Growth method and application of cesium triiodide birefringent crystal

Abstract

The invention relates to a growth method and application of a cesium triiodide birefringent crystal. The chemical formula of the crystal is CsI3, the molecular weight is 513.62, the crystal is an orthorhombic system, the space group is Pnma, the cell parameters a are equal to 11.3180, the cell parameters b are equal to 7.2266, the cell parameters c are equal to 10.4659, and the cell volume V is equal to 856.013. Growing crystals by adopting an aqueous solution method; the cesium triiodide birefringent crystal obtained through the method can be used for manufacturing polarization beam splitting prisms such as Glan prisms and light separation polarizers and optical elements such as optical isolators, circulators and beam displacers, and has important application in the fields of optics and communication. And the birefringence at the wavelength of 1064 nm is 0.901.

Description

Technical Field

[0001] The invention relates to a growth method and application of a cesium triiodide birefringent crystal. Background Art

[0002] Birefringence refers to the phenomenon that a beam of light is projected onto the surface of a crystal to produce two beams of refracted light. The fundamental reason for this phenomenon is the anisotropy of the crystal material. When light propagates in an optically inhomogeneous body (such as crystals other than the cubic system), except for a few special directions (along the optical axis), its vibration characteristics will change and it will be decomposed into two polarized light beams with mutually perpendicular electric field vector vibration directions, different propagation speeds, and different refractive indices. This phenomenon is called birefringence, and such crystals are called birefringent crystals. The birefringence property of crystals is an important optical performance parameter of optoelectronic functional material crystals. The characteristics of birefringent crystals can be used to obtain linearly polarized light and achieve the displacement of light beams, making birefringent crystals a key material for making optical components such as optical isolators, circulators, beam shifters, optical polarizers, and optical modulators.

[0003] Commonly used commercial birefringent crystals include MgF2, α -BaB2O4, CaCO3, YVO4, TiO2 and LiNbO3, among which only MgF2 and α -BaB2O4 is used as a deep ultraviolet birefringent material. MgF2 has a short ultraviolet cutoff edge (110 nm) and a small birefringence index (0.014 @193 nm); α -BaB2O4 has a large birefringence (0.122 @532 nm) and a UV cutoff edge close to 200 nm (189 nm). Because the transmission range of commercial birefringent materials is narrow and only applicable to short wavelengths, scientists from various countries are still paying close attention to the exploration and research of large birefringent crystals in the visible-infrared region. Therefore, the exploration of large birefringent crystals is of great strategic significance in high-tech industries and major equipment, and the growth of birefringent materials is a huge challenge in this direction. Summary of the invention

[0004] The present invention aims to provide a method for growing a cesium triiodide birefringent crystal, wherein the chemical formula of the crystal is CsI3, the molecular weight is 513.62, the crystal is an orthorhombic system, and the space group is Pnma , unit cell parameters a = 11.3180 Å, b = 7.2266 Å, c = 10.4659 Å, unit cell volume V = 856.01 Å 3The cesium triiodide birefringent crystal obtained by the method of the present invention can be used to make polarization beam splitting prisms such as Glan prisms, light separation polarizers, and optical components such as optical isolators, circulators, and beam shifters, and has important applications in the fields of optics and communications; the birefringence is 0.901 at 1064 nm.

[0005] The method for growing a cesium triiodide birefringent crystal of the present invention adopts a room temperature solution method to grow the crystal, and the specific operation is carried out according to the following steps: a. Grind CsI3 powder with a purity of 99.9% for 3 minutes, then add 10-100 mL of deionized water to mix and dissolve the powder to obtain a mixed solution; b. Transfer the mixed solution in step a into a container with a volume of 50-200 mL, perform ultrasonic treatment to fully mix and dissolve it, then seal it with a polyvinyl chloride film, place it in a static environment without shaking, pollution, and air convection, pierce a number of small holes in the seal to adjust the volatilization rate of the solvent in the solution, let it stand at room temperature, and wait for the growth to be completed, thereby obtaining a cesium triiodide birefringent crystal.

[0006] The cesium triiodide birefringent crystal obtained by the method is used in preparing polarization beam splitting prisms such as Glan prisms, light separation polarizers, and optical isolators, circulators, and beam shifter optical elements.

[0007] The cesium triiodide birefringent crystal obtained by the method of the present invention has a birefringence of 0.901 at 1064 nm. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A comparison diagram of the X-ray powder diffraction pattern of the polycrystalline powder of the present invention and the theoretical value; Figure 2 It is a schematic diagram of the wedge-shaped birefringent crystal polarization beam splitter of the present invention; Figure 3 Schematic diagram of the optical isolator of the present invention; Figure 4 Schematic diagram of the beam displacer of the present invention, wherein 1 is incident light, 2 is o light, 3 is e light, 4 is the optical axis, 5 is the cesium triiodide crystal, 6 is the light transmission direction, and 7 is the optical axis plane. DETAILED DESCRIPTION

[0009] The present invention is described in detail by the following embodiments, but is not limited to the above embodiments. Example 1

[0010] Growth of Cesium Triiodide Birefringent Crystals: a. Grind CsI3 powder with a purity of 99.9% for 3 minutes, add 10 mL of deionized water to mix and dissolve it to obtain a mixed solution; b. Transfer the mixed solution in step a into a container with a volume of 50 mL, perform ultrasonic treatment to fully mix and dissolve it, and then seal it with a polyvinyl chloride film. Place it in a static environment without shaking, pollution, and air convection. Punch a number of small holes in the seal to adjust the volatilization rate of the solvent in the solution. Let it stand at room temperature until the growth is completed, and a cesium triiodide birefringent crystal with a size of 0.5 mm × 0.4 mm × 4 mm is obtained. Example 2

[0011] a. Grind CsI3 powder with a purity of 99.9% for 3 minutes, add 50 mL of deionized water to mix and dissolve it to obtain a mixed solution; b. Transfer the mixed solution in step a into a container with a volume of 100 mL, perform ultrasonic treatment to fully mix and dissolve it, and then seal it with a polyvinyl chloride film. Place it in a static environment without shaking, pollution, and air convection, pierce a number of small holes in the seal to adjust the volatilization rate of the solvent in the solution, and let it stand at room temperature until the growth is completed, thereby obtaining a cesium triiodide birefringent crystal with a size of 0.6 mm × 0.4 mm × 5 mm. Example 3

[0012] a. Grind CsI3 powder with a purity of 99.9% for 3 minutes, add 100 mL of deionized water to mix and dissolve it to obtain a mixed solution; b. The mixed solution in step a is transferred into a container with a volume of 200 mL, subjected to ultrasonic treatment to fully mix and dissolve, and then sealed with a polyvinyl chloride film. The container is placed in a static environment without shaking, pollution, or air convection, and a number of small holes are punched in the seal to adjust the volatilization rate of the solvent in the solution. The container is allowed to stand at room temperature until the growth is completed, thereby obtaining a cesium triiodide birefringent crystal with a size of 0.7 mm × 0.4 mm × 6 mm. Example 4

[0013] a. Grind CsI3 powder with a purity of 99.9% for 3 minutes, add 80 mL of deionized water to mix and dissolve it to obtain a mixed solution; b. The mixed solution in step a is transferred into a container with a volume of 150 mL, subjected to ultrasonic treatment to fully mix and dissolve, and then sealed with a polyvinyl chloride film, placed in a static environment without shaking, pollution, and air convection, and a number of small holes are pierced in the seal to adjust the volatilization rate of the solvent in the solution. The mixture is allowed to stand at room temperature until the growth is completed, and a cesium triiodide birefringent crystal with a size of 0.7 mm × 0.4 mm × 8 mm is obtained. Example 5

[0014] a. Grind CsI3 powder with a purity of 99.9% for 3 minutes, add 30 mL of deionized water to mix and dissolve it to obtain a mixed solution; b. Transfer the mixed solution in step a into a container with a volume of 80 mL, perform ultrasonic treatment to fully mix and dissolve it, and then seal it with a polyvinyl chloride film. Place it in a static environment without shaking, pollution, and air convection, pierce a number of small holes in the seal to adjust the volatilization rate of the solvent in the solution, and let it stand at room temperature until the growth is completed, thereby obtaining a cesium triiodide birefringent crystal with a size of 1 mm × 1 mm × 10 mm. Example 6

[0015] Any of the cesium triiodide birefringent crystals of Examples 1-5 is used to prepare a birefringent crystal polarization beam splitter such as Figure 2 As shown, a wedge-shaped birefringent crystal has the orientation of the optical axis. After a beam of natural light is incident on the crystal, it can be separated into two beams of linearly polarized light. The greater the birefringence, the farther the two beams of light can be separated, which facilitates the separation of the light beams. Example 7

[0016] Any of the cesium triiodide birefringent crystals of Examples 1-5 is used to prepare an optical isolator. A Faraday light rotator that rotates the polarization plane of an incident light beam by 45° is placed between a pair of birefringent crystal deflectors that are placed at 45° to each other. This can form an optical isolator that only allows forward-propagating light beams to pass through the system, while blocking reverse-propagating light beams. Figure 3 a means that the incident light beam can pass through, Figure 3 b indicates that the reflected light is blocked. Example 8

[0017] Any of the cesium triiodide birefringent crystals of Examples 1-5 is used to prepare a beam displacer, and a birefringent crystal is processed so that its optical axis plane forms an angle with the edge. θ (like Figure 4 a), when natural light is incident vertically, it can be divided into two linearly polarized lights with vibration directions perpendicular to each other (as shown in Figure 4 b), which are o light and e light respectively. The greater the birefringence, the farther the two light beams can be separated, which facilitates the separation of the light beams.

Claims

1. A method for growing a cesium triiodide birefringent crystal, characterized in that The room temperature solution method was used to grow crystals. The specific operation was carried out in the following steps: a. Grind CsI3 powder with a purity of 99.9% for 3 minutes, then add 10-100 mL of deionized water to mix and dissolve the powder to obtain a mixed solution; b. Transfer the mixed solution in step a into a container with a volume of 50-200 mL, perform ultrasonic treatment to fully mix and dissolve it, then seal it with a polyvinyl chloride film, place it in a static environment without shaking, pollution, and air convection, pierce a number of small holes in the seal to adjust the volatilization rate of the solvent in the solution, let it stand at room temperature, and wait for the growth to be completed, thereby obtaining a cesium triiodide birefringent crystal.

2. Use of the cesium triiodide birefringent crystal obtained by the method as claimed in claim 1 in the preparation of polarization beam splitting prisms such as Glan prisms, light separation polarizers, and optical isolators, circulators, and beam shifters.

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