A salt-coated infrared nonlinear optical crystal, its preparation method and applications

Abstract

This invention belongs to the field of inorganic nonlinear optical materials technology, specifically disclosing a salt-coated infrared nonlinear optical crystal, its preparation method, and its applications. The molecular formula of the optical crystal of this invention is: [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 The crystal structure of this invention belongs to the cubic crystal system, and its space group is [insert space group here]. The optical crystal of this invention has excellent second-order nonlinear optical properties, can achieve phase matching in the infrared band, has a wide transmission range, and a strong infrared frequency doubling response. Its powder frequency doubling intensity can reach 1.0 to 2.0 times that of commercial material AgGaS2, and its laser damage threshold is 30 to 40 times that of AgGaS2 crystal. It has important application value in high-tech fields such as laser frequency conversion, near-infrared probes, and photorefractive information processing, especially for infrared detectors and infrared lasers.

Description

Technical Field

[0001] This invention belongs to the field of inorganic nonlinear optical materials technology, specifically relating to a salt-coated infrared nonlinear optical crystal, its preparation method and applications. Background Technology

[0002] Nonlinear optical crystals are a very important class of optoelectronic functional materials, with wide applications in laser communication, optical information processing, integrated circuits, and military technology. Generally speaking, an ideal nonlinear optical crystal must meet the following conditions: (1) a large second-order frequency doubling coefficient; (2) a high laser damage threshold; (3) a moderate birefringence; (4) a wide optical transmission range; and (5) good physicochemical and mechanical properties. Nonlinear optical crystal materials can be classified into inorganic materials, organic materials, polymer materials, and organometallic complex materials according to their physicochemical properties. Currently, most commercially available nonlinear optical crystal materials are inorganic materials, which can be divided into three main categories according to their application bands: ultraviolet, visible, and infrared. Among them, nonlinear optical crystal materials in the ultraviolet and visible bands can already meet the requirements of practical applications.

[0003] Nonlinear optical crystal materials in the infrared band are mainly ABC2-type chalcopyrite-structured semiconductor materials, such as AgGaS2, AgGaSe2, and ZnGeP2. These compounds possess large nonlinear optical coefficients and high mid-to-far infrared transmittance, but they also suffer from serious drawbacks such as low laser damage threshold and two-photon absorption, thus limiting their applications. Therefore, exploring novel infrared nonlinear optical crystal materials with promising applications is a current challenge and hot topic in the field of nonlinear optical materials research. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a salt-coated infrared nonlinear optical crystal, its preparation method, and its applications. This optical crystal material possesses excellent second-order nonlinear optical properties, achieving phase matching in the infrared band. Its powder frequency doubling intensity can reach 1.0 to 2.0 times that of commercially available AgGaS2 crystal, and its laser damage threshold is 30 to 40 times that of AgGaS2 crystal. Thus, a good balance is achieved between a large second-order frequency doubling coefficient and a high laser damage threshold.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a chemical formula [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 Compounds of [ ].

[0007] The present invention also provides the [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 The preparation method of the compound includes mixing Ba source, Zn source, Ga source, elemental S and alkali metal halide AX raw materials, and preparing [Ba] by a high-temperature solid-state method. 22 (SO4)5][Zn 14 Ga 18 S 58 ] compound.

[0008] According to an embodiment of the present invention, the Ba source is at least one of elemental Ba, BaO, BaS, or BaSO4.

[0009] According to an embodiment of the present invention, the Zn source is elemental Zn, ZnO, or ZnS.

[0010] According to an embodiment of the present invention, the Ga source is elemental Ga, GaO, or Ga2S3.

[0011] According to an embodiment of the present invention, in the alkali metal halide AX, A is selected from K, Rb or Cs, preferably Cs; X is selected from Cl, Br or I, preferably I.

[0012] According to an embodiment of the present invention, the molar ratio of Ba source, Zn source, Ga source, elemental S and alkali metal halide AX can be 22:14:18:(1-60):(1-15).

[0013] According to an embodiment of the present invention, the heat preservation temperature of the high-temperature solid-state method is 700-1200℃, preferably 900-1100℃, and exemplary values ​​are 700℃, 800℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, and 1200℃.

[0014] According to an embodiment of the present invention, the heat preservation time of the high-temperature solid-state method is not less than 50 hours, preferably 100 to 200 hours. Examples include 70 hours, 100 hours, 120 hours, 150 hours, 180 hours, and 200 hours.

[0015] According to an embodiment of the present invention, the high-temperature solid-state method specifically includes: placing the raw material into a sealed container and placing it in a heating device, heating it to a high temperature, holding it at a high temperature, and cooling it to room temperature to obtain the [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 ] compound.

[0016] In this invention, room temperature refers to a temperature not higher than 100°C, preferably not higher than 50°C.

[0017] Preferably, the high-temperature solid-state method is carried out under vacuum conditions. More preferably, the sealed container has a vacuum environment, for example, a vacuum pressure of 10... -4 ~10 -3 Pa.

[0018] Preferably, the sealed container is a sealed quartz reaction tube.

[0019] Preferably, the cooling refers to cooling the product prepared by the high-temperature solid-state method, preferably cooling to 200-500°C at a rate not exceeding 5°C / hour and then cooling to room temperature; for example, cooling to 400°C at a rate not exceeding 3°C / hour and then cooling to room temperature.

[0020] According to an embodiment of the present invention, the preparation method further includes washing and drying the product obtained by natural cooling to room temperature to obtain the [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 [Compound. For example, wash with water (e.g., deionized water) and dry with ethanol.]

[0021] The present invention also provides an optical crystal, the optical crystal having the molecular formula [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 ].

[0022] According to an embodiment of the present invention, the optical crystal has a cubic crystal system and its space group is . Its unit cell parameters are α=90°, β=90°, γ=90°.

[0023] For example, the unit cell parameters of the optical crystal are: α=90°, β=90°, γ=90°.

[0024] According to an embodiment of the present invention, the optical crystal has a non-central three-dimensional mesh structure composed of a large [Zn] 12 Ga 16 S 58 Clusters and [(Zn / Ga)S4] tetrahedra are interconnected through shared vertices S; the alkaline earth metal ions Ba 2 + and sulfate ions SO4 2– They are dispersed and filled in the gaps of the three-dimensional grid structure as a form of charge balance.

[0025] According to an embodiment of the present invention, the optical crystal has the following structure: Figure 1 As shown.

[0026] According to an embodiment of the present invention, the optical crystal has substantially the following characteristics: Figure 2 The X-ray crystal diffraction pattern shown in 'a' is an example of this pattern.

[0027] According to an embodiment of the present invention, the optical crystal is an infrared nonlinear optical crystal.

[0028] According to an embodiment of the present invention, the powder frequency doubling intensity of the optical crystal is 1.0 to 2.0 times that of commercial material AgGaS2 crystal, for example, 1.5 times.

[0029] According to an embodiment of the present invention, the laser damage threshold of the optical crystal is 30 to 40 times that of commercial material AgGaS2 crystal, for example, 37 times.

[0030] The present invention also provides a method for preparing the above-mentioned optical crystal, comprising mixing Ba source, Zn source, Ga source, elemental S and alkali metal halide AX raw materials, and preparing the optical crystal by high temperature solid-state method.

[0031] According to an embodiment of the present invention, the Ba source is at least one of elemental Ba, BaO, BaS, or BaSO4.

[0032] According to an embodiment of the present invention, the Zn source is elemental Zn, ZnO, or ZnS.

[0033] According to an embodiment of the present invention, the Ga source is elemental Ga, GaO, or Ga2S3.

[0034] According to an embodiment of the present invention, in the alkali metal halide AX, A is selected from K, Rb or Cs, preferably Cs; X is selected from Cl, Br or I, preferably I.

[0035] According to an embodiment of the present invention, the molar ratio of Ba source, Zn source, Ga source, elemental S and alkali metal halide AX can be 22:14:18:(1-60):(1-15).

[0036] According to an embodiment of the present invention, the heat preservation temperature of the high-temperature solid-state method is 700-1200℃, preferably 900-1100℃, and exemplary values ​​are 700℃, 800℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, and 1200℃.

[0037] According to an embodiment of the present invention, the heat preservation time of the high-temperature solid-state method is not less than 50 hours, preferably 100 to 200 hours. Examples include 70 hours, 100 hours, 120 hours, 150 hours, 180 hours, and 200 hours.

[0038] According to an embodiment of the present invention, the high-temperature solid-state method specifically includes: placing the raw material into a sealed container and placing it in a heating device, heating to a high temperature, maintaining the temperature at a high temperature, and cooling to room temperature to obtain the optical crystal. In this invention, room temperature refers to a temperature not exceeding 100°C, preferably not exceeding 50°C.

[0039] Preferably, the high-temperature solid-state method is carried out under vacuum conditions. More preferably, the sealed container has a vacuum environment, for example, a vacuum pressure of 10... -4 ~10 -3 Pa.

[0040] Preferably, the sealed container is a sealed quartz reaction tube.

[0041] Preferably, the heating and temperature rise refers to raising the temperature to the holding temperature, which is selected from 700 to 1200°C, preferably 900 to 1100°C. For example, the temperature can be 1000°C.

[0042] Preferably, the high-temperature insulation time is not less than 50 hours, and more preferably 100 to 200 hours. For example, the high-temperature insulation refers to insulation at 950°C for 150 hours.

[0043] Preferably, the cooling refers to cooling the product prepared by the high-temperature solid-state method, preferably cooling to 200-500°C at a rate not exceeding 5°C / hour and then cooling to room temperature; for example, cooling to 400°C at a rate not exceeding 3°C / hour and then cooling to room temperature.

[0044] Preferably, the preparation method further includes washing and drying the product obtained by natural cooling to room temperature to obtain the optical crystal, for example, washing with water (e.g., deionized water) and drying with ethanol.

[0045] The present invention also provides a nonlinear optical crystal material, namely the [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 Optical crystal.

[0046] The present invention also provides the above-mentioned [Ba 22 (SO4)5][Zn 14 Ga 18 S 58Applications of compounds and / or optical crystal materials, such as for infrared detectors, infrared lasers, photorefractive information processing, laser frequency conversion, near-infrared probes, etc.

[0047] The present invention also provides an infrared detector, the infrared detector comprising the above-mentioned [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 Compounds and / or optical crystals.

[0048] The present invention also provides an infrared laser, wherein the infrared laser contains the above-mentioned [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 Compounds and / or optical crystals.

[0049] The beneficial effects of this invention are:

[0050] This invention provides a salt-coated infrared nonlinear optical crystal material with excellent second-order nonlinear optical properties, namely, phase matching in the infrared band, moderate birefringence, wide transmission range, strong frequency doubling response, and frequency doubling intensity that is 1.0 to 2.0 times that of commercial material AgGaS2. Moreover, its laser damage threshold is 30 to 40 times that of AgGaS2 crystal, thus achieving a good balance between a large second-order frequency doubling coefficient and a high laser damage threshold.

[0051] This infrared nonlinear optical crystal has important application value in high-tech fields such as laser frequency conversion, near-infrared probes, and photorefractive information processing, especially for infrared detectors and infrared lasers. Attached Figure Description

[0052] Figure 1 This invention [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 A schematic diagram of the crystal structure.

[0053] Figure 2 This invention [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 Simulated X-ray diffraction pattern of the crystal. Detailed Implementation

[0054] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0055] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0056] Example 1

[0057] BaO, BaS, ZnS, Ga2S3, and KI were mixed evenly in a molar ratio of 20:2:14:9:10 to obtain the raw material. The raw material was placed in a quartz crucible, and the crucible containing the raw material was placed in a quartz reaction tube. A vacuum of 1000 elapsed was then applied. -3 Pa was used to melt and seal the quartz reaction tube with an oxyhydrogen flame. The quartz reaction tube was placed in a tube furnace equipped with a temperature controller and heated to 950°C, which was maintained for 120 hours. Then, the temperature was programmed to decrease to 350°C at a rate of 2°C / hour, and then heating was stopped. After natural cooling to room temperature, the product was washed with deionized water and dried with ethanol. The resulting pale yellow blocky crystals were the infrared nonlinear optical crystal material [Ba]. 22 (SO4)5][Zn 14 Ga 18 S 58 ], denoted as sample 1.

[0058] Example 2

[0059] BaSO4, BaS, ZnS, Ga2S3, and CsI were mixed evenly in a molar ratio of 5:17:14:9:5 to obtain the raw material. The raw material was placed in a quartz crucible, and the crucible containing the raw material was placed in a quartz reaction tube. A vacuum of 1000 ppm was then applied. -3 Pa was used to melt and seal the quartz reaction tube with an oxyhydrogen flame. The quartz reaction tube was placed in a tube furnace equipped with a temperature controller and heated to 1000°C, which was maintained for 100 hours. Then, the temperature was programmed to decrease to 450°C at a rate of 3°C / hour, and then heating was stopped. After natural cooling to room temperature, the product was washed with deionized water and dried with ethanol. The resulting pale yellow blocky crystals were the infrared nonlinear optical crystal material [Ba]. 22 (SO4)5][Zn 14 Ga 18 S 58 ], denoted as sample 2.

[0060] Example 3

[0061] Ba, BaO, BaS, ZnS, Ga, S, and RbI were mixed evenly in a molar ratio of 7:5:10:14:18:39:8 to obtain the raw material. The raw material was placed in a quartz crucible, and the crucible containing the raw material was placed in a quartz reaction tube. A vacuum of 1000 ppm was then applied. -3 Pa was used to melt and seal the quartz reaction tube with an oxyhydrogen flame. The quartz reaction tube was placed in a tube furnace equipped with a temperature controller and heated to 1050°C, which was maintained for 70 hours. Then, the temperature was programmed to decrease to 500°C at a rate of 4°C / hour, and then heating was stopped. After natural cooling to room temperature, the product was washed with deionized water and dried with ethanol. The resulting pale yellow blocky crystals were the infrared nonlinear optical crystal material [Ba]. 22 (SO4)5][Zn 14 Ga 18 S 58 ], denoted as sample 3.

[0062] (1) Structural characterization of the sample

[0063] X-ray single-crystal diffraction of the sample in Example 1 was performed on a Mercury 724 single-crystal diffractometer with a Mo target and K. α The radiation source was λ = 0.07107 nm, and the test temperature was 293 K. The structure was analyzed using a Shelx-2014 crystallography system. The crystallographic data of the sample are shown in Table 1, and the crystal structure diagram is shown below. Figure 1 As shown.

[0064] Table 1 Samples [Ba] 22 (SO4)5][Zn 14 Ga 18 S 58 Crystallographic data

[0065]

[0066] The resulting crystal has a non-central three-dimensional lattice structure, consisting of a large [Zn]... 12 Ga 16 S 58 Clusters and [(Zn / Ga)S4] tetrahedra are interconnected through shared vertices S; the alkaline earth metal ions Ba 2+ and sulfate ions SO4 2– They are dispersed and filled in the gaps of the three-dimensional grid structure as a form of charge balance.

[0067] (2) Characterization of optical properties of the sample

[0068] The powder frequency doubling performance and laser damage threshold of the samples are shown in Table 2.

[0069] Table 2 Optical performance data of the samples

[0070]

[0071] The exemplary embodiments of the present invention have been described above. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nonlinear optical crystal, characterized in that, The molecular formula of the optical crystal is [Ba 22 (SO4)5][Zn 14 Ga 18 S 58 The optical crystal has a cubic crystal system and its space group is [missing information]. Its unit cell parameters are α=90°, β=90°, γ=90°.

2. The method for preparing the nonlinear optical crystal according to claim 1, characterized in that, The preparation method includes mixing Ba source, Zn source, Ga source, elemental S and alkali metal halide AX raw materials, and preparing the optical crystal by high-temperature solid-state method.

3. The preparation method according to claim 2, characterized in that, The Ba source is at least one of elemental Ba, BaO, BaS, or BaSO4; And / or, the Zn source is elemental Zn, ZnO, or ZnS; and / or, the Ga source is elemental Ga, GaO, or Ga2S3.

4. The preparation method according to claim 2, characterized in that, In the alkali metal halide AX, A is selected from K, Rb, or Cs; X is selected from Cl, Br, or I.

5. The preparation method according to any one of claims 2-4, characterized in that, The molar ratio of Ba source, Zn source, Ga source, elemental S and alkali metal halide AX is 22:14:18:(1~60):(1~15).

6. The preparation method according to claim 5, characterized in that, The heat preservation temperature of the high-temperature solid-state method is 700-1200℃; the heat preservation time of the high-temperature solid-state method is not less than 50 hours.

7. The preparation method according to claim 6, characterized in that, The holding temperature of the high-temperature solid-state method is 900-1100℃; the holding time of the high-temperature solid-state method is 100-200 hours.

8. The use of the nonlinear optical crystal according to claim 1, for use in infrared detectors, infrared lasers, photorefractive information processing, laser frequency conversion, and near-infrared probes.

9. An infrared detector, characterized in that, The infrared detector contains the nonlinear optical crystal as described in claim 1.

10. An infrared laser, characterized in that, The infrared laser contains the nonlinear optical crystal as described in claim 1.

Images