Frequency doubling chalcogenide microcrystalline glass and preparation method thereof

Abstract

The invention discloses frequency-doubled chalcogenide glass ceramics and a preparation method thereof, and belongs to the technical field of glass ceramics. The microcrystalline glass is composed of AsmS1-m (m is greater than or equal to 0.30 and less than or equal to 0.45) matrix glass and Pb (Mg1 / 3Nb2 / 3) O3-xPbTiO3 (PMN-xPT, x is greater than or equal to 0.28 and less than or equal to 0.40) micron crystals which are randomly distributed in the matrix glass. The preparation method comprises the following steps: preparing a glass mixture from high-purity elementary substances As and S, sealing a tube in vacuum, melting and quenching at 650-850 DEG C, and grinding into fine powder; t; 001gt, 001gt; the preparation method comprises the following steps: grinding and screening a PMN-xPT single crystal with crystal orientation to be less than 10 microns, mixing the PMN-xPT single crystal with fine glass powder according to the proportion of 1-10wt%, performing vacuum tube sealing again, melting and quenching at the temperature of 450-500 DEG C, annealing at the temperature of 160-190 DEG C for 4-6 hours, and slowly cooling to the room temperature. The prepared microcrystalline glass can keep the PMN-xPT crystal structure intact, the preparation cost is low, good broadband frequency doubling emission can be achieved without strict phase matching, and the microcrystalline glass is suitable for the optical field of broadband frequency conversion and the like.

Description

Technical Field

[0001] This invention relates to an optical frequency doubling material, and more particularly to a frequency doubling chalcogenide microcrystalline glass and its preparation method. Background Technology

[0002] As an important relaxor ferroelectric-piezoelectric single crystal material, Pb(Mg) 1 / 3 Nb 2 / 3 O3-xPbTiO3 (PMN-xPT) single crystals possess high electronic polarizability and a large electro-optic coefficient γ. 33 (Up to approximately 320 pm·V) -1 It also has a relatively high refractive index (n≈2.58 at 633 nm). Its maximum second-order nonlinear coefficient d... 31 77.9pm·V -1 , approximately the maximum nonlinear coefficient d of lithium niobate 33 (25.4pm·V) -1 The efficiency of PMN-PT is three times that of optical second harmonic generation (SHG). Therefore, PMN-PT is an excellent material for optical second harmonic generation (SHG). However, its efficient second harmonic generation depends on precise phase matching conditions, which not only limits the operating wavelength range but also imposes strict requirements on polarization and incident angle.

[0003] Glass materials are characterized by long-range disorder and macroscopic isotropy, with no overall breaking of inversion symmetry in their bulk phase. In this case, according to the selection rules of nonlinear optics, even-order nonlinear polarization terms cancel each other out within the material, resulting in zero intrinsic second-order nonlinear polarizability χ² (or equivalent even-order nonlinear coefficients). Therefore, ideal homogeneous glass itself does not possess even-order nonlinear optical effects such as second-harmonic generation (SHG). This is the fundamental motivation for achieving glass-based second-order nonlinear responses by introducing non-centrosymmetric crystalline phases or constructing disordered nonlinear structures. Compared to ordered single-crystal materials, although disordered nonlinear media typically exhibit lower peak SHG efficiency, their significantly relaxed phase-matching conditions endow the system with high flexibility. In such media, the SHG intensity is insensitive to changes in pump wavelength, polarization state, and incident angle, giving them unique advantages in achieving broadband frequency conversion and making them an alternative to traditional bulk single crystals. However, the SHG conversion efficiency in the currently reported disordered nonlinear media is still limited, especially since there has been no relevant research on effectively introducing and compositing PMN-xPT with extremely high second-order nonlinear coefficients into disordered systems. Summary of the Invention

[0004] The purpose of this invention is to propose a frequency-doubling chalcogenide microcrystalline glass and its preparation method. This addresses the limitations of existing technologies, such as PMN-xPT single-crystal frequency doubling relying on strict phase matching and having a limited applicability; the lack of second harmonic generation capability in pure glass; and the low frequency doubling conversion efficiency of existing disordered nonlinear media. The invention addresses these limitations by randomly dispersing high-nonlinear-coefficient PMN-xPT microcrystals on As... m S 1-m By combining specific vacuum sealing, melt quenching and annealing processes in a chalcogenide glass matrix, the strict dependence of traditional PMN-xPT single crystals on phase matching is overcome, and the defects of pure glass in having no second harmonic generation capability and the low frequency doubling efficiency of existing disordered nonlinear media are compensated for, thus realizing broadband frequency doubling output.

[0005] The technical solution adopted in this invention is as follows: This invention proposes a frequency-doubled chalcogenide microcrystalline glass, which is made of As m S 1-m The matrix glass and the randomly distributed Pb(Mg) within it 1 / 3 Nb 2 / 3 It is composed of micron-sized O3-xPbTiO3 crystals, where 0.30≤m≤0.45 and 0.28≤x≤0.40.

[0006] This invention also proposes a method for preparing a frequency-doubled chalcogenide microcrystalline glass based on the above description, comprising the following steps:

[0007] Step 1) Prepare a glass mixture using elemental arsenic and elemental sulfur according to the chemical formula;

[0008] Step 2) Load the glass mixture from Step 1) into a quartz glass tube, and then evacuate the quartz glass tube to a vacuum level of less than 10. -2 Pa, then seal the quartz glass tube with an oxyhydrogen flame;

[0009] Step 3) Place the sealed quartz glass tube containing the glass mixture into a swing furnace, heat it to 650~850℃, keep it at the temperature for melting for more than 12 hours, then lower the temperature of the swing furnace to 450℃~550℃, take out the quartz glass tube and quench it in water to make the melt inside the quartz glass tube form glass, and grind the prepared glass into fine glass powder.

[0010] Step 4) Grind the PMN-xPT single crystal into fine powder, and after sieving, obtain PMN-xPT micron crystal particles with a particle size of ≤10μm. Then, weigh them and mix them with the glass fine powder in Step 3) at a ratio of 1-10wt% to form a powder mixture.

[0011] Step 5) Load the powder mixture from Step 4) into a quartz glass tube, and then evacuate the quartz glass tube to a vacuum level of less than 10. -2 Pa, then seal the quartz glass tube with an oxyhydrogen flame;

[0012] Step 6) Place the sealed quartz glass tube into a swing furnace, heat it to 450-500℃, hold it at that temperature for 5-15 minutes to melt it, and then take out the quartz glass tube and quench it in water.

[0013] Step 7) Place the quartz glass tube into an electric furnace preheated to 160~190℃ and keep it at that temperature for 4~6 hours. Then cool it to room temperature at a rate of 0.05~0.2℃ / min to obtain frequency-doubled chalcogenide microcrystalline glass.

[0014] As a preferred embodiment of the method for preparing a frequency-doubled chalcogenide microcrystalline glass according to the present invention, the grain size of the PMN-xPT microcrystals contained in the frequency-doubled chalcogenide microcrystalline glass is ≤10μm.

[0015] As a preferred embodiment of the method for preparing a frequency-doubled chalcogenide microcrystalline glass according to the present invention, the purity of the elemental As and S is not less than 99.999%.

[0016] As a preferred embodiment of the method for preparing a frequency-doubled chalcogenide microcrystalline glass according to the present invention: the crystal orientation of the PMN-xPT single crystal is as follows: <001> .

[0017] As a preferred embodiment of the method for preparing a frequency-doubled chalcogenide microcrystalline glass according to the present invention, the hydroxyl content of the quartz glass tube is less than 20 ppm.

[0018] The present invention discloses a method for preparing frequency-doubled chalcogenide microcrystalline glass, which employs a melt-quenching method to prepare As m S 1-m The matrix glass is then mixed with glass powder and PMN-xPT single crystal powder, and then frequency-doubled chalcogenide microcrystalline glass is obtained by melt quenching. The composition, size and morphology of the grains can be selected. Compared with the basic chalcogenide glass, the frequency-doubled chalcogenide microcrystalline glass of the present invention has broadband frequency doubling characteristics and can be applied to the field of broadband frequency conversion.

[0019] Beneficial effects of the invention

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

[0021] (1) Compared with traditional PMN-xPT single crystals, the frequency-doubling chalcogenide microcrystalline glass of the present invention has lower preparation and maintenance costs, and can achieve broadband frequency doubling output without meeting strict phase matching conditions;

[0022] (2) Compared with other frequency-doubled oxide glass-ceramics, the chalcogenide glass-ceramics of the present invention can ensure the integrity of the crystal structure of PMN-xPT and prevent digestion and transformation to the pyrochlore phase;

[0023] (3) Compared with traditional chalcogenide glass, the chalcogenide microcrystalline glass of the present invention has broadband frequency doubling characteristics. Attached Figure Description

[0024] Figure 1 These are scanning electron micrographs (SEM images) of the microcrystalline glass prepared in Example 1;

[0025] Figure 2 This is the visible and near-infrared transmission spectrum of the microcrystalline glass prepared in Example 1;

[0026] Figure 3 This is the broadband frequency-doubled emission spectrum of the microcrystalline glass prepared in Example 1;

[0027] Figure 4 These are SEM images of the microcrystalline glass prepared in Example 2;

[0028] Figure 5 This is an SEM image of the microcrystalline glass prepared in Example 3. Detailed Implementation

[0029] The following examples will further illustrate the essential features and significant advancements of the present invention, but the present invention is not limited to the examples given.

[0030] Example 1

[0031] A frequency-doubled chalcogenide microcrystalline glass, the microcrystalline glass being made of As 0.3 S 0.70 The matrix glass and the randomly distributed Pb(Mg) within it 1 / 3 Nb 2 / 3 Composition of O3-0.28PbTiO3 (PMN-0.28PT) micron-sized crystals

[0032] The specific steps of the above-mentioned method for preparing frequency-doubled chalcogenide microcrystalline glass are as follows:

[0033] A glass mixture was obtained by weighing elemental As and S with a purity ≥ 99.999% according to their chemical formulas; the glass mixture was then placed into a clean quartz glass tube with a hydroxyl content of less than 20 ppm, and a vacuum was drawn until the vacuum degree was less than 10. -2 Pa, seal the quartz glass tube with an oxyhydrogen flame; place the sealed quartz glass tube containing the glass mixture into a oscillating furnace, heat to 650℃ and hold at that temperature for 12 hours; cool the oscillating furnace to 450℃, remove the quartz glass tube and quench it in water to allow the melt inside the quartz glass tube to form glass, and grind the prepared glass into fine powder using an agate mortar; grind PMN-0.28PT single crystal into fine powder using an agate mortar, sieve the fine powder through a 10μm standard sieve to obtain microcrystalline particles with a particle size ≤10μm, and then weigh and mix it with the glass fine powder at a ratio of 1wt% to form a powder mixture; load the powder mixture into a quartz glass tube, and then evacuate the quartz glass tube to a vacuum degree of less than 10. -2Pa, then seal the quartz glass tube with an oxyhydrogen flame; place the sealed quartz glass tube in a swing furnace, heat it to 450℃, hold it at that temperature for 5 minutes to melt it, remove the quartz glass tube and quench it in water; then place the quartz glass tube in an electric furnace preheated to 160℃, hold it at that temperature for 4 hours, and then cool it to room temperature at a rate of 0.05℃ / min to obtain frequency-doubled chalcogenide microcrystalline glass.

[0034] The morphology and microstructure of the micron-sized crystals were observed using a Hitachi SU8010 field emission scanning electron microscope (MIS). Figure 1 As shown; the transmission spectrum of a 2 mm thick microcrystalline glass slide from 500 to 2000 nm was measured using a PerkinElmer Lambda 1050+ spectrophotometer. Figure 2 As shown; a 1500nm femtosecond laser was used as the pump source, and the generated SHG signal was subsequently collected by a spectrometer, see [reference needed]. Figure 3 As shown.

[0035] The test results of the glass in this embodiment: by Figure 1 It can be seen that PMN-0.28PT micron-sized crystals are randomly distributed in this glass-ceramic, with a crystal size ≤10μm; furthermore, from Figure 2 It can be seen that the transmittance of glass-ceramics in the 0.65-2.0μm wavelength range is greater than 40%; from Figure 3 It is known that microcrystalline glass can achieve good frequency doubling emission.

[0036] Example 2

[0037] A frequency-doubled chalcogenide microcrystalline glass, the microcrystalline glass being made of As 0.38 S 0.62 The matrix glass and the randomly distributed Pb(Mg) within it 1 / 3 Nb 2 / 3 It is composed of micron-sized O3-0.33PbTiO3 (PMN-0.33PT) crystals.

[0038] The specific steps of the above-mentioned method for preparing frequency-doubled chalcogenide microcrystalline glass are as follows:

[0039] A glass mixture was obtained by weighing elemental As and elemental S with a purity ≥ 99.999% according to their chemical formulas; the glass mixture was then placed into a clean quartz glass tube with a hydroxyl content of less than 20 ppm, and a vacuum was drawn until the vacuum degree was less than 10. -2Pa, seal the quartz glass tube with an oxyhydrogen flame; place the sealed quartz glass tube containing the glass mixture into a shaking furnace, heat to 750℃ and hold at that temperature for 12 hours; cool the shaking furnace to 500℃, remove the quartz glass tube and quench it in water to allow the melt inside the quartz glass tube to form glass, and grind the prepared glass into fine powder using an agate mortar; grind PMN-0.33PT single crystal into fine powder using an agate mortar, sieve the fine powder through an 8μm standard sieve to obtain microcrystalline particles with a particle size ≤8μm, and then weigh and mix it with the glass fine powder at a ratio of 5wt% to form a powder mixture; load the powder mixture into a quartz glass tube, and then evacuate the quartz glass tube to a vacuum degree of less than 10. -2 Pa, then seal the quartz glass tube with an oxyhydrogen flame; place the sealed quartz glass tube in a swing furnace, heat it to 470℃, hold it at that temperature for 10 minutes to melt it, remove the quartz glass tube and quench it in water; then place the quartz glass tube in an electric furnace preheated to 170℃, hold it at that temperature for 5 hours, and then cool it to room temperature at a rate of 0.12℃ / min to obtain frequency-doubled chalcogenide microcrystalline glass.

[0040] The morphology and microstructure of the micron-sized crystals were observed using a Hitachi SU8010 field emission scanning electron microscope (MIS). Figure 4 As shown, the 500–2000 nm transmission spectrum of a 2 mm thick glass-ceramic sheet was measured using a PerkinElmer Lambda 1050+ spectrophotometer; a 1500 nm femtosecond laser was used as the pump source, and the generated SHG signal was subsequently collected by the spectrometer.

[0041] The test results of the glass in this embodiment: by Figure 4 It can be seen that the PMN-0.33PT micron crystals in the glass-ceramic are randomly distributed, and the crystal size is ≤8μm; in addition, the transmittance of the glass-ceramic in the 0.65-2.0μm band is greater than 43% according to the transmission spectrum; and the frequency doubling laser test shows that the glass-ceramic can achieve good frequency doubling emission.

[0042] Example 3

[0043] A frequency-doubled chalcogenide microcrystalline glass, the microcrystalline glass being made of As 0.45 S 0.55 The matrix glass and the randomly distributed Pb(Mg) within it 1 / 3 Nb 2 / 3 Composed of micron-sized O3-0.4PbTiO3 (PMN-0.4PT) crystals.

[0044] The specific steps for preparing the above-mentioned chalcogenide microcrystalline glass are as follows:

[0045] A glass mixture was obtained by weighing elemental As and S with a purity ≥ 99.999% according to their chemical formulas; the glass mixture was then placed into a clean quartz glass tube with a hydroxyl content of less than 20 ppm, and a vacuum was drawn until the vacuum degree was less than 10. -2 Pa, seal the quartz glass tube with an oxyhydrogen flame; place the sealed quartz glass tube containing the glass mixture into a shaking furnace, heat to 850℃ and hold at that temperature for 12 hours; cool the shaking furnace to 550℃, remove the quartz glass tube and quench it in water to allow the melt inside the quartz glass tube to form glass, and grind the prepared glass into fine powder using an agate mortar; grind PMN-0.4PT single crystal into fine powder using an agate mortar, sieve the fine powder through a 5μm standard sieve to obtain microcrystalline particles with a particle size ≤5μm, and then weigh and mix it with the glass fine powder at a ratio of 10wt% to form a powder mixture; load the powder mixture into a quartz glass tube, and then evacuate the quartz glass tube to a vacuum degree of less than 10. -2 Pa, then seal the quartz glass tube with an oxyhydrogen flame; place the sealed quartz glass tube in a swing furnace, heat it to 500℃, hold it at that temperature for 15 minutes to melt it, remove the quartz glass tube and quench it in water; then place the quartz glass tube in an electric furnace preheated to 190℃, hold it at that temperature for 6 hours, and then cool it to room temperature at a rate of 0.2℃ / min to obtain frequency-doubled chalcogenide microcrystalline glass.

[0046] The morphology and microstructure of the micron-sized crystals were observed using a Hitachi SU8010 field emission scanning electron microscope (MIS). Figure 5 As shown, the 500–2000 nm transmission spectrum of a 2 mm thick glass-ceramic sheet was measured using a PerkinElmer Lambda 1050+ spectrophotometer; a 1500 nm femtosecond laser was used as the pump source, and the generated SHG signal was subsequently collected by the spectrometer.

[0047] The test results of the glass in this embodiment: by Figure 5 It can be seen that the PMN-0.4PT micron crystals in the glass-ceramic are randomly distributed, and the crystal size is ≤5μm; in addition, the transmittance of the glass-ceramic in the 0.65-2.0μm band is greater than 37% according to the transmission spectrum; and the frequency doubling laser test shows that the glass-ceramic can achieve good frequency doubling emission.

[0048] In summary, this invention relates to a method for preparing frequency-doubled chalcogenide glass-ceramics. By precisely controlling the composition and size of PMN-xPT microcrystals and the composition of the matrix glass, glass-ceramics with randomly distributed PMN-xPT microcrystals can be stably prepared. The transmittance remains above 37% in the 0.65-2.0μm band, and the grain size can be controlled to ≤10μm. This ensures the integrity of the PMN-xPT crystal structure, achieves effective broadband frequency-doubled emission without strict phase matching conditions, has lower preparation costs, and combines performance stability with application flexibility.

[0049] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes that can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention are within the protection scope of the claims of the present invention.

Claims

1. A frequency-doubling chalcogenide glass-ceramic, characterized in that, The glass-ceramics consist of a matrix glass and randomly distributed Pb(Mg m S 1-m Nb 1 / 3 Nb 2 / 3 micrometric crystals of Pb(Mg 0.30≤m≤0.45, 0.28≤x≤0.

40.

2. The preparation method of the frequency-doubling chalcogenide glass-ceramics according to claim 1, characterized in that: The method comprises the following steps: Step 1) preparing a glass mixture according to a chemical formula by using elemental arsenic and elemental sulfur as raw materials; Step 2) The glass mixture of Step 1) is charged into a quartz glass tube, and the quartz glass tube is evacuated to a vacuum degree of less than 10 -2 Pa, and the quartz glass tube is sealed with a hydrogen-oxygen flame. Step 3) placing the sealed quartz glass tube containing the glass mixture into a rocking furnace, heating to 650-850 DEG C, and keeping the temperature for 12 hours or more, then reducing the temperature of the rocking furnace to 450-550 DEG C, taking out the quartz glass tube and quenching in water, so that the melt in the quartz glass tube forms glass, and grinding the prepared glass into glass powder; Step 4) grinding the PMN-xPT single crystal into fine powder, screening to obtain PMN-xPT micron crystal particles with a particle size of ≤10 μm, and then mixing the particles with the glass powder in step 3) into a powder mixture according to a ratio of 1-10 wt%; Step 5) The powder mixture of Step 4) is charged into a quartz glass tube, which is then evacuated to a vacuum degree of less than 10 -2 Pa, and the quartz glass tube is then sealed with a hydrogen-oxygen flame; Step 6) placing the sealed quartz glass tube in step 5) into a rocking furnace, heating to 450-500 DEG C, keeping the temperature for 5-15 minutes, taking out the quartz glass tube and quenching in water; Step 7) placing the quenched quartz glass tube into an electric furnace preheated to 160-190 DEG C, keeping the temperature for 4-6 hours, and then cooling to room temperature at a rate of 0.05-0.2 DEG C / min, thereby obtaining the frequency-doubling sulfur-based microcrystalline glass.

3. The method for preparing a frequency-doubling chalcogenide glass ceramic according to claim 2, characterized in that: The grain size of the PMN-xPT micron crystal contained in the frequency-doubling sulfur-based microcrystalline glass is ≤10 μm.

4. The method for preparing a frequency-doubling chalcogenide glass ceramic according to claim 2, characterized in that: The purity of the elemental arsenic and the elemental sulfur is not less than 99.999%.

5. The method for preparing a frequency-doubling chalcogenide glass ceramic according to claim 2, characterized in that: The crystal orientation of the PMN-xPT single crystal is <001>.

6. The method for preparing a frequency-doubling chalcogenide glass ceramic according to claim 2, characterized in that: The hydroxyl content of the quartz glass tube is less than 20 ppm.

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