A second-order nonlinear optical crystal material of trimethylammonium methanesulfonate and its preparation and application

Abstract

The present invention relates to a trimethylammonium methanesulfonate second-order nonlinear optical crystal material and its preparation and application. The chemical formula of the crystal material is [(CH3)3NH] + [SO3CH3] ‑ , molecular weight is 154.21, belongs to the orthorhombic system, space group is Pca21 (No.29). The unit cell parameters are α=γ=β=90°, Z=4, and the unit cell volume is the nonlinear optical crystal [(CH3)3NH] + [SO3CH3] ‑ Under 1064nm laser irradiation, the powder's frequency-doubled effect is approximately 0.5 times that of potassium dihydrogen phosphate crystals, and phase matching is achieved, with a UV absorption cutoff edge less than 200nm. This crystal material is easy to grow and exhibits significant application value in electro-optical modulation, holographic storage elements, and frequency-doubled devices.

Description

Technical Field

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

[0002] Coherent deep ultraviolet (DUV, λ < 200nm) light sources are widely used in laser frequency conversion, laser ranging, laser communications, medical treatment, and defense and military fields. The most effective method for generating DUV coherent light is to utilize the second harmonic generation (SHG) effect of nonlinear optical (NLO) crystal materials. [PO4] 3- and [SO4] 2- Non-π conjugated structural units such as [PO4] have attracted widespread attention due to their large energy gap. However, the polarizability anisotropy and hyperpolarizability of these structural units are low, which limits the practical application of crystalline materials. 3- and [SO4] 2- Introducing heteroatoms or organic groups into non-π-conjugated structural units to form heterotetrahedra is an effective strategy for enhancing structural anisotropy. According to the Inorganic Crystal Structure Database, only 26% of sulfur-containing heterotetrahedral crystals possess non-centrosymmetric structures (non-centrosymmetric structures are a prerequisite for second harmonic generation). Therefore, the development of novel sulfur-containing heterotetrahedral DUV NLO crystal materials is a research hotspot and a challenge in the field of optoelectronics. Summary of the Invention

[0003] The purpose of the present invention is to provide a second-order nonlinear optical crystal material of trimethylammonium methanesulfonate and its preparation and application, and the heterogeneous tetrahedron [SO3CH3] in the provided material is - The group enhances the nonlinear optical properties of methanesulfonate, making it exhibit a moderate frequency response (0.5×KH2PO4(KDP)) and a short ultraviolet absorption cutoff edge (λ<200nm).

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

[0005] In one aspect, the present invention provides a second-order nonlinear optical crystal material of trimethylammonium methanesulfonate, whose chemical formula is [(CH3)3NH] + [SO3CH3] - , molecular weight is 154.21, belongs to the orthorhombic system, space group is Pca21 (No.29). The unit cell parameters are α=γ=β=90°,Z=4,the unit cell volume is

[0006] Furthermore, the unit cell parameters of the crystal material are α=β=γ=90°,Z=4。 Most preferably, the unit cell parameters are α=β=γ=90°, Z=4.

[0007] The inorganic compound crystal [(CH3)3NH] of the present invention + [SO3CH3] - The crystal structure of Figure 1 As shown. Each [SO3CH3] - The tetrahedron is formed by a central S atom coordinated by three O atoms and a CH3 group. [(CH3)3NH] + and [SO3CH3] - The tetrahedra are connected to each other through NH···O hydrogen bonds to form a three-dimensional structure.

[0008] On the other hand, the present invention provides a method for preparing a second-order nonlinear optical crystal material of trimethylammonium methanesulfonate, comprising mixing a N source, an S source, and ethanol and continuously stirring until a clear and transparent solution is obtained. The clear and transparent solution is then concentrated by rotary evaporation, and ethanol is added. The solution is cooled and crystallized under low temperature to finally obtain colorless and transparent flaky crystals, which are the target product.

[0009] Furthermore, the added amounts of the N source and the S source satisfy the following molar ratio of the N element to the S element: (1-10):(1-10), preferably (1-5):(1-5).

[0010] Furthermore, the nitrogen source is trimethylamine hydrochloride or a trimethylamine aqueous solution. Preferably, the nitrogen source is trimethylamine hydrochloride.

[0011] Furthermore, the S source is sodium methanesulfonate or methanesulfonic acid. Preferably, the S source is silver methanesulfonate.

[0012] Furthermore, the ratio of the added amount of the N source to that of ethanol was 1 mmol:3 mL.

[0013] Furthermore, the temperature of the rotary evaporation concentration is 35-45°C.

[0014] Furthermore, the temperature of the cooling crystallization is 0-4°C and the time is not less than 1 week.

[0015] In a third aspect, the present invention provides an application of a trimethylammonium methanesulfonate second-order nonlinear optical crystal material in a laser frequency converter, a photoelectric rectifier, an optical parametric oscillator, an optical parametric amplifier, and a frequency doubling generator.

[0016] Furthermore, when trimethylammonium methanesulfonate second-order nonlinear optical crystal material is used in a laser frequency converter, the crystal can output 532nm green light under 1064nm laser irradiation. Specifically, under 1064nm laser irradiation, the output of 532nm green laser light is very strong, with a powder frequency-doubled intensity approximately 0.5 times that of KDP crystal, and phase matching is achieved.

[0017] The present invention utilizes the strategy of element substitution to form heterocoordinate tetrahedron [SO3CH3] - As an optical functional structural unit, the nonlinear optical crystal material [(CH3)3NH] was successfully synthesized. + [SO3CH3] - , which exhibits a moderate frequency-shuffling effect (0.5×KDP) and a short UV absorption cutoff edge (λ<200nm).

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) This application provides a new second-order nonlinear optical crystal [(CH3)3NH] + [SO3CH3] - Under 1064nm laser irradiation, this crystal material has a frequency-doubled intensity approximately 0.5 times that of a KDP crystal, enabling phase matching. Furthermore, this crystal material exhibits high transmittance in the 200-800nm ​​spectral range, with an ultraviolet absorption cutoff wavelength less than 200nm. Its thermal decomposition temperature is 220°C. Therefore, this crystal material has broad application prospects in the field of second-order nonlinear optics.

[0020] (2) The present application also provides the nonlinear optical crystal [(CH3)3NH] + [SO3CH3] - The preparation method is to concentrate by rotary evaporation and cool and crystallize, and finally grow colorless flaky crystals [(CH3)3NH] + [SO3CH3] - This method is convenient and has mild reaction conditions. It can efficiently prepare single crystals with high optical quality and high purity, which is conducive to large-scale industrial production.

[0021] (3) The trimethylammonium methanesulfonate crystal material of the present invention can be applied to a laser frequency converter, which can convert a laser beam into a second harmonic output. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is [(CH3)3NH] + [SO3CH3] - Schematic diagram of the crystal structure;

[0023] Figure 2The following are comparisons of X-ray diffraction patterns; (a) is the X-ray diffraction pattern obtained by analyzing and simulating the single crystal X-ray diffraction data of sample 1#; (b) is the pattern obtained by X-ray diffraction testing after grinding sample 1# into powder;

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

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

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

[0027] Figure 6 This is the second harmonic signal diagram of sample 1-1# and standard KDP sample with sample size ranging from 200 to 280 μm;

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

[0029] 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.

[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] Example 1

[0032] Preparation of samples 1# to 8#

[0033] Mix the N source, S source, and ethanol in a certain proportion to form a raw material, and stir continuously until a clear and transparent solution is obtained. After the clear and transparent solution is concentrated by rotary evaporation, a small amount of ethanol (concentration of 98%) is added, and cooled and crystallized at a low temperature of about 2°C to finally obtain colorless and transparent flakes [(CH3)3NH] + [SO3CH3] - crystal.

[0034] The relationship between the types and ratios of raw materials in the initial mixture, rotary evaporation temperature, cooling time and sample number is shown in Table 1.

[0035] Table 1 Correspondence between samples, raw materials and synthesis conditions

[0036]

[0037] Crystal structure analysis of samples 1# to 8#

[0038] Single crystal X-ray diffraction and powder X-ray diffraction methods were used to perform structural analysis and phase analysis on samples 1# to 8#, respectively.

[0039] Single crystal X-ray diffraction measurements were performed on a Bruker D8 VENTURE CMOS X-ray single crystal diffractometer from Germany. The data collection temperature was 298.15 K, and the diffraction light source was graphite monochromatized Mo-Kα radiation. The scanning mode was ω; the data were processed for absorption correction using the Multi-Scan method. The structure was solved using the Olex2 program package; the positions of heavy atoms were determined by direct method, and the coordinates of the remaining atoms were obtained by 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.

[0040] Single crystal X-ray diffraction results show that samples 1# to 8# have the same chemical formula and crystal structure, and the chemical formula is [(CH3)3NH] + [SO3CH3] - , molecular weight is 154.21, belongs to the orthorhombic crystal system, space group is Pca21 (No.29). The unit cell parameters are α=γ=β=90°,Z=4,the unit cell volume is

[0041] Take sample 1-1# as a typical example, its crystal structure data is α=β=γ=90°, Z=4. [(CH3)3NH] + [SO3CH3] - Crystal structure such as Figure 1 shown.

[0042] 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°.

[0043] The powder X-ray diffraction test results show that in the XRD spectra of samples 1# to 8#, the peak positions of each sample are basically the same, but the peak intensities are slightly different.

[0044] Take sample 1# as a typical example. Figure 2As shown in the figure, the peak positions of the fitted X-ray diffraction pattern obtained based on the crystal structure analyzed by single crystal X-ray diffraction are consistent with the pattern obtained by X-ray diffraction testing of sample 1 after grinding into powder. This indicates that the obtained sample has a high purity.

[0045] UV-visible-near-infrared absorption spectroscopy test

[0046] 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, the compound has no significant absorption in the range of 200nm to 800nm, and its optical band gap is less than 6.20eV. This wide optical band gap facilitates the generation of second harmonic ultraviolet light from fundamental frequency light passing through the crystal, and the material can be used in fields such as ultraviolet laser frequency conversion and laser lithography.

[0047] Infrared spectrum test

[0048] The infrared spectrum test of sample 1# was conducted on a Nicolet iS10 Fourier infrared spectrometer from Thermo Fisher Scientific Inc., USA. Figure 4 As shown, 769cm in the infrared spectrum -1 、1024cm -1 The characteristic absorption peaks of [SO3CH3] - The presence of groups.

[0049] Thermogravimetric testing

[0050] The thermogravimetric test of sample 1# was carried out on a Netzsch STA 409PC thermogravimetric analyzer manufactured by Netzsch Equipment Manufacturing Co., Ltd., Germany. Figure 5 As shown, the decomposition temperature of this compound is 220°C.

[0051] Frequency doubling test experiment and results

[0052] The frequency-doubled-harmonic (SHG) test experiment for sample 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 of varying particle sizes: 26-50, 50-105, 105-150, 150-200, and 200-280 μm, respectively. The SHG signal was observed as a function of particle size to determine whether phase matching was achieved. Under the same test conditions, the SHG intensities of the sample and the reference KDP crystal, irradiated at 1064 nm, were compared to determine the relative magnitude of the SHG effect.

[0053] The test results showed that the compound [(CH3)3NH] + [SO3CH3] - When the crystal is irradiated with 1064nm wavelength laser, the frequency doubled signal intensity is 0.5 times that of KDP crystal (such as Figure 6 ).like Figure 7 As shown, the crystal material can achieve phase matching at a laser wavelength of 1064nm.

[0054] 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. A trimethylammonium methanesulfonate second-order nonlinear optical crystal material, characterized in that: Its chemical formula is [(CH3)3NH] + [SO3CH3] - , molecular weights are 154.21, belong to the orthorhombic crystal system, space group is Pca21 (No.29), unit cell parameters are α=γ=β=90°,Z=4,the unit cell volume is 2. The trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 1, characterized in that: The unit cell parameters of the crystal material are α=β=γ=90°, Z=4.

3. The method for preparing a trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 1 or 2, characterized in that: Mix the N source, S source and ethanol and stir continuously until a clear and transparent solution is obtained. Then, the clear and transparent solution is concentrated by rotary evaporation, and ethanol is added. The solution is cooled and crystallized at low temperature to finally obtain colorless and transparent flaky crystals, which are the target product.

4. The method for preparing a trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 3, characterized in that: The addition amount of the N source and the S source satisfies: the molar ratio of the N element to the S element is (1-10):(1-10).

5. The method for preparing a trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 3, characterized in that: The nitrogen source is trimethylamine hydrochloride or trimethylamine aqueous solution.

6. The method for preparing a trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 3, characterized in that: The S source is sodium methanesulfonate or methanesulfonic acid.

7. The method for preparing a trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 3, characterized in that: The ratio of the added amount of N source to ethanol was 1 mmol:3 mL.

8. The method for preparing a trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 3, characterized in that: The temperature of rotary evaporation concentration is 35-45°C; the temperature of cooling crystallization is 0-4°C, and the time is not less than 1 week.

9. Use of the trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 1 or 2 in a laser frequency converter, a photoelectric rectifier, an optical parametric oscillator, an optical parametric amplifier and a frequency doubling generator.

10. Use of the trimethylammonium methanesulfonate second-order nonlinear optical crystal material according to claim 9, It is characterized in that When trimethylammonium methanesulfonate second-order nonlinear optical crystal material is used in laser frequency converter, It can generate 532nm green light output under the irradiation of 1064nm laser.

Images