Compound potassium rubidium barium borate, potassium rubidium barium borate birefringent crystal and preparation method and application thereof

Abstract

The invention relates to a compound potassium rubidium barium borate, a potassium rubidium barium borate birefringent crystal and a preparation method and application thereof. The chemical formula of the compound is KxRb (2-x) BaB6O11, x is equal to 0.7-1, the molecular weight is 502.74-517.61, and the compound is synthesized by adopting a solid-phase reaction method. The chemical formula of the crystal is KxRb (2-x) BaB6O11, x is equal to 0.7-1, the molecular weight is 502.74-517.61, the crystal belongs to an orthorhombic system, the space group is Pnma, the cell parameters are as follows: a is equal to 15.1923 (9), b is equal to 7.6510 (5), c is equal to 8.7527 (5), Z is equal to 4 and V is equal to 1017.38 (11) 3, and the crystal is prepared by adopting a high-temperature melt method; the crystal is used for a deep ultraviolet-infrared band and is a biaxial crystal, the transmission range of the crystal is 200-3500 nm, and the birefringence of the crystal is 0.08 (546 nm). The method has important application in the fields of optics and communication, and can be used for manufacturing polarization beam splitting prisms, phase delay devices and electro-optical modulators.

Description

Technical Field

[0001] The present invention relates to a compound rubidium barium potassium borate and a rubidium barium potassium borate birefringent crystal, and a preparation method and use thereof, in particular to a molecular formula K for the deep ultraviolet-infrared band x Rb (2-x) BaB6O 11 (x = 0.7-1) rubidium barium potassium borate birefringent crystal and a preparation method and application thereof. Background Art

[0002] The birefringence phenomenon is one of the important properties exhibited when light propagates in a non-uniform dielectric crystal. The fundamental reason for this phenomenon is the anisotropy of the crystal material, which can be explained by the transverse wave nature of light. When light propagates in an optically anisotropic homogeneous body (such as a crystal other than the cubic system), except for individual special directions (along the optical axis direction), its vibration characteristics will change, and it will be decomposed into two polarized lights with mutually perpendicular vibration directions of the electric field vectors, different propagation speeds, and unequal refractive indices. This phenomenon is called birefringence, and such a crystal is called a birefringent crystal. Among the two polarized lights, the o light (ordinary ray) obeys the refraction law, and its refractive index is represented by n o The e light (extraordinary ray) does not follow the refraction law, and its refractive index is represented by n e The included angle between these two refracted light rays is related to the propagation direction and polarization state of the light wave. By utilizing this linear optical property of crystal birefringence, the polarization state of light can be modulated, and crystals with large birefringence can be applied in optical isolators, Glan prisms, polarizers / analyzers, circulators, electro-optical modulators, and laser polarization technologies, etc.

[0003] At present, commercial birefringent materials mainly include CaCO3, TiO2, LiNbO3, YVO4, α-BaB2O4, and MgF2 crystals, etc. CaCO3 in its natural form, namely calcite crystal, is a widely used birefringent crystal, which is widely used in the visible-near infrared band but cannot reach the deep ultraviolet region. In addition, it is difficult to synthesize artificially. Naturally formed CaCO3 crystals have dissociation planes and are prone to cracking and breaking during processing, unable to meet the requirements of large-size optical polarizing elements. Rutile TiO2 crystal has a large birefringence and is a well-known infrared birefringent crystal, but it also mainly exists in its natural form, is difficult to synthesize artificially, has a large hardness itself, and has difficulties in device processing and cutting. LiNbO3 crystals are easy to obtain large-size crystals, but have a small birefringence, which is not conducive to the miniaturization of devices in practical applications. YVO4 crystal is a birefringent crystal prepared artificially with good performance, but its transmission cut-off edge is higher than 400 nm and cannot be used in the ultraviolet region. Moreover, due to the high melting point of YVO4, an iridium crucible must be used for Czochralski growth, and the growth atmosphere is a weakly oxygen atmosphere, resulting in the problem of variable valence of iridium elements during growth, thus reducing the quality of the crystal and making it difficult to obtain high-quality crystals. α-BaB2O4 is the only commercial birefringent material with large birefringence and deep ultraviolet transparency ability, but α-BaB2O4 crystals have a certain deliquescence property and are prone to cracking during the crystal growth process due to the existence of solid-state phase transitions. MgF2 crystals have a wide transmission range, which can reach 110 - 8500 nm, but their birefringence is too small and not suitable for manufacturing Glan prisms, and can only be used for Rochon prisms, and the light speed separation angle is small, the device size is large, and it is inconvenient to use.

[0004] For ideal birefringent materials, the following several basic but strict requirements must be met: sufficiently large birefringence, sufficiently short ultraviolet cut-off edge (corresponding to a wide bandgap) and high transmittance, high laser-induced damage threshold (LIDT), easy to grow and having good chemical stability. Therefore, discovering new excellent birefringent optical crystal materials is still an urgent problem to be solved, which requires a large amount of systematic and in-depth research work and continuous exploration to discover birefringent crystals with better performance. Summary of the Invention

[0005] The object of the present invention is to provide a rubidium barium potassium borate compound, and the chemical formula of this compound is K x Rb (2-x) BaB6O 11 , where x = 0.7 - 1, the molecular weight is 502.74 - 517.61, and it is synthesized by the solid-phase reaction method.

[0006] Another object of the present invention is to provide a rubidium barium potassium borate birefringent crystal with a wide transmission range, large birefringence and applicable to the deep ultraviolet band, and the chemical formula of this crystal is Kx Rb (2-x) BaB6O 11 , where x = 0.7 - 1, the molecular weight is 502.74 - 517.61, belonging to the orthorhombic system, the space group is Pnma, and the unit cell parameters are Z = 4,

[0007] Another object of the present invention is to provide a preparation method of rubidium barium potassium borate birefringent crystal.

[0008] Another object of the present invention is to provide an application of rubidium barium potassium borate birefringent crystal.

[0009] A compound rubidium barium potassium borate according to the present invention, the chemical formula of the compound is K x Rb (2-x) BaB6O 11 , where x = 0.7 - 1, the molecular weight is 502.74 - 517.61, belonging to the orthorhombic system, the space group is Pnma, and the unit cell parameters are Z = 4,

[0010] The preparation method of the compound rubidium barium potassium borate, the compound is synthesized by a solid-phase reaction method, and the specific operation is carried out according to the following steps:

[0011] Weigh potassium-containing compound, rubidium-containing compound, barium-containing compound and boron-containing compound according to the molar ratio of K:Rb:Ba:B = 0.7 - 1:1.3 - 1:1:3, put them into a mortar and grind them evenly, then put them into an open ceramic crucible with a diameter of Φ100mm × 100mm and put it into a muffle furnace, slowly heat up to 300 - 500 °C, keep it at a constant temperature for 12 - 36 hours, take out the crucible after cooling, at this time the sample is relatively loose, then take out the sample and grind it evenly again, then place it in the crucible, keep it at a constant temperature of 500 - 700 °C in the muffle furnace for 1 - 5 days, take out the sample after cooling and grind it sufficiently to obtain a single-phase polycrystalline powder of rubidium barium potassium borate compound, conduct X-ray analysis, and the obtained X-ray spectrum is consistent with that of K x Rb (2-x) BaB6O 11 (x = 0.7 - 1) The X-ray spectrum obtained from the single crystal structure Figure 1 consistent, the potassium-containing compound is potassium oxide, potassium hydroxide, potassium fluoride, potassium chloride, potassium bromide, potassium carbonate or potassium nitrate with a purity of 99.9%, the rubidium-containing compound is rubidium oxide, rubidium hydroxide, rubidium fluoride, rubidium chloride, rubidium bromide, rubidium carbonate or rubidium nitrate with a purity of 99.9%, the barium-containing compound is barium oxide, barium hydroxide, barium fluoride, barium chloride, barium carbonate or barium nitrate with a purity of 99.9% and the boron-containing compound is boric acid or boron oxide with a purity of 99.9%.

[0012] A potassium borate rubidium barium birefringent crystal, the chemical formula of the crystal is K x Rb (2-x) BaB6O 11 , where x = 0.7-1, the molecular weight is 502.74-517.61, belongs to the orthorhombic system, the space group is Pnma, and the unit cell parameters are Z=4, The method for preparing the potassium borate rubidium barium birefringent crystal adopts a high-temperature melt method to prepare the potassium borate rubidium barium birefringent crystal, and the specific operation is carried out according to the following steps:

[0013] a. Directly weighing the raw materials potassium-containing compound, rubidium-containing compound, barium-containing compound and boron-containing compound in a molar ratio of K:Rb:Ba:B=0.7-1:1.3-1:1:3, placing them in a mortar and grinding them thoroughly to obtain a mixture, wherein the potassium-containing compound is potassium oxide, potassium hydroxide, potassium fluoride, potassium chloride, potassium bromide, potassium carbonate or potassium nitrate with a purity of 99.9%, the rubidium-containing compound is rubidium oxide, rubidium hydroxide, rubidium fluoride, rubidium chloride, rubidium bromide, rubidium carbonate or rubidium nitrate with a purity of 99.9%, the barium-containing compound is barium oxide, barium hydroxide, barium fluoride, barium chloride, barium carbonate or barium nitrate with a purity of 99.9%, and the boron-containing compound is boric acid or boron oxide with a purity of 99.9%;

[0014] b. The mixture in step a is placed in an open platinum crucible and placed in a single crystal furnace, and the temperature is increased to 500-700° C. at a rate of 10-50° C. / h, maintained at a constant temperature for 1-5 days, and then slowly decreased to 300-500° C. at a cooling rate of 0.5-2° C. / h, and finally decreased to room temperature at a rate of 10-20° C. / h to allow spontaneous crystallization, and the sample is separated by mechanical separation to obtain potassium rubidium barium borate birefringent crystals.

[0015] The potassium borate rubidium barium birefringent crystal is used in preparing an optical isolator, a circulator, a beam displacer, an optical polarizer or an optical modulator.

[0016] The optical polarizer is a polarizing beam splitter prism.

[0017] The polarization beam splitter prism is a Glan prism, a Wollaston prism or a Rochon prism.

[0018] The compound potassium rubidium barium borate and the potassium rubidium barium borate birefringent crystal described in the present invention, as well as their preparation method and use, adopt a solid-phase reaction to synthesize the compound and a high-temperature melt method to prepare the potassium rubidium barium borate birefringent crystal. The chemical reaction formula of the compound is:

[0019] Rb2CO3+K2CO3+2BaCO3+12H3BO3=2KRbBaB6O 11 +4CO2↑+18H2O↑;

[0020] RbNO3 + KNO3 + Ba(NO3)2 + 6H3BO3 = KRbBaB6O 11 + 4NO2↑ + O2↑ + 9H2O↑;

[0021] 1.3Rb2CO3 + 0.7K2CO3 + 2BaCO3 + 12H3BO3 = 2K 0.7 Rb 1.3 BaB6O 11 + 4CO2↑ + 18H2O↑;

[0022] 1.3RbNO3 + 0.7KNO3 + Ba(NO3)2 + 6H3BO3 = K 0.7 Rb 1.3 BaB6O 11 + 4NO2↑ + O2↑ + 9H2O↑;

[0023] 1.2Rb2CO3 + 0.8K2CO3 + 2Ba(NO3)2 + 12H3BO3 = 2K 0.8 Rb 1.2 BaB6O 11 + 2CO2↑ + 4NO2↑ + O2↑ + 18H2O↑;

[0024] 2RbNO3 + 2KNO3 + 2BaCO3 + 12H3BO3 = 2KRbBaB6O 11 + 2CO2↑ + 4NO2↑ + O2↑ + 18H2O↑;

[0025] 1.25RbOH + 0.75KOH + Ba(OH)2 + 6H3BO3 = K 0.75 Rb 1.25 BaB6O 11 + 11H2O↑;

[0026] 1.15RbOH + 0.85KOH + BaCO3 + 6H3BO3 = K 0.85 Rb 1.15 BaB6O 11 + CO2↑ + 10H2O↑;

[0027] 2RbOH + 2KOH + 2Ba(NO3)2 + 12H3BO3 = 2KRbBaB6O 11 + 4NO2↑ + O2↑ + 20H2O↑;

[0028] 1.1Rb2O + 0.9K2O + 2BaO + 12H3BO3 = 2K 0.9 Rb 1.1 BaB6O 11+18H2O↑;

[0029] 1.23Rb2O + 0.77K2O + 2BaCO3 + 12H3BO3 = 2K 0.77 Rb 1.23 BaB6O 11 +2CO2↑ + 18H2O↑;

[0030] 1.18Rb2O + 0.82K2O + 2Ba(NO3)2 + 12H3BO3 = 2K 0.82 Rb 1.18 BaB6O 11 +4NO2↑ + O2↑ + 18H2O↑;

[0031] Rb2CO3 + K2CO3 + 2BaCO3 + 12H3BO3 + 0.5RbF = 2KRbBaB6O 11 +4CO2↑ + 18H2O↑ + 0.5RbF;

[0032] 1.3Rb2CO3 + 0.7K2CO3 + 2BaCO3 + 12H3BO3 + 0.5RbF = 2K 0.7 Rb 1.3 BaB6O 11 +4CO2↑ + 18H2O↑ + 0.5RbF;

[0033] Rb2CO3 + K2CO3 + 2BaCO3 + 12H3BO3 + RbF = 2KRbBaB6O 11 +4CO2↑ + 18H2O↑ + RbF;

[0034] Rb2CO3 + K2CO3 + 2BaCO3 + 12H3BO3 + 1.5Ba(NO3)2 = 2KRbBaB6O 11 +4CO2↑ + 18H2O↑ + 1.5Ba(NO3)2;

[0035] Rb2CO3 + K2CO3 + 2BaCO3 + 12H3BO3 + 2Ba(NO3)2 = 2KRbBaB6O 11 +4CO2↑ + 18H2O↑ + 2Ba(NO3)2;

[0036] Rb2CO3 + K2CO3 + 2BaCO3 + 12H3BO3 + 0.5RbF + 2Ba(NO3)2 = 2KRbBaB6O 11 +4CO2↑ + 18H2O↑ + 0.5RbF + 2Ba(

[0037] NO3)2;

[0038] Rb2CO3 + K2CO3 + 2BaCO3 + 12H3BO3 + RbF + 2Ba(NO3)2 = 2KRbBaB6O 11 + 4CO2↑ + 18H2O↑ + RbF + 2Ba(NO3)2;

[0039] Rb2CO3 + K2CO3 + 2BaCO3 + 12H3BO3 + 2B2O3 = 2KRbBaB6O 11 + 4CO2↑ + 18H2O↑ + 2B2O3;

[0040] 1.3Rb2CO3 + 0.7K2CO3 + 2BaCO3 + 12H3BO3 + 2B2O3 = 2K 0.7 Rb 1.3 BaB6O 11 + 4CO2↑ + 18H2O↑ + 2B2O3;

[0041] Rb2CO3 + K2CO3 + 2BaCO3 + 12H3BO3 + 0.5RbF + 2B2O3 = 2KRbBaB6O 11 + 4CO2↑ + 18H2O↑ + 0.5RbF + 2B2O3。

[0042] The rubidium barium potassium borate birefringent crystal described in the present invention is a biaxial crystal used in the deep ultraviolet-infrared band. Its chemical formula is K x Rb (2-x) BaB6O 11 (x = 0.7 - 1), with a molecular weight of 502.74 - 517.61, belonging to the orthorhombic crystal system, the space group is Pnma, and the unit cell parameters are Z = 4, Its transmission range is 200nm - 3500nm, and the birefringence is 0.08 (546nm). The present invention synthesizes the compound by solid-phase reaction and prepares the rubidium barium potassium borate birefringent crystal by the high-temperature solution method.

[0043] In the present invention, the potassium-containing compound, rubidium-containing compound, barium-containing compound, and boron-containing compound can all use commercially available reagents and raw materials, which have the advantages of simple operation method, fast growth rate, and low cost. The crystal is easy to grow, cut, grind, polish, and preserve, and is stable in air. It can be used to make polarization beam splitting prisms such as Glan-type prisms, Wollaston prisms, Rochon prisms, or beam separation polarizers, and has important applications in the optical and communication fields.

[0044] The rubidium barium potassium borate birefringent crystal has no special requirements for optical processing accuracy. Brief Description of the Drawings

[0045] Figure 1is the powder X-ray diffraction pattern of the present invention;

[0046] Figure 2 K of the present invention x Rb (2-x) BaB6O 11 (x=0.7-1) crystal structure diagram;

[0047] Figure 3 Schematic diagram of the wedge-shaped birefringent crystal polarization beam splitter of the present invention;

[0048] Figure 4 Schematic diagram of the optical isolator of the present invention;

[0049] Figure 5 Schematic diagram of the beam displacer of the present invention, where 1 is the incident light, 2 is the o light, 3 is the e light, 4 is the optical axis, and 5 is the K x Rb (2-x) BaB6O 11 (x=0.7-1) crystal, 6 is the light transmission direction, 7 is the optical axis plane;

[0050] Figure 6 This is the crystal structure diagram of the present invention. DETAILED DESCRIPTION

[0051] The present invention is described in detail below with reference to the accompanying drawings and examples: The present invention is further described below with reference to the examples. It should be noted that the present invention is not limited to the examples listed, and any improvements made on the basis of the present invention do not violate the spirit of the present invention. The raw materials or equipment used in the present invention, unless otherwise specified, are all commercially available.

[0052] Example 1

[0053] According to the chemical reaction formula Rb2CO3+K2CO3+2BaCO3+12H3BO3=2KRbBaB6O 11 +4CO2↑+18H2O↑synthesize compound KRbBaB6O 11 :

[0054] The raw materials Rb2CO3, K2CO3, BaCO3 and H3BO3 were weighed in a molar ratio of 1:1:2:12, mixed and put into a mortar and ground evenly, then put into an open ceramic crucible of Φ100mm×100mm and placed in a muffle furnace, slowly heated to 300℃, kept at this temperature for 72 hours, and taken out of the crucible after cooling. At this time, the sample was relatively loose, and then the sample was taken out and ground evenly again, and then placed in a crucible, kept at a temperature of 500℃ in a muffle furnace for 1 day, and after cooling, the sample was taken out and ground thoroughly to obtain a single-phase polycrystalline powder of potassium rubidium barium borate compound. The powder X-ray diffraction experiment was used for analysis, and the obtained X-ray spectrum was consistent with that of KRbBaB6O 11X-ray spectrum obtained from single crystal structure Figure 1 caused by

[0055] Example 2

[0056] Using the chemical reaction formula 1.3Rb2CO3 + 0.7K2CO3 + 2BaCO3 + 12H3BO3 = 2K 0.7 Rb 1.3 BaB6O 11 + 4CO2↑ + 18H2O↑ to synthesize the compound K 0.7 Rb 1.3 BaB6O 11 :

[0057] Weigh the raw materials Rb2CO3, K2CO3, BaCO3 and H3BO3 according to the molar ratio of 1.3:0.7:2:12, mix them and put them into a mortar to grind evenly. Then put them into an open ceramic crucible with a diameter of Φ100mm×100mm and place it in a muffle furnace. Slowly heat up to 350°C and keep it at a constant temperature for 60 hours. After cooling, take out the crucible. At this time, the sample is relatively loose. Then take out the sample, grind it evenly again, put it back into the crucible, and keep it at a constant temperature of 550°C in the muffle furnace for 2 days. After cooling, take out the sample and grind it sufficiently to obtain the single-phase polycrystalline powder of rubidium barium potassium borate compound. Use powder X-ray diffraction experiment for analysis. The obtained X-ray spectrum is consistent with that of K 0.7 Rb 1.3 BaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1 caused by

[0058] Example 3

[0059] Using the chemical reaction formula RbNO3 + KNO3 + Ba(NO3)2 + 6H3BO3 = KRbBaB6O 11 + 4NO2↑ + O2↑ + 9H2O↑ to synthesize the compound KRbBaB6O 11 :

[0060] Weigh the raw materials Rb2(NO3)2, KNO3, Ba(NO3)2 and H3BO3 according to the molar ratio of 1:1:1:6, mix them and put them into a mortar to grind carefully until evenly mixed. Then put them into an open ceramic crucible with a diameter of Φ100mm×100mm and place it in a muffle furnace. Slowly heat up to 400°C and keep it at a constant temperature for 48 hours. After cooling, take out the crucible. At this time, the sample is relatively loose. Then take out the sample, grind it evenly again, put it back into the crucible, and keep it at a constant temperature of 600°C in the muffle furnace for 3 days. After cooling, take out the sample and grind it sufficiently to obtain the single-phase polycrystalline powder of rubidium barium potassium borate compound. Use powder X-ray diffraction experiment for analysis. The obtained X-ray spectrum is consistent with that of KRbBaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1 caused by

[0061] Example 4

[0062] According to the chemical reaction formula 1.3RbNO3+0.7KNO3+Ba(NO3)2+6H3BO3=K 0.7 Rb 1.3 BaB6O 11 +4NO2↑+O2↑+9H2O↑synthesize compound K 0.7 Rb 1.3 BaB6O 11 :

[0063] The raw materials RbNO3, KNO3, Ba(NO3)2 and H3BO3 were weighed in a molar ratio of 1.3:0.7:1:6, mixed and put into a mortar and ground evenly, then loaded into an open ceramic crucible of Φ100mm×100mm and placed in a muffle furnace, slowly heated to 400℃, kept constant temperature for 48 hours, and taken out the crucible after cooling. At this time, the sample was relatively loose, then the sample was taken out and ground evenly again, and then placed in a crucible, kept constant temperature at 600℃ in a muffle furnace for 3 days, and after cooling, the sample was taken out and ground thoroughly to obtain a single-phase polycrystalline powder of potassium borate rubidium barium compound. The powder X-ray diffraction experiment was used for analysis, and the obtained X-ray spectrum was consistent with K 0.7 Rb 1.3 BaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1 To.

[0064] Example 5

[0065] According to the chemical reaction formula 1.2Rb2CO3+0.8K2CO3+2Ba(NO3)2+12H3BO3=2K 0.8 Rb 1.2 BaB6O 11 +2CO2↑+4NO2↑+O2↑

[0066] +18H2O↑Synthesize compound K 0.8 Rb 1.2 BaB6O 11 :

[0067] The raw materials Rb2CO3, K2CO3, Ba(NO3)2 and H3BO3 were weighed in a molar ratio of 1.2:0.8:2:12, mixed and put into a mortar and ground evenly, then loaded into an open ceramic crucible of Φ100mm×100mm and placed in a muffle furnace, slowly heated to 450℃, kept constant temperature for 36 hours, and taken out the crucible after cooling. At this time, the sample was relatively loose, then the sample was taken out and ground evenly again, and then placed in a crucible, kept constant temperature at 650℃ in a muffle furnace for 4 days, and after cooling, the sample was taken out and ground thoroughly to obtain a single-phase polycrystalline powder of potassium borate rubidium barium compound. The powder X-ray diffraction experiment was used for analysis, and the obtained X-ray spectrum was consistent with that of K0.8 Rb 1.2 BaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1 To.

[0068] Example 6

[0069] According to the chemical reaction formula 2RbNO3+2KNO3+2BaCO3+12H3BO3=2KRbBaB6O 11 +2CO2↑+4NO2↑+O2↑+18H2O↑

[0070] Synthetic compound KRbBaB6O 11 :

[0071] The raw materials RbNO3, KNO3, BaCO3 and H3BO3 were weighed in a molar ratio of 2:2:2:12, mixed and put into a mortar and ground evenly, then put into an open ceramic crucible of Φ100mm×100mm and placed in a muffle furnace, slowly heated to 500℃, kept at this temperature for 24 hours, and taken out of the crucible after cooling. At this time, the sample was relatively loose, and then the sample was taken out and ground evenly again, and then placed in a crucible, kept at a temperature of 700℃ in a muffle furnace for 5 days, and after cooling, the sample was taken out and ground thoroughly to obtain a single-phase polycrystalline powder of potassium rubidium barium borate compound. The powder X-ray diffraction experiment was used for analysis, and the obtained X-ray spectrum was consistent with that of KRbBaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1 To.

[0072] Example 7

[0073] According to the chemical reaction formula 1.25RbOH+0.75KOH+Ba(OH)2+6H3BO3=K 0.75 Rb 1.25 BaB6O 11 +11H2O↑Synthesize compound K 0.75 Rb 1.25 BaB6O 11 :

[0074] The raw materials RbOH, KOH, Ba(OH)2 and H3BO3 were weighed in a molar ratio of 1.25:0.75:1:6, mixed and put into a mortar and ground evenly, then loaded into an open ceramic crucible of Φ100mm×100mm and placed in a muffle furnace, slowly heated to 480℃, kept constant temperature for 26 hours, and taken out the crucible after cooling. At this time, the sample was relatively loose, then the sample was taken out and ground evenly again, and then placed in a crucible, kept constant temperature at 680℃ in a muffle furnace for 4 days, and after cooling, the sample was taken out and ground sufficiently to obtain a single-phase polycrystalline powder of potassium borate rubidium barium compound. The powder X-ray diffraction experiment was used for analysis, and the obtained X-ray spectrum was consistent with that of K 0.75 Rb1.25 BaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1 To.

[0075] Example 8

[0076] According to the chemical reaction formula 1.15RbOH+0.85KOH+BaCO3+6H3BO3=K 0.85 Rb 1.15 BaB6O 11 +CO2↑+10H2O↑synthesize compound K 0.85 Rb 1.15 BaB6O 11 :

[0077] The raw materials RbOH, KOH, BaCO3 and H3BO3 were weighed in a molar ratio of 1.15:0.85:1:6, mixed and put into a mortar and ground evenly, then loaded into an open ceramic crucible of Φ100mm×100mm and placed in a muffle furnace, slowly heated to 430℃, kept constant temperature for 29 hours, and taken out the crucible after cooling. At this time, the sample was relatively loose, then the sample was taken out and ground evenly again, and then placed in a crucible, kept constant temperature at 630℃ in a muffle furnace for 3 days, and after cooling, the sample was taken out and ground sufficiently to obtain a single-phase polycrystalline powder of potassium borate rubidium barium compound. The powder X-ray diffraction experiment was used for analysis, and the obtained X-ray spectrum was consistent with that of K 0.85 Rb 1.15 BaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1 To.

[0078] Example 9

[0079] According to the chemical reaction formula 2RbOH+2KOH+2Ba(NO3)2+12H3BO3=2KRbBaB6O 11 +4NO2↑+O2↑+20H2O↑synthesize compound KRbBaB6O 11 :

[0080] The raw materials RbOH, KOH, Ba(NO3)2 and H3BO3 were weighed in a molar ratio of 2:2:2:12, mixed and put into a mortar and ground evenly, then loaded into an open ceramic crucible of Φ100mm×100mm and placed in a muffle furnace, slowly heated to 380℃, kept at this temperature for 35 hours, and taken out of the crucible after cooling. At this time, the sample was relatively loose, and then the sample was taken out and ground evenly again, and then placed in a crucible, kept at a temperature of 580℃ in a muffle furnace for 3 days, and after cooling, the sample was taken out and ground thoroughly to obtain a single-phase polycrystalline powder of potassium rubidium barium borate compound. The powder X-ray diffraction experiment was used for analysis, and the obtained X-ray spectrum was consistent with that of KRbBaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1To.

[0081] Example 10

[0082] Using the chemical reaction formula 1.1Rb2O + 0.9K2O + 2BaO + 12H3BO3 = 2K 0.9 Rb 1.1 BaB6O 11 + 18H2O↑ to synthesize the compound K 0.9 Rb 1.1 BaB6O 11 :

[0083] Weigh the raw materials Rb2O, K2O, BaO, and H3BO3 according to the molar ratio of 1.1:0.9:2:12, mix them and put them into a mortar to grind evenly. Then load them into an open ceramic crucible with a diameter of Φ100mm × 100mm and put it into a muffle furnace. Slowly heat it up to 330°C and keep it at a constant temperature for 39 hours. After cooling, take out the crucible. At this time, the sample is relatively loose. Then take out the sample, grind it evenly again, and put it back into the crucible. Keep it at a constant temperature of 530°C in the muffle furnace for 2 days. After cooling, take out the sample and grind it thoroughly to obtain the single-phase polycrystalline powder of potassium rubidium barium borate compound. Use powder X-ray diffraction experiment for analysis. The obtained X-ray spectrum is the same as that of K 0.9 Rb 1.1 BaB6O 11 The X-ray spectrum obtained from the single crystal structure Figure 1 To.

[0084] Example 11

[0085] Using the chemical reaction formula 1.23Rb2O + 0.77K2O + 2BaCO3 + 12H3BO3 = 2K 0.77 Rb 1.23 BaB6O 11 + 2CO2↑ + 18H2O↑ to synthesize the compound K 0.77 Rb 1.23 BaB6O 11 :

[0086] Weigh the raw materials Rb2O, K2O, BaCO3, and H3BO3 according to the molar ratio of 1.23:0.77:2:12, mix them and put them into a mortar to grind evenly. Then load them into an open ceramic crucible with a diameter of Φ100mm × 100mm and put it into a muffle furnace. Slowly heat it up to 310°C and keep it at a constant temperature for 41 hours. After cooling, take out the crucible. At this time, the sample is relatively loose. Then take out the sample, grind it evenly again, and put it back into the crucible. Keep it at a constant temperature of 540°C in the muffle furnace for 1 day. After cooling, take out the sample and grind it thoroughly to obtain the single-phase polycrystalline powder of potassium rubidium barium borate compound. Use powder X-ray diffraction experiment for analysis. The obtained X-ray spectrum is the same as that of K 0.77 Rb 1.23 BaB6O 11X-ray spectrum obtained from single crystal structure Figure 1 To.

[0087] Example 12

[0088] According to the chemical reaction formula 1.18Rb2O+0.82K2O+2Ba(NO3)2+12H3BO3=2K 0.82 Rb 1.18 BaB6O 11 +4NO2↑+O2↑+18H2O↑ to prepare compound K 0.82 Rb 1.18 BaB6O 11 :

[0089] The raw materials Rb2O, K2O, Ba(NO3)2 and H3BO3 were weighed in a molar ratio of 1.18:0.82:2:12, mixed and put into a mortar and ground evenly, then put into an open ceramic crucible of Φ100mm×100mm and placed in a muffle furnace, slowly heated to 490℃, kept at this temperature for 33 hours, and taken out the crucible after cooling. At this time, the sample was relatively loose, and then the sample was taken out and ground evenly again, and then placed in a crucible, kept at a temperature of 680℃ in a muffle furnace for 3 days, and after cooling, the sample was taken out and ground sufficiently to obtain a single-phase polycrystalline powder of potassium borate rubidium barium compound. The powder X-ray diffraction experiment was used for analysis, and the obtained X-ray spectrum was consistent with that of K 0.82 Rb 1.18 BaB6O 11 X-ray spectrum obtained from single crystal structure Figure 1 To.

[0090] Example 13

[0091] According to the chemical reaction formula Rb2CO3+K2CO3+2BaCO3+12H3BO3=2KRbBaB6O 11 +4CO2↑+18H2O↑KRbBaB6O was prepared by high temperature melt method 11 Birefringent crystals:

[0092] a. Weigh the raw materials Rb2CO3, K2CO3, BaCO3 and H3BO3 according to the molecular formula molar ratio, place them in a mortar and grind them thoroughly to obtain a mixture;

[0093] b. The mixture obtained in step a was placed in an open platinum crucible and placed in a single crystal furnace. The temperature was raised to 500 degrees Celsius at a rate of 10°C / h, kept constant for 1 day, then slowly lowered to 300 degrees Celsius at a rate of 0.5°C / h, and finally lowered to room temperature at a rate of 10°C / h to allow spontaneous crystallization. The sample was separated by mechanical separation to obtain KRbBaB6O 11 Birefringent crystals.

[0094] Example 14

[0095] Using the chemical reaction formula 1.3Rb2CO3 + 0.7K2CO3 + 2BaCO3 + 12H3BO3 = 2K 0.7 Rb 1.3 BaB6O 11 BaB6O + 4CO2↑ + 18H2O↑, the K 0.7 Rb 1.3 BaB6O 11 birefringent crystal is prepared by the high-temperature solution method:

[0096] a. Weigh the raw materials Rb2CO3, K2CO3, BaCO3, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0097] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it to 550 degrees Celsius at a rate of 15°C / h, keep it at a constant temperature for 2 days, then slowly cool it to 350 degrees Celsius at a cooling rate of 1°C / h, and finally cool it to room temperature at a rate of 15°C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain the K 0.7 Rb 1.3 BaB6O 11 birefringent crystal.

[0098] Example 15

[0099] Using the chemical reaction formula RbNO3 + KNO3 + Ba(NO3)2 + 6H3BO3 = KRbBaB6O 11 KRbBaB6O + 4NO2↑ + O2↑ + 9H2O↑, the KRbBaB6O 11 birefringent crystal is prepared by the high-temperature solution method:

[0100] a. Weigh the raw materials Rb2(NO3)2, K2(NO3)2, Ba(NO3)2, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0101] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it to 600 degrees Celsius at a rate of 20°C / h, keep it at a constant temperature for 3 days, then slowly cool it to 400 degrees Celsius at a cooling rate of 1.5°C / h, and finally cool it to room temperature at a rate of 20°C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain the KRbBaB6O 11 birefringent crystal.

[0102] Example 16

[0103] Using the chemical reaction formula 1.3RbNO3 + 0.7KNO3 + Ba(NO3)2 + 6H3BO3 = K 0.7 Rb 1.3BaB6O 11 + 4NO2↑ + O2↑ + 9H2O↑ is prepared by the high-temperature solution method to obtain K 0.7 Rb 1.3 BaB6O 11 Birefringent crystal:

[0104] a. Weigh the raw materials Rb2(NO3)2, KNO3, Ba(NO3)2, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0105] b. Put the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it to 650 degrees Celsius at a rate of 25°C / h, keep it at a constant temperature for 4 days, then slowly cool it to 450 degrees Celsius at a cooling rate of 2°C / h, and finally cool it to room temperature at a rate of 10°C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain K 0.7 Rb 1.3 BaB6O 11 Birefringent crystal.

[0106] Example 17

[0107] Using the chemical reaction formula 1.2Rb2CO3 + 0.8K2CO3 + 2Ba(NO3)2 + 12H3BO3 = 2K 0.8 Rb 1.2 BaB6O 11 + 2CO2↑ + 4NO2↑ + O2↑ + 18H2O↑ is prepared by the high-temperature solution method to obtain K 0.8 Rb 1.2 BaB6O 11 Birefringent crystal:

[0108] a. Weigh the raw materials Rb2CO3, K2CO3, Ba(NO3)2, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0109] b. Put the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it to 700 degrees Celsius at a rate of 30°C / h, keep it at a constant temperature for 5 days, then slowly cool it to 500 degrees Celsius at a cooling rate of 0.5°C / h, and finally cool it to room temperature at a rate of 15°C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain K 0.8 Rb 1.2 BaB6O 11 Birefringent crystal.

[0110] Example 18

[0111] Using the chemical reaction formula 2RbNO3 + 2KNO3 + 2BaCO3 + 12H3BO3 = 2KRbBaB6O 11+2CO2↑ + 4NO2↑ + O2↑ + 18H2O↑ KRbBaB6O is prepared by the high-temperature molten solution method 11 Birefringent crystal:

[0112] a. Weigh the raw materials RbNO3, KNO3, BaCO3, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0113] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it to 500 degrees Celsius at a rate of 35 °C / h, keep it at a constant temperature for 1 day, then slowly cool it to 300 degrees Celsius at a cooling rate of 1 °C / h, and finally cool it to room temperature at a rate of 20 °C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain the KRbBaB6O 11 Birefringent crystal.

[0114] Example 19

[0115] Using the chemical reaction formula 1.25RbOH + 0.75KOH + Ba(OH)2 + 6H3BO3 = K 0.75 Rb 1.25 BaB6O 11 +11H2O↑ K 0.75 Rb 1.25 BaB6O 11 Birefringent crystal:

[0116] a. Weigh the raw materials RbOH, KOH, Ba(OH)2, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0117] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it to 550 degrees Celsius at a rate of 40 °C / h, keep it at a constant temperature for 2 days, then slowly cool it to 350 degrees Celsius at a cooling rate of 1.5 °C / h, and finally cool it to room temperature at a rate of 10 °C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain the K 0.75 Rb 1.25 BaB6O 11 Birefringent crystal.

[0118] Example 20

[0119] Using the chemical reaction formula 1.15RbOH + 0.85KOH + BaCO3 + 6H3BO3 = K 0.85 Rb 1.15 BaB6O 11 +CO2↑ + 10H2O↑ K 0.85 Rb 1.15 BaB6O 11 Birefringent crystal:

[0120] a. Weigh the raw materials RbOH, KOH, BaCO3, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0121] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it at a rate of 45 °C / h to 600 °C, keep it at a constant temperature for 3 days, then slowly cool it at a rate of 2 °C / h to 400 °C, and finally cool it to room temperature at a rate of 15 °C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain the K 0.85 Rb 1.15 BaB6O 11 double refraction crystal.

[0122] Example 21

[0123] Using the chemical reaction formula 2RbOH + 2KOH + 2Ba(NO3)2 + 12H3BO3 = 2KRbBaB6O 11 + 4NO2↑ + O2↑ + 20H2O↑, prepare the KRbBaB6O double refraction crystal by the high-temperature solution method: 11 a. Weigh the raw materials RbOH, KOH, Ba(NO3)2, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0124] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it at a rate of 50 °C / h to 650 °C, keep it at a constant temperature for 4 days, then slowly cool it at a rate of 0.5 °C / h to 450 °C, and finally cool it to room temperature at a rate of 20 °C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain the KRbBaB6O

[0125] double refraction crystal. 11 Example 22

[0126] Using the chemical reaction formula 1.1Rb2O + 0.9K2O + 2BaO + 12H3BO3 = 2K

[0127] Rb 0.9 Rb 1.1 BaB6O 11 + 18H2O↑, prepare the K 0.9 Rb 1.1 BaB6O 11 double refraction crystal by the high-temperature solution method:

[0128] a. Weigh the raw materials Rb2O, K2O, BaO, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0129] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it to 700 degrees Celsius at a rate of 10 °C / h, keep it at a constant temperature for 5 days, then slowly cool it to 500 degrees Celsius at a rate of 1 °C / h, and finally cool it to room temperature at a rate of 10 °C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain K 0.9 Rb 1.1 BaB6O 11 birefringent crystal.

[0130] Example 23

[0131] Using the chemical reaction formula 1.23Rb2O + 0.77K2O + 2BaCO3 + 12H3BO3 = 2K 0.77 Rb 1.23 BaB6O 11 + 2CO2↑ + 18H2O↑, prepare K 0.77 Rb 1.23 BaB6O 11 birefringent crystal:

[0132] a. Weigh the raw materials Rb2O, K2O, BaCO3, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0133] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it to 500 degrees Celsius at a rate of 15 °C / h, keep it at a constant temperature for 1 day, then slowly cool it to 300 degrees Celsius at a rate of 1.5 °C / h, and finally cool it to room temperature at a rate of 15 °C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain K 0.77 Rb 1.23 BaB6O 11 birefringent crystal.

[0134] Example 24

[0135] Using the chemical reaction formula 1.18Rb2O + 0.82K2O + 2Ba(NO3)2 + 12H3BO3 = 2K 0.82 Rb 1.18 BaB6O 11 + 4NO2↑ + O2↑ + 18H2O↑, prepare K 0.82 Rb 1.18 BaB6O 11 birefringent crystal:

[0136] a. Weigh the raw materials Rb2O, K2O, Ba(NO3)2, and H3BO3 according to the molar ratio of the molecular formula and place them in a mortar for thorough grinding to obtain a mixture;

[0137] b. Load the mixture obtained in step a into an open platinum crucible and place it in a single crystal furnace. Heat it at a rate of 20 °C / h to 550 °C, keep it at a constant temperature for 2 days, then slowly cool it to 350 °C at a cooling rate of 2 °C / h, and finally cool it to room temperature at a rate of 20 °C / h to allow spontaneous crystallization. Use the mechanical separation method to separate the sample to obtain K 0.82 Rb 1.18 BaB6O 11 birefringent crystal.

[0138] Example 25

[0139] Use any of the rubidium barium potassium borate birefringent crystals obtained in Examples 13 - 24 to prepare a wedge-shaped birefringent crystal polarizing beam splitter as Figure 3 shown. For a wedge-shaped birefringent crystal, the orientation of the optical axis is as Figure 3 shown. When a beam of natural light is incident and passes through the crystal, it can be split into two linearly polarized light beams. The greater the birefringence, the farther apart the two light beams can be separated, which is convenient for the separation of the light beams.

[0140] Example 26

[0141] Use any of the rubidium barium potassium borate birefringent crystals obtained in Examples 13 - 24 to prepare an optical isolator. Place a Faraday optical rotator that rotates the polarization plane of an incident light beam by 45° between a pair of birefringent crystal deflectors placed crosswise at 45° to each other, then an optical isolator can be formed. It only allows the light beam propagating in the forward direction to pass through the system, while blocking the light beam propagating in the reverse direction. Figure 4 a indicates that the incident light beam can pass through. Figure 4 b indicates that the reflected light is blocked.

[0142] Example 27

[0143] Use any of the rubidium barium potassium borate birefringent crystals obtained in Examples 13 - 24 to prepare a beam displacer. Machine a birefringent crystal such that its optical axis plane forms an angle θ with the edge as Figure 5 shown in a. When natural light is incident perpendicularly, it can be split into two linearly polarized light beams with mutually perpendicular vibration directions as Figure 5 shown in b, which are the o-ray and e-ray respectively. The greater the birefringence, the farther apart the two light beams can be separated, which is convenient for the separation of the light beams.

Claims

1. A compound rubidium barium potassium borate, characterized in that The chemical formula of this compound is K x Rb (2-x) BaB6O 11 , where x = 0.7 - 1, the molecular weight is 502.74 - 517.61, it belongs to the orthorhombic crystal system, and the space group is Pnma , and the unit cell parameters are a = 15.1923(9) Å, b = 7.6510 (5) Å, c = 8.7527(5) Å, Z = 4, V = 1017.38(11) Å 3 .

2. The preparation method of the rubidium barium potassium borate compound according to claim 1, characterized in that The compound is synthesized by the solid-phase reaction method, and the specific operation is carried out according to the following steps: The potassium-containing compound, the rubidium-containing compound, the barium-containing compound and the boron-containing compound are weighed in a molar ratio of K:Rb:Ba:B=0.7-1:1.3-1:1:3, put into a mortar and grind and mix evenly, then put into an open ceramic crucible of Φ100 mm×100 mm and put into a muffle furnace, slowly heat to 300-500 ° C, keep constant temperature for 12-36 hours, take out the crucible after cooling, at this time the sample is relatively loose, then take out the sample and grind it evenly again, then put it into the crucible, keep constant temperature at 500-700 ° C in the muffle furnace for 1-5 days, take out the sample after cooling and grind it thoroughly to obtain a single-phase polycrystalline powder of potassium borate rubidium barium compound, and perform X-ray analysis. The obtained X-ray spectrum is consistent with that of K x Rb (2-x) BaB6O 11 (x=0.7-1) The X-ray spectrum obtained from the single crystal structure is consistent, the potassium-containing compound is 99.9% pure potassium oxide, potassium hydroxide, potassium fluoride, potassium chloride, potassium bromide, potassium carbonate or potassium nitrate, the rubidium-containing compound is 99.9% pure rubidium oxide, rubidium hydroxide, rubidium fluoride, rubidium chloride, rubidium bromide, rubidium carbonate or rubidium nitrate, the barium-containing compound is 99.9% pure barium oxide, barium hydroxide, barium fluoride, barium chloride, barium carbonate or barium nitrate, and the boron-containing compound is 99.9% pure boric acid or boron oxide.

3. A rubidium barium potassium borate double refraction crystal, characterized in that The chemical formula of this crystal is K x Rb (2-x) BaB6O 11 , where x = 0.7 - 1, the molecular weight is 502.74 - 517.61, it belongs to the orthorhombic crystal system, and the space group is Pnma , the unit cell parameters are a = 15.1923(9) Å, b = 7.6510 (5) Å, c = 8.7527(5) Å, Z = 4, V = 1017.38(11) Å 3 .

4. The preparation method of the rubidium barium potassium borate birefringent crystal according to claim 3, characterized in that The rubidium barium potassium borate birefringent crystal is prepared by the high-temperature solution method, and the specific operation is carried out according to the following steps: a. Weigh the raw material potassium-containing compound, rubidium-containing compound, barium-containing compound and boron-containing compound directly according to the molar ratio of K:Rb:Ba:B = 0.7-1:1.3-1:1:3, and place them in a mortar for sufficient grinding to obtain a mixture. The potassium-containing compound is potassium oxide, potassium hydroxide, potassium fluoride, potassium chloride, potassium bromide, potassium carbonate or potassium nitrate with a purity of 99.9%. The rubidium-containing compound is rubidium oxide, rubidium hydroxide, rubidium fluoride, rubidium chloride, rubidium bromide, rubidium carbonate or rubidium nitrate with a purity of 99.9%. The barium-containing compound is barium oxide, barium hydroxide, barium fluoride, barium chloride, barium carbonate or barium nitrate with a purity of 99.9%. The boron-containing compound is boric acid or boron oxide with a purity of 99.9%. b. Load the mixture in step a into an open platinum crucible and place it in a single crystal furnace. Heat it at a rate of 10-50 °C / h to 500-700 °C, keep it at a constant temperature for 1-5 days, then slowly cool it at a cooling rate of 0.5-2 °C / h to 300-500 °C, and finally cool it to room temperature at a rate of 10-20 °C / h to make it crystallize spontaneously. Use the mechanical separation method to separate the sample to obtain the rubidium barium potassium borate birefringent crystal.

5. Use of the rubidium barium potassium borate birefringent crystal according to claim 3 in the preparation of an optical isolator, a circulator, a beam displacer, an optical polarizer or an optical modulator.

6. The use according to claim 5, wherein In the optical polarizer, it is a polarization beam splitting prism.

7. The use according to claim 6, characterized in that The polarization beam splitting prism is a Glan prism, a Wollaston prism or a Rochon prism.

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