Rubidium zinc sulfate compound, nonlinear optical crystal thereof and preparation method and application thereof

Abstract

The application discloses a rubidium zinc sulfate compound, a nonlinear optical crystal of the rubidium zinc sulfate compound, and a preparation method and application of the rubidium zinc sulfate compound. 12 The rubidium zinc sulfate compound and the nonlinear optical crystal of the rubidium zinc sulfate compound both have a molecular formula of Rb2Zn2S3O 12 , do not have a symmetry center, are crystallized in a monoclinic crystal system, have a space group P21, have a unit cell parameter of Z=2, and have a unit cell volume of 2. The alkali metal sulfate salt usually has a large band gap, and the ultraviolet transmittance range thereof can be extended to about 150 nm, and is a candidate material for exploring UV or DUV optical crystals. In addition, the alkali metal sulfate salt has the properties of low melting point and high solubility, and therefore can be synthesized by using a high-temperature solution method, a hydrothermal method or an aqueous solution method, and the synthesis condition is relatively mild. Therefore, the alkali metal sulfate salt is an effective means for designing deep ultraviolet nonlinear optical materials.

Description

Technical Field

[0001] This invention relates to zinc rubidium sulfate compounds, methods for preparing zinc rubidium sulfate nonlinear optical crystals, and nonlinear optical devices fabricated using these crystals. Background Technology

[0002] Deep ultraviolet coherent light with wavelengths between 200 and 150 nm is becoming increasingly important due to its potential applications in semiconductor lithography, laser micromachining, and modern scientific instruments. For solid-state lasers, obtaining deep ultraviolet coherent light is achieved through cascaded frequency conversion techniques using nonlinear optical crystals. However, suitable deep ultraviolet nonlinear optical crystals must meet the following stringent structural and performance requirements, including i) a non-centrosymmetric structure; ii) a large second-order nonlinear optical coefficient (d). ij ), at least with KDP's d 36 The properties of wide-bandgap materials are: iii) high transparency in the deep ultraviolet region with the shortest possible ultraviolet cutoff wavelength; and iv) ease of growth, non-toxicity, chemical stability, and good mechanical properties. However, some of these properties are contradictory, as wide-bandgap materials tend to exhibit small overtone responses, making the design and synthesis of deep ultraviolet nonlinear optical crystals a significant challenge. Summary of the Invention

[0003] In view of the above-mentioned problems in the prior art, one of the objectives of the present invention is to provide a zinc sulfate rubidium compound to provide at least one new method for preparing deep ultraviolet nonlinear optical crystal materials.

[0004] The zinc rubidium sulfate compound provided by this invention has the molecular formula Rb₂Zn₂S₃O. 12 It lacks a center of symmetry, crystallizes in the monoclinic system, space group P21, and its unit cell parameters are... Z=2, unit cell volume

[0005] A second objective of this invention is to provide a method for preparing zinc rubidium sulfate compounds, wherein the zinc rubidium sulfate compounds are prepared by solid-phase reaction, hydrothermal method, or solution method according to any of the following chemical reaction formulas:

[0006] 1) Rb₂SO₄ + 2ZnSO₄ → Rb₂Zn₂S₃O 12

[0007] 2)Rb2O+2ZnSO4+H2SO4→Rb2Zn2S3O 12 +H2O

[0008] 3)Rb2SO4+2ZnO+2H2SO4→Rb2Zn2S3O 12 +2H2O

[0009] 4) Rb2CO3 + 2ZnO + 2H2SO4→ Rb2Zn2S3O 12 + H2O + CO2↑

[0010] 5) Rb2CO3 + 2ZnCO3 + 3H2SO4→ Rb2Zn2S3O 12 + 3H2O + 3CO2↑.

[0011] A third object of the present application is to provide a rubidium zinc sulfate nonlinear optical crystal, the molecular general formula of which is Rb2Zn2S3O 12 , which has no symmetry center, crystallizes in a monoclinic system, space group P21, and cell parameters are Z = 2, unit cell volume

[0012] A fourth object of the present application is to provide a preparation method of the rubidium zinc sulfate nonlinear optical crystal, which is a high-temperature solution method or a hydrothermal method or a solution method for growing the rubidium zinc sulfate nonlinear optical crystal.

[0013] Further, the step of growing the rubidium zinc sulfate nonlinear optical crystal by the high-temperature melt method is as follows:

[0014] a. uniformly mixing rubidium zinc sulfate compound single-phase polycrystal powder with a fluxing agent, heating it to a temperature of 300-800°C, keeping the temperature constant for a period of time to obtain a mixed melt, and then cooling it to a temperature of 200-650°C, wherein the molar ratio of the rubidium zinc sulfate single-phase polycrystal powder to the fluxing agent is 1:0-20;

[0015] b. preparing a rubidium zinc sulfate seed crystal: slowly cooling the mixed melt obtained in step a to room temperature to spontaneously crystallize and obtain a rubidium zinc sulfate seed crystal;

[0016] c. placing the crucible containing the mixed melt prepared in step a into a crystal growth furnace, fixing the seed crystal obtained in step b on a seed crystal rod, lowering the seed crystal from the top of the crystal growth furnace, preheating the seed crystal rod, lowering the seed crystal to contact the surface of the mixed melt or to remelt in the mixed melt, keeping the temperature constant for a period of time, and then slowly cooling to the saturation temperature;

[0017] d. continuing to slowly cool and rotate the seed crystal rod to grow the crystal, taking the crystal away from the surface of the mixed melt when the single crystal grows to the desired size, slowly cooling to room temperature, and then taking the crystal out of the furnace, thereby obtaining the rubidium zinc sulfate nonlinear optical crystal.

[0018] Further, the step a is to heat the mixture of rubidium compound, zinc-containing compound and sulfur-containing compound or the mixture of rubidium compound, zinc-containing compound and sulfur-containing compound and flux to a temperature of 350-800℃, keep constant temperature for a period of time, obtain a mixed melt, and then cool to a temperature of 200-650℃, wherein the molar ratio of rubidium compound, zinc-containing compound and sulfur-containing compound to flux is 1.5-3.5:1.5-3.5:1.5-7:0-30.

[0019] Further, the flux is at least one or more of rubidium carbonate, rubidium nitrate, rubidium sulfate, rubidium oxalate, rubidium fluoride, rubidium chloride, rubidium bromide, rubidium oxide, rubidium hydroxide, zinc carbonate, zinc nitrate, zinc sulfate, zinc oxalate, zinc oxide, zinc hydroxide, zinc fluoride, zinc chloride and zinc bromide.

[0020] Further, the single-phase polycrystalline powder of the rubidium zinc sulfate compound is prepared by a solid phase synthesis method, including the following steps: mixing rubidium compound, zinc-containing compound and sulfur-containing compound, and obtaining the compound rubidium zinc sulfate by a solid phase reaction method, wherein the molar ratio of rubidium in the rubidium-containing compound, zinc in the zinc-containing compound and sulfur in the sulfur-containing compound is 1.5-3.5:1.5-3.5:1.5-7.

[0021] The rubidium compound, zinc-containing compound and sulfur-containing compound raw materials are mixed uniformly, ground, and then put into a muffle furnace for pre-burning to remove water and gas in the raw materials, cooled to room temperature, taken out, ground, and then put into a muffle furnace for calcination, heated to 250-700℃, kept constant temperature for a period of time, cooled to room temperature, and then taken out to obtain the single-phase polycrystalline powder of rubidium zinc sulfate.

[0022] Further, the step of growing the rubidium zinc sulfate nonlinear optical crystal by a hydrothermal method is as follows:

[0023] a. The rubidium compound, zinc-containing compound and sulfur-containing compound are added to the polytetrafluoroethylene liner of a high-pressure reaction kettle, deionized water 0.1-50mL or mineralizer 0.1-50g is added, and they are mixed uniformly to obtain a mixed solution, wherein the molar ratio of the rubidium compound, zinc-containing compound and sulfur-containing compound is 1.5-3.5:1.5-3.5:1.5-7.

[0024] b. The cover of the polytetrafluoroethylene liner containing the mixed solution in step a is screwed tightly, and then the corresponding high-pressure reaction kettle is loaded;

[0025] c. The high-pressure reaction kettle in step b is placed in a thermostat, heated to 120-330℃, kept constant temperature for a period of time, and then cooled to room temperature;

[0026] d. The high-pressure reaction kettle is opened, and the solution containing the crystal is filtered to obtain a transparent rubidium zinc sulfate nonlinear optical crystal.

[0027] Further, the solution method for growing the rubidium zinc sulfate nonlinear optical crystal is as follows:

[0028] a. adding a rubidium-containing compound, a zinc-containing compound and a sulfur-containing compound into a beaker, and then adding 0.1-1000 mL of deionized water, and stirring the solution until it is clear;

[0029] b. placing the beaker on a heating table, heating the temperature to 25-400℃, and obtaining the rubidium zinc sulfate nonlinear optical crystal after a period of time.

[0030] The fifth object of the present application is to provide an application of the rubidium zinc sulfate nonlinear optical crystal, which comprises a nonlinear optical device comprising a device for generating at least one output radiation having a different frequency from the incident electromagnetic radiation after at least one incident electromagnetic radiation passes through at least one piece of nonlinear optical crystal, wherein the nonlinear optical crystal is a rubidium zinc sulfate crystal having a molecular formula of Rb2Zn2S3O 12 .

[0031] The rubidium zinc sulfate belongs to an alkali metal sulfate, which generally has a large band gap, and its ultraviolet transmittance range can be extended to about 150 nm, and is a candidate material for exploring UV or DUV optical crystals. In addition, the alkali metal sulfate has the properties of low melting point and high solubility, so it can be synthesized by high-temperature solution method, hydrothermal method and aqueous solution method, and its synthesis conditions are relatively mild. Therefore, the design of synthesizing the alkali metal sulfate is an effective means for designing deep ultraviolet nonlinear optical materials. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a theoretical X-ray spectrum of the compound Rb2Zn2S3O 12 crystal prepared in the present application;

[0033] Figure 2 is a crystal structure diagram of Rb2Zn2S3O 12 crystal of the present application;

[0034] Figure 3 is a working principle diagram of the nonlinear optical device prepared in the present application.

[0035] 1, laser; 2, light beam; 3, single crystal device; 4, outgoing light beam; 5, filter. DETAILED DESCRIPTION

[0036] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application, so that those skilled in the art can better understand the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of the present application.

[0037] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence.

[0038] Embodiment 1

[0039] According to the reaction formula: Rb2SO4+2ZnSO4→Rb2Zn2S3O 12 , synthesis of Rb2Zn2S3O 12 Crystal:

[0040] Rb2SO4, 2ZnSO4 were weighed according to the molar ratio of 1:2 and then loaded into a Φ100mm×100mm open corundum crucible, placed in a muffle furnace, slowly heated to 250℃, and kept at this temperature for 24 hours, then cooled to room temperature. After grinding, it was placed in a muffle furnace and heated to 500℃ again, kept at this temperature for 24 hours, then cooled to room temperature. After the second grinding, it was placed in a muffle furnace and kept at 510℃ for 48 hours. The obtained single-phase polycrystalline powder of rubidium zinc sulfate compound was ground and analyzed by X-ray. The obtained X-ray spectrum was consistent with the X-ray spectrum of rubidium zinc sulfate Rb2Zn2S3O 12 single crystal structure;

[0041] The obtained single-phase polycrystalline powder of rubidium zinc sulfate compound Rb2Zn2S3O 12 was loaded into a Φ80mm×80mm open platinum-gold crucible, heated to 600℃ at a temperature rise rate of 30℃ / h, kept at this temperature for 3 hours to obtain a mixed melt, and then cooled to 540℃;

[0042] Slowly cooled to room temperature at a rate of 0.5℃ / h, and spontaneously crystallized to obtain a rubidium zinc sulfate seed crystal;

[0043] Growth of crystal in compound melt: the obtained Rb2Zn2S3O 12 seed crystal was fixed on a seed crystal rod and lowered from the top of the crystal growth furnace. The seed crystal was preheated on the surface of the mixed melt for 10 minutes, then immersed into the liquid surface, and the seed crystal was subjected to remelting in the mixed melt. The temperature was kept constant for 30 minutes, and then rapidly cooled to the saturation temperature of 540℃;

[0044] The temperature is decreased at a rate of 0.1 ℃ / day, the seed crystal rod is rotated at a speed of 10 rpm, and after the crystal growth is completed, the crystal is separated from the liquid surface, and the temperature is decreased to room temperature at a rate of 10 ℃ / h, so that the Rb2Zn2S3O 12 crystal.

[0045] Example 2

[0046] According to the reaction formula: Rb2O + 2ZnSO4+ H2SO4→ Rb2Zn2S3O 12 + H2O, the Rb2Zn2S3O 12 compound is synthesized:

[0047] a. Rb2O, ZnSO4, H2SO4 are weighed according to a molar ratio of 1:2:1 as raw materials, and are added to a polytetrafluoroethylene liner of a high-pressure reaction kettle with a volume of 21 mL, 3 mL of deionized water is added, and it is fully mixed and uniform, to obtain a mixed solution;

[0048] b. The polytetrafluoroethylene liner cover of the mixed solution in step a is tightly screwed, and then a clean and uncontaminated high-pressure reaction kettle is loaded, and the piston of the reaction kettle is tightly screwed;

[0049] c. The high-pressure reaction kettle in step b is placed in a thermostat, and the temperature is increased to 220 ℃ at a rate of 20 ℃ / h, and is kept constant for 5 days, and then is cooled to room temperature at a rate of 4 ℃ / h;

[0050] d. The high-pressure reaction kettle is opened, and the solution containing the crystal is filtered, to obtain the rubidium zinc sulfate crystal.

[0051] Example 3

[0052] According to the reaction formula: Rb2CO3+ 2ZnO + 3H2SO4→ Rb2Zn2S3O 12 + 3H2O + CO2↑crystal:

[0053] Rb2CO3, ZnO, H2SO4 are weighed according to a molar ratio of 1:2:3 as raw materials and are added to a beaker with a volume of 500 mL, and 450 mL of deionized water is added, and the solution is stirred until it is clear. Then the beaker is placed on a heating table, and is kept at a constant temperature of 25 degrees Celsius, and after 2 days, the rubidium zinc sulfate nonlinear optical crystal is obtained. In order to further grow it, a seed crystal of the rubidium zinc sulfate crystal is suspended in the solution by using a fine platinum wire. In order to reduce the evaporation of water, a layer of polyethylene plate is covered on the beaker and dozens of holes with a size of tens of millimeters are punched on it. After 5 weeks, a centimeter-sized rubidium zinc sulfate nonlinear optical crystal is taken out from the solution.

[0054] Example 4

[0055] Any of Rb2Zn2S3O 12 The crystal is processed into a single crystal device 3, which is arranged as shown in the accompanying drawings, at room temperature, a Nd:YAG Q-switched laser source with a wavelength of 1064 nm is used as a pump source to irradiate the single crystal device 3, frequency-doubled light with a wavelength of 532 nm is generated, the outgoing light beam 4 contains infrared light with a wavelength of 1064 nm and frequency-doubled light with a wavelength of 532 nm, and after filtering by the filter 5, laser light with a wavelength of 532 nm is obtained. Figure 3

[0056] Example 5:

[0057] Any of Rb2Zn2S3O 12 The crystal is processed into a single crystal device 3, which is arranged as shown in the accompanying drawings, at room temperature, a Nd:YAG Q-switched laser source with a wavelength of 1064 nm is used as a pump source to irradiate the single crystal device 3, frequency-doubled light with a wavelength of 532 nm is generated, the outgoing light beam 4 contains infrared light with a wavelength of 1064 nm and frequency-doubled light with a wavelength of 532 nm, and after filtering by the filter 5, laser light with a wavelength of 532 nm is obtained. Figure 3

[0058] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that after reading the present application, the technical personnel can still modify or equivalently replace the specific embodiments of the present application, but these modifications or changes do not deviate from the scope of the present application.​​

Claims

1. A rubidium zinc sulfate compound characterized in that, The molecular formula of the rubidium zinc sulfate compound is Rb2Zn2S3O 12 , has no symmetry center, crystallizes in monoclinic system, space group P 21, the cell parameters are a = 14.389(19) Å, b = 4.875(17) Å, c = 16.435(12) Å, Z = 2, and the unit cell volume V = 1153(33) Å 3 .

2. The method of claim 1, wherein the rubidium zinc sulfate compound is prepared by the steps of: The zinc rubidium sulfate compound is prepared by a solid phase reaction method, a hydrothermal method or a solution method, and is prepared according to any one of the following chemical reaction formulas: 1) Rb2SO4+ 2ZnSO4→ Rb2Zn2S3O 12 2) Rb2O + 2ZnSO4+ H2SO4→ Rb2Zn2S3O 12 + H2O 3) Rb2SO4+ 2ZnO + 2H2SO4→ Rb2Zn2S3O 12 + 2H2O 4) Rb2CO3 + 2ZnO + 2H2SO4→ Rb2Zn2S3O 12 + H2O + CO2↑ 5) Rb2CO3 + 2ZnCO3 + 3H2SO4→ Rb2Zn2S3O 12 + 3H2O + 3CO2↑.

3. The nonlinear optical crystal of rubidium zinc sulfate as claimed in claim 1, wherein, The molecular general formula of the rubidium zinc sulfate nonlinear optical crystal is Rb2Zn2S3O 12 , which has no symmetry center, is crystallized in a monoclinic system, and a space group P 21, the cell parameters are a=14.389(19) Å, b=4.875(17) Å, c=16.435(12) Å, Z=2, and the unit cell volume V=1153(33) Å 3 .

4. The method of claim 3, wherein the RbZnSO4 nonlinear optical crystal is prepared by the steps of: preparing a solution of Rb2SO4 and ZnSO4 in a solvent; and crystallizing the RbZnSO4 from the solution. The preparation method of the zinc rubidium sulfate nonlinear optical crystal is a high-temperature solution method or a hydrothermal method or a solution method for growing the zinc rubidium sulfate nonlinear optical crystal.

5. The method of claim 4, wherein the RbZnSO4 nonlinear optical crystal is prepared by the steps of: preparing a solution of Rb2SO4 and ZnSO4 in a solvent; and crystallizing the RbZnSO4 from the solution. The step of growing the zinc rubidium sulfate nonlinear optical crystal by the high-temperature solution method is as follows: a. The single-phase polycrystalline powder of rubidium zinc sulfate compound is mixed with fluxing agent uniformly, heated to a temperature of 300 800°C, kept constant for a period of time, to obtain a mixed melt, and then cooled to a temperature of 200 650°C, wherein the molar ratio of the single-phase polycrystalline powder of rubidium zinc sulfate compound to fluxing agent is 1:0 20. b. Preparing a zinc rubidium sulfate seed crystal: the mixed melt obtained in step a is slowly cooled to room temperature, and a zinc rubidium sulfate seed crystal is spontaneously crystallized; c. Placing the crucible containing the mixed melt prepared in step a into a crystal growth furnace, fixing the seed crystal obtained in step b on a seed crystal rod, lowering the seed crystal from the top of the crystal growth furnace, preheating the seed crystal rod, lowering the seed crystal to contact the surface of the mixed melt or the mixed melt for remelting, keeping the temperature constant for a period of time, and then slowly cooling to the saturation temperature; d. Continuing to slowly cool and rotate the seed crystal rod to grow the crystal, taking the crystal away from the surface of the mixed melt when the single crystal grows to the required size, slowly cooling to room temperature, then taking the crystal out of the furnace, and obtaining the zinc rubidium sulfate nonlinear optical crystal.

6. The method of claim 5, wherein the RbZnSO4 nonlinear optical crystal is prepared by the steps of: Step a is heating a mixture of rubidium compound, zinc compound and sulfur compound or a mixture of rubidium compound, zinc compound and sulfur compound with flux to a temperature of 350 800°C, keeping the temperature constant for a certain period of time, obtaining a mixed melt, and then cooling to a temperature of 200 650°C, wherein the molar ratio of rubidium compound, zinc compound and sulfur compound to flux is 1.5 3.5: 1.5 3.5:1.5-7:0 30。 7. The method of claim 4, wherein the RbZnSO4 nonlinear optical crystal is prepared by the steps of: preparing a solution of Rb2SO4 and ZnSO4 in a solvent; and crystallizing the RbZnSO4 from the solution. The single-phase polycrystalline powder of the rubidium zinc sulfate compound is prepared by a solid-phase synthesis method, including the following steps: mixing a rubidium-containing compound, a zinc-containing compound and a sulfur-containing compound, and preparing the rubidium zinc sulfate compound by a solid-phase reaction method, wherein the molar ratio of rubidium in the rubidium-containing compound, zinc in the zinc-containing compound and sulfur in the sulfur-containing compound is 1.5 3.5:1.5 3.5:1.5-7; The raw materials of rubidium compound, zinc compound and sulfur compound are mixed uniformly, grinded, and then put into a muffle furnace to pre-burn to remove water and gas in the raw materials. After cooling to room temperature, the grinded materials are taken out and put into the muffle furnace to calcine. The temperature is raised to 250 700℃, kept constant for a period of time, cooled to room temperature, and then taken out to obtain the single-phase polycrystalline powder of zinc rubidium sulfate.

8. The method of claim 4, wherein the RbZnSO4 nonlinear optical crystal is prepared by the steps of: preparing a solution of Rb2SO4 and ZnSO4 in a solvent; and crystallizing the RbZnSO4 from the solution. The step of growing the zinc rubidium sulfate nonlinear optical crystal by the hydrothermal method is as follows: a. The rubidium-containing compound, zinc-containing compound, and sulfur-containing compound are added to the polytetrafluoroethylene liner of a high-pressure reaction kettle, and then deionized water 0.1 50 mL or mineralizer 0.1 50 g, and mix them well to obtain a mixed solution, wherein the molar ratio of the rubidium-containing compound, zinc-containing compound, and sulfur-containing compound is 1.5 3.5:1.5 3.5:1.5-7； b. Tightening the lid of the polytetrafluoroethylene liner containing the mixed solution in step a, then placing the liner into a corresponding high-pressure reaction kettle, and tightening the piston of the reaction kettle; c. The high-pressure reactor in step b is placed in a thermostat, and heated to 120 330 °C for a period of time, and then cooled to room temperature. d. Opening the high-pressure reaction kettle, filtering the solution containing the crystal, and obtaining the transparent zinc rubidium sulfate nonlinear optical crystal.

9. The method of claim 4, wherein the RbZnSO4 nonlinear optical crystal is prepared by the steps of: preparing a solution of Rb2SO4 and ZnSO4 in a solvent; and crystallizing the RbZnSO4 from the solution. The step of growing the zinc rubidium sulfate nonlinear optical crystal by the solution method is as follows: a. Add the rubidium-containing compound, zinc-containing compound, and sulfur-containing compound to a beaker and add 0.1 1000 mL, stir the solution until clear; b. The beaker is placed on the heating table, and the temperature is heated to 25 400°C, and a rubidium zinc sulfate nonlinear optical crystal is obtained after a period of time.

10. Use of the rubidium zinc sulfate nonlinear optical crystal according to any one of claims 3 to 9, characterized in that, The nonlinear optical device comprises a device for generating at least one output radiation with a frequency different from that of the incident electromagnetic radiation after at least one piece of nonlinear optical crystal is passed through at least one incident electromagnetic radiation, and the nonlinear optical crystal uses the zinc rubidium sulfate crystal.

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