Indium-based selenite second-order nonlinear optical crystal material and preparation and application thereof

Abstract

The invention relates to an indium-based selenite second-order nonlinear optical crystal material as well as preparation and application thereof. The chemical formula of the crystal material is In (HSeO3) 3.3 H2O, the molecular weight is 552.77, the crystal material belongs to a trigonal system, the space group of the crystal material is R3c (No.161), and the cell parameters are as follows: # imgabs0 # alpha = beta = 90 degrees, gamma = 120 degrees and Z = 6. The powder frequency doubling effect of the second-order nonlinear optical crystal In (HSeO3) 3. 3H2O disclosed by the invention under the irradiation of 1064nm laser is about 0.1 time that of a KH2PO4 crystal, and phase matching can be realized. In addition, the crystal material has a short ultraviolet absorption cut-off 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 invention belongs to the technical field of nonlinear optical crystal materials, and relates to an indium-based selenite second-order nonlinear optical crystal material and a preparation method and application thereof. Background Art

[0002] As the core device of solid-state lasers, second-order nonlinear optical crystals (NLO) can realize the conversion of laser frequency and have wide applications in communication, storage, medical, military, industrial manufacturing and other fields. With the continuous development of science and technology, the exploration of nonlinear optical crystals with better performance and wider application band has become a hot research topic in the field of optoelectronics. Selenite containing lone pair electrons has a large frequency response and shows broad application prospects 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 often find it difficult to take into account a moderate refractive index, a short ultraviolet absorption cutoff edge and a high optical band gap while maintaining a 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 becoming increasingly urgent. Summary of the invention

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

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] In one aspect, the present invention provides an indium selenite second-order nonlinear optical crystal material, whose chemical formula is In(HSeO3)3·3H2O, and the crystal material belongs to the trigonal system, the space group is R3c, and the unit cell parameters are α=β=90°, γ=120°, Z=6.

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

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

[0008] In the second aspect, the present invention provides a method for preparing an indium-based selenite second-order nonlinear optical crystal material, which comprises mixing an In source, a Se source and water, performing a hydrothermal reaction, filtering and drying to obtain a colorless and transparent bulk crystal, which is the target product.

[0009] Furthermore, the added amounts of the In source and the Se source satisfy: the molar ratio of the In element to the Se element is 1:(9-18).

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

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

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

[0013] Further, after the hydrothermal reaction is completed, it is cooled to 30° C. at a rate of 4° C. per hour.

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

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

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

[0017] Specifically, In(HSeO3)3·3H2O crystal, as a nonlinear optical crystal material, can output 532nm laser under 1064nm laser irradiation, and its powder double frequency intensity is 0.1 times that of KDP crystal, and phase matching can be achieved.

[0018] The present invention introduces the main group metal cation In into the traditional selenite system. 3+Indium selenite double-frequency crystal In(HSeO3)3·3H2O was prepared. The crystalline material crystallizes in a non-centrosymmetric space group, and thus exhibits a powder double-frequency effect (0.1×KDP), a moderate birefringence (0.029@546nm) and a short ultraviolet absorption cutoff edge (216nm).

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

[0020] (1) The present application provides a new second-order nonlinear optical crystal In(HSeO3)3·3H2O. The crystal material has a frequency doubling effect. The frequency doubling intensity under 1064nm laser irradiation is 0.1 times that of KDP crystal, and phase matching can be achieved. 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). The crystal material has broad application prospects in the field of nonlinear optics.

[0021] (2) The present application also provides a method for preparing the nonlinear optical crystal In(HSeO3)3·3H2O. A colorless block-shaped In(HSeO3)3·3H2O crystal is prepared by a hydrothermal method. The synthesis method is simple. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0023] Figure 2 The X-ray diffraction pattern of sample 1# obtained by fitting the crystal structure analyzed by single crystal X-ray diffraction is compared with the pattern obtained by X-ray diffraction test after sample 1# is ground into powder;

[0024] Figure 3 is the UV-Vis-NIR absorption spectrum of sample 1#;

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

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

[0027] Figure 6 It is the second harmonic signal diagram of sample 1# and standard KDP sample with the sample size ranging from 105 to 150 μm;

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

[0029] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0030] In the following examples, unless otherwise specified, raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0031] Embodiment 1:

[0032] Preparation of samples 1# to 8#

[0033] In source, Se source and water were mixed in a certain proportion and placed in a 23 mL polytetrafluoroethylene liner. The sealed reactor was placed in an oven at 230°C for 72 hours and then cooled to 30°C at a rate of 4°C per hour. The product was filtered, washed with deionized water, and dried to obtain colorless block-like In(HSeO3)3·3H2O crystals.

[0034] The relationship between the type and ratio of raw materials in the initial mixture, the volatilization temperature, the volatilization time and the sample number is shown in Table 1.

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

[0036] Single crystal X-ray diffraction and powder X-ray diffraction techniques were used to perform structural analysis and phase analysis on samples 1# to 8#, respectively.

[0037] Table 1 Correspondence between samples, raw materials and synthesis conditions

[0038]

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

[0040] The single crystal X-ray diffraction results show that samples 1# to 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 unit cell parameters are α=β=90°,γ=120°,Z=6. Its crystal structure is as follows Figure 1 shown.

[0041] The powder X-ray diffraction test was carried out on a Bruker D8 X-ray powder diffractometer from Bruker, Germany. The test conditions were a fixed target monochromatic light source Cu Kα, a wavelength of The voltage and current are 40 kV / 20 A, the slits DivSlit / RecSlit / SctSlit are 2.00 deg / 0.3 mm / 2.00 deg respectively, the scanning range is 10-70°, and the scanning step is 0.02°.

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

[0043] Take sample 1# as a typical example. Figure 2 The X-ray diffraction pattern obtained by fitting the crystal structure analyzed by single crystal X-ray diffraction is consistent with the peak position and peak intensity of the pattern obtained by X-ray diffraction test after sample 1# is ground into powder, indicating that the obtained sample has high purity.

[0044] UV-Vis-NIR absorption spectroscopy test

[0045] The diffuse reflectance absorption spectrum test of sample 1# was conducted on the Agilent Carry 5000 UV-Vis-NIR spectrophotometer. The results are as follows: Figure 3 As shown by Figure 3 It can be seen that the ultraviolet absorption cutoff edge of the compound is 216nm and the optical band gap of the compound is 4.56eV.

[0046] Infrared spectrum test

[0047] The infrared spectrum test of sample 1# was conducted on a Nicolet iS10 Fourier infrared spectrometer from Thermo Fisher Scientific Inc., USA. The results are as follows Figure 4 As shown, 1284cm -1 The characteristic absorption peak of Se-O at 47° confirmed the existence of [SeO3] groups in the crystal structure.

[0048] Thermogravimetric testing

[0049] The thermogravimetric test of sample 1# was conducted on a Netzsch STA 409PC thermogravimetric analyzer manufactured by Netzsch Equipment Manufacturing Co., Ltd., Germany. The results are shown in the figure below. Figure 5 As shown, the thermal decomposition temperature of this compound is 100°C.

[0050] Frequency doubling test experiment and results

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

[0052] The laser with a wavelength of 1064nm generated by a Q-switched Nd:YAG solid laser is used as the fundamental frequency light to irradiate the tested crystal powder. The second harmonic generated 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 separately, and crystals of different particle sizes are sieved out with a standard sieve. The particle size ranges are less than 26, 26-50, 50-74, 74-105, and 105-150μm. The change law of the frequency doubling signal with the particle size is observed to determine whether it can achieve phase matching. Under the same test conditions, the second harmonic intensity generated by the sample and the standard sample KDP is compared to obtain the relative size of the sample frequency doubling effect.

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

[0054] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

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, the space group is R3c, and the unit cell parameters are 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: The In source, Se source and water are mixed, subjected to a hydrothermal reaction, filtered and dried to obtain a colorless and transparent block crystal, which is the target product.

3. The method for preparing an indium-based selenite second-order nonlinear optical crystal material according to claim 2, characterized in that: The added amounts of the In source and the Se source satisfy the following conditions: the molar ratio of the In element to the Se element is 1:(9-18).

4. The method for preparing an indium-based selenite second-order nonlinear optical crystal material according to claim 2, characterized in that: The temperature of the hydrothermal reaction is 180-240°C, and the time is 72-168h.

5. The method for preparing an indium-based selenite second-order nonlinear optical crystal material according to claim 2, characterized in that: The In source is selected from at least one of indium oxide, indium hydroxide, indium nitrate and indium chloride.

6. The method for preparing an indium-based selenite second-order nonlinear optical crystal material according to claim 2, characterized in that: The Se source is one of selenium dioxide and sodium selenite.

7. The method for preparing an indium-based selenite second-order nonlinear optical crystal material according to claim 2, characterized in that: After the hydrothermal reaction was completed, the mixture was cooled to 30°C at a rate of 4°C per hour.

8. Application of an 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.

9. The use of an indium-based selenite second-order nonlinear optical crystal material according to claim 8, characterized in that: The indium selenite second-order nonlinear optical crystal material is used in a laser frequency converter.

10. The use of an indium-based selenite second-order nonlinear optical crystal material according to claim 9, characterized in that: The laser frequency converter outputs 532nm laser under 1064nm laser irradiation.

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