CN107399722A - Selenium silicon silver barium and selenium silicon silver barium mid and far infrared nonlinear optical crystal and preparation method and purposes - Google Patents

Abstract

The present invention relates to a compound selenium silicon silver barium and selenium silicon silver barium mid-far infrared nonlinear optical crystal and its preparation method and application. Its chemical formula is BaAg ₂ SiSe ₄ and its molecular weight is 697.01. The crystal is tetragonal and its space group is noncentrosymmetric space group , the unit cell parameters are a = b =7.066(3)Å, c =8.233(7)Å, α = β = γ =90°, Z =2, unit cell volume V=411.1(5)Å ³ ; the preparation The method is a solid-state reaction of elemental barium, elemental silver, elemental silicon and elemental selenium under vacuum conditions; the powder XRD spectrum of the compound selenium-silicon-silver-barium and mid-far infrared nonlinear optical crystal of the present invention coincides with the theoretical value ; Under 2090 nm laser irradiation, the frequency doubling effect of BaAg ₂ SiSe ₄ with a particle size of 55‑88 μm is twice that of AgGaS ₂ with the same particle size.

Description

Selenium silicon silver barium and selenium silicon silver barium mid-far infrared nonlinear optical crystal and preparation method and use

technical field

The invention belongs to the field of infrared nonlinear optical crystal materials, and specifically relates to a selenium-silicon-silver-barium and mid-far infrared nonlinear optical crystal, a preparation method and an application thereof.

Background technique

As a high-intensity, coherent monochromatic light source with good directionality, laser is widely used in scientific research, industry, transportation, national defense, medical and health and other related fields. However, the laser wave bands directly output by various lasers at present are limited, and there are still blank laser wave bands from the ultraviolet band to the infrared band. Due to the particularity of the laser generation mechanism, it is impossible to find a practical laser medium for every wavelength. Therefore, the use of nonlinear optical crystals for frequency conversion to obtain various laser sources with wide tuning has become a frontier topic in the development of laser technology.

Nonlinear optical effects originate from the interaction between laser and medium. When the laser propagates in a medium with non-zero second-order polarizability, nonlinear optical effects such as frequency doubling, sum frequency, difference frequency, and optical parametric amplification will occur. Nonlinear optical crystal materials can be divided into three categories according to their transmission range: 1. Infrared and mid-to-far infrared nonlinear optical materials; 2. Visible and near-infrared nonlinear optical materials; 3. Ultraviolet and deep Ultraviolet band nonlinear optical materials. At present, the main nonlinear optical materials are: KDP (KH ₂ PO ₄ ), BBO (β-BaB ₂ O ₄ ), LBO (LiB ₃ O ₅ ), AGS (AgGaS ₂ ), etc., but due to various reasons, they have not been obtained yet. All kinds of nonlinear optical crystals applicable to all wave bands. The work of the present invention belongs to visible light and mid-far infrared nonlinear optical materials. Nonlinear optical crystal materials in this band have a wide range of applications, such as applications in the preparation of laser guidance, infrared remote sensors, environmental monitors, and infrared laser radars

As the core device of laser frequency conversion technology, infrared nonlinear optical crystal is a type of single crystal material that uses phase matching technology to convert laser frequency and output tunable mid-to-far infrared laser. Since two important atmospheric windows (3-5 μm and 8-14 μm ) are in this wavelength range, the current exploration and development of infrared nonlinear optical crystals generally need to ensure high Through ability.

Today's practical infrared nonlinear optical materials are mostly ABC ₂ -type chalcopyrites, such as commercialized crystals such as AgGaS ₂ and ZnGeP ₂ . However, this type of crystal has some serious shortcomings, such as low laser damage threshold, two-photon absorption problem for near-infrared laser (such as Nd:YAG 1064 nm), and severe anisotropic thermal expansion, which make it difficult to obtain large-scale high-quality single crystals. Crystal, etc., have severely limited their practical applications.

At present, although some oxide nonlinear optical crystals discovered in the world have solved the problem of near-infrared frequency conversion, for lasers in the range of 3-5 μm , the lattice vibration frequency of many oxide crystals is different from that of this band. The laser frequency of the laser is equivalent, thereby causing the strong competition between the non-radiative relaxation and the laser emission, which will cause the high passive loss of the laser, and it is difficult to output the middle and far infrared laser above 4 μm . Therefore, the current exploration of effective mid- and far-infrared nonlinear optical crystals mainly focuses on non-oxygen halides, sulfides, or phosphides.

Contents of the invention

The first object of the present invention is to provide a compound barium selenium silicon silver, the chemical formula of the compound is BaAg ₂ SiSe ₄ , the molecular weight is 697.01, it is a non-centrosymmetric single crystal, it belongs to the tetragonal crystal system, and the space group is , the unit cell parameters are a = b = 7.066(3) Å, c = 8.233(7) Å, α = β = γ = 90°, Z = 2, and the unit cell volume V =411.1(5) Å ³ . Phase reaction method to make polycrystalline powder;

The second object of the present invention is to provide a mid-far infrared nonlinear optical crystal of selenium silicon silver barium and its preparation method. The chemical formula of the crystal is BaAg ₂ SiSe ₄ and the molecular weight is 697.01. It is a non-centrosymmetric single crystal and belongs to the tetragonal crystal system. , the space group is , the unit cell parameters are a = b = 7.066(3) Å, c = 8.233(7) Å, α = β = γ = 90°, Z = 2, and the unit cell volume V = 411.1(5) Å ³ . The preparation method is a solid phase reaction of elemental barium, elemental silver, elemental silicon and elemental selenium under vacuum conditions; the powder XRD spectrum and theory of the compound selenium silicon silver barium and selenium silicon silver barium mid-far infrared nonlinear optical crystal of the present invention The values are consistent; under 2090 nm laser irradiation, the frequency doubling effect of BaAg ₂ SiSe ₄ with a particle size of 55-88 μm is twice that of silver gallium sulfide (AgGaS ₂ ) with the same particle size.

The third object of the present invention is to provide the use of selenium silicon silver barium mid-far infrared nonlinear optical crystals in the preparation of infrared communication devices, infrared band laser frequency doubling crystals and infrared laser guidance devices.

A compound of the present invention, barium selenium silicon silver, is characterized in that the chemical formula of the compound is BaAg ₂ SiSe ₄ , the molecular weight is 697.01, it belongs to the tetragonal crystal system, and the space group is , the unit cell parameters are a = b = 7.066(3) Å, c = 8.233(7) Å, α = β = γ = 90°, Z = 2, and the unit cell volume V = 411.1(5) Å ³ , which is multi Crystal powder.

The preparation method of the compound selenium-silicon-silver-barium adopts a high-temperature solid-state reaction method, and the specific operation is carried out according to the following steps:

a. In an airtight container with a water content and an oxygen content of 0.01-0.1 ppm, it is a glove box filled with inert gas nitrogen and mixed evenly according to the molar ratio of Ba:Ag:Si:Se 1:2:1:4, and then put it into a clean In a graphite crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and seal the quartz tube with the raw material after ^{vacuuming at a vacuum of 10-5-10-3 Pa} ;

b. The sealed quartz tube in step a is raised from room temperature to 400-700°C at a temperature rise rate of 20-40°C/h, kept for 30-60 hours, and then heated to 800°C at a temperature of 20-40°C/h -1050 ℃, keep warm for 70-110 hours;

c. Cool down to room temperature at a rate of 2-7 °C/h, take out the sample and put it in a mortar, crush it, and grind it to obtain the compound BaAg ₂ SiSe ₄ polycrystalline powder. The obtained compound selenium silicon silver barium polycrystalline The powder is analyzed by X-ray, and the obtained X-ray diffraction spectrum is consistent with the theoretical X-ray spectrum of BaAg ₂ SiSe ₄ analyzed by single crystal structure.

A middle-far-infrared nonlinear optical crystal of barium selenium silicon silver, the crystal chemical formula is BaAg ₂ SiSe ₄ , the molecular weight is 697.01, it is a non-centrosymmetric single crystal, it belongs to the tetragonal crystal system, and the space group is , the unit cell parameters are a = b =7.066(3) Å, c = 8.233(7) Å, α = β = γ = 90°, Z = 2, and the unit cell volume V = 411.1(5) Å ³ .

The preparation method of the described mid-far infrared nonlinear optical crystal of selenium silicon silver barium is carried out according to the following steps:

a. In a glove box filled with an inert gas nitrogen in an airtight container with a water content and an oxygen content of 0.01-0.1 ppm, mix it evenly according to the molar ratio of Ba:Ag:Si:Se 1:2:1:4 and put it in In a clean graphite crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and seal the quartz tube containing the raw material after ^{vacuuming at a vacuum of 10-5-10-3 Pa} ;

b. Heat the sealed quartz tube in step a from room temperature to 400-700°C at a temperature of 20-40°C/h, keep it warm for 30-60 hours, and then raise the temperature to 800°C at a temperature of 20-40°C/h -1050 ℃, keep warm for 70-110 hours;

c. Cool down to room temperature at a rate of 2-7° C./h to obtain mid-far infrared nonlinear optical crystals of BaAg ₂ SiSe ₄ .

Use of the mid-far infrared nonlinear optical crystal of selenium silicon silver barium in the preparation of infrared communication devices, infrared band laser frequency doubling crystals and infrared laser guidance devices.

The powder XRD pattern of silver barium selenium silicon and silver barium selenium silicon in the present invention is consistent with the theoretical value; under 2090 nm laser irradiation, the BaAg ₂ SiSe ₄ frequency doubling effect with a particle size of 55-88 μm It is twice that of AgGaS ₂ with the same particle size.

In the crystal structure of selenium-silicon-silver-barium of the present invention, the valences of Ba atom, Ag atom, Si atom, and Se atom are respectively +2, +1, +4, -2; Si atom exists in isolation with the adjacent four Se atoms [SiSe ₄ ] tetrahedral structure; Ag atoms also form [AgSe ₄ ] tetrahedrons with four adjacent Se atoms, and form a layered structure in a common-vertex connection mode, and the layers are separated by isolated [SiSe ₄ ] tetrahedra connected to form [Ag ₂ Si ₂ ] four-membered ring channel; Ba atoms are only embedded in the four-membered ring channel formed by [AgSe ₄ ] tetrahedron and [SiSe ₄ ] tetrahedron, forming 8-coordination The [BaSe ₈ ] polyhedron; all atoms are interconnected to form a three-dimensional network structure.

The selenium-silicon-silver-barium and selenium-silicon-silver-barium mid-to-far-infrared nonlinear optical crystals and their preparation methods and uses described in the present invention adopt a high-temperature solid-phase synthesis method to successfully synthesize a compound of selenium-silicon-silver-barium and selenium-silicon-silver-barium Middle and far infrared nonlinear optical crystals. Compared with the patent application No. 201710388528.4 Selenium Silicon Copper Barium and Selenium Silicon Copper Barium Mid-Far Infrared Nonlinear Optical Crystal and its preparation method and application, the crystal system it belongs to has changed from the trigonal system (BaCu ₂ SiSe ₄ ) to the tetragonal system (BaAg ₂ SiSe ₄ ), from a structural point of view, it changes from a three-dimensional network structure (BaCu ₂ SiSe ₄ ) to a layered structure (BaAg ₂ SiSe ₄ ); this shows that these two compounds are not just a simple isomorphic substitution of elements, Instead, a structural transformation occurred, and this structural transformation resulted in better optical properties of the SiSiSiAgBar crystal: (1) The UV-Vis-NIR diffuse reflectance spectrometer was used to evaluate the Band gap, the results show that the compound has a larger band gap than that of selenium-silicon-copper-barium crystal; (2) The powder laser damage threshold of the powder sample is tested by irradiating the powder sample under 1064 nm laser, and the results show that the selenium-silicon Silver-barium crystal powder has a larger laser damage threshold; (3) The nonlinear response intensity of silver-barium selenium silicon was measured by powder frequency doubling method, and the results showed that it can achieve Ho:Tm:Cr:YAG (2090 nm) 2 frequency doubling, and its powder frequency doubling effect is twice that of AgGaS ₂ crystals with the same particle size, indicating that the selenium silicon silver barium crystal has a stronger nonlinear optical effect. The above-mentioned excellent optical properties of selenium silicon silver barium crystal make it have greater potential application value.

The selenium-silicon-silver-barium compound in the present invention is polycrystalline powder of selenium-silicon-silver-barium.

Description of drawings

Fig. 1 is the comparative figure of polycrystalline powder X-ray powder diffraction pattern of the present invention and theoretical value, and wherein A is theoretical value, and B is experimental value;

Fig. 2 is the structural diagram of BaAg of the present invention ₂ SiSe ₄ crystals;

Fig. 3 is the mid-far-infrared nonlinear optical crystal of the present invention under 2090 nm laser, when the particle size is 55-88 μ m and the same particle size sulfur-gallium-silver frequency doubling comparison diagram, wherein A is AgGaS ₂ times times Frequency effect diagram, B is BaAg ₂ SiSe ₄ secondary frequency effect diagram;

Fig. 4 is a schematic diagram of the frequency doubling effect of the present invention.

detailed description

The invention is illustrated in detail by means of examples, but is not limited to the examples given.

Example 1

Preparation of compound selenium silicon silver barium polycrystalline powder:

a. Mix elemental Ba, elemental Ag, elemental Si and elemental Se in a molar ratio of 1:2:1:4 in a glove box filled with an inert gas nitrogen in an airtight container with a water content and an oxygen content of 0.01-0.1 ppm After uniformity, put it into a clean graphite crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and pump the quartz tube with the raw material under the condition of a vacuum of ^{10-5-10-3 Pa} . Sealed after vacuum;

b. Heat the sealed quartz tube in step a from room temperature to 400-700°C at a temperature of 20-40°C/h, keep it warm for 30-60 hours, and then raise the temperature to 800°C at a temperature of 20-40°C/h -1050 ℃, heat preservation for 70-110 hours to obtain the compound;

c. Cool the compound obtained in step b to room temperature at a rate of 2-7 °C/h, take out the sample, put it into a mortar, crush it, and grind it to obtain a dark red compound BaAg ₂ SiSe ₄ polycrystalline powder, which will be obtained The compound selenium silicon silver barium polycrystalline powder carries out X-ray analysis, and the obtained X-ray diffraction spectrum is consistent with the BaAg ₂ SiSe ₄ theoretical X-ray spectrum analyzed by single crystal structure, the result is shown in Figure 1, as can be seen from the figure, the experimental The values are in good agreement with the theoretical values, indicating that the obtained powder samples are phase-pure.

Example 2

Preparation of mid- and far-infrared nonlinear optical crystals of selenium, silicon, silver, and barium:

a. In a glove box filled with an inert gas nitrogen in an airtight container with a water content and an oxygen content of 0.01 ppm, put clean graphite after mixing evenly according to the molar ratio of Ba:Ag:Si:Se 1:2:1:4 In the crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and seal the quartz tube with the raw material after ^{vacuuming at a vacuum degree of 10-5-10-3 Pa} ;

b. The quartz tube sealed in step a is raised from room temperature to 400°C at a heating rate of 20°C/h, and kept at a temperature of 30 hours, then raised to 800°C at a temperature of 20°C/h, and kept at a temperature of 70 hours;

c. Cool down to room temperature at a rate of 2 °C/h, take out the graphite crucible, and obtain a dark red bulk BaAg ₂ SiSe ₄ mid-to-far infrared nonlinear optical crystal, which is shown by single crystal X-ray diffraction analysis. It is a mid-to-far infrared nonlinear optical crystal of selenium silicon silver barium.

Example 3

Preparation of mid- and far-infrared nonlinear optical crystals of selenium, silicon, silver, and barium:

a. In a glove box filled with an inert gas nitrogen in an airtight container with a water content and an oxygen content of 0.05 ppm, the elemental Ba, elemental Ag, elemental Si and elemental Se are mixed evenly in a molar ratio of 1:2:1:4 Put it into a clean graphite crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and vacuumize the quartz tube with the raw material at a vacuum degree of 10 ^-5 -10 ^-3 Pa seal;

b. The quartz tube sealed in step a is raised from room temperature to 600°C at a heating rate of 40°C/h, and kept at a temperature of 50 hours, then raised to 1000°C at a temperature of 30°C/h, and kept at a temperature of 100 hours;

c. Cool down to room temperature at a rate of 4 °C/h, take out the graphite crucible, and obtain a dark red bulk BaAg ₂ SiSe ₄ mid-to-far infrared nonlinear optical crystal.

Example 4

Preparation of mid- and far-infrared nonlinear optical crystals of selenium, silicon, silver, and barium:

a. In a glove box filled with an inert gas nitrogen in an airtight container with a water content and an oxygen content of 0.08 ppm, put clean graphite after mixing evenly according to the molar ratio of Ba:Ag:Si:Se 1:2:1:4 In the crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and seal the quartz tube with the raw material after ^{vacuuming at a vacuum degree of 10-5-10-3 Pa} ;

b. The quartz tube sealed in step a is raised from room temperature to 700°C at a heating rate of 38°C/h, and kept at a temperature of 60 hours, then raised to 1050°C at a temperature of 40°C/h, and kept at a temperature of 110 hours;

c. Cool down to room temperature at a rate of 7°C/h, take out the graphite crucible, and obtain dark red bulk BaAg ₂ SiSe ₄ mid-to-far infrared nonlinear optical crystal.

Example 5

Preparation of mid- and far-infrared nonlinear optical crystals of selenium, silicon, silver, and barium:

a. In a glove box filled with inert gas nitrogen in an airtight container with a water content and an oxygen content of 0.1 ppm, the elemental Ba, elemental Ag, elemental Si and elemental Se are mixed evenly in a molar ratio of 1:2:1:4 Put it into a clean graphite crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and vacuumize the quartz tube with the raw material at a vacuum degree of 10 ^-5 -10 ^-3 Pa seal;

b. The quartz tube sealed in step a is raised from room temperature to 500°C at a heating rate of 35°C/h, and kept for 45 hours, then raised to 950°C at a temperature of 35°C/h, and kept for 95 hours;

c. Cool down to room temperature at a rate of 5°C/h, take out the graphite crucible, and obtain a dark red bulk BaAg ₂ SiSe ₄ mid-to-far infrared nonlinear optical crystal.

Example 6

Any one of the middle-far-infrared nonlinear optical crystals of selenium-silicon-silver-barium obtained in Examples 2-5 is arranged at position 3 as shown in accompanying drawing 4, and at room temperature, use Q-switching Ho:Tm:Cr:YAG The 2090 nm output of the laser was used as the light source, and an obvious 1045 nm frequency-doubled light output was observed, and the intensity of the output was equal to that of AgGaS ₂ under the same particle size (as shown in Figure 3). The infrared beam with a wavelength of 2090 nm emitted by the Q-switched Ho:Tm:Cr:YAG laser 1 is injected into the non-linear optical crystal of selenium-silicon-silica-silver-barium through the all-condensing lens 2 to generate frequency-doubled light with a wavelength of 1045 nm, and the outgoing beam 4 contains wavelength Infrared light of 2090 nm and light of 1045 nm are filtered by filter 5 to obtain frequency-doubled light with a wavelength of 1045 nm.

Claims (5)

1. A compound barium selenium silicon silver, characterized in that the chemical formula of the compound is BaAg ₂ SiSe ₄ , the molecular weight is 697.01, belongs to the tetragonal crystal system, and the space group is , the unit cell parameters are a = b = 7.066(3) Å, c = 8.233(7) Å, α = β = γ = 90°, Z = 2, and the unit cell volume V = 411.1(5) Å ³ , which is multi Crystal powder. 2. the preparation method of compound selenium silicon silver barium according to claim 1 is characterized in that adopting high-temperature solid-phase reaction method, concrete operation is carried out by the following steps: a. In an airtight container with a water content and an oxygen content of 0.01-0.1 ppm, it is a glove box filled with inert gas nitrogen and mixed evenly according to the molar ratio of Ba:Ag:Si:Se 1:2:1:4, and then put it into a clean In a graphite crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and seal the quartz tube with the raw material after ^{vacuuming at a vacuum of 10-5-10-3 Pa} ; b. The sealed quartz tube in step a is raised from room temperature to 400-700°C at a temperature rise rate of 20-40°C/h, kept for 30-60 hours, and then heated to 800°C at a temperature of 20-40°C/h -1050 ℃, keep warm for 70-110 hours; c. Cool down to room temperature at a rate of 2-7 °C/h, take out the sample and put it in a mortar, crush it, and grind it to obtain the compound BaAg ₂ SiSe ₄ polycrystalline powder. The obtained compound selenium silicon silver barium polycrystalline The powder is analyzed by X-ray, and the obtained X-ray diffraction spectrum is consistent with the theoretical X-ray spectrum of BaAg ₂ SiSe ₄ analyzed by single crystal structure. 3. A middle-far-infrared nonlinear optical crystal of selenium, silicon, silver, and barium, characterized in that the crystal chemical formula is BaAg ₂ SiSe ₄ , the molecular weight is 697.01, and it is a non-centrosymmetric single crystal, belonging to the tetragonal crystal system, and the space group is , the unit cell parameters are a = b = 7.066(3) Å, c = 8.233(7) Å, α = β = γ = 90°, Z = 2, and the unit cell volume V = 411.1(5) Å ³ . 4. the preparation method of far-infrared nonlinear optical crystal of selenium silicon silver barium as claimed in claim 3 is characterized in that carrying out according to the following steps: a. In a glove box filled with an inert gas nitrogen in an airtight container with a water content and an oxygen content of 0.01-0.1 ppm, mix it evenly according to the molar ratio of Ba:Ag:Si:Se 1:2:1:4 and put it in In a clean graphite crucible, put it into a quartz glass tube with a length of 20 cm and a diameter of 10 mm, and seal the quartz tube containing the raw material after ^{vacuuming at a vacuum of 10-5-10-3 Pa} ; b. Heat the sealed quartz tube in step a from room temperature to 400-700°C at a temperature of 20-40°C/h, keep it warm for 30-60 hours, and then raise the temperature to 800°C at a temperature of 20-40°C/h -1050 ℃, keep warm for 70-110 hours; c. Cool down to room temperature at a rate of 2-7° C./h to obtain mid-far infrared nonlinear optical crystals of BaAg ₂ SiSe ₄ . 5. The use of the mid-to-far infrared nonlinear optical crystal of selenium silicon silver barium as claimed in claim 3 in the preparation of infrared communication devices, infrared band laser frequency doubling crystals and infrared laser guidance devices.