut the precursor glass into the required size, place it in a muffle furnace for heat treatment at 900℃ for 1 hour, and take it out after natural cooling to room temperature to obtain LiNbO3 microcrystalline glass.

[0106] Figure 18This is a photograph of the LiNbO3 microcrystalline glass obtained in this embodiment. Figure 14 It can be seen that the sample maintains high optical transparency after heat treatment.

[0107] Figure 19 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Figure 15 It can be seen that the sample has high crystallinity, and LiNbO3 is the main crystalline phase.

[0108] Figure 20 This is the XRD pattern of the LiNbO3 glass-ceramic sample prepared in this embodiment, showing a diffraction peak at approximately 23.7°. Analysis of the finely scanned XRD pattern reveals that the LiNbO3 microcrystalline diffraction peak of this sample is located at 23.71°. The XRD diffraction peak shifts to higher angles, indicating a decrease in Li defect content in the LiNbO3 microcrystalline phase; conversely, a shift to lower angles indicates an increase. Compared to the LiNbO3 glass-ceramic sample prepared in Comparative Example 1, the XRD diffraction peak shifted to higher angles by 0.05°, demonstrating that the Li defect content in the LiNbO3 microcrystalline phase of the glass-ceramic material prepared in this embodiment is lower than that in Comparative Example 1.

[0109] Figure 21 This is a graph showing the octave response test results of the LiNbO3 microcrystalline glass sample prepared in this embodiment. The octave response intensity of the sample prepared in this embodiment was measured according to the measurement apparatus and method described in the literature (Y. Xie, et al. Strong, anisotropic, layer-independent secondharmonic generation in multilayer SnS film, Opt. Express, 2023, 31, 9779). The octave response intensity of the sample prepared in this embodiment was measured under the same test conditions. The test results showed that the octave response intensity of this system was 1.54 times that of the sample in Comparative Example 1.

[0110] Figure 22This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Following the method described in the literature (K. Yoshimoto, et al. Low phonon energies and wideband optical windows of La2O3-Ga2O3 glasses prepared using an aerodynamic levitation technique. Scientific Reports, 2017, 7, 45600), the ultraviolet cutoff edge of the sample was fitted, yielding a cutoff edge of 356 nm for the LiNbO3 microcrystalline glass sample prepared in this embodiment. Compared to the comparative sample, the ultraviolet cutoff edge of the LiNbO3 microcrystalline glass sample prepared in this embodiment shows a blue shift of 10 nm.

[0111] Figure 23 This is the frequency harmonic response (HHR) diagram of the LiNbO3 microcrystalline glass prepared in this embodiment under an 800 nm femtosecond laser, obtained through a self-built optical path. The upper left corner shows the spatial distribution of the HHR signal. Following the measurement apparatus and method described in the literature (X. Feng, et al. Manipulating Nonlinear Optical Response via Domain Control in Nanocrystal-in-glass Composites. Advanced Materials, 2021, 3, 2006482), the HHR response intensity of the sample in this embodiment under the same conditions was measured. The test results showed that the HHR response intensity of this system was 5.3 times that of the sample in Comparative Example 1.

[0112] Example 4:

[0113] The preparation steps of a LiNbO3 microcrystalline glass material with a short ultraviolet cutoff edge and high octave response are as follows:

[0114] (1) Weigh the raw materials according to the following molar percentages: 24Nb2O5-17Al2O3-25SiO2-30Li2CO3-4Rb2CO3, grind them thoroughly, and then melt them at 1500℃ for 0.5h to obtain glass melt;

[0115] (2) Pour the molten glass from step (1) onto a stainless steel plate and press it into shape with another iron plate to obtain the precursor glass.

[0116] (3) Cut the precursor glass into the required size, place it in a muffle furnace for heat treatment at 800℃ for 2 hours, and take it out after natural cooling to room temperature to obtain LiNbO3 microcrystalline glass.

[0117] Figure 24 This is a photograph of the LiNbO3 microcrystalline glass obtained in this embodiment. Figure 24 It can be seen that the sample maintains high optical transparency after heat treatment.

[0118] Figure 25 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Figure 25 It can be seen that the sample has high crystallinity, and LiNbO3 is the main crystalline phase.

[0119] Figure 26 The XRD pattern is a fine-scan XRD pattern of the LiNbO3 glass-ceramic sample prepared in this embodiment, showing a diffraction peak at approximately 23.7°. Analysis of the fine-scan XRD pattern reveals that the LiNbO3 microcrystalline diffraction peak of this sample is located at 23.70°. The XRD diffraction peak shifts to higher angles, indicating a decrease in Li defect content in the LiNbO3 microcrystalline phase; conversely, a shift to lower angles indicates an increase. Compared to the LiNbO3 glass-ceramic sample prepared in Comparative Example 1, the XRD diffraction peak shifted to higher angles by 0.04°, demonstrating a reduction in Li defects in the LiNbO3 microcrystalline phase of the glass-ceramic material prepared in this embodiment compared to Comparative Example 1.

[0120] Figure 27 This is a graph showing the octave response test results of the LiNbO3 microcrystalline glass sample prepared in this embodiment. The octave response intensity of the sample prepared in this embodiment was measured according to the measurement apparatus and method described in the literature (Y. Xie, et al. Strong, anisotropic, layer-independent secondharmonic generation in multilayer SnS film, Opt. Express, 2023, 31, 9779). The octave response intensity of the sample prepared in this embodiment was measured under the same test conditions. The test results showed that the octave response intensity of this system was 1.12 times that of the sample in Comparative Example 1.

[0121] Figure 28This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Following the method described in the literature (K. Yoshimoto, et al. Low phonon energies and wideband optical windows of La2O3-Ga2O3 glasses prepared using an aerodynamic levitation technique. Scientific Reports, 2017, 7, 45600), the UV cutoff edge of the sample was fitted, yielding a UV cutoff edge of 361 nm for the LiNbO3 microcrystalline glass sample prepared in this embodiment. Compared to the comparative sample, the UV cutoff edge of the LiNbO3 microcrystalline glass sample prepared in this embodiment shows a blue shift of 5 nm.

[0122] Example 5:

[0123] The preparation steps of a LiNbO3 glass-ceramic with a short ultraviolet cutoff edge and high octave response are as follows:

[0124] (1) Weigh the raw materials according to the following molar percentages: 24Nb2O5-18Al2O3-24SiO2-30Li2CO3-4Cs2CO3, grind them thoroughly, and then melt them at 1500℃ for 40 minutes to obtain glass melt.

[0125] (2) Pour the molten glass from step (1) onto a stainless steel plate and press it into shape with another iron plate to obtain the precursor glass.

[0126] (3) Cut the precursor glass into the required size, place it in a muffle furnace for heat treatment at 800℃ for 2 hours, and take it out after natural cooling to room temperature to obtain LiNbO3 microcrystalline glass.

[0127] Figure 29 This is a photograph of the LiNbO3 microcrystalline glass obtained in this embodiment. Figure 29 It can be seen that the samples all maintained high optical transparency after heat treatment.

[0128] Figure 30 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Figure 30 It can be seen that the sample has high crystallinity, and LiNbO3 is the main crystalline phase.

[0129] Figure 31This is the XRD pattern of the LiNbO3 glass-ceramic sample prepared in this embodiment, obtained by fine scanning of the diffraction peak at approximately 23.7°. Analysis of the fine-scan XRD pattern shows that the LiNbO3 microcrystalline diffraction peak of this sample is located at 23.71°. The XRD diffraction peak shifts to a higher angle, indicating a decrease in the Li defect content in the LiNbO3 microcrystalline phase; conversely, a shift to a lower angle indicates an increase. Compared to the LiNbO3 glass-ceramic sample prepared in Comparative Example 1, the XRD diffraction peak shifted to a higher angle by 0.05°, demonstrating that the Li defect content in the LiNbO3 microcrystalline phase of the glass-ceramic material prepared in this embodiment is lower than that in Comparative Example 1.

[0130] Figure 32 These are transmission electron microscope (TEM) images of the transparent microcrystalline glass sample prepared in this embodiment. From... Figure 24 It can be seen that the LiNbO3 microcrystals in this sample are uniformly dispersed and have a high grain density. As can be seen from the inset, the average grain size of the LiNbO3 microcrystals in the sample is 12.5 nm, which is similar to the 10.6 nm of the LiNbO3 microcrystalline glass sample prepared in Comparative Example 1.

[0131] Figure 33 This is a graph showing the octave response test results of the LiNbO3 microcrystalline glass sample prepared in this embodiment. The octave response intensity of the sample prepared in this embodiment was measured according to the measurement apparatus and method described in the literature (Y. Xie, et al. Strong, anisotropic, layer-independent secondharmonic generation in multilayer SnS film, Opt. Express, 2023, 31, 9779). The octave response intensity of the sample prepared in this embodiment was measured under the same test conditions. The test results showed that the octave response intensity of this system was 1.99 times that of the sample in Comparative Example 1.

[0132] Figure 34 This is the diffuse reflectance absorption spectrum of the LiNbO3 microcrystalline glass sample prepared in this embodiment. Following the method described in the literature (K. Yoshimoto, et al. Low phonon energies and wideband optical windows of La2O3-Ga2O3 glasses prepared using an aerodynamic levitation technique. Scientific Reports, 2017, 7, 45600), the ultraviolet cutoff edge of the sample was fitted, yielding a cutoff edge of 356 nm for the LiNbO3 microcrystalline glass sample prepared in this embodiment. Compared to the comparative sample, the ultraviolet cutoff edge of the LiNbO3 microcrystalline glass sample prepared in this embodiment shows a blue shift of 10 nm.

[0133] Figure 35 This is the frequency harmonic response diagram of the LiNbO3 microcrystalline glass prepared in this embodiment under an 800nm ​​femtosecond laser through a self-built optical path. The upper left corner shows the spatial distribution of the frequency harmonic signal. Following the measurement apparatus and method described in the literature (X. Feng, et al. Manipulating Nonlinear Optical Response via Domain Control in Nanocrystal-in-glass Composites. Advanced Materials, 2021, 33, 2006482), the frequency harmonic response intensity of the sample in this embodiment under an 800nm ​​femtosecond laser was measured under the same conditions. The test results showed that the frequency harmonic response intensity of this system was 6.9 times that of the sample in Comparative Example 1.

[0134] Comparative Example 2: The preparation steps of a LiNbO3 microcrystalline glass are as follows:

[0135] (1) Weigh the raw materials according to the following molar percentages: 24Nb2O5-18Al2O3-24SiO2-22Li2CO3-12K2CO3, grind them thoroughly, and then melt them at 1500℃ for 40 minutes to obtain glass melt.

[0136] (2) Pour the molten glass from step (1) onto a stainless steel plate and press it into shape with another iron plate to obtain the precursor glass.

[0137] (3) Cut the precursor glass into the required size, place it in a muffle furnace for heat treatment at 650°C for 2 hours, and remove it after natural cooling to room temperature to obtain LiNbO3 microcrystalline glass.

[0138] Figure 36 This is a photograph of the LiNbO3 glass-ceramic obtained in this comparative example. Figure 36 It can be seen that the samples all maintained high optical transparency after heat treatment.

[0139] Figure 37 This is the XRD pattern of the LiNbO3 microcrystalline glass sample prepared in this comparative example. Figure 37 It can be seen that the sample has obvious glass phase diffraction peaks, low crystallinity, and LiNbO3 is the main crystalline phase.

[0140] Figure 38This is the XRD pattern of the LiNbO3 glass-ceramic sample prepared in this comparative example, obtained by fine scanning of the diffraction peak at approximately 23.7°. Analysis of the finely scanned XRD pattern shows that the LiNbO3 microcrystalline diffraction peak of this sample is located at 23.66°. The XRD diffraction peak shifts to higher angles, indicating a decrease in Li defect content in the LiNbO3 microcrystalline phase; conversely, a shift to lower angles indicates an increase. Compared to the LiNbO3 glass-ceramic sample prepared in Comparative Example 1, the XRD diffraction peak remains unchanged, indicating that the Li defect content of the LiNbO3 microcrystalline phase in the glass-ceramic material prepared in this comparative example is similar to that in Comparative Example 1, but higher than that in the glass-ceramic materials prepared in Examples 1-5.

[0141] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described. 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 LiNbO3 glass-ceramics, characterized in that, consists of the following components in mole percentage: Li2CO3 25-40% SiO2 15-25% Al2O3 10-20% Nb2O5 10-30% R2CO3 2-10%; wherein R is one of K, Rb or Cs; the ultraviolet cutoff edge of the LiNbO3 glass-ceramics is 356nm-365nm; the preparation method of the LiNbO3 glass-ceramics comprises the following steps: (1) taking Li2CO3, SiO2, Al2O3, Nb2O5 and R2CO3 according to the components and mole percentage, grinding thoroughly, then melting to obtain a glass liquid; (2) cooling and pressing the glass liquid to form a precursor glass; (3) heat treating the precursor glass, taking it out after cooling to room temperature to prepare the LiNbO3 glass-ceramics; the heat treatment condition in step (3) is: 700-900℃ for 1-4h.

2. The method for preparing LiNbO3 glass-ceramics according to claim 1, characterized in that, comprises the following steps: (1) taking Li2CO3, SiO2, Al2O3, Nb2O5 and R2CO3 according to the components and mole percentage, grinding thoroughly, then melting to obtain a glass liquid; (2) cooling and pressing the glass liquid to form a precursor glass; (3) heat treating the precursor glass, taking it out after cooling to room temperature to prepare the LiNbO3 glass-ceramics; the heat treatment condition in step (3) is: 700-900℃ for 1-4h.

3. The method for preparing LiNbO3 microcrystalline glass according to claim 2, characterized in that, the melting condition in step (1) is: 1300℃-1700℃ for 0.5h-2h.

4. The application of the LiNbO3 glass-ceramics in claim 1 in the field of optical frequency conversion.

5. The application of the LiNbO3 glass-ceramics in claim 1 in the field of ultra-short pulse measurement.

6. The application of the LiNbO3 glass-ceramics in claim 1 in the field of optical communication.

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