An aminoguanidine oxalate second-order nonlinear optical crystal material and its preparation and application

Abstract

The present invention relates to an aminoguanidine oxalate second-order nonlinear optical crystal material and its preparation and application. The chemical formula of the crystal material is (CN4H7) + (C2O4H) ‑ , belongs to the monoclinic system, the space group is P21, the unit cell parameters are α = 90°, β = 95-100°, γ = 90°, Z = 2. The nonlinear optical crystal (CN4H7) of the present invention + (C2O4H) ‑ Under 1064nm laser irradiation, the powder's frequency-doubled effect is approximately 1.0 times that of KH2PO4 (KDP) crystal, and phase matching is achieved. Furthermore, this crystal material has advantages such as a short UV absorption cutoff edge (290nm) and ease of growth, making it valuable for applications in optoelectronic conversion, including stereolithography, solid-state lasers, optical communications, optical parametric amplifiers, optical parametric oscillators, and laser frequency converters.

Description

Technical Field

[0001] The invention belongs to the technical field of nonlinear optical crystalline materials and relates to an aminoguanidine oxalate second-order nonlinear optical crystal material and a preparation method and application thereof. Background Art

[0002] As an important optoelectronic functional material, nonlinear optical (NLO) crystalline materials are widely used in many fields such as laser frequency conversion, optical communication, optoelectronic modulation, 3D printing, stereolithography, and national defense and military. With the continuous development of society and the expansion of application fields, existing commercial frequency-doubling crystals can no longer meet the growing production and scientific research needs. Therefore, the research and development of new NLO materials with better performance and applicable to different wavelength ranges has become an important task and challenge facing modern scientific researchers. At present, the use of π-conjugated planar structural units (such as [BO3] 3- , [CO3] 2- , [NO3] - )Developing new NLO materials is an effective strategy. For example, LiB3O5(LBO), CsB3O5(CBO), CsLiB6O 10 Crystals such as CLBO, β-BaB2O4 (BBO), and KBe2BO3F2 (KBBF) are all based on this type of structural unit. However, the inherent optical performance shortcomings of these materials limit their application in cutting-edge fields. Therefore, the development of new high-performance NLO crystalline materials is an important research direction in the field of optoelectronic functional materials. Summary of the Invention

[0003] The purpose of the present invention is to provide an aminoguanidine oxalate second-order nonlinear optical crystal material and its preparation and application. The crystalline material has a planar functional unit (CN4H7) with defective symmetry. + This unit breaks the microscopic symmetry of the traditional planar triangular unit and has large microscopic polarizability and polarizability anisotropy. The crystalline material exhibits a strong powder harmonic generation effect (1.0×KDP@1064nm), a suitable birefringence (0.016@546nm), and a short UV absorption cutoff edge (290nm).

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

[0005] In the first aspect, the present invention provides an aminoguanidine oxalate second-order nonlinear optical crystal material, the chemical formula of which is (CN4H7) + (C2O4H) - , belongs to the monoclinic system, the space group is P21, and the unit cell parameters are α=90°, β=95~100°, γ=90°, Z=2.

[0006] Furthermore, the unit cell parameters of the crystal material are α=90°,β=96~98°,γ=90°,Z=2。 Further preferably, the unit cell parameters are α=90°,β=97~98°,γ=90°,Z=2。 Most preferably, the unit cell parameters are α=90°, β=97.814(4)°, γ=90°, Z=2.

[0007] In the second aspect, the present invention provides a method for preparing an aminoguanidine oxalate second-order nonlinear optical crystal material, comprising mixing an aminoguanidine source, an oxalic acid source, and a solvent, adding the mixture to a reaction vessel and stirring, heating the reaction, cooling the mixture to room temperature, and volatilizing the solvent to obtain colorless and transparent block crystals, which are the target product.

[0008] Furthermore, the molar ratio of the aminoguanidine source to the oxalic acid source is (1-10):(1-10).

[0009] Furthermore, the aminoguanidine source is selected from at least one of aminoguanidine bicarbonate, aminoguanidine sulfate or aminoguanidine hydrochloride.

[0010] Furthermore, the oxalic acid source is selected from at least one of anhydrous oxalic acid, oxalic acid dihydrate or sodium oxalate.

[0011] Furthermore, the heating reaction temperature is 30-60° C. and the time is not less than 10 minutes.

[0012] Furthermore, the solvent is distilled water.

[0013] Aminoguanidine oxalate (CN4H7) of the present invention + (C2O4H) - The crystal structure of Figure 1 As shown. The protonated aminoguanidine cation reacts with the deprotonated hydrogen oxalate anion via N–H … O hydrogen bonds form a network structure.

[0014] In a third aspect, the present invention provides an application of an aminoguanidine oxalate second-order nonlinear optical crystal material in stereolithography, solid-state lasers, optical communications, optical parametric amplifiers, optical parametric oscillators, and laser frequency converters.

[0015] Furthermore, the crystal material is used in a laser frequency converter and outputs 532nm laser under 1064nm laser irradiation. Its powder frequency-doubled intensity is 1.0 times that of KDP crystal and can achieve phase matching.

[0016] The present invention combines a symmetry-defective planar cation with a π-conjugated anion to create an aminoguanidine oxalate second-order nonlinear optical crystal (CN4H7). + (C2O4H) - The crystalline material possesses a planar structural unit with incomplete symmetry, which is conducive to the generation of large microscopic polarizability and polarizability anisotropy. The crystalline material exhibits a strong powder harmonic generation effect (1.0×KDP@1064nm), a moderate birefringence (0.016@546nm), and a short UV absorption cutoff edge (290nm).

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) This application provides a new second-order nonlinear optical crystal (CN4H7) + (C2O4H) - This crystalline material exhibits a strong frequency-doubled effect, with a frequency-doubled intensity 1.0 times that of the commercial frequency-doubled crystal KDP under 1064nm laser irradiation, and is capable of phase matching. Furthermore, the crystalline material has a UV absorption cutoff edge of 290nm and a birefringence of 0.016@546nm. This crystalline material has achieved the optical performance indicators of commercial frequency-doubled crystals, demonstrating broad application potential in the field of nonlinear optics.

[0019] (2) This application also provides the second-order nonlinear optical crystal (CN4H7) + (C2O4H) - The preparation method is to prepare colorless and transparent block (CN4H7) by solvent evaporation method. + (C2O4H) - The synthesis method is simple, the synthesis conditions are mild, it is easy to obtain high-purity millimeter-scale single crystals, and it is easy to prepare in large quantities. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Yes (CN4H7) + (C2O4H) - Schematic diagram of the crystal structure;

[0021] Figure 2 The X-ray diffraction pattern of sample 1-1# obtained by fitting the crystal structure analyzed by single crystal X-ray diffraction is compared with the X-ray diffraction pattern of sample 1-1# after it was ground into powder;

[0022] Figure 3 is the UV-visible absorption spectrum of sample 1-1#;

[0023] Figure 4is the infrared spectrum of sample 1-1#;

[0024] Figure 5 This is the second harmonic phase matching diagram of sample 1-1# in the 1064nm band;

[0025] Figure 6 This is the second harmonic signal diagram of sample 1-1# and standard KDP sample with sample size ranging from 150 to 200 μm. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to 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.

[0027] 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.

[0028] Example 1:

[0029] Preparation of samples 1# to 8#

[0030] The aminoguanidine source (i.e. (CN4H7) + Mix HCO3, aminoguanidine bicarbonate), an oxalic acid source (i.e., anhydrous oxalic acid), and a solvent and add them to a beaker. Place the beaker on a constant temperature magnetic heating table, heat and stir until a clear and transparent solution is obtained, and then cool to room temperature. By slowly evaporating the solvent, colorless and transparent block crystals (CN4H7) are obtained. + (C2O4H) - .

[0031] The relationship between the types and ratios of raw materials in the initial mixture, heating temperature, stirring time and sample number is shown in Table 1.

[0032] Table 1 Correspondence between samples, raw materials and synthesis conditions

[0033]

[0034] Crystal structure analysis of samples 1-1# to 1-8#

[0035] The structures of samples 1-1# to 1-8# were analyzed using single crystal X-ray diffraction and powder X-ray diffraction methods.

[0036] The single crystal X-ray diffraction test was performed on a Bruker D8 VENTURE CMOS X-ray single crystal diffractometer in 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 SHELXTL-2018 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; the F-based 2 The coordinates of all atoms and anisotropic thermal parameters were refined using the full-matrix least-squares method.

[0037] 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 5 to 70°, and the scanning step is 0.02°.

[0038] Among them, the single crystal X-ray diffraction results show that samples 1-1# to 1-8# have the same chemical formula and crystal structure, and the chemical formula is (CN4H7) + (C2O4H) - , which belongs to the monoclinic system, the space group is P21, and the unit cell parameters are α=90°, β=97.8~97.9°, γ=90°, Z=2;

[0039] Take sample 1-1# as a typical example, its crystal structure data is α=90°,β=97.814(4)°,γ=90°,Z=2. Its crystal structure is as follows Figure 1 shown.

[0040] The powder X-ray diffraction test results show that in the XRD spectra of samples 1-1# to 1-8#, the diffraction peaks of the samples and the diffraction peaks fitted by the single crystal data have the same position, but the peak intensities are slightly different.

[0041] Take sample 1-1# as a typical example. Figure 2 As shown, the X-ray diffraction pattern obtained by fitting the crystal structure analyzed by single crystal X-ray diffraction is consistent with the peak position of the pattern obtained by X-ray diffraction test after sample 1-1# is ground into powder, indicating that the obtained sample has high purity.

[0042] UV-visible absorption spectrum test

[0043] The diffuse reflectance absorption spectrum of sample 1-1# was tested on a Carry 5000 UV-visible-near infrared spectrophotometer from Agilent Technologies, USA. Figure 3 As shown by Figure 3It can be seen that the ultraviolet absorption cutoff edge of the compound is 290nm.

[0044] Infrared spectrum test

[0045] The infrared spectrum test of sample 1-1# was conducted on a Nicolet iS10 Fourier infrared spectrometer from Thermo Fisher Scientific Inc., USA. Figure 4 As shown in the infrared spectrum, 3187, 3348 and 3451 cm -1 The characteristic absorption peak at confirms that [CN4H7] + The presence of groups.

[0046] Frequency doubling test experiment and results

[0047] The SHG test experiment for sample 1-1# was conducted as follows: a Q-switched Nd:YAG solid-state laser with a wavelength of 1064 nm was used as the fundamental frequency to illuminate the crystal powder under test. The generated second harmonics were detected using a spectrometer, and the harmonic intensity was displayed using an oscilloscope. The sample crystal and a standard KDP crystal were ground separately and sieved using a standard sieve to produce crystals with different particle sizes: 26-50, 50-74, 74-105, 105-150, and 150-200 μm, respectively. The SHG signal was observed to determine whether phase matching was achieved. Under identical test conditions, the SHG intensity of the sample and the standard KDP sample were compared to determine the relative magnitude of the SHG effect.

[0048] The test results show that compound (CN4H7) + (C2O4H) - It has a large powder frequency-doubled effect. Under 1064nm wavelength laser irradiation, the frequency-doubled signal intensity is 1.0 times that of KDP crystal (such as Figure 6 The crystalline material can achieve phase matching under 1064nm laser irradiation (such as Figure 5 ).

[0049] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. 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 aminoguanidine oxalate second-order nonlinear optical crystal material, characterized in that: Its chemical formula is (CN4H7) + (C2O4H) - , belongs to the monoclinic system, the space group is P21, and the unit cell parameters are α=90°, β=95~100°, γ=90°, Z=2.

2. The aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 1, characterized in that: The unit cell parameters of the crystal material are α=90°, β=96~98°, γ=90°, Z=2.

3. The method for preparing the aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 1 or 2, characterized in that: An aminoguanidine source, an oxalic acid source and a solvent are mixed, added to a reaction vessel, stirred, heated for reaction, cooled to room temperature, and the solvent is evaporated to obtain colorless and transparent block crystals, which are the target product.

4. The method for preparing the aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 3, characterized in that: The molar ratio of the aminoguanidine source to the oxalic acid source is (1-10):(1-10).

5. The method for preparing the aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 3, characterized in that: The aminoguanidine source is selected from at least one of aminoguanidine bicarbonate, aminoguanidine sulfate or aminoguanidine hydrochloride.

6. The method for preparing the aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 3, characterized in that: The oxalic acid source is selected from at least one of anhydrous oxalic acid, oxalic acid dihydrate or sodium oxalate.

7. The method for preparing the aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 3, characterized in that: The heating reaction temperature is 30-60°C and the time is not less than 10 minutes.

8. The method for preparing the aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 3, characterized in that: The solvent is distilled water.

9. Use of the aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 1 or 2 in stereolithography, solid-state lasers, optical communications, optical parametric amplifiers, optical parametric oscillators, and laser frequency converters.

10. The use of the aminoguanidine oxalate second-order nonlinear optical crystal material according to claim 9, characterized in that: The crystal material is used in a laser frequency converter and outputs 532nm laser light under 1064nm laser irradiation.

Images