An infrared birefringent optical crystal, its preparation method and applications

Abstract

This invention discloses an infrared birefringent crystal with the molecular formula Ba3CdGe3O2S8, its preparation method, and its applications. The crystal crystallizes in a monoclinic system with space group P21 / m and cell parameters α = 90°, β = 90.8 ± 0.1°, and γ = 90°. Prepared using a high-temperature solid-state method, it possesses advantages such as a high birefringence (0.13–0.15), a wide infrared transmission range, and good crystal growth habits. It has significant application value in high-tech fields such as optics, laser lithography, and communications, especially for fabricating optical components such as polarizing beam splitters, optical isolators, beam shifters, phase delay devices, and electro-optic modulation devices.

Description

Technical Field

[0001] This invention belongs to the field of birefringent optical crystal material technology, and relates to an infrared birefringent optical crystal, its preparation method and application, specifically an infrared birefringent crystal with the molecular formula Ba3CdGe3O2S8, its preparation method and application. Background Technology

[0002] Birefringent crystals are a crucial class of functional materials, playing a vital role in optical modulation. They are used in the fabrication of devices such as polarizers, optical isolators, ring devices, and phase retarders, and have wide applications in many scientific and engineering fields, including laser technology, polarization measurement, and optical communication. They also have broad applications in laser communication, optical information processing, integrated circuits, and military technology. Generally speaking, an ideal birefringent crystal requires the highest possible birefringence and good crystal growth habits in its operating wavelength range.

[0003] Currently, significant progress has been made in the research of birefringent crystals in the ultraviolet and visible light regions, with the development of numerous well-known oxide-based birefringent crystals, such as TiO2, YVO4, CaCO3, α-BaB2O4, and LiNbO3. However, these birefringent crystals cannot be used in the infrared band due to infrared absorption caused by metal-oxygen bonds. Therefore, there is an urgent need to develop novel infrared birefringent crystal materials with high birefringence, wide infrared transmission range, and favorable crystal growth habits. Summary of the Invention

[0004] To improve the above-mentioned technical problems, the present invention provides an infrared birefringent crystal with the molecular formula Ba3CdGe3O2S8, a preparation method and applications thereof. This optical crystal material has advantages such as a large birefringence (0.13-0.15), a wide infrared transmission range and good crystal growth habits.

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

[0006] This invention provides a compound with the chemical formula Ba3CdGe3O2S8.

[0007] The present invention also provides a method for preparing the Ba3CdGe3O2S8 compound, comprising mixing a Ba source, a Cd source, a Ge source and elemental S, and preparing the Ba3CdGe3O2S8 compound by a high-temperature solid-state method.

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

[0009] According to an embodiment of the present invention, the Cd source is elemental Cd, CdO, or CdS.

[0010] According to an embodiment of the present invention, the Ge source is elemental Ge, GeO2, or GeS2.

[0011] According to an embodiment of the present invention, the molar ratio of the Ba source, Cd source, Ge source and S is 3:1:3:(2-8).

[0012] According to an embodiment of the present invention, the heat preservation temperature of the high-temperature solid-state method is 700-1200℃, preferably 800-1100℃, and exemplary values ​​are 700℃, 800℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, and 1200℃.

[0013] 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 70 to 150 hours. Examples include 70 hours, 80 hours, 100 hours, 110 hours, 120 hours, 150 hours, 180 hours, and 200 hours.

[0014] According to an embodiment of the present invention, the high-temperature solid-state method specifically includes: heating the mixed raw materials to a high temperature, holding them at a high temperature, and then cooling them to room temperature to obtain the Ba3CdGe3O2S8 compound.

[0015] In this invention, room temperature refers to a temperature not higher than 100°C, preferably not higher than 50°C.

[0016] Preferably, the high-temperature solid-state method is carried out under vacuum conditions. More preferably, the vacuum pressure is 10... -4 ~10 -3 Pa.

[0017] According to an embodiment of the present invention, the high-temperature solid-phase reaction is carried out in a sealed container. Preferably, the sealed container has a vacuum environment, for example, the sealed container is a sealed quartz reaction tube.

[0018] Preferably, the cooling process includes cooling to 300°C and then allowing it to cool naturally to room temperature. More preferably, the cooling process is carried out at a rate not exceeding 5°C / hour.

[0019] 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 is performed using water (e.g., deionized water), and drying is performed using ethanol (e.g., spraying ethanol onto the sample surface to accelerate the drying process).

[0020] The present invention also provides an optical crystal with the molecular formula Ba3CdGe3O2S8.

[0021] According to an embodiment of the present invention, the optical crystal has a monoclinic crystal system, a space group of P21 / n, and its cell parameters are as follows: α = 90°, β = 90–91°, γ = 90°; for example, its unit cell parameters are: α=90°, β=90.8±0.1°, γ=90°.

[0022] According to an embodiment of the present invention, the optical crystal has a one-dimensional chain structure, which is mainly formed by tetrahedral [GeOS3], [GeO2S2] and octahedral [CdOS5] as basic asymmetric units, which are interconnected by sharing vertices. The alkaline earth metal element Ba is dispersed and filled in the one-dimensional chain structure as a charge balance.

[0023] According to an embodiment of the present invention, the optical crystal has substantially the following characteristics: Figure 1 The crystal structure shown.

[0024] 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.

[0025] According to an embodiment of the present invention, the optical crystal is an infrared birefringent optical crystal.

[0026] According to an embodiment of the present invention, the optical crystal has advantages such as a large birefringence (0.13-0.15), a wide infrared transmission range, and good crystal growth habits.

[0027] The present invention also provides a method for preparing the above-mentioned Ba3CdGe3O2S8 compound and / or optical crystal, the method comprising mixing a Ba source, a Cd source, a Ge source and elemental S, and preparing the optical crystal by a high-temperature solid-state method.

[0028] According to an embodiment of the present invention, the Ba source is elemental Ba, BaO, or BaS; the Cd source is elemental Cd, CdO, or CdS; and the Ge source is elemental Ge, GeO2, or GeS2.

[0029] According to an embodiment of the present invention, the molar ratio of the Ba source, Cd source, Ge source and S is 3:1:3:(2-8).

[0030] According to an embodiment of the present invention, the heat preservation temperature of the high-temperature solid-state method is 700-1200℃, preferably 800-1100℃, and exemplary values ​​are 700℃, 800℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, and 1200℃.

[0031] 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 70 to 150 hours. Examples include 70 hours, 80 hours, 100 hours, 110 hours, 120 hours, 150 hours, 180 hours, and 200 hours.

[0032] According to an embodiment of the present invention, the high-temperature solid-state method specifically includes: heating the mixed raw materials to a high temperature, holding them at a high temperature, and then cooling them to room temperature to obtain the optical crystal.

[0033] In this invention, room temperature refers to a temperature not higher than 100°C, preferably not higher than 50°C.

[0034] Preferably, the high-temperature solid-state method is carried out under vacuum conditions. More preferably, the vacuum pressure is 10... -4 ~10 -3 Pa.

[0035] According to an embodiment of the present invention, the high-temperature solid-phase reaction is carried out in a sealed container. Preferably, the sealed container has a vacuum environment, for example, the sealed container is a sealed quartz reaction tube.

[0036] Preferably, the heating refers to heating to the holding temperature, and the holding temperature of the high-temperature solid-phase method is 700-1200℃, preferably 800-1100℃, such as 950℃, 1000℃, or 1050℃.

[0037] Preferably, the high-temperature insulation time is not less than 50 hours, and more preferably 70 to 150 hours, such as 100 hours, 110 hours, or 120 hours.

[0038] Preferably, the cooling process includes cooling to 300°C and then allowing it to cool naturally to room temperature. More preferably, the cooling process is carried out at a rate not exceeding 5°C / hour.

[0039] 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 is performed using water (e.g., deionized water), and drying is performed using ethanol (e.g., spraying ethanol onto the sample surface to accelerate the drying process).

[0040] The present invention also provides an infrared birefringent optical crystal, namely the Ba3CdGe3O2S8 optical crystal.

[0041] The present invention also provides the application of the above-mentioned Ba3CdGe3O2S8 compound and / or optical crystal in the fabrication of optical components such as polarizing beam splitters, optical isolators, beam shifters, phase delay devices and electro-optic modulation devices.

[0042] The beneficial effects of this invention are:

[0043] This invention provides an infrared birefringent crystal material with the molecular formula Ba3CdGe3O2S8 and its preparation method. The method includes mixing a Ba source, a Cd source, a Ge source, and elemental S, and preparing the optical crystal by a high-temperature solid-state method. The crystal material prepared by this invention has advantages such as a large birefringence (0.13-0.15), a wide infrared transmission range, and good crystal growth habits.

[0044] The infrared birefringent crystal prepared by the method of this invention has important application value in high-tech fields such as optics, laser lithography and communications, especially for the fabrication of optical components such as polarization beam splitters, optical isolators, beam shifters, phase delay devices and electro-optic modulation devices. Attached Figure Description

[0045] Figure 1 This is the crystal structure diagram of Ba3CdGe3O2S8 of the present invention.

[0046] Figure 2 This is the theoretical X-ray diffraction pattern of the Ba3CdGe3O2S8 crystal of this invention.

[0047] Figure 3 This is a calculation curve of the birefringence of the Ba3CdGe3O2S8 crystal of the present invention. Detailed Implementation

[0048] 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.

[0049] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0050] Example 1

[0051] BaS, CdO, Ge, and S were thoroughly mixed in a molar ratio of 3:1:3:5 to obtain the raw material. The raw material was placed in a quartz crucible, which was then placed in a quartz reaction tube, and a vacuum of 1000 elapsed. -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, heated to 1000℃, and held at that temperature for 80 hours. Then, the temperature was programmed to decrease to 300℃ at a rate of 5℃ / hour, and then the heating was stopped. The product was allowed to cool naturally to room temperature. The product was washed with deionized water and dried with ethanol to obtain infrared birefringent crystal Ba3CdGe3O2S8, denoted as sample 1.

[0052] Example 2

[0053] BaO, CdS, Ge, and S were thoroughly mixed in a molar ratio of 3:1:3:7 to obtain the raw material. The raw material was placed in a quartz crucible, which was then placed in a quartz reaction tube, and the mixture was evacuated to 10°C. -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, heated to 950°C, and held at that temperature for 100 hours. Then, the temperature was programmed to decrease to 300°C at a rate of 4°C / hour, and then the heating was stopped. The product was allowed to cool naturally to room temperature. The product was washed with deionized water and dried with ethanol to obtain infrared birefringent crystal Ba3CdGe3O2S8, denoted as sample 2.

[0054] Example 3

[0055] BaO, Cd, GeS2, and S were thoroughly mixed in a molar ratio of 3:1:3:2 to obtain the raw material. The raw material was placed in a quartz crucible, which was then placed in a quartz reaction tube, and the mixture was evacuated to 10°C. -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, heated to 850°C, and held at that temperature for 120 hours. Then, the temperature was programmed to decrease to 300°C at a rate of 3°C / hour, and then the heating was stopped. The product was allowed to cool naturally to room temperature. The product was washed with deionized water and dried with ethanol to obtain infrared birefringent crystal Ba3CdGe3O2S8, denoted as sample 3.

[0056] (1) Structural characterization of the sample

[0057] 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.

[0058] Table 1 Crystallographic data of sample Ba3CdGe3O2S8

[0059]

[0060]

[0061] The resulting crystal has a one-dimensional chain structure, which is mainly formed by tetrahedral [GeOS3], [GeO2S2] and octahedral [CdOS5] as basic asymmetric units, which are connected to each other by sharing vertices. The alkaline earth metal element Ba is dispersed and filled in the one-dimensional chain structure as a charge balance.

[0062] (2) Characterization of optical properties of the sample

[0063] The optical transmission range and birefringence values ​​of the samples are shown in Table 2.

[0064] Table 2 Optical performance data of the samples

[0065]

[0066] 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. An optical crystal, characterized in that, The optical crystal has the molecular formula Ba3CdGe3O2S8 and its structure belongs to the monoclinic crystal system with a space group of 1. P twenty one / n Its unit cell parameters are a=8.8294(10)Å, b=11.9334(13)Å, c=15.2993(17)Å, α=90°, β=90.839(2)°, γ=90°.

2. The optical crystal as described in claim 1, characterized in that, The optical crystal has a one-dimensional chain structure, which is mainly formed by tetrahedral [GeOS3], [GeO2S2] and octahedral [CdOS5] as basic asymmetric units, which are connected to each other by sharing vertices. The alkaline earth metal element Ba is dispersed and filled in the one-dimensional chain structure as a charge balance.

3. The method for preparing the optical crystal according to claim 1 or 2, characterized in that, The preparation method includes mixing Ba source, Cd source, Ge source and S elemental, and preparing the optical crystal by high-temperature solid-state method.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the Ba source, Cd source, Ge source, and S is 3:1:3:(2~8).

5. The preparation method according to claim 3, characterized in that, The high-temperature solid-state method is carried out under vacuum conditions, and the vacuum pressure is 10. -4 ~10 -3 Pa.

6. The preparation method according to any one of claims 3-5, characterized in that, The heat preservation temperature of the high-temperature solid-state method is 700~1200℃.

7. The preparation method according to claim 6, characterized in that, The heat preservation temperature of the high-temperature solid-state method is 800~1100℃.

8. The preparation method according to any one of claims 3-5, characterized in that, The high-temperature insulation time shall not be less than 50 hours.

9. The preparation method according to claim 8, characterized in that, The high-temperature insulation time is 70-150 hours.

10. The application of the optical crystal according to claim 1 or 2 in the fabrication of polarizing beam splitters, optical isolators, beam shifters, phase delay devices, and electro-optic modulation devices.

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