Cadmium rubidium bromovanadate infrared nonlinear optical crystal as well as preparation method and application thereof

Abstract

The chemical formula of the compound is Rb3CdV4O12Br, the molecular weight is 844.47, the space group is Pab2, the cell parameters are as follows: a = 8.4485 (2), b = 16.9513 (5), c = 5.5270 (2), alpha = beta = gamma = 90 degrees, V = 791.54 (4) 3 and Z = 2, polycrystalline powder is synthesized by adopting a solid-phase reaction method, and a monoclinic system material is prepared by adopting a high-temperature melt solution method. Compared with the prior art, the crystal material disclosed by the invention has a relatively strong frequency-doubled effect which is about 7.7 times of that of a KH2PO4 crystal and 0.9 times of that of an AgGaS2 crystal. In addition, the transmission range of the crystal material is 0.38-10 [mu] m, the crystal material covers important 3-5 [mu] m mid-infrared atmosphere windows, has moderate birefringence, is stable in air, is not suitable for deliquescence, is insoluble in water, and has wide application prospects in the fields of nonlinear optics, electro-optical modulation, photorefractive information processing and the like.

Description

Technical Field

[0001] The present invention relates to a vanadium halide-based nonlinear optical crystal, a preparation method thereof, and an application thereof, belonging to the field of infrared nonlinear optical crystal materials. Background Art

[0002] The generation of lasers has greatly interested people in the research and application of laser technology. The laser generated by a laser can be frequency-converted through a nonlinear optical device to obtain lasers with more useful wavelengths, which has important and wide applications in fields such as expanding the laser frequency, gas sensing, optical communication, and laser medicine. As an important part of all-solid-state lasers, nonlinear optical crystal materials play an important role in the modern laser science field. According to the working wavelength band, nonlinear optical crystals can be divided into four bands, namely the deep ultraviolet band (DUV, <200 nm), the ultraviolet band (UV, 200 - 400 nm), the visible / near-infrared band (Vis-NIR, 0.4 - 3 μm), and the mid / far-infrared band (M-FIR, including the 3 - 5 μm and 8 - 13 μm atmospheric transparent windows). Among them, infrared nonlinear optical materials play a crucial role in mid-infrared laser frequency conversion, environmental monitoring, and atmospheric remote sensing. However, in the mid-infrared to far-infrared region, the available nonlinear optical materials are very limited, and the commercialized crystals mainly include AgGaS 2 (AGS), AgGaSe 2 (AGSe), and ZnGeP 2 (ZGP). However, the low laser damage threshold of AGS, the narrow bandgap of AGSe, and the large two-photon absorption effect of ZGP severely limit their further application in the high-power mid-infrared band. Aiming at the fact that traditional commercial materials cannot meet the applications in the high-end infrared laser technology field, exploring new infrared nonlinear optical crystals with excellent performance is an urgent problem to be solved. Summary of the Invention

[0003] A compound rubidium cadmium bromovanadate, the chemical formula of the compound is Rb 3 CdV 4 O 12 Br, with a molecular weight of 844.47, a space group of Pab 2, the unit cell parameters are a = 8.4485(2) Å, b = 16.9513(5) Å, c = 5.5270(2) Å, α = β = γ = 90°, V = 791.54(4) Å 3 , Z = 2, polycrystalline powder is prepared by a solid-phase reaction method, and monoclinic materials are prepared by a high-temperature melt solution method.

[0004] The object of the present invention is to provide a compound rubidium cadmium bromovanadate, the chemical formula of which is Rb 3 CdV 4 O 12 Br, with a molecular weight of 844.47, belonging to the polar space group Pab 2, and its infrared absorption edge can reach 10 μm.

[0005] The preparation method of the compound rubidium cadmium bromovanadate adopts the solid-phase synthesis method, and the specific operation is carried out according to the following steps: According to the molar ratio of Rb:Cd:V:Br = 3:1:4:1, the Rb source materials are RbF, Rb 2 CO 3 , RbNO 3 , RbOH or RbBr, the Cd source materials are CdO, CdCO 3 , Cd(OH) 2 , Cd(NO 3 ) 2 or CdBr 2 , the V source materials are V 2 O 5 or NH 4 VO 3 are placed in a clean corundum mortar and ground for 1 h. Then the uniformly mixed raw materials are placed in a corundum crucible with a diameter of 1 - 10 cm, and the crucible is put into a programmable temperature-controlled high-temperature furnace. The temperature is raised to 370 - 400 °C at a heating rate of 12 - 20 °C / h for solid-phase reaction, and kept warm for 1 - 2 days. During the heat preservation period, take it out and grind it 3 - 4 times, each time for half an hour. Then perform powder XRD testing. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep it warm for 1 day. Finally, cool it to room temperature at a speed of 20 °C / h to obtain the Rb 3 CdV 4 O 12 Br compound.

[0006] The use of the Rb 3 CdV 4 O 12 Br nonlinear optical crystal in the preparation of frequency doubling generators, up and down frequency converters, and optical parametric oscillators.

[0007] In the preparation method and use of the compound rubidium cadmium bromovanadate of the present invention, when selecting and combining raw materials, it must be ensured that at least one of the source materials is a bromide.

[0008] The polycrystalline powder (i.e., the compound) of Rb 3 CdV 4 O 12 Br prepared by the solid-phase synthesis method of the present invention can be prepared through the following chemical reaction formula: A compound rubidium cadmium bromovanadate according to the present invention, the chemical formula of the compound is Rb 3 CdV 4 O 12 Br, with a molecular weight of 844.47 g / mol, crystallizes in the monoclinic system and belongs to the non-centrosymmetric space group: Pab 2. The unit cell parameters are: a = 8.4485(2) Å, b = 16.9513(5) Å, c = 5.5270(2) Å, α = β = γ = 90°, V = 791.54(4) Å 3 , Z = 2, and is prepared by the high-temperature melt solution method. The specific operation steps are as follows: According to the molar ratio of Rb:Cd:V:Br = 5:1:5:1, the Rb source materials are RbF, Rb 2 CO 3 , RbNO 3 , RbOH or RbBr, the Cd source materials are CdO, CdCO 3 , Cd(OH) 2 , Cd(NO 3 ) 2 or CdBr 2 , the V source materials are V 2 O 5 or NH 4 VO 3 are placed in a clean corundum mortar and ground for 1 h. Then, the uniformly mixed raw materials are placed in a corundum crucible with a diameter of 1 - 10 cm. The crucible is placed in a single-crystal growth furnace with programmable temperature control and heated to 450 - 490 °C at a heating rate of 12 - 20 °C / h for high-temperature melt solution reaction. Keep warm for 3 - 5 days, and finally cool to room temperature at a rate of 15 - 20 °C per day. Then, colorless transparent block crystals are selected from the crucible for single-crystal XRD testing. The measured single-crystal unit cell data is consistent with the theoretical value, and it is determined that Rb 3 CdV 4 O 12 Br optical crystal is obtained.

[0009] The working principle of the nonlinear optical device is: passing at least one beam of incident electromagnetic radiation through at least one piece of Rb 3 CdV 4 O 12 Br nonlinear optical crystal, and generating at least one beam of output radiation with a frequency different from that of the incident electromagnetic radiation.

[0010] The rubidium cadmium bromovanadate nonlinear optical crystal according to the present invention has the following beneficial effects compared with the prior art: (1) It has good optical properties, with an infrared optical transmittance reaching 10 μm, a relatively large nonlinear optical effect of 7.7×KDP@1064 nm and 0.9×AGS@2.1 μm, which can meet phase matching. The calculated birefringence is 0.084 at 1064 nm, and it is expected to be used in the frequency doubling conversion process in the mid-infrared region; (2) Rb 3 CdV 4 O 12 During the growth process of the Br nonlinear optical crystal, the crystal is transparent and free of inclusions, and the growth rate is relatively fast; (3) The Rb 3 CdV 4 O 12 Br crystal prepared by the present invention can be used to fabricate nonlinear optical devices in the visible and near-infrared bands; (4) The Rb 3 CdV 4 O 12 Br crystal prepared by the present invention can be used to fabricate nonlinear optical devices in the mid-infrared band and has important applications in the fields of spectroscopy, military, laser manufacturing, and communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The X-ray diffraction pattern of the polycrystalline powder of Rb 3 CdV 4 O 12 Br and the X-ray diffraction pattern simulated based on the crystal structure of Rb 3 CdV 4 O 12 Br in the present invention; Figure 2 The crystal structure schematic diagram of Rb 3 CdV 4 O 12 Br in the present invention, including the two-dimensional layer structure and the charge-balancing Rb ions between the layers; Figure 3 The comparison of the frequency doubling of Rb 3 CdV 4 O 12 Br crystal with KDP of different particle size ranges under 1064 nm excitation; Figure 4 The comparison of the frequency doubling of Rb 3 CdV 4 O 12 Br crystal with AGS of different particle size ranges under 2.1 μm excitation. DETAILED DESCRIPTION OF THE INVENTION

[0012] To make the innovative content of the present invention more understandable, the present invention will be described in detail in combination with the accompanying drawings and embodiments of the present invention, but it is not limited to the present invention. The raw materials or equipment used in the present invention are commercially available unless otherwise specified.

[0013] Example 1 Using the chemical reaction formula 1.5Rb 2 CO 3 +CdO + 2V 2 O 5 +NH 4 Br → Rb 3 CdV 4 O 12 Br + 1.5CO 2 +NH 3 , the compound Rb 3 CdV 4 O 12 Br is prepared by the solid-phase synthesis method. The specific operation is carried out according to the following steps: Weigh 2 g of Rb 2 CO 3 , CdO, V 2 O 5 and NH 4 Br in a molar ratio of 1.5:1:2:1 respectively, put them into a clean corundum mortar, grind for 1 h, and then place the uniformly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a high-temperature furnace with program-controlled temperature, raise the temperature to 370 °C at a heating rate of 12 °C / h for solid-phase reaction, keep the temperature for 2 days, take it out and grind 4 times during the heat preservation period, each time for half an hour, and then conduct powder XRD testing. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep it for 1 day, and finally cool it to room temperature at a rate of 20 °C / h to obtain the Rb 3 CdV 4 O 12 Br compound.

[0014] Example 2 Using the chemical reaction formula Rb 2 CO 3 +CdO + 2V 2 O 5 +RbBr → Rb 3 CdV 4 O 12 Br + CO 2 , the compound Rb 3 CdV 4 O 12Br, and the specific operation is carried out according to the following steps: Weigh 2 g of Rb, CdO, V, and RbBr in a molar ratio of 1:1:2:1 respectively, 2 CO 3 , CdO, V 2 O 5 put them into a clean corundum mortar, grind for 1 h, then place the uniformly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm, put the crucible into a high-temperature furnace with programmable temperature control, raise the temperature to 400 °C at a heating rate of 20 °C / h for solid-phase reaction, keep the temperature for 1 day, take it out and grind it 3 times during the heat preservation period, each time for half an hour, then conduct powder XRD test. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep the temperature for 1 day, and finally cool it to room temperature at a rate of 20 °C / h to obtain the Rb 3 CdV 4 O 12 Br compound.

[0015] Example 3 Using the chemical reaction formula 1.5Rb 2 CO 3 +0.5CdO + 2V 2 O 5 +0.5CdBr → Rb 3 CdV 4 O 12 Br + 1.5CO 2 , the compound Rb 3 CdV 4 O 12 Br is prepared by solid-phase synthesis method, and the specific operation is carried out according to the following steps: Weigh 2 g of Rb, CdO, V, and CdBr in a molar ratio of 1.5:0.5:2:0.5 respectively, 2 CO 3 , CdO, V 2 O 5 put them into a clean corundum mortar, grind for 1 h, then place the uniformly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm, put the crucible into a high-temperature furnace with programmable temperature control, raise the temperature to 390 °C at a heating rate of 20 °C / h for solid-phase reaction, keep the temperature for 2 days, take it out and grind it 3 times during the heat preservation period, each time for half an hour, then conduct powder XRD test. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep the temperature for 1 day, and finally cool it to room temperature at a rate of 20 °C / h to obtain the Rb 3 CdV 4 O 12 Br compound.

[0016] Example 4 With the chemical reaction formula 3RbOH + CdO + 2V 2 O 5 +NH 4 Br → Rb 3 CdV 4 O 12 Br + 1.5H 2 O +NH 3 , the compound Rb 3 CdV 4 O 12 Br is prepared by the solid-phase synthesis method. The specific operation is carried out according to the following steps: Weigh 2 g of RbOH, CdO, V 2 O 5 and NH 4 Br in a molar ratio of 3:1:2:1, mix them evenly, put them into a clean corundum mortar, grind for 1 h, then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a high-temperature furnace with programmable temperature control, raise the temperature to 390 °C at a heating rate of 20 °C / h for solid-phase reaction, keep the temperature for 2 days, take it out and grind 4 times during the heat preservation period, each time for half an hour, then conduct powder XRD testing. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep the temperature for 1 day, and finally cool it to room temperature at a rate of 20 °C / h to obtain the Rb 3 CdV 4 O 12 Br compound.

[0017] Example 5 With the chemical reaction formula 1.5Rb 2 CO 3 +CdCO 3 +2V 2 O 5 +NH 4 Br → Rb 3 CdV 4 O 12 Br + 2.5CO 2 + NH 3 , the compound Rb 3 CdV 4 O 12 Br is prepared by the solid-phase synthesis method. The specific operation is carried out according to the following steps: Weigh 2 g of Rb 2 CO 3 , CdCO 3 , V 2 O5 and NH 4 Mix evenly with Br, put it into a clean corundum mortar, grind for 1 h, then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a high-temperature furnace with program-controlled temperature, raise the temperature to 380 °C at a heating rate of 20 °C / h for solid-phase reaction, keep the temperature for 2 days, take it out and grind 4 times during the heat preservation period, grind for half an hour each time, then conduct powder XRD test. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep the temperature for 1 day, and finally cool it to room temperature at a rate of 20 °C / h to obtain Rb 3 CdV 4 O 12 Br compound.

[0018] Example 6 Using the chemical reaction formula 1.5Rb 2 CO 3 +0.5CdCO 3 +2V 2 O 5 +0.5CdBr 2 →Rb 3 CdV 4 O 12 Br +2CO 2 , prepare the compound Rb 3 CdV 4 O 12 Br by solid-phase synthesis method. The specific operation is carried out according to the following steps: Weigh 2 g of Rb 2 CO 3 , CdCO 3 , V 2 O 5 and CdBr 2 respectively according to the molar ratio of 1.5: 0.5:2: 0.5, mix them evenly, put them into a clean corundum mortar, grind for 1 h, then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a high-temperature furnace with program-controlled temperature, raise the temperature to 400 °C at a heating rate of 20 °C / h for solid-phase reaction, keep the temperature for 2 days, take it out and grind 3 times during the heat preservation period, grind for half an hour each time, then conduct powder XRD test. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep the temperature for 1 day, and finally cool it to room temperature at a rate of 20 °C / h to obtain Rb 3 CdV 4 O 12 Br compound.

[0019] Example 7 Using the chemical reaction formula Rb 2 CO3 + CdCO 3 + 2V 2 O 5 +RbBr→Rb 3 CdV 4 O 12 Br+2CO 2 , the compound Rb 3 CdV 4 O 12 Br is prepared by a solid-phase synthesis method. The specific operation is carried out according to the following steps: Weigh 2 g in total of Rb 2 CO 3 , CdCO 3 , V 2 O 5 and RbBr and mix them evenly. Put them into a clean corundum mortar and grind for 1 h. Then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a high-temperature furnace with programmable temperature control. Raise the temperature to 400 °C at a heating rate of 20 °C / h for solid-phase reaction, keep the temperature for 1 day. During the heat preservation period, take it out and grind it 3 times, each time for half an hour. Then conduct powder XRD testing. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep the temperature for 1 day. Finally, cool it to room temperature at a rate of 20 °C / h to obtain the Rb 3 CdV 4 O 12 Br compound.

[0020] Example 8 Using the chemical reaction formula 1.5Rb 2 CO 3 +CdO+4NH 4 VO 3 +NH 4 Br→Rb 3 CdV 4 O 12 Br +1.5CO 2 +5NH 3 , the compound Rb 3 CdV 4 O 12 Br is prepared by a solid-phase synthesis method. The specific operation is carried out according to the following steps: Weigh 2 g in total of Rb 2 CO 3 , CdO, NH 4 VO 3 and NH 4Mix the RbBr evenly and put it into a clean corundum mortar. Grind it for 1 h. Then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a high-temperature furnace with programmable temperature control. Raise the temperature to 370 °C at a heating rate of 20 °C / h for solid-phase reaction, keep the temperature for 2 days. During the heat preservation period, take it out and grind it 3 times, each time for half an hour. Then conduct powder XRD testing. When the measured powder XRD is consistent with the theoretical value, put the sample into the furnace and keep the temperature for 1 day. Finally, cool it to room temperature at a rate of 20 °C / h to obtain Rb 3 CdV 4 O 12 Br compound.

[0021] Example 9 Weigh about 5 g of raw materials according to the molar ratio Rb 2 CO 3 :CdO:V 2 O 5 :NH 4 Br = 2:1:2.5:4, and put them into a clean corundum mortar. Grind it for 1 h. Then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a single-crystal growth furnace with programmable temperature control. Raise the temperature to 450 °C at a heating rate of 20 °C / h for high-temperature melt solution reaction, keep the temperature for 3 days. Finally, cool it to room temperature at a rate of 15 °C / day. Then select colorless and transparent block crystals in the crucible for single-crystal XRD testing. When the measured single-crystal unit cell data is consistent with the theoretical value, it is determined that Rb 3 CdV 4 O 12 Br optical crystal is obtained.

[0022] Example 10 Weigh about 3 g of raw materials according to the molar ratio Rb 2 CO 3 :CdO:V 2 O 5 :RbBr = 2:1:2.5:2, and put them into a clean corundum mortar. Grind it for 1 h. Then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a single-crystal growth furnace with programmable temperature control. Raise the temperature to 470 °C at a heating rate of 20 °C / h for high-temperature melt solution reaction, keep the temperature for 4 days. Finally, cool it to room temperature at a rate of 20 °C / day. Then select colorless and transparent block crystals in the crucible for single-crystal XRD testing. When the measured single-crystal unit cell data is consistent with the theoretical value, it is determined that Rb 3 CdV 4 O 12 Br optical crystal is obtained.

[0023] Example 11 Weigh according to the molar ratio Rb2 CO 3 : CdO:V 2 O 5 : CdBr = 3:0.5:5:2 Weigh about 5 g of the raw materials and put them into a clean corundum mortar. Grind for 1 h, then place the well-mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a single-crystal growth furnace with programmable temperature control, and raise the temperature to 490 °C at a heating rate of 20 °C / h for high-temperature melt solution reaction. Keep the temperature for 5 days, and finally cool to room temperature at a rate of 15 °C / day. Then select colorless and transparent block crystals in the crucible for single-crystal XRD testing. When the measured unit cell data of the single crystal is consistent with the theoretical value, it is determined that Rb 3 CdV 4 O 12 Br optical crystal.

[0024] Example 12 According to the molar ratio Rb 2 CO 3 : CdCO 3 : V 2 O 5 : NH 4 Br = 2:1:2.5:4 Weigh about 4 g of the raw materials and put them into a clean corundum mortar. Grind for 1 h, then place the well-mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a single-crystal growth furnace with programmable temperature control, and raise the temperature to 460 °C at a heating rate of 15 °C / h for high-temperature melt solution reaction. Keep the temperature for 3 days, and finally cool to room temperature at a rate of 20 °C / day. Then select colorless and transparent block crystals in the crucible for single-crystal XRD testing. When the measured unit cell data of the single crystal is consistent with the theoretical value, it is determined that Rb 3 CdV 4 O 12 Br optical crystal.

[0025] Example 13 According to the molar ratio Rb 2 CO 3 : CdCO 3 : V 2 O 5: Weigh about 5 g of raw materials with a molar ratio of RbBr = 1.5:1:2.5:2, and put them into a clean corundum mortar. Grind for 1 h, then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a single crystal growth furnace with programmable temperature control, and raise the temperature to 470 °C at a heating rate of 18 °C / h for high-temperature melt solution reaction. Keep the temperature for 5 days, and finally cool to room temperature at a rate of 16 °C / day. Then select colorless and transparent block crystals in the crucible for single crystal XRD testing. When the measured unit cell data of the single crystal is consistent with the theoretical value, it is determined that Rb 3 CdV 4 O 12 Br optical crystal is obtained.

[0026] Example 14 Weigh about 5 g of raw materials according to the molar ratio of Rb 2 CO 3 : CdO: NH 4 VO 3 : NH 4 Br = 3:1:5:4, and put them into a clean corundum mortar. Grind for 1 h, then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a single crystal growth furnace with programmable temperature control, and raise the temperature to 490 °C at a heating rate of 20 °C / h for high-temperature melt solution reaction. Keep the temperature for 5 days, and finally cool to room temperature at a rate of 15 °C / day. Then select colorless and transparent block crystals in the crucible for single crystal XRD testing. When the measured unit cell data of the single crystal is consistent with the theoretical value, it is determined that Rb 3 CdV 4 O 12 Br optical crystal is obtained.

[0027] Example 15 Weigh about 5 g of raw materials according to the molar ratio of RbOH: CdO: V 2 O 5 : NH 4 Br = 4:1:2.5:4, and put them into a clean corundum mortar. Grind for 1 h, then place the evenly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a single crystal growth furnace with programmable temperature control, and raise the temperature to 450 °C at a heating rate of 20 °C / h for high-temperature melt solution reaction. Keep the temperature for 4 days, and finally cool to room temperature at a rate of 15 °C / day. Then select colorless and transparent block crystals in the crucible for single crystal XRD testing. When the measured unit cell data of the single crystal is consistent with the theoretical value, it is determined that Rb 3 CdV 4 O 12 Br optical crystal is obtained.

[0028] Example 16 By molar ratio of CdO:V 2 O 5 :RbBr = 1:2.5:4 Weigh about 5 g of raw materials and put them into a clean corundum mortar. Grind for 1 h, then place the uniformly mixed raw materials in a corundum crucible with a diameter of 1 - 10 cm. Put the crucible into a single crystal growth furnace with program temperature control, and raise the temperature to 480 °C at a heating rate of 12 °C / h for high-temperature melt solution reaction. Keep the temperature for 5 days, and finally cool to room temperature at a rate of 16 °C / day. Then select colorless transparent block crystals in the crucible for single crystal XRD testing. When the measured single crystal cell data is consistent with the theoretical value, it is determined that Rb 3 CdV 4 O 12 Br optical crystal is obtained.

[0029] Example 17 After testing, the Rb prepared in Examples 9 - 16 3 CdV 4 O 12 Br nonlinear optical crystal belongs to the monoclinic system, and the space group is Pab 2. This nonlinear optical crystal does not have a center of symmetry. The unit cell parameters are: a = 8.4485(2) Å, b = 16.9513(5) Å, c = 5.5270(2) Å, α = β = γ = 90°, V = 791.54(4) Å 3 , Z = 2; Figure 1 is the XRD pattern of Rb 3 CdV 4 O 12 Br polycrystalline powder and the simulated diffraction pattern, Figure 2 is the structural schematic diagram of Rb 3 CdV 4 O 12 Br nonlinear optical crystal. Figure 3 For Rb 3 CdV 4 O 12 Br, when comparing the second harmonic generation intensity with KDP and AGS under 1064 nm and 2.1 μm excitation, it is found that Rb 3 CdV 4 O 12 Br has a strong second harmonic generation effect, about 7.7×KDP@1064 nm and 0.9×AGS@2.1 μm, and can satisfy phase matching, which is convenient for applications in second harmonic generators, up and down frequency converters, and optical parametric oscillators.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A compound cadmium rubidium bromovanadate, characterized in that The chemical formula of this compound is Rb3CdV4O 12 Br, molecular weight is 844.47, space group is Pab 2, the unit cell parameters are a=8.4485(2) Å, b=16.9513(5) Å, c=5.5270(2) Å, α = β = γ =90°,V=791.54(4) Å 3 , Z=2.

2. The compound according to claim 1, characterized in that: The compound is single crystal or polycrystal.

3. A compound according to claim 2, characterized in that: The polycrystalline powder is prepared by solid phase reaction method, and the single crystal material is prepared by high temperature melt solution method.

4. A method for preparing the compound cadmium rubidium bromovanadate optical crystal according to claim 2 or 3, characterized in that: The polycrystalline powder is prepared by solid phase reaction method, and the specific operation steps are as follows: The Rb source material, Cd source material, and V source material are ground in a molar ratio of Rb:Cd:V:Br =3:1:4:1, and then placed in a high-temperature furnace and heated to 370-400 °C at a rate of 12-20 °C / h for solid phase reaction. The temperature is kept for 1-2 days, and then cooled to room temperature at a rate of 20 °C / h to obtain Rb3CdV4O 12 Br compounds.

5. The preparation method according to claim 4, characterized in that: The Rb source material is RbF, Rb2CO3, RbNO3, RbOH or RbBr, the Cd source material is CdO, CdCO3, Cd(OH)2, Cd(NO3)2 or CdBr2, and the V source material is V2O5 or NH4VO3. When selecting and combining the raw materials, it must be ensured that at least one of the source materials is a bromide.

6. A method for preparing the compound cadmium bromovanadate rubidium optical crystal according to claim 2 or 3, characterized in that: The monoclinic material is prepared by high temperature melt solution method, and the specific operation steps are as follows: The molar ratio of Rb:Cd:V:Br is 5:1:5:

1. The Rb source material, Cd source material, and V source material are ground and placed in a single crystal growth furnace. The temperature is raised to 450-490 °C at a heating rate of 12-20 °C / h for high-temperature melt solution reaction. The temperature is kept for 3-5 days, and finally cooled to room temperature at a rate of 15-20 °C / day to obtain Rb3CdV4O 12 Br optical crystal.

7. The preparation method according to claim 6, characterized in that: The Rb source material is RbF, Rb2CO3, RbNO3, RbOH or RbBr, the Cd source material is CdO, CdCO3, Cd(OH)2, Cd(NO3)2 or CdBr2, and the V source material is V2O5 or NH4VO3. When selecting and combining the raw materials, it must be ensured that at least one of the source materials is a bromide.

8. Rb3CdV4O as claimed in claim 1 12 The use of Br nonlinear optical crystals in the preparation of optical frequency doubling generators, optical frequency converters, and optical parametric oscillators.

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