A diamond-like structure crystal material, a preparation method thereof and application thereof as an infrared nonlinear optical material

Abstract

This application discloses a diamond-like carbon (DLC) crystal material, its preparation method, and its application as an infrared nonlinear optical material, belonging to the field of crystal preparation technology. The DLC crystal material has a triclinic structure with the chemical formula AM5Q8; wherein A is selected from at least one of Na, K, Rb, and Cs; M is selected from at least one of Ga and In; and Q is selected from at least one of S, Se, and Te. This crystal material exhibits a frequency doubling effect 0.5-5 times that of AgGaS2 and a laser damage threshold 1-50 times that of AgGaS2, demonstrating significantly improved performance and making it a potential infrared nonlinear optical material.

Description

Technical Field

[0001] This application relates to a diamond-like crystal material, its preparation method, and its application as an infrared nonlinear optical material, belonging to the field of crystal preparation technology. Background Technology

[0002] Nonlinear optical (NLO) materials, with their frequency conversion capabilities in the ultraviolet to mid-infrared region (2.5 to 25 micrometers), can generate tunable coherent lasers, playing a crucial role in driving the development of solid-state lasers, particularly in high-tech fields such as medicine, radar, and remote sensing. To date, oxide crystals such as LiB3O5, β-BaB2O4, KH2PO4, and KTiPO4 have been widely used in the deep ultraviolet, ultraviolet, and visible to near-infrared regions. However, their application in the mid-infrared and far-infrared regions is greatly limited due to their strong chemical absorption. In contrast, chalcogenides exhibit higher transparency in the mid-infrared region due to the redshift of their interatomic stretching frequencies, making them excellent NLO materials in the infrared spectral region. Furthermore, the high polarizability microstructure of chalcogenides can generate strong NLO coefficients, meeting the standards of commercial NLO materials such as AgGaS2, AgGaSe2, and ZnGeP2. Nevertheless, these materials also face challenges such as a low laser-induced damage threshold, two-photon absorption, and non-phase-matching behavior, which limit their commercial applications. Therefore, there is an urgent need to develop novel chalcogenide materials with superior NLO performance to overcome the limitations of existing materials. Summary of the Invention

[0003] To address the challenge of balancing a large NLO effect and a high laser damage threshold in existing infrared nonlinear optical (NLO) crystal technologies, this application provides a diamond-like crystal material with an NLO effect 0.5-5 times that of commercial AgGaS2 and a laser damage threshold 1-50 times that of commercial AgGaS2, demonstrating significantly improved overall performance and making it a potential infrared NLO material.

[0004] This application adopts the following scheme:

[0005] According to one aspect of this application, a diamond-like structure crystal material is provided, characterized in that the structure of the diamond-like structure crystal material is triclinic phase, and the chemical formula is AM5Q8;

[0006] Wherein, A is selected from at least one of Na, K, Rb, and Cs;

[0007] M is selected from at least one of Ga and In;

[0008] Q is selected from at least one of S, Se, and Te.

[0009] Optionally, the diamond-like crystal material has a diamond-like structure, that is, the tetrahedral structural units are connected by anions at common points to form a three-dimensional honeycomb-like open channel framework.

[0010] Optionally, the diamond-like crystal material belongs to the triclinic crystal system. P1 Space group.

[0011] Optionally, the cell parameters of the diamond-like carbon crystal material are: a =7.7114(4)- 9.7927(3); b =8.7450(3)- 10.5872(1) Å, c = 10.6067(4)- 13.581(1) Å, α = 87.858(3)- 89.961(3)︒, β = 70.162(4)- 73.189(4)︒, γ = 70.600(4)- 73.680(4)︒, V = 634.19(5)- 1293.58(5)Å 3 Z = 1.

[0012] Optionally, the powder laser damage threshold of the diamond-like structure crystal material is 1 to 50 times that of AgGaS2.

[0013] Optionally, the powder laser damage threshold of the diamond-like structure crystal material is 1 to 47 times that of AgGaS2.

[0014] Optionally, the frequency doubling intensity of the diamond-like structure crystal material is 0.5 to 5 times that of AgGaS2.

[0015] According to another aspect of this application, a method for preparing the diamond-like structure crystal material described above is provided, comprising the following steps:

[0016] A mixture of raw materials containing element A, element M, element Q, and element Ax is placed into a reaction vessel, sealed under vacuum, heated to the reaction temperature, and reacted to obtain the diamond-like crystal material.

[0017] In AX, X is selected from at least one of Cl, Br, and I.

[0018] Optionally, the raw materials containing elements A, M, Q, and AX are prepared and mixed evenly in a molar ratio of A:M:Q:AX = 1:(4~6):(7~9):(3~6).

[0019] Optionally, in the raw material mixture, the source of element M is selected from elemental M;

[0020] The source of element Q is selected from element Q.

[0021] Optionally, the reaction conditions are as follows:

[0022] The reaction temperature is 700°C ~ 1000°C, and the reaction time is 1 h ~ 150 h.

[0023] Optionally, the reaction temperature is reached by heating at a rate of 1°C / h to 60°C / h.

[0024] Optionally, cooling is required after the reaction;

[0025] The cooling is either natural cooling or cooling to 300°C-400°C at a rate of 1°C / h-10°C followed by natural cooling.

[0026] Optionally, the pressure range inside the reaction vessel after vacuuming is 10. -3 Pa -10Pa.

[0027] Optionally, the sealing method is welding sealing.

[0028] Optionally, the reaction vessel is a quartz tube.

[0029] According to another aspect of this application, the above-described diamond-like structure crystal material or the diamond-like structure crystal material obtained according to the above preparation method is also provided as a nonlinear optical crystal for use in the field of lasers.

[0030] The beneficial effects that this application can produce include:

[0031] The diamond-like carbon crystal material provided in this application exhibits a frequency doubling effect that is 0.5-5 times that of commercial AgGaS2, and a laser damage threshold that is 1-50 times that of commercial AgGaS2, demonstrating a significant improvement in performance and making it a potential infrared nonlinear optical material. Attached Figure Description

[0032] Figure 1 Powder diffraction pattern of RbGa5Se8 prepared for the embodiments of this application;

[0033] Figure 2 The frequency harmonics signals of NaGa5S8, KGa5S8, RbGa5Se8, KIn5Se8, CsIn5Se8, and CsIn5Te8 polycrystalline powders at 1910 nm are shown.

[0034] Figure 3 The crystal structure of RbGa5Se8 prepared for the embodiments of this application. Detailed Implementation

[0035] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0036] Unless otherwise specified, the raw materials used in the embodiments of this application were purchased commercially.

[0037] The instrument used for single-crystal X-ray diffraction was a Rigaku FR−X micro-focusing diffractometer.

[0038] Test conditions: 293 K, structural analysis was performed using SHELXTL crystallography software.

[0039] The instrument used for powder X-ray diffraction was a Rigaku Flex600 X-ray diffractometer.

[0040] Test conditions: 293 K.

[0041] The method for calculating the laser damage threshold described in this application uses a VIBRANTHE 355 LD laser instrument manufactured by OPOTEK Corporation, USA. First, Example 1 and commercially available AgGaS2 (Comparative Example 1) were sieved to select particles with a diameter range of 150-200 nm. These particles were then placed under a 1064 nm laser beam with a pulse width of 10 ns. The surface damage of the samples was observed by continuously increasing the laser power. When a damaged spot appeared on the sample, the laser power was recorded, and the size of the damaged spot was measured. The laser power / damage area was used as the laser damage threshold value for comparison.

[0042] The frequency doubling signal testing method described in this application involves screening the sample crystal and the AgGaS2 crystal used as a reference using standard sieves to select crystals with particle sizes in five ranges: 30–50, 50–75, 75–100, 100–150, and 150–200 nm. These samples are then mounted separately and placed under a laser light path. Their nonlinear optical properties are tested using a near-infrared charge-coupled detector at a laser intensity of 1910 nm. A graph is then plotted with particle size as the abscissa and the measured nonlinear optical properties as the ordinate to determine the magnitude of the nonlinear optical properties of the crystal material and the phase matching of the crystal material.

[0043] Example 1

[0044] After mixing Na (13 mg), Ga (159 mg), S (128 mg), and NaCl (150 mg) thoroughly, the mixture was placed into a quartz tube and evacuated to 10°C. -3 The tube was sealed with Pa and placed in a muffle furnace and slowly heated to 980°C. After holding at that temperature for 144 hours, the temperature was lowered to 400°C at a rate of 3°C / h. The muffle furnace was then turned off and allowed to cool naturally to room temperature, yielding a crystal with the chemical formula triclinic NaGa5S8.

[0045] Example 2

[0046] After mixing K (19 mg), Ga (162 mg), S (119 mg), and KI (180 mg) thoroughly, the mixture was placed into a quartz tube and evacuated to 10°C. -2 The tube was sealed with Pa and placed in a muffle furnace and slowly heated to 700°C. After holding at that temperature for 15 hours, it was cooled to 400°C at a rate of 3°C / h. The muffle furnace was then turned off and allowed to cool naturally to room temperature, yielding a crystal with the chemical formula triclinic KGa5S8.

[0047] Example 3

[0048] Rb (24 mg), Ga (98 mg), Se (177 mg), and RbCl (180 mg) were mixed thoroughly and then placed into a quartz tube and evacuated to 10°C. -3 The tube was sealed with Pa and slowly heated to 620°C in a muffle furnace. After holding at that temperature for 72 hours, it was cooled to 400°C at a rate of 4°C / h. The muffle furnace was then turned off, and the tube was allowed to cool naturally to room temperature, yielding a triclinic RbGa5Se8 crystal. The powder diffraction pattern of this crystal is shown below. Figure 1 As shown, the crystal structure is as follows Figure 3 As shown.

[0049] Example 4

[0050] K (9 mg), In (152 mg), Se (140 mg) and KCl (150 mg) were mixed evenly and placed in a quartz tube. The tube was then evacuated to 1 Pa and sealed. The tube was placed in a muffle furnace and slowly heated to 850°C. After holding at this temperature for several hundred hours, the temperature was lowered to 400°C at a rate of 3°C / h. The muffle furnace was then turned off and allowed to cool naturally to room temperature to obtain a triclinic KIn5Se8 crystal.

[0051] Example 5

[0052] After mixing Cs (37 mg), In (130 mg), Se (133 mg) and CsBr (220 mg) evenly, the mixture was placed in a quartz tube, vacuumed to 10 Pa, sealed, and placed in a muffle furnace. The mixture was then slowly heated to 870°C and held at that temperature for several hundred hours. After cooling to 300°C at a rate of 5°C / h, the muffle furnace was turned off and allowed to cool naturally to room temperature, yielding a triclinic phase CsIn5Se8 crystal.

[0053] Example 6

[0054] K (8 mg), In (105 mg), Te (187 mg) and KBr (160 mg) were mixed evenly and placed in a quartz tube. The tube was then evacuated to 10 Pa and sealed. The tube was placed in a muffle furnace and slowly heated to 870°C. After holding at that temperature for several hundred hours, the temperature was lowered to 300°C at a rate of 5°C / h. The muffle furnace was then turned off and allowed to cool naturally to room temperature to obtain a crystal with the chemical formula triclinic CsIn5Te8.

[0055] Test Example 1

[0056] NLO performance testing method: The sample crystal and the AgGaS2 crystal used as a reference were screened with standard sieves to select crystals with particle sizes in five ranges: 30–50, 50–75, 75–100, 100–150, and 150–200 nm. The samples were then mounted and placed under a laser light path. The nonlinear optical properties were tested using a near-infrared charge-coupled detector at a laser intensity of 1910 nm. The particle size was plotted on the x-axis and the measured nonlinear optical properties were plotted on the y-axis to determine the magnitude of the NLO performance of the crystal material and the phase matching of the crystal material.

[0057] Figure 2 This indicates the triclinic phase NaGa5S 8， KGa5S 8， RbGa5Se 8， KIn5Se 8， CsIn5Se 8， The harmonic overtones of the polycrystalline powder of CsIn5Te8 compound were 0.9, 1.1, 2.1, 2.8, 2.8, and 3.8 times that of AgGaS2, with a particle size of 150-200 μm and a value at 1910 nm.

[0058] Test Example 2

[0059] Laser damage threshold test of samples: The sample crystal and the AgGaS2 crystal used as a reference were screened with standard sieves to select crystals with a particle size range of 150–200 nm. The samples were then placed under a 1064 nm laser with a pulse width of 10 ns. The laser power was continuously increased, and the damage on the sample surface was observed until a damage spot appeared on the sample. The laser power at this time was recorded, and the size of the damage spot was measured. The laser damage threshold of the sample can be calculated.

[0060] The results are shown in Table 1, which compares the laser damage thresholds of AM5Q8 (A = Na, K, Rb, Cs; M = Ga, In; Q = S, Se, Te) and AgGaS2 polycrystalline powder at 1064 nm. 8， KGa5S 8， RbGa5Se 8， KIn5Se8， CsIn5Se 8， The laser damage threshold of CsIn5Te8 is 47.0, 46.0, 21.4, 18.0, 17.5, and 7.6 times that of AgGaS2.

[0061] Table 1

[0062]

[0063] Test Example 3

[0064] Crystallographic data were tested on Examples 1-6, and the results can be summarized as follows:

[0065] NaGa5S8 belongs to the triclinic crystal system. P1 Space group, a =7.71 Å; b =8.74 Å, c = 10.6 Å, α = 87.8︒, β = 70.16︒, γ = 70.6︒, V = 634.2Å 3 Z = 1.

[0066] KGa5S8 belongs to the triclinic crystal system. P1 Space group, a =8.11 Å; b =9.02 Å, c = 11.2 Å, α = 89.0︒, β = 71.18︒, γ = 71.8︒, V = 734.2Å 3 Z = 1.

[0067] RbGa5Se8 belongs to the triclinic crystal system. P1 Space group, a =8.81 Å; b =8.79 Å, c = 10.60 Å, α =89.8︒, β = 72.3︒, γ = 71.8︒, V = 736.5Å 3 Z = 1.

[0068] KIn5Se8 belongs to the triclinic crystal system. P1 Space group, a =9.03 Å; b =9.39 Å, c = 12.08 Å, α = 89.5︒, β = 72.9︒, γ = 72.0︒, V = 927.9 Å 3 Z = 1.

[0069] CsIn5Se8 belongs to the triclinic crystal system. P1 Space group, a =9.19 Å; b =9.88 Å, c = 12.58 Å, α =89.5︒, β = 73.0︒, γ = 72.2︒, V = 1039.9 Å 3 Z = 1.

[0070] CsIn5Te8 belongs to the triclinic crystal system. P1 Space group, a =9.79 Å; b =10.58 Å, c = 13.58 Å, α =89.9︒, β = 73.1︒, γ = 73.6︒, V = 1293.5Å 3 Z = 1.

[0071] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A diamond-like crystal material, characterized in that, The diamond-like crystal material has a triclinic phase structure and the chemical formula AM5Q8. The specific chemical formulas of the diamond-like structure crystal materials are NaGa5S8, KGa5S8, RbGa5Se8, KIn5Se8, and CsIn5Te8. The diamond-like structure crystal material has a diamond-like structure, that is, the tetrahedral structural units are connected by anions at common points to form a three-dimensional honeycomb-like open channel framework. The diamond-like crystal material described above belongs to the triclinic crystal system. P1 Space group; The powder laser damage threshold of the diamond-like structure crystal material is 1 to 50 times that of AgGaS2; The frequency doubling intensity of the diamond-like structure crystal material is 0.5 to 5 times that of AgGaS2; in, The cell parameters of NaGa5S8 are: a =7.71 Å; b =8.74 Å, c = 10.6 Å, α = 87.8︒, β = 70.16︒, γ =70.6︒, V = 634.2Å 3 Z = 1; The cell parameters of KGa5S8 are a =8.11 Å; b =9.02 Å, c = 11.2 Å, α = 89.0︒, β = 71.18︒, γ =71.8︒, V = 734.2Å 3 Z = 1; The cell parameters of RbGa5Se8 are: a =8.81 Å; b =8.79 Å, c = 10.60 Å, α = 89.8︒, β = 72.3︒, γ =71.8︒, V = 736.5Å 3 Z = 1; The cell parameters of KIn5Se8 are: a =9.03 Å; b =9.39 Å, c = 12.08 Å, α = 89.5︒, β = 72.9︒, γ =72.0︒, V = 927.9 Å 3 Z = 1; The cell parameters of CsIn5Te8 are a =9.79 Å; b =10.58 Å, c = 13.58 Å, α = 89.9︒, β = 73.1︒, γ = 73.6︒, V = 1293.5Å 3 Z = 1.

2. The method for preparing the diamond-like carbon crystal material according to claim 1, characterized in that, Includes the following steps: A mixture of raw materials containing element A, element M, element Q, and element Ax is placed into a reaction vessel, sealed under vacuum, heated to the reaction temperature, and reacted to obtain the diamond-like crystal material. In AX, X is selected from at least one of Cl, Br, and I.

3. The preparation method according to claim 2, characterized in that, Raw materials containing elements A, M, Q, and AX are prepared and mixed evenly in a molar ratio of A:M:Q:AX = 1:(4~6):(7~9):(3~6).

4. The preparation method according to claim 2, characterized in that, In the raw material mixture, the source of element M is selected from elemental M; The source of element Q is selected from element Q.

5. The preparation method according to claim 2, characterized in that, The conditions for the reaction are: The reaction temperature is 700°C ~ 1000°C, and the reaction time is 1 h ~ 150 h.

6. The preparation method according to claim 2, characterized in that, The reaction temperature is reached by heating at a rate of 1°C / h to 60°C / h.

7. The preparation method according to claim 2, characterized in that, Cooling is required after the reaction; The cooling is either natural cooling or cooling at a rate of 1°C / h-10°C to 300°C-400°C followed by natural cooling.

8. The preparation method according to claim 2, characterized in that, After vacuuming, the pressure range inside the reaction vessel is 10. -3 Pa -10Pa.

9. The application of the diamond-like carbon crystal material of claim 1 or the diamond-like carbon crystal material obtained by the preparation method according to any one of claims 2 to 8 as a nonlinear optical crystal in the field of lasers.

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