An indium-based selenite second-order nonlinear optical crystal material, preparation and application thereof

Abstract

The application relates to an indium-based selenite second-order nonlinear optical crystal material and preparation and application thereof, the chemical formula of the crystal material is In(HSeO3)3.3H2O, the molecular weight is 552.77, the crystal material belongs to the trigonal system, the space group is R3c (No. 161), the cell parameter is alpha = beta = 90 DEG, gamma = 120 DEG, and Z = 6. The powder frequency doubling effect of the second-order nonlinear optical crystal In(HSeO3)3.3H2O under 1064nm laser irradiation is about 0.1 times that of a KH2PO4 crystal, and phase matching can be realized. In addition, the crystal material has a short ultraviolet absorption cutoff edge (216nm), and has important application value in the fields of laser modulation, radio equipment, satellite communication and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nonlinear optical crystal materials, and relates to an indium-based selenite second-order nonlinear optical crystal material and preparation and application thereof. BACKGROUND

[0002] As a core device of solid-state lasers, second-order nonlinear optical crystals (NLO) can realize laser frequency conversion and have wide applications in the fields of communication, storage, medical treatment, military affairs, industrial manufacturing and the like. With the continuous development of science and technology, exploring nonlinear optical crystals with more excellent performance and wider application bands has become a hotspot in the field of optoelectronics. Selenite containing a lone pair of electrons has a large frequency doubling response and shows a broad application prospect in the field of nonlinear optics. Existing commercial second-order nonlinear optical crystals, such as LiB3O5 (LBO), CsB3O5 (CBO), CsLiB6O 10 (CLBO), β-BaB2O4 (BBO) and KBe2BO3F2 (KBBF), etc. However, many current second-order nonlinear optical crystal materials are difficult to have moderate refractive index, short ultraviolet absorption cutoff edge and high optical band gap while maintaining high powder frequency doubling effect. Therefore, with the continuous development of laser technology, the demand for research and development of new nonlinear optical crystal materials is increasingly urgent. SUMMARY

[0003] The purpose of the present application is to provide an indium-based selenite second-order nonlinear optical crystal material and preparation and application thereof. The crystalline material introduces a highly asymmetric [SeO3] group, which is beneficial to crystallization in a non-centrosymmetric space group and exhibits powder frequency doubling effect (0.1 x KDP @ 1064 nm), moderate birefringence (0.029 @ 546 nm) and short ultraviolet absorption cutoff edge (216 nm) and the like.

[0004] The purpose of the present application can be achieved by the following technical solutions.

[0005] In one aspect, the present application provides an indium-based selenite second-order nonlinear optical crystal material, which has a chemical formula of In(HSeO3)3·3H2O. The crystal material belongs to a trigonal system, has a space group of R3c, and has a unit cell parameter of a = b = 10. 1(1) A, c = 10. 1(1) A, α = β = 90°, γ = 120° and Z = 6. α = β = 90°, γ = 120°, Z = 6.

[0006] The crystal structure of the inorganic compound crystal In(HSeO3)3·3H2O of the present application is shown in Figure 1 .

[0007] Each In atom is coordinated with six oxygen atoms to form [InO6] octahedron, Se is coordinated with three oxygen atoms to form [SeO3] triangular pyramid, the isolated [InO6] octahedron is arranged in parallel to the c-axis in three-dimensional space, the [SeO3] group connects the isolated octahedrons into a three-dimensional structure by sharing three O atoms, and the H2O molecules are connected with the [SeO3] through hydrogen bonds.

[0008] In the second aspect, the application provides a preparation method of an indium-based selenite second-order nonlinear optical crystal material, wherein an In source, a Se source and water are mixed, a hydrothermal reaction is carried out, and then filtering and drying are performed to obtain a colorless transparent block crystal, which is the target product.

[0009] Further, the addition amount of the In source and the Se source satisfies that the molar ratio of In element to Se element is 1:(9-18).

[0010] Further, the temperature of the hydrothermal reaction is 180-240 DEG C, and the time is 72-168 h.

[0011] Further, the In source is selected from at least one of indium oxide, indium hydroxide, indium nitrate and indium chloride, and preferably is indium oxide.

[0012] Further, the Se source is one of selenium dioxide and sodium selenite, and more preferably is selenium dioxide.

[0013] Further, after the hydrothermal reaction is completed, cooling is performed to 30 DEG C at a speed of 4 DEG C per hour.

[0014] In the third aspect, the application provides an application of the indium-based selenite second-order nonlinear optical crystal material in electro-optical deflection, laser modulation, frequency conversion, communication and information processing.

[0015] Further, the indium-based selenite second-order nonlinear optical crystal material is used in a laser frequency converter.

[0016] Further, the laser frequency converter outputs 532 nm laser under 1064 nm laser irradiation.

[0017] Specifically, the In(HSeO3)3.3H2O crystal as the nonlinear optical crystal material can output 532 nm laser under 1064 nm laser irradiation, the powder frequency doubling intensity thereof is 0.1 times that of KDP crystal, and phase matching can be realized.

[0018] The application introduces the main group metal cation In into the traditional selenite system 3+An indium-based selenite In(HSeO3)3·3H2O is prepared. The crystal material crystallizes in a non-centrosymmetric space group, and thus exhibits powder frequency doubling effect (0.1 times KDP), moderate birefringence (0.029@546nm) and short UV absorption cutoff edge (216nm).

[0019] Compared with the prior art, the present application has the following advantages:

[0020] (1) The present application provides a new second-order nonlinear optical crystal In(HSeO3)3·3H2O, which has frequency doubling effect, and the frequency doubling intensity under 1064nm laser irradiation is 0.1 times that of KDP crystal, and phase matching can be realized. In addition, the ultraviolet absorption cutoff wavelength of the crystal material is 216nm, and the optical band gap is 4.56eV, which is higher than that of traditional selenite (<4eV), and the crystal material has wide application prospect in the field of nonlinear optics.

[0021] (2) The present application also provides a preparation method of the nonlinear optical crystal In(HSeO3)3·3H2O, which is prepared by a hydrothermal method to obtain colorless block In(HSeO3)3·3H2O crystal, and the synthesis method is simple. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of the crystal structure of In(HSeO3)3·3H2O;

[0023] Figure 2 is a comparison between the X-ray diffraction spectrum of sample 1# obtained by fitting the crystal structure according to single crystal X-ray diffraction and the spectrum obtained by X-ray diffraction test after sample 1# is ground into powder;

[0024] Figure 3 is the ultraviolet-visible-near infrared absorption spectrum of sample 1#;

[0025] Figure 4 is the infrared spectrum of sample 1#;

[0026] Figure 5 is the thermogravimetric analysis spectrum of sample 1#;

[0027] Figure 6 is the second harmonic signal diagram of sample 1# and standard sample KDP sample size in the range of 105-150μm;

[0028] Figure 7 is the second harmonic phase matching diagram of sample 1# under 1064nm wavelength. DETAILED DESCRIPTION

[0029] The application will be described in detail below with reference to the drawings and specific embodiments. The embodiments are implemented on the premise of the technical solutions of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following examples.

[0030] In the following examples, if no special description is given for raw materials or processing techniques, it is indicated that they are all conventional commercially available raw materials or conventional processing techniques in the art.

[0031] Example 1

[0032] Preparation of samples 1#-8#

[0033] The In source, Se source and water were mixed in a certain proportion and placed in a 23 mL polytetrafluoroethylene liner, and the sealed reaction kettle was placed in an oven at 230°C for 72 h, and then cooled to 30°C at a rate of 4°C per hour. The product was suction filtered, washed with deionized water, and dried after standing to obtain colorless In(HSeO3)3·3H2O crystal blocks.

[0034] The types and proportions of raw materials in the initial mixture, the volatilization temperature, the volatilization time, and the sample number are shown in Table 1.

[0035] Crystal structure analysis of samples 1#-8#

[0036] Single crystal X-ray diffraction and powder X-ray diffraction techniques were used to analyze the structure and phase of samples 1#-8# respectively.

[0037] Table 1 Correspondence of samples with raw materials and synthesis conditions

[0038]

[0039] The single crystal X-ray diffraction test was performed on a D8 VENTURE CMOS X X-ray single crystal diffractometer of Bruker Company in Germany. The data collection temperature was 298.15 K, and the diffraction light source was graphite monochromatic Mo Kα ray The scanning mode was ω, and the data was processed by absorption correction using the Multi-Scan method. The structure analysis was completed using the Olex2 program package; the positions of heavy atoms were determined by the direct method, and the coordinates of the remaining atoms were obtained by the difference Fourier synthesis method; and the coordinates of all atoms and anisotropic thermal parameters were refined using the full matrix least squares method based on F 2

[0040] The single crystal X-ray diffraction results show that samples 1#-8# have the same chemical formula and crystal structure, the chemical formula is In(HSeO3)3·3H2O, the crystal material belongs to the trigonal system, the space group is R3c, and the cell parameters are a= 10. 1 1(1) A, c= 17. 1 1(1) A, α= 90°, β= 90°, γ= 120°. ​α = β = 90°, γ = 120°, Z = 6. The crystal structure thereof is shown in Figure 1 .

[0041] The powder X-ray diffraction test was performed on an X-ray powder diffractometer of Bruker D8 type of Bruker Company in Germany, with the test conditions being fixed target monochromatic light source Cu Kα, wavelength 40 kV / 20 A, and slit DivSlit / RecSlit / SctSlit being 2.00 deg / 0.3 mm / 2.00 deg, respectively, scanning range 10-70°, and scanning step 0.02°.

[0042] The powder X-ray diffraction test results show that the peak positions are the same on the XRD spectra of samples 1#-8#.

[0043] Taking sample 1# as a typical representative, the X-ray diffraction spectrum obtained by grinding sample 1# into powder is shown in Figure 2 . The peak positions and peak intensities of the X-ray diffraction spectrum obtained by fitting the crystal structure analyzed by single crystal X-ray diffraction are consistent with those obtained by the X-ray diffraction test, indicating that the obtained sample has high purity.

[0044] UV-Vis-NIR absorption spectrum test

[0045] The diffuse reflectance absorption spectrum test of sample 1# was performed on a UV-Vis-NIR spectrophotometer of Carry 5000 type of Agilent Company in the United States. The results are shown in Figure 3 . It can be seen from Figure 3 that the ultraviolet absorption cutoff edge of the compound is 216 nm, and the optical band gap of the compound is 4.56 eV.

[0046] Infrared spectrum test

[0047] The infrared spectrum test of sample 1# was performed on a Fourier infrared spectrometer of Nicolet iS10 type of Thermo Fisher Scientific Company in the United States. The results are shown in Figure 4 . The characteristic absorption peak of Se-O at 1284 cm -1 confirms the existence of [SeO3] group in the crystal structure.

[0048] Thermogravimetric test

[0049] The thermogravimetric test of sample 1# was performed on a thermogravimetric analyzer of Netzsch STA 409PC type of Netzsch Equipment Manufacturing Company in Germany. The results are shown in Figure 5 . The thermal decomposition temperature of the compound is 100℃.

[0050] Frequency doubling test experiment and results

[0051] The frequency doubling test experiment of sample 1# is as follows:

[0052] The laser with wavelength of 1064 nm generated by Q-switched Nd:YAG solid laser is used as the fundamental light to irradiate the tested crystal powder, the generated second harmonic is detected by a spectrometer, and the harmonic intensity is displayed by an oscilloscope. The crystal sample and the standard sample KDP crystal are ground respectively, and the crystals with different particle sizes are sieved by a standard sieve, the particle size ranges are less than 26, 26-50, 50-74, 74-105 and 105-150 μm respectively. The change rule of the frequency doubling signal with the particle size is observed, and whether it can realize phase matching is judged. Under the same test conditions, the second harmonic intensities generated by the sample and the standard sample KDP are compared, so that the relative size of the frequency doubling effect of the sample is obtained.

[0053] The test results show that under the irradiation of 1064 nm wavelength laser, the frequency doubling signal intensity of compound In(HSeO3)3·3H2O is 0.1 times that of KDP crystal (as shown in Figure 6 ). The crystal material can realize phase matching under the irradiation of 1064 nm laser (as shown in Figure 7 ).

[0054] The above description of the embodiments is for facilitating the ordinary skilled person in the art to understand and use the application. The person skilled in the art can obviously easily make various modifications to the embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the application is not limited to the above embodiments, and the improvements and modifications made by the person skilled in the art according to the disclosure of the application without departing from the scope of the application should be within the protection scope of the application.

Claims

1. An indium-based selenite second-order nonlinear optical crystal material, characterized in that: Its chemical formula is In(HSeO3)3·3H2O. The crystal material belongs to the trigonal system and its space group is R 3 c , the unit cell parameters are a = 9.9~10.0 Å, b = 9.9~10.0Å, c = 20.0~20.1 Å, α = β = 90°, γ = 120°, Z = 6.

2. The method for preparing an indium-based selenite second-order nonlinear optical crystal material according to claim 1, characterized in that: Mix the In source, Se source and water, perform a hydrothermal reaction, and filter and dry to obtain colorless and transparent block crystals, which are the target product; The amount of In source and Se source added satisfies the following conditions: the molar ratio of In element to Se element is 1: (9-18); The hydrothermal reaction temperature is 180~240℃ and the reaction time is 72~168h; The In source is selected from at least one of indium oxide, indium hydroxide, indium nitrate, and indium chloride; The Se source is one of selenium dioxide or sodium selenite; After the hydrothermal reaction was completed, the mixture was cooled to 30 °C at a rate of 4 °C per hour.

3. Application of the indium-based selenite second-order nonlinear optical crystal material as claimed in claim 1 in electro-optical deflection, laser modulation, frequency conversion, communication and information processing.

4. The use of an indium-based selenite second-order nonlinear optical crystal material according to claim 3, characterized in that: The indium-based selenite second-order nonlinear optical crystal material is used in a laser frequency converter.

5. The use of an indium-based selenite second-order nonlinear optical crystal material according to claim 4, characterized in that: The laser frequency converter outputs 532 nm laser under 1064 nm laser irradiation.

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