Cesium-magnesium-gallium-sulfur-chlorine mid-far infrared nonlinear optical crystal and preparation method and application thereof

Abstract

The invention relates to a Cs2Mg2Ga3S7Cl mid-far infrared nonlinear optical crystal as well as a preparation method and application thereof. The crystal has a chemical formula of Cs2Mg2Ga3S7Cl and a molecular weight of 783.47 amu, is crystallized in an orthorhombic crystal system, has a space group of Cmc21 and has cell parameters of a = 7.3913 (4), b = 33.593 (2) and c = 6.2173 (3). The alpha is 90 degrees, the beta is 90 degrees, the gamma is 90 degrees, and the V is 1543.73 (14) 3. The obtained cesium, magnesium, gallium, sulfur and chlorine is a colorless and transparent crystal with a non-centrosymmetric structure, and a structural element is composed of [GaS4], [MgS3Cl] tetrahedrons and [MgS6] hexahedrons. The material is prepared by adopting a high-temperature melt spontaneous crystallization method or a Bridgman-Stockbarger method, and can be used for preparing infrared band laser frequency conversion, infrared laser guidance, infrared laser radar, energy detection and long-distance laser communication. The material has the advantages of excellent optical performance, long infrared absorption cut-off side, wide band gap, high laser damage threshold and large nonlinear optical coefficient. The method has important application value in a high-power infrared laser system.

Description

Technical Field

[0001] The invention relates to a cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystal material, a preparation method and an application thereof, and belongs to the field of infrared nonlinear optical crystals. Background Art

[0002] Nonlinear optical materials play a vital role in modern laser science and technology. They can expand the spectral range of lasers through frequency conversion technology and are widely used in long-distance laser communications, infrared remote sensing, laser lithography, environmental monitoring and photon technology. In the past, significant progress has been made in the field of ultraviolet and visible light, and a series of nonlinear optical crystals such as β-BaB 2 O 4 (BBO), LiB 3 O 5 (LBO), CsLiB 6 O 10 (CLBO), KBe 2 BO 3 F 2 (KBBF), KH 2 PO 4 (KDP), KTiOPO 4 (KTP), etc. However, their transmittance in the mid- and far-infrared bands is insufficient, the infrared cutoff edge is narrow, and the nonlinear coefficient is small, which severely limits their application in the infrared band. Currently, the nonlinear optical materials that can be commercially applied in the infrared band are mainly AgGaS 2 、AgGaSe 2 and ZnGeP 2 These materials have a wide transmission range and large nonlinear optical coefficient in the infrared band, but they also have some defects, such as low laser damage threshold, ZnGeP 2 There is strong two-photon absorption under the 1μm pump light source, which makes it difficult to achieve high-power laser output in the mid-infrared and far-infrared bands, and cannot fully meet the needs of current laser technology development. It is urgent to develop and design new infrared nonlinear optical crystal materials that have both large frequency doubling and high damage threshold.

[0003] Excellent infrared nonlinear optical crystal materials need to meet the following basic requirements: (1) non-centrosymmetric structure; (2) large nonlinear optical coefficient (≥0.5×AGS); (3) wide infrared wave transmission range (covering two atmospheric windows of 3-5μm and 8-12μm); (4) high laser damage threshold (≥2×AGS); (5) moderate birefringence to meet phase matching conditions (0.03-0.10); (6) stable physical and chemical properties and good mechanical processing performance; (7) good crystal growth habits to facilitate the acquisition of high-quality large-size single crystals, etc. Chalcogenides usually show larger band gaps and wider infrared transparent regions, and are excellent candidates for exploring new mid- and far-infrared nonlinear optical materials. Usually, the Ga atoms in the structure are four-coordinated with the chalcogenide elements Q (Q=S, Se) to form a strong covalent chemical bond, with strong electron delocalization and large electron cloud dispersion. They are easily polarized under an external electric field. If their arrangement directions are consistent, they will cause the superposition of polarizabilities and can produce a large frequency doubling effect. In order to increase the band gap of chalcogenides and effectively control the crystal structure, introducing highly electronegative halogens and alkali metals with large atomic radius into chalcogenides has been proven to be a feasible strategy. Under the guidance of this idea, a high-temperature solid-phase reaction was successfully synthesized to have a band gap and laser damage threshold far exceeding the current commercial AgGaS 2 The new infrared nonlinear optical crystal material of the material is cesium magnesium gallium sulfur chloride. In its structure, the Mg atom exhibits two different coordination modes, forming MgS 6 With MgS 3 Cl group, it is rare for the same atom to exhibit different coordination modes in one compound, and MgS 3 As far as we know, this is the first time that the Cl mixed anion group has been discovered and reported. Ga atoms are combined with S atoms in a four-coordinated form to form GaS 4 group, and three GaS 4 The groups are connected to form Ga 3 S 9 These trimers are in MgS 6 Under the regulation of , the compounds are orderly assembled to form a regular arrangement with consistent orientation. These structural features indicate that the compound may have balanced nonlinear optical properties. Summary of the invention

[0004] The present invention aims to provide a cesium magnesium gallium sulfur chlorine mid-to-far infrared nonlinear optical crystal and a preparation method and application thereof. The chemical formula of the crystal is Cs 2 Mg 2 Ga 3 S 7 Cl, molecular weight 783.47amu, belongs to the orthorhombic system, space group is Cmc2 1 , the unit cell parameters are α=90°, β=90°, γ=90°, The cesium magnesium gallium sulfur chlorine mid-to-far infrared nonlinear optical crystal of the present invention is prepared by a high-temperature melt spontaneous crystallization method or a crucible descent method and is used in the preparation of infrared band laser frequency conversion, infrared laser guidance, infrared laser radar, energy detection, and long-distance laser communication. The obtained cesium magnesium gallium sulfur chlorine mid-to-far infrared nonlinear optical crystal has excellent optical properties, and its infrared absorption cutoff side is long, the band gap is wide, the laser damage threshold is high, and the nonlinear optical coefficient is large. As a new mid-to-far infrared nonlinear optical crystal, it has important application value in high-power infrared laser systems.

[0005] The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystal of the present invention has a chemical formula of Cs 2 Mg 2 Ga 3 S 7 Cl, molecular weight 783.47amu, belongs to the orthorhombic system, space group is Cmc2 1 , the unit cell parameters are α=90°, β=90°, γ=90°, The crystal structure is [GaS 4 ]、[MgS 3 Cl] tetrahedron and [MgS 6 The hexahedral group is the basic structural unit, the crystal band gap is 3.83eV, and the frequency doubling effect is the commercial material AgGaS 2 1.1 times of.

[0006] The preparation method of the cesium magnesium gallium sulfur chlorine mid-to-far infrared nonlinear optical crystal adopts a high-temperature melt spontaneous crystallization method or a crucible descent method:

[0007] The high temperature melt spontaneous crystallization method is used to grow the Cesium Magnesium Gallium Sulfur Chloride mid- and far-infrared nonlinear optical crystal, and the specific operation is carried out according to the following steps:

[0008] a. Cs or its compound CsCl, Mg or its compound MgS, Ga or its compound Ga 2 S 3 , and elemental S are mixed evenly, placed in a clean graphite crucible, and then placed in a quartz glass tube. The quartz tube is pumped to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0009] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850-950°C at a rate of 30-40°C / h, and keep warm for 40-50h;

[0010] c. Cooling to room temperature at a cooling rate of 3-5°C / h to obtain a cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystal;

[0011] The crucible descent method for growing the CsMgGaSCl mid- and far-infrared nonlinear optical crystal is specifically performed in the following steps:

[0012] a. Cs or its compound CsCl, Mg or its compound MgS, Ga or its compound Ga 2 S 3 , and elemental S are mixed evenly, placed in a clean graphite crucible, and then placed in a quartz glass tube. The quartz tube is pumped to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0013] b. Place the sealed quartz tube in step a into a crucible descending furnace, raise the temperature to 850-950°C at a rate of 30-40°C / h, and keep warm for 40-50h;

[0014] c and then vertically descend at a speed of 0.1-10 mm / h. Crystal growth is carried out during the descending process of the crystal growth device. The growth cycle is 10-40 days. After the crystal growth is completed, the crystal is still left in the growth furnace for annealing and cooled to room temperature at a rate of 30-80°C / h to obtain a cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystal.

[0015] The cesium magnesium gallium sulfur chlorine mid-to-far infrared nonlinear optical crystal is used in the preparation of infrared band laser frequency conversion, infrared laser guidance, infrared laser radar, energy detection, and long-distance laser communication.

[0016] The cesium magnesium gallium chlorine sulfur mid- and far-infrared nonlinear optical crystal, preparation method and application of the present invention are prepared according to the following chemical reaction formula:

[0017] (1) 4CsCl+4Mg+6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 ;

[0018] (2) 4CsCl+4MgS+6Ga+10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 ;

[0019] (3) 4CsCl+4Mg+3Ga 2 S 3+5S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 ;

[0020] (4) 4CsCl+4MgS+3Ga 2 S 3 +S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 ;

[0021] (5) 4Cs+4MgCl 2 +6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+3Cl 2 ;

[0022] (6) 4Cs+4MgCl 2 +3Ga 2 S 3 +5S=2Cs 2 Mg 2 Ga 3 S 7 Cl+3Cl 2 ;

[0023] (7) 4Cs+4Mg+6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+8Cl 2 ;

[0024] (8) 4Cs+4MgS+6GaCl 3 +10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+8Cl 2 ;

[0025] (9) 4Cs+4MgCl 2 +6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+12Cl 2 ;

[0026] (10) 4CsCl+4MgCl 2 +6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+5Cl 2 ;

[0027] (11) 4CsCl+4Mg+6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+10Cl 2 ;

[0028] (12) 4CsCl+4MgCl 2 +6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+14Cl 2 ;

[0029] (13) 4CsCl+4MgCl 2 +3Ga 2 S 3 +5S=2Cs 2 Mg 2 Ga 3 S 7 Cl+5Cl 2 ;

[0030] (14) 4CsCl+4MgS+6GaCl 3 +10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+10Cl 2 .

[0031] The cesium magnesium gallium sulfide chlorine mid- and far-infrared nonlinear optical crystal, preparation method and application thereof disclosed in the present invention, wherein the method involves the crucible descent method for growing the cesium magnesium gallium sulfide chlorine mid- and far-infrared nonlinear optical crystal, and further comprises post-treatment of the cesium magnesium gallium sulfide chlorine nonlinear optical crystal: after the crystal growth is completed, the crystal is still left in the growth furnace for annealing, and is cooled to room temperature at a rate of 30-80°C / h, preferably at a cooling rate of 30-40°C / h.

[0032] Both the high temperature melt spontaneous crystallization method and the crucible descent method can obtain a crystal with a size of 1.23×0.77×0.12mm.2 By using a large crucible and extending the growth period, correspondingly larger cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals can be obtained.

[0033] According to the crystallographic data of the crystal, the crystal blank is oriented, the crystal is cut according to the required angle, thickness and cross-sectional size, and the light-transmitting surface of the crystal is polished, and it can be used as a nonlinear optical device.

[0034] The cesium magnesium gallium sulfide chlorine mid- and far-infrared nonlinear optical crystal, preparation method and application of the present invention can be used to prepare a nonlinear optical device, which comprises a device for generating at least one beam of output radiation with a frequency different from the incident electromagnetic radiation after at least one beam of incident electromagnetic radiation passes through at least one cesium magnesium gallium sulfide chlorine nonlinear optical crystal.

[0035] The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystal, preparation method and application described in the present invention have excellent optical properties, infrared absorption cutoff length, wide band gap, high laser damage threshold and large nonlinear optical coefficient. It has excellent infrared nonlinear optical properties: the frequency doubling effect is the commercial material AgGaS 2 The band gap can reach 3.83eV, which is 1.1 times that of AgGaS. 2 The band gap of the crystal is 2.64eV. As a new type of mid- and far-infrared nonlinear optical crystal, it has important application value in high-power infrared laser systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Cs 2 Mg 2 Ga 3 S 7 The crystal structure of Cl, where a is the coordination form of Ga atoms and Mg atoms in the compound, and b is the Ga formed under the squeeze constraint of Cs atoms. 3 S 9 Group and Mg 2 S 8 Cl connects the alternating structure, c is Ga 3 S 9 The interweaving of the groups forms [Ga 3 S 9 ] layer, d is [Mg 2 S 8 Cl] chain and [Ga 3 S 9 ] layer in the b direction, e is the schematic diagram of [Mg 2 S 8 Cl] chain and [Ga 3 S 9] layered structure, f is Cs 2 Mg 2 Ga 3 S 7 Crystal structure of Cl crystal in b direction;

[0037] Figure 2 Cs 2 Mg 2 Ga 3 S 7 Bandgap diagram of Cl;

[0038] Figure 3 Cs 2 Mg 2 Ga 3 S 7 Cl and AgGaS 2 The relationship between the nonlinear strength and particle size;

[0039] Figure 4 The figure is a working principle diagram of a nonlinear optical system, wherein 1 is a laser, 2 is a convex lens, 3 is a cesium magnesium gallium sulfur chloride crystal, 4 is a prism, and 5 is a filter. The laser beam emitted by the laser 1 passes through the convex lens 2 and enters the cesium magnesium gallium sulfur chloride single crystal 3, and the generated outgoing laser beam passes through the prism 4 and the filter 5, thereby obtaining the required laser beam. DETAILED DESCRIPTION

[0040] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other alternative features that are equivalent or have similar purposes. Unless otherwise stated, each feature is only an example of a series of equivalent or similar features. The description is only to help understand the present invention and should not be regarded as a specific limitation of the present invention.

[0041] The present invention is described in detail by the following drawings and the following embodiments.

[0042] Example 1

[0043] According to the chemical reaction formula 4CsCl+4Mg+6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0044] a. Weigh 0.247 g CsCl, 0.036 g Mg, 0.153 g Ga and 0.165 g S in a molar ratio of 2:2:3:7, mix them evenly, put them into a clean graphite crucible, and then put them into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0045] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850°C at a rate of 30°C / h, and keep warm for 50h;

[0046] c. Cool down to room temperature at a cooling rate of 3°C / h to obtain a size of 2.21×1.72×0.21mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0047] Example 2

[0048] According to the chemical reaction formula 4CsCl+4MgS+6Ga+10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0049] a. Weigh 0.247 g CsCl, 0.083 g MgS, 0.153 g Ga and 0.118 g S in a molar ratio of 2:2:3:5, mix them evenly, put them into a clean graphite crucible, and then put them into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0050] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850°C at a rate of 35°C / h, and keep warm for 40h;

[0051] c. Cool down to room temperature at a cooling rate of 4°C / h to obtain a size of 1.23×0.77×0.12mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0052] Example 3

[0053] The chemical reaction formula is 4CsCl+4Mg+3Ga 2 S 3 +5S=2Cs 2 Mg 2 Ga3 S 7 Cl+Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0054] a. Weigh 0.247 g CsCl, 0.036 g Mg, and 0.259 g Ga in a molar ratio of 4:4:3:5. 2 S 3 Mix the mixture with 0.059 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0055] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850° C. at a rate of 37° C. / h, and keep the temperature for 45 h;

[0056] c. Cool down to room temperature at a cooling rate of 5°C / h to obtain a size of 2.31×1.88×0.41mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0057] Example 4

[0058] The chemical reaction formula is 4CsCl+4MgS+3Ga 2 S 3 +S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0059] a. Weigh 0.247 g CsCl, 0.083 g MgS, and 0.259 g Ga in a molar ratio of 4:4:3:1. 2 S 3 Mix the mixture with 0.012 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0060] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850°C at a rate of 40°C / h, and keep warm for 50h;

[0061] c. Cool down to room temperature at a cooling rate of 5°C / h to obtain a size of 3.42×2.33×0.21mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0062] Example 5

[0063] According to the chemical reaction formula 4Cs+4MgCl 2 +6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+3Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0064] a. Weigh 0.196 g Cs and 0.083 g MgCl in a molar ratio of 2:2:3:7 2 , 0.155 g of Ga and 0.166 g of S were mixed evenly, put into a clean graphite crucible, and then loaded into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was pumped to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0065] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900°C at a rate of 30°C / h, and keep warm for 50h;

[0066] c. Cool down to room temperature at a cooling rate of 5°C / h to obtain a size of 4.31×3.21×0.52mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0067] Example 6

[0068] According to the chemical reaction formula 4Cs+4MgCl 2 +3Ga 2 S 3 +5S=2Cs 2 Mg 2 Ga 3 S 7 Cl+3Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0069] a. Weigh 0.196 g Cs, 0.083 g MgS, and 0.261 g Ga in a molar ratio of 4:4:3:5. 2 S 3Mix the mixture with 0.059 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0070] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900°C at a rate of 40°C / h, and keep warm for 40h;

[0071] c. Cool down to room temperature at a cooling rate of 3°C / h to obtain a size of 2.22×2.01×0.16mm 3 Cesium magnesium gallium sulfur chloride infrared nonlinear optical crystal;

[0072] Example 7

[0073] According to the chemical reaction formula 4Cs+4Mg+6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+8Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0074] a. Weigh 0.149 g Cs, 0.027 g Mg, and 0.297 g GaCl in a molar ratio of 2:2:3:7. 3 Mix the mixture with 0.126 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0075] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900°C at a rate of 33°C / h, and keep warm for 42h;

[0076] c. Cool down to room temperature at a cooling rate of 3.5°C / h to obtain a size of 0.86×0.51×0.26mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0077] Example 8

[0078] The chemical reaction formula is 4Cs+4MgS+6GaCl 3 +10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+8Cl2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0079] a. Weigh 0.149 g Cs, 0.063 g MgS, and 0.297 g GaCl in a molar ratio of 2:2:3:5. 3 and 0.090 g S were mixed evenly, and then placed into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was pumped to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0080] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0081] c. Cool down to room temperature at a cooling rate of 4°C / h to obtain a size of 1.21×1.32×0.53mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0082] Example 9

[0083] According to the chemical reaction formula 4Cs+4MgCl 2 +6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+12Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0084] a. Weigh 0.132 g Cs and 0.095 g MgCl in a molar ratio of 2:2:3:7 2 , 0.262 g GaCl 3 Mix the mixture with 0.111 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0085] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 930° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0086] c. Cool down to room temperature at a cooling rate of 4°C / h to obtain a size of 1.01×0.99×0.23mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0087] Example 10

[0088] According to the chemical reaction formula 4CsCl+4MgCl 2 +6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+5Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0089] a. Weigh 0.210 g CsCl and 0.119 g MgCl in a molar ratio of 2:2:3:7 2 , 0.131 g of Ga and 0.140 g of S were mixed evenly, placed in a clean graphite crucible, and then loaded into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was pumped to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0090] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 920°C at a rate of 38°C / h, and keep the temperature for 46h;

[0091] c. Cool down to room temperature at a cooling rate of 4°C / h to obtain a size of 0.71×0.65×0.15mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0092] Embodiment 11

[0093] According to the chemical reaction formula 4CsCl+4Mg+6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+10Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0094] a. Weigh 0.178 g CsCl, 0.026 g Mg, and 0.279 g GaCl in a molar ratio of 2:2:3:7. 3 Mix the mixture with 0.118 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0095] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 950° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0096] c. Cool down to room temperature at a cooling rate of 4°C / h to obtain a size of 1.11×1.01×0.15mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0097] Example 12

[0098] According to the chemical reaction formula 4CsCl+4MgCl 2 +6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+14Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0099] a. Weigh 0.158 g CsCl and 0.089 g MgCl in a molar ratio of 2:2:3:7 2 , 0.248 g GaCl 3 Mix the mixture with 0.105 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0100] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 930° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0101] c. Cool down to room temperature at a cooling rate of 4°C / h to obtain a size of 1.01×0.88×0.15mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0102] Example 13

[0103] According to the chemical reaction formula 4CsCl+4MgCl 2 +3Ga 2 S 3 +5S=2Cs 2 Mg 2 Ga 3 S 7 Cl+5Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0104] a. Weigh 0.210 g CsCl and 0.119 g MgCl in a molar ratio of 4:4:3:5. 2 , 0.221 g Ga 2 S 3 Mix the mixture with 0.050 g S, put it into a clean graphite crucible, and then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0105] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 890° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0106] c. Cool down to room temperature at a cooling rate of 4°C / h to obtain a size of 1.83×1.52×0.31mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0107] Embodiment 14

[0108] According to the chemical reaction formula 4CsCl+4MgS+6GaCl 3 +10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+10Cl 2 The cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals were prepared by high-temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0109] a. Weigh 0.178 g CsCl, 0.060 g MgS, and 0.279 g GaCl in a molar ratio of 2:2:3:5. 3 Mix the mixture with 0.085 g S, put it into a clean graphite crucible, and then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0110] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0111] c. Cool down to room temperature at a cooling rate of 4°C / h to obtain a size of 1.27×1.22×0.17mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0112] Embodiment 15

[0113] According to the chemical reaction formula 4CsCl+4Mg+6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0114] a. Weigh 0.247 g CsCl, 0.036 g Mg, 0.153 g Ga and 0.165 g S in a molar ratio of 2:2:3:7, mix them evenly, put them into a clean graphite crucible, and then put them into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0115] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850°C at a rate of 30°C / h, and keep warm for 50h;

[0116] c. Then the crystal is vertically lowered at a speed of 0.1 mm / h. The crystal grows during the descending process of the crystal growth device. The growth cycle is 10 days. After the crystal growth is completed, the crystal is still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 0.72×0.41×0.13 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0117] Example 16

[0118] According to the chemical reaction formula 4CsCl+4MgS+6Ga+10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0119] a. Weigh 0.247 g CsCl, 0.083 g MgS, 0.153 g Ga and 0.118 g S in a molar ratio of 2:2:3:5, mix them evenly, put them into a clean graphite crucible, and then put them into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0120] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850°C at a rate of 35°C / h, and keep warm for 40h;

[0121] c. Then the crystal is vertically lowered at a speed of 0.1 mm / h. The crystal grows during the descending process of the crystal growth device. The growth cycle is 10 days. After the crystal growth is completed, the crystal is still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 0.77×0.74×0.27 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0122] Embodiment 17

[0123] The chemical reaction formula is 4CsCl+4Mg+3Ga 2 S 3 +5S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2 The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0124] a. Weigh 0.247 g CsCl, 0.036 g Mg, and 0.259 g Ga in a molar ratio of 4:4:3:5. 2 S 3 Mix the mixture with 0.059 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0125] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850° C. at a rate of 37° C. / h, and keep the temperature for 45 h;

[0126] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 1.21×0.25×0.15 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0127] Embodiment 18

[0128] The chemical reaction formula is 4CsCl+4MgS+3Ga 2 S 3 +S=2Cs 2 Mg 2 Ga 3 S 7 Cl+Cl 2The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0129] a. Weigh 0.247 g CsCl, 0.083 g MgS, and 0.259 g Ga in a molar ratio of 4:4:3:1. 2 S 3 Mix the mixture with 0.012 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0130] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850°C at a rate of 40°C / h, and keep warm for 50h;

[0131] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 2.12×1.75×0.77 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0132] Embodiment 19

[0133] According to the chemical reaction formula 4Cs+4MgCl 2 +6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+3Cl 2 The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0134] a. Weigh 0.196 g Cs and 0.083 g MgCl in a molar ratio of 2:2:3:7 2 , 0.155 g of Ga and 0.166 g of S were mixed evenly, put into a clean graphite crucible, and then loaded into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was pumped to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0135] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900°C at a rate of 30°C / h, and keep warm for 50h;

[0136] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 2.25×1.99×0.85 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0137] Embodiment 20

[0138] According to the chemical reaction formula 4Cs+4MgCl 2 +3Ga 2 S 3 +5S=2Cs 2 Mg 2 Ga 3 S 7 Cl+3Cl 2 The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0139] a. Weigh 0.196 g Cs, 0.083 g MgS, and 0.261 g Ga in a molar ratio of 4:4:3:5. 2 S 3 Mix the mixture with 0.059 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0140] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900°C at a rate of 40°C / h, and keep warm for 40h;

[0141] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 3.52×3.15×2.25 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0142] Embodiment 21

[0143] According to the chemical reaction formula 4Cs+4Mg+6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+8Cl 2The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0144] a. Weigh 0.149 g Cs, 0.027 g Mg, and 0.297 g GaCl in a molar ratio of 2:2:3:7. 3 Mix the mixture with 0.126 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0145] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900°C at a rate of 33°C / h, and keep warm for 42h;

[0146] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 1.98×1.75×0.86 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0147] Embodiment 22

[0148] The chemical reaction formula is 4Cs+4MgS+6GaCl 3 +10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+8Cl 2 The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0149] a. Weigh 0.149 g Cs, 0.063 g MgS, and 0.297 g GaCl in a molar ratio of 2:2:3:5. 3 and 0.090 g S were mixed evenly, and then placed into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was pumped to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0150] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0151] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 2.11×1.85×0.51 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0152] Embodiment 23

[0153] According to the chemical reaction formula 4Cs+4MgCl 2 +6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+12Cl 2 The crucible descent method is used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0154] a. Weigh 0.132 g Cs and 0.095 g MgCl in a molar ratio of 2:2:3:7 2 , 0.262 g GaCl 3 Mix the mixture with 0.111 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0155] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 930° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0156] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 2.22×1.55×0.38 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0157] Embodiment 24

[0158] According to the chemical reaction formula 4CsCl+4MgCl 2 +6Ga+14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+5Cl 2The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0159] a. Weigh 0.210 g CsCl and 0.119 g MgCl in a molar ratio of 2:2:3:7 2 , 0.131 g of Ga and 0.140 g of S were mixed evenly, placed in a clean graphite crucible, and then loaded into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was pumped to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0160] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 920°C at a rate of 38°C / h, and keep the temperature for 46h;

[0161] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 2.36×1.77×0.82 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0162] Embodiment 25

[0163] According to the chemical reaction formula 4CsCl+4Mg+6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+10Cl 2 The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0164] a. Weigh 0.178 g CsCl, 0.026 g Mg, and 0.279 g GaCl in a molar ratio of 2:2:3:7. 3 Mix the mixture with 0.118 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0165] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 950° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0166] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 3.11×1.02×0.32 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0167] Embodiment 26

[0168] According to the chemical reaction formula 4CsCl+4MgCl 2 +6GaCl 3 +14S=2Cs 2 Mg 2 Ga 3 S 7 Cl+14Cl 2 The preparation of cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals is carried out in the following steps:

[0169] a. Weigh 0.158 g CsCl and 0.089 g MgCl in a molar ratio of 2:2:3:7 2 , 0.248 g GaCl 3 Mix the mixture with 0.105 g S and put it into a clean graphite crucible. Then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0170] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 930° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0171] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 2.17×1.02×0.29 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0172] Embodiment 27

[0173] According to the chemical reaction formula 4CsCl+4MgCl 2 +3Ga 2 S 3 +5S=2Cs 2 Mg 2 Ga 3 S 7 Cl+5Cl 2The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0174] a. Weigh 0.210 g CsCl and 0.119 g MgCl in a molar ratio of 4:4:3:5. 2 , 0.221 g Ga 2 S 3 Mix the mixture with 0.050 g S, put it into a clean graphite crucible, and then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0175] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 890° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0176] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 1.02×0.85×0.43 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0177] Embodiment 28

[0178] According to the chemical reaction formula 4CsCl+4MgS+6GaCl 3 +10S=2Cs 2 Mg 2 Ga 3 S 7 Cl+10Cl 2 The crucible descent method was used to prepare the CsMgGaSCl mid- and far-infrared nonlinear optical crystals. The specific operation was carried out in the following steps:

[0179] a. Weigh 0.178 g CsCl, 0.060 g MgS, and 0.279 g GaCl in a molar ratio of 2:2:3:5. 3 Mix the mixture with 0.085 g S, put it into a clean graphite crucible, and then put it into a quartz glass tube with a length of 24 cm and a diameter of 12 mm. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing;

[0180] b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 900° C. at a rate of 38° C. / h, and keep the temperature for 46 hours;

[0181] c and then vertically descended at a speed of 0.1 mm / h. The crystal grew during the descending process of the crystal growth device. The growth cycle was 10 days. After the crystal growth was completed, the crystal was still left in the growth furnace for annealing and cooled to room temperature at a rate of 30°C / h to obtain a crystal with a size of 0.98×0.75×0.26 mm 3 Cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals.

[0182] Embodiment 29

[0183] After testing, the cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystals prepared in Examples 1-16 belong to the orthorhombic system, and the space group is Cmc2 1 , the unit cell parameters are α=90°, β=90°, γ=90°, The crystal structure diagram is shown in Figure 1 As shown in the crystal structure of cesium magnesium gallium sulfur chlorine, the valences of Cs atoms, Mg atoms, Ga atoms and S atoms are +1, +2, +3 and -2 respectively; Mg atoms and Ga atoms are [MgS 6 ]、[MgS 3 Cl] and [GaS 4 ]Tetrahedral groups form structural units: In this crystal, under the extrusion of the six-membered ring composed of Cs atoms with large atomic radius, [GaS 4 ] group composition [Ga 3 S 9 ] trimer and [MgS 6 ] and the first discovered [MgS 3 Cl] groups composed of [Mg 2 S 8 Cl] chains are regularly distributed in the Cs six-membered ring, [MgS 6 ] and [MgS 3 Cl] are intertwined to form a one-dimensional [Mg 2 S 8 Cl] chain; [Ga 3 S 9 ] trimer in [MgS 6 ] are orderly assembled under the traction of the c-axis direction by alternating top connections on both sides, and [MgS 6 ] bridges to form [Ga 3 S 9 ] column, adjacent to [Ga 3 S 9 ]The columns are formed by sharing vertices [Ga 3 S 9 ] layers, Cs atoms are distributed between layers and within layers [Ga 3 S 9] The pores between the columns; the band gap of the obtained cesium magnesium gallium sulfur chloride crystal was measured by UV-visible-near infrared diffuse reflectance spectrometer, and the results are as follows Figure 2 As shown in the figure, it can be concluded that the band gap of CsMgGaSCl mid-to-far infrared nonlinear optical crystal is 3.83eV, which is much larger than the current commercially available AgGaS 2 )The band gap of the crystal is 2.64eV.

[0184] Embodiment 30

[0185] Any one of the cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystals obtained in Examples 1-16 is prepared according to the following method: Figure 4 As shown in the figure, it is placed at position 3. At room temperature, using the 2090nm output of the Q-switched Ho:Tm:Cr:YAG laser as the light source, obvious 1045nm double frequency light output is observed, and the output intensity is equal to that of AgGaS under the same conditions. 2 1.1 times ( Figure 3 ),like Figure 4 As shown: an infrared beam with a wavelength of 2090nm emitted by a Q-switched Ho:Tm:Cr:YAG laser 1 is incident into a cesium magnesium gallium sulfur chlorine nonlinear optical crystal 3 through a convex lens 2, generating a frequency-doubled light with a wavelength of 1045nm. The outgoing beam after passing through a prism 4 contains incident light with a wavelength of 2090nm and frequency-doubled light of 1045nm, which is filtered out by a filter 5 to obtain a frequency-doubled light with a wavelength of 1045nm.

[0186] The present invention provides a cesium magnesium gallium sulfur chlorine mid-to-far infrared nonlinear optical crystal and a preparation method and use thereof. The crystal has a large optical band gap of 3.83 eV (such as Figure 2 As shown), high nonlinear optical effect (powder frequency doubling effect is AgGaS 2 1.1 times of that) and can achieve a type of phase matching ( Figure 3 ); This infrared nonlinear optical crystal achieves a balance between large frequency doubling and large band gap, and has potential application prospects in the field of high-energy laser technology.

Claims

1. A cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystal, characterized in that: The chemical formula of the crystal is Cs2Mg2Ga3S7Cl, the molecular weight is 783.47 amu, it belongs to the orthorhombic system, and the space group is Cmc 21, unit cell parameters are a = 7.3913(4) Å, b = 33.593(2) Å, c = 6.2173(3) Å; α = 90°, β = 90°, γ = 90°, V = 1543.73(14) Å 3 The crystal structure is composed of [GaS4], [MgS3Cl] tetrahedrons and [MgS6] hexahedron groups as basic structural units, the crystal band gap is 3.83 eV, and the frequency doubling effect is 1.1 times that of the commercial material AgGaS2.

2. The method for preparing the cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystal according to claim 1, characterized in that: Prepared by high temperature melt spontaneous crystallization method or crucible descent method; The high temperature melt spontaneous crystallization method grows the cesium magnesium gallium sulfur chlorine infrared nonlinear optical crystal, and the specific operation is carried out according to the following steps: a. Mix single substance Cs or compound CsCl, single substance Mg or compound MgS, single substance Ga or compound Ga2S3, and single substance S evenly, put them into a clean graphite crucible, and then put them into a quartz glass tube. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing; b. Place the quartz tube in step a into a programmed temperature-controlled muffle furnace, raise the temperature to 850-950°C at a heating rate of 30-40°C / h, and keep warm for 40-50h; c. Cooling to room temperature at a cooling rate of 3-5 °C / h to obtain a cesium magnesium gallium sulfur chloride mid- and far-infrared nonlinear optical crystal; The crucible descent method for growing the cesium magnesium gallium sulfur chlorine infrared nonlinear optical crystal is specifically performed in the following steps: a. Mix single substance Cs or compound CsCl, single substance Mg or compound MgS, single substance Ga or compound Ga2S3, and single substance S evenly, put them into a clean graphite crucible, and then put them into a quartz glass tube. Pump the quartz tube to 10 -5 -10 -3 Pa vacuum degree and then melt sealing; b. Place the sealed quartz tube in step a into a crucible descending furnace, raise the temperature to 850-950°C at a heating rate of 30-40°C / h, and keep warm for 40-50 h; c Then vertically descend at a speed of 0.1-10 mm / h. During the descending process of the crystal growth device, cesium magnesium gallium sulfur chlorine infrared nonlinear optical crystal growth is carried out. The growth cycle is 10-40 days. After the crystal growth is completed, the crystal is still left in the growth furnace for annealing and cooled to room temperature at a rate of 30-80℃ / h to obtain cesium magnesium gallium sulfur chlorine mid- and far-infrared nonlinear optical crystal.

3. Use of the cesium magnesium gallium sulfur chlorine medium and far infrared nonlinear optical crystal as claimed in claim 1 in the preparation of infrared band laser frequency conversion, infrared laser guidance, infrared laser radar, energy detection, and long-distance laser communication.

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