Diamond-like structure crystal material, preparation method thereof and application of diamond-like structure crystal material as infrared nonlinear optical material

Abstract

The invention discloses a diamond-like structure crystal material, a preparation method thereof and application of the diamond-like structure crystal material as an infrared nonlinear optical material, and belongs to the technical field of crystal preparation. The structure of the diamond-like structure crystal material is a triclinic phase, and the chemical formula of the diamond-like structure crystal material is 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; q is selected from at least one of S, Se and Te. The frequency-doubled effect of the crystal material is 0.5-5 times of that of AgGaS2, the laser damage threshold is 1-50 times of that of AgGaS2, the performance is greatly improved, and the crystal material is a potential infrared nonlinear optical material.

Description

Technical Field

[0001] The present application relates to a diamond-like structure crystal material and a preparation method thereof and application thereof as an infrared nonlinear optical material, belonging to the technical field of crystal preparation. Background Art

[0002] Nonlinear optical (NLO) materials, with their frequency conversion capability in the UV to mid-infrared region (2.5 to 25 microns), can generate tunable coherent lasers, which plays a vital role in promoting the development of solid-state lasers, especially 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 UV, UV and visible to near-infrared regions. However, due to the strong chemical absorption of these materials, their application in the mid-infrared and far-infrared regions is greatly limited. In contrast, chalcogenides have become excellent NLO materials in the infrared spectral region because of their red-shifted interatomic stretching frequency, which shows higher transparency in the mid-infrared region. In addition, the large polarizability microstructure of chalcogenides can produce strong NLO coefficients, meeting the standards of commercial NLO materials such as AgGaS2, AgGaSe2 and ZnGeP2. Nevertheless, these materials also face several challenges, such as low laser-induced damage threshold, two-photon absorption, and non-phase-matching behavior, which limit their commercial applications. Therefore, it is urgent to develop new chalcogenide materials with excellent NLO performance to overcome the limitations of existing materials. Summary of the invention

[0003] In order to solve the problem that it is difficult to balance a large NLO effect and a high laser damage threshold in the existing technology of nonlinear optical (NLO) crystals in the infrared spectral region, the present application provides a diamond-like structure crystal material, whose NLO effect is 0.5-5 times that of commercial AgGaS2, and whose laser damage threshold is 1-50 times that of commercial AgGaS2. The comprehensive performance is greatly improved, and it is a potential infrared NLO material.

[0004] This application adopts the following scheme:

[0005] According to one aspect of the present application, a diamond-like structure crystal material is provided, characterized in that the structure of the diamond-like structure crystal material is a 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 at least one selected from S, Se, and Te.

[0009] Optionally, 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 pore-like framework.

[0010] Optionally, the diamond-like structure crystal material belongs to the P1 space group of the monoclinic system.

[0011] Optionally, the unit cell parameters of the diamond-like structure crystal material are α=87.858(3)-89.961(3)°, β=70.162(4)-73.189(4)°, γ=70.600(4)-73.680(4)°, 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 double-frequency intensity of the diamond-like structure crystal material is 0.5 to 5 times that of AgGaS2.

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

[0016] Putting a raw material mixture containing single substance A, element M, element Q, and AX into a reaction container, evacuating and sealing it, heating it to a reaction temperature, and reacting it to obtain the diamond-like structure crystal material;

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

[0018] Optionally, the raw materials containing the A element, the M element, the Q element and the AX are prepared in a molar ratio of A:M:Q:AX=1:(4-6):(7-9):(3-6) and mixed uniformly to obtain the material.

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

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

[0021] Optionally, the reaction conditions are:

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

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

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

[0025] The cooling is one of natural cooling or cooling to 300°C to 400°C at a cooling rate of 1°C / h-10°C / h and then natural cooling.

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

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

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

[0029] According to another aspect of the present application, there is also provided an application of the diamond-like structure crystal material or the diamond-like structure crystal material obtained according to the above preparation method as a nonlinear optical crystal in the laser field.

[0030] The beneficial effects of this application include:

[0031] The diamond-like structure crystal material provided in the present application has 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. The performance is greatly improved, and it is a potential infrared nonlinear optical material. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The powder diffraction pattern of RbGa5Se8 prepared in the embodiment of the present application;

[0033] Figure 2 It is the frequency-doubled signal of NaGa5S8, KGa5S8, RbGa5Se8, KIn5Se8, CsIn5Se8, and CsIn5Te8 polycrystalline powder at 1910nm;

[0034] Figure 3 This is the crystal structure of RbGa5Se8 prepared in the example of the present application. DETAILED DESCRIPTION

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

[0036] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0037] Instrument used for single crystal X-ray diffraction: Rigaku FR-X microfocus diffractometer;

[0038] Test conditions: 293K, structure analysis using SHELXTL crystallography software.

[0039] Instrument used for powder X-ray diffraction: Rigaku Flex600 X-ray diffractometer;

[0040] Test conditions: 293K.

[0041] The calculation method of the laser damage threshold described in this application is to use a VIBRANTHE 355LD laser produced by OPOTEK, USA. First, Example 1 and commercially available AgGaS2 (Comparative Example 1) are screened separately to screen out particles with a particle size range of 150-200nm, and then placed under a 1064nm laser light path with a pulse width of 10ns. By continuously increasing the laser power, the surface damage of the sample is observed. When a damage spot appears on the sample, the laser power is recorded, and the size of the damage spot is measured. The laser power / damage area is used as the value of the laser damage threshold for comparison.

[0042] The test method of the frequency doubling signal described in the present application is to use a standard sieve to screen out crystals with particle sizes of 30-50, 50-75, 75-100, 100-150, and 150-200 nm from the sample crystals and the AgGaS2 crystals used as a reference, respectively, and load the samples separately, place them under the laser light path, and use a near-infrared charge-coupled detector to test their nonlinear optical properties at a laser intensity of 1910 nm. Then, a graph is drawn with the particle size as the horizontal axis and the measured nonlinear optical performance as the vertical axis to determine the size of the nonlinear optical performance of the crystal material and the phase matching of the crystal material.

[0043] Example 1

[0044] Na (13 mg), Ga (159 mg), S (128 mg) and NaCl (150 mg) were mixed and placed in a quartz tube and evacuated to 10 -3 The Pa sealed tube was placed in a muffle furnace and slowly heated to 980°C. After keeping the temperature for 144 hours, the temperature was reduced to 400°C at 3°C / h. The muffle furnace was turned off and naturally cooled to room temperature to obtain a crystal with the chemical formula of monoclinic NaGa5S8.

[0045] Example 2

[0046] K (19 mg), Ga (162 mg), S (119 mg) and KI (180 mg) were mixed and placed in a quartz tube and evacuated to 10 -2The Pa sealed tube was placed in a muffle furnace and slowly heated to 700°C. After keeping the temperature for 15 hours, the tube was cooled to 400°C at 3°C / h. The muffle furnace was turned off and the tube was naturally cooled to room temperature to obtain a crystal with the chemical formula of monoclinic KGa5S8.

[0047] Example 3

[0048] Rb (24 mg), Ga (98 mg), Se (177 mg) and RbCl (180 mg) were mixed and placed in a quartz tube and evacuated to 10 -3 The Pa sealed tube was placed in a muffle furnace and slowly heated to 620°C. After keeping the temperature for 72 hours, the temperature was lowered to 400°C at 4°C / h. The muffle furnace was turned off and naturally cooled to room temperature to obtain a crystal with a chemical formula of monoclinic RbGa5Se8. The powder diffraction pattern of the crystal is shown in Figure 1 The crystal structure is shown in Figure 3 shown.

[0049] Example 4

[0050] K (9 mg), In (152 mg), Se (140 mg) and KCl (150 mg) were prepared and mixed evenly, placed in a quartz tube, evacuated to 1 Pa and sealed, and then slowly heated to 850°C in a muffle furnace. After keeping warm for 100 hours, the temperature was reduced to 400°C at 3°C / h, and the muffle furnace was turned off and naturally cooled to room temperature to obtain crystals with the chemical formula of monoclinic KIn5Se8.

[0051] Example 5

[0052] Cs (37 mg), In (130 mg), Se (133 mg) and CsBr (220 mg) were prepared and mixed evenly, placed in a quartz tube, evacuated to 10 Pa and sealed, and then slowly heated to 870°C in a muffle furnace. After keeping warm for 100 hours, the temperature was reduced to 300°C at 5°C / h, and the muffle furnace was turned off and naturally cooled to room temperature to obtain crystals with the chemical formula of monoclinic CsIn5Se8.

[0053] Example 6

[0054] K (8 mg), In (105 mg), Te (187 mg) and KBr (160 mg) were prepared and mixed evenly, placed in a quartz tube, evacuated to 10 Pa and sealed, placed in a muffle furnace and slowly heated to 870°C. After keeping warm for 100 hours, the temperature was reduced to 300°C at 5°C / h, the muffle furnace was turned off and naturally cooled to room temperature to obtain a crystal with the chemical formula of monoclinic CsIn5Te8.

[0055] Test Example 1

[0056] NLO performance test method: Use standard sieves to screen out crystals with particle sizes of 30-50, 50-75, 75-100, 100-150, and 150-200nm from the sample crystals and the reference AgGaS2 crystals. Load the samples separately and place them under the laser light path. Use a near-infrared charge-coupled detector to test their nonlinear optical properties at a laser intensity of 1910nm. Draw a graph with the particle size as the horizontal axis and the measured nonlinear optical performance as the vertical axis to determine the NLO performance of the crystal material and the phase matching of the crystal material.

[0057] Figure 2 It shows that monoclinic NaGa5S 8， K5S 8， RbGa5Se 8， KIn5Se 8， CsIn5Se 8， The double frequency signals of the compound polycrystalline powder of CsIn5Te8 are 0.9, 1.1, 2.1, 2.8, 2.8 and 3.8 times of AgGaS2 respectively, with a particle size of 150-200um at 1910nm.

[0058] Test Example 2

[0059] Laser damage threshold test of samples: Use standard sieves to screen out crystals with a particle size range of 150-200nm from the sample crystals and the AgGaS2 crystals used as reference, load the samples separately, and place them under a 1064nm laser light path with a pulse width of 10ns. Continuously increase the laser power and observe the damage on the sample surface until a damage spot appears on the sample. Record the laser power at this time, and measure the size of the damage spot to calculate the laser damage threshold of the sample.

[0060] The results are shown in Table 1. At 1064nm, the laser damage thresholds of AM5Q8 (A = Na, K, Rb, Cs; M = Ga, In; Q = S, Se, Te) compounds and AgGaS2 polycrystalline powder are compared. 8， K5S 8， RbGa5Se 8， KIn5Se 8， CsIn5Se 8， The laser damage thresholds of CsIn5Te8 are 47.0, 46.0, 21.4, 18.0, 17.5, and 7.6 times that of AgGaS2.

[0061] Table 1

[0062] sample <![CDATA[Laser damage threshold MW / cm 2 > <![CDATA[AgGaS2]]> 2.0 <![CDATA[NaGa5S8]]> 94.0 <![CDATA[KGa5S8]]> 92.8 <![CDATA[RbGa5Se8]]> 42.8 <![CDATA[KIn5Se8]]> 36.0 <![CDATA[CsIn5Se8]]> 35.6 <![CDATA[CsIn5Te8]]> 15.2

[0063] Test Example 3

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

[0065] NaGa5S8, belongs to the monoclinic P1 space group, α=87.8°, β=70.16°, γ=70.6°, Z=1.

[0066] KGa5S8, belongs to the monoclinic P1 space group, α=89.0°, β=71.18°, γ=71.8°, Z=1.

[0067] RbGa5Se8, belongs to the monoclinic P1 space group, α=89.8°, β=72.3°, γ=71.8°, Z=1.

[0068] KIn5Se8, belongs to the monoclinic P1 space group, α=89.5°, β=72.9°, γ=72.0°, Z=1.

[0069] CsIn5Se8, belongs to the monoclinic P1 space group, α=89.5°, β=73.0°, γ=72.2°, Z=1.

[0070] CsIn5Te8, belongs to the monoclinic P1 space group, α=89.9°, β=73.1°, γ=73.6°, Z=1.

[0071] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A diamond-like structure crystal material, characterized in that: The structure of the diamond-like crystal material is triclinic phase, and the chemical formula is 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; Q is at least one selected from S, Se, and Te.

2. The diamond-like structure crystal material according to claim 1, characterized in that: The diamond-like structure crystal material belongs to the P1 space group of the monoclinic system.

3. The diamond-like structure crystal material according to claim 1, characterized in that: The unit cell parameter of the diamond-like structure crystal material is a=7.7114(4)-9.7927(3); α=87.858(3)-89.961(3)°, β=70.162(4)-73.189(4)°, γ=70.600(4)-73.680(4)°, Z=1.

4. The diamond-like structure crystal material according to claim 1, characterized in that: The powder laser damage threshold of the diamond-like structure crystal material is 1 to 50 times that of AgGaS2.

5. The diamond-like structure crystal material according to claim 1, characterized in that: The frequency doubling intensity of the diamond-like structure crystal material is 0.5 to 5 times that of AgGaS2.

6. The method for preparing the diamond-like structure crystal material according to any one of claims 1 to 5, characterized in that: The steps include: Putting a raw material mixture containing single substance A, element M, element Q, and AX into a reaction container, vacuumizing and sealing it, heating it to a reaction temperature, and reacting it to obtain the diamond-like structure crystal material; Wherein, X in AX is selected from at least one of Cl, Br and I.

7. The preparation method according to claim 6, characterized in that: The raw materials containing the A element, the M element, the Q element and the AX are prepared in a molar ratio of A:M:Q:AX=1:(4-6):(7-9):(3-6) and mixed uniformly to obtain; Preferably, in the raw material mixture, the source of the M element is selected from M single substance; The source of the Q element is selected from Q single substance.

8. The preparation method according to claim 6, characterized in that: The reaction conditions are: The reaction temperature is 700°C to 1000°C, and the reaction time is 1h to 150h; Preferably, the reaction temperature is reached by heating, and the heating rate is 1° C. / h to 60° C. / h.

9. The preparation method according to claim 6, characterized in that: After the reaction, the temperature needs to be lowered; The cooling is one of natural cooling or cooling to 300°C to 400°C at a cooling rate of 1°C / h-10°C / h and then natural cooling; Preferably, the pressure range of the reaction container after vacuuming is 10 -3 Pa-10Pa.

10. Use of the diamond-like structure crystal material according to any one of claims 1 to 5 or the diamond-like structure crystal material obtained by the preparation method according to any one of claims 6 to 9 as a nonlinear optical crystal in the laser field.

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