Compound sulfur-phosphorus-mercury-zinc and sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal and preparation method and application thereof

Abstract

The present invention relates to a compound of sulfur-phosphorus-mercury-zinc and a sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal and a preparation method and application thereof. The chemical formula of the compound is Zn2HgP2S8, the molecular weight is 649.79 g / mol, and the crystal is synthesized by a high-temperature solid phase method. The chemical formula of the crystal is Zn2HgP2S8, the molecular weight is 649.79 g / mol, the crystal has no symmetry center, crystallizes in an orthorhombic system, and the space group is Aea 2, the unit cell parameters are: a = 16.2706 (12) Å, b = 7.9266 (7) Å, c = 9.0620 (7) Å, Z = 4. The infrared nonlinear optical crystal is prepared by high temperature melt spontaneous crystallization method, chemical vapor transport method, flux method and crucible descent method. The sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal obtained by the present invention can be used to make infrared nonlinear optical devices, providing an important use in the fields of optics, laser lithography and communications.

Description

Technical Field

[0001] The invention belongs to the field of preparation of infrared nonlinear optical crystals, and specifically relates to a compound of sulfur-phosphorus-mercury-zinc and a sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal, and a preparation method and application thereof. Background Art

[0002] Nonlinear optical materials occupy an important position in modern laser science and technology. Crystals with nonlinear optical effects such as frequency doubling, sum frequency, difference frequency, and parametric amplification are called nonlinear optical crystals. Using the nonlinear optical effect of crystals, nonlinear optical devices such as second harmonic generators, up and down frequency converters, and optical parametric oscillators can be made. The laser generated by the laser can be frequency-converted through nonlinear optical devices to obtain more useful wavelengths of laser light, which has important applications in the fields of expanding laser frequency, ultrashort / ultra-intense laser pulses, optical communications, and generating entangled photon pairs. According to the working band, nonlinear optical crystals can be divided into four bands, namely deep ultraviolet (DUV, <200nm), ultraviolet band (UV, 200-400nm), visible / near infrared band (vis-NIR, 0.4-3μm), and mid / far infrared band (MF-IR, including 3-5 and 8-13μm atmospheric transparent windows).

[0003] Nonlinear optical crystal materials in the visible and ultraviolet regions can basically meet the requirements of practical applications. The practical crystals mainly include KTP (KTiOPO4), BBO (β-BaB2O4), and LBO (LiB3O5) crystals; in deep ultraviolet crystals, KBBF (KBe2BO3F2), ABF (NH4B4O6F), and CBF (CsB4O6F) are available. At present, the crystals that have been commercialized in the infrared region include AgGaS2 (AGS), AgGaSe2 (AGSe), and ZnGeP2 (ZGP). They have excellent performance in the infrared band, including large frequency doubling coefficients and a wide mid-infrared transmission range. However, with the rapid development of laser applications in various industries, some intrinsic problems of commercial materials have been found in their applications, such as the low laser damage threshold of AGS crystals, the low thermal conductivity of AGSe, and the two-photon absorption of ZGP crystals near 1μm laser output by the most commonly used Nd:YAG. These problems have caused them to be increasingly unable to meet the growing application needs in various fields. There is an urgent need to develop new infrared nonlinear optical crystal materials with balanced large double frequency and high damage threshold. Summary of the invention

[0004] The present invention aims to provide a compound of sulfur, phosphorus, mercury and zinc, the chemical formula of which is Zn2HgP2S8, the molecular weight of which is 649.79 g / mol, and which is synthesized by a high-temperature solid phase method.

[0005] Another object of the present invention is to provide a sulfur-phosphorus-mercury-zinc mid-to-far infrared nonlinear optical crystal, the chemical formula of the crystal is Zn2HgP2S8, the molecular weight is 649.79 g / mol, it belongs to the orthorhombic system, the space group is Aea2, and the unit cell parameters are: α=β=γ=90°, Z=4.

[0006] Another object of the present invention is to provide a method for preparing Zn2HgP2S8 infrared nonlinear optical crystal.

[0007] Another object of the present invention is to provide the use of Zn2HgP2S8 infrared nonlinear optical crystal.

[0008] The compound of sulfur, phosphorus, mercury and zinc described in the present invention has a chemical formula of Zn2HgP2S8 and a molecular weight of 649.79 g / mol and is prepared by a high-temperature solid phase method.

[0009] The preparation method of the compound sulfur, phosphorus, mercury and zinc adopts a high-temperature solid phase method, and the specific operation steps are as follows:

[0010] a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree is followed by melting sealing, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5;

[0011] b. Place the sealed quartz tube in step a into a programmed temperature-controlled muffle furnace, heat the temperature to 600-630° C. at a rate of 15-18° C. / h, perform solid phase reaction, and cool to room temperature at a rate of 3-5° C. / h to obtain the compounds sulfur, phosphorus, mercury and zinc.

[0012] A sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal, the crystal chemical formula is Zn2HgP2S8, the molecular weight is 649.79g / mol, it is an orthorhombic crystal system, belongs to the non-central space group: Aea2, and the unit cell parameters are: α=β=γ=90°, Z=4.

[0013] The method for preparing the sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal adopts a high-temperature melt spontaneous crystallization method, a chemical vapor transport method, a flux method or a crucible descent method to grow the crystal;

[0014] The high temperature melt spontaneous crystallization method for growing crystals is specifically performed in the following steps:

[0015] a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, melt-seal, put into a program-controlled muffle furnace, heat to 600-630°C at a rate of 15-18°C / h, carry out solid phase reaction, and cool to room temperature at a rate of 3-5°C / h to obtain a compound of sulfur, phosphorus, mercury and zinc, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5;

[0016] b. Put the compound sulfur, phosphorus, mercury and zinc polycrystalline powder obtained in step a into a quartz tube with a length of 20 cm and a diameter of 35 mm, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; put the sealed quartz tube into a program-controlled muffle furnace, and heat it to 600-630°C at a heating rate of 20-35°C / h, and react at a constant temperature for 26-98h, and then cool it to room temperature at a cooling rate of 2-8°C / h to make it spontaneously crystallize to obtain Zn2HgP2S8 infrared nonlinear optical crystal;

[0017] The chemical vapor transport method for growing Zn2HgP2S8 nonlinear optical crystals is specifically performed in the following steps:

[0018] a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, melt-seal, put into a program-controlled muffle furnace, heat to 600-630°C at a rate of 15-18°C / h, carry out solid phase reaction, and cool to room temperature at a rate of 3-5°C / h to obtain a compound of sulfur, phosphorus, mercury and zinc, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5;

[0019] b. Put the compound sulfur, phosphorus, mercury and zinc powder obtained in step a into a quartz tube with a length of 20 cm and a diameter of 35 mm, and evacuate the quartz tube to 10 -3 -10 -5Pa vacuum degree, and then melt-seal; put the sealed quartz tube into a tube furnace growth device, slowly heat it to 650-680°C, and react at a constant temperature for 30-95h, and then slowly cool it to room temperature at 3-8°C / h, and perform vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystals through a horizontal gradient temperature field, with a growth cycle of 12-45 days, to obtain Zn2HgP2S8 infrared nonlinear optical crystals;

[0020] The flux method for growing Zn2HgP2S8 nonlinear optical crystals is specifically performed in the following steps:

[0021] a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, melt-seal, put into a program-controlled muffle furnace, heat to 600-630°C at a rate of 15-18°C / h, carry out solid phase reaction, and cool to room temperature at a rate of 3-5°C / h to obtain a compound of sulfur, phosphorus, mercury and zinc, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5;

[0022] b. Mix the sulfur, phosphorus, mercury and zinc powder obtained in step a with the flux ZnCl2 in a mass ratio of 1:0.5-4.50, put them into a quartz tube with a length of 20 cm and a diameter of 35 mm, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; put the sealed quartz tube into a program-controlled muffle furnace, heat it to 610-650°C, keep the temperature constant for 30-68h, and then cool it down to room temperature at a cooling rate of 2-9°C / h to obtain a light green transparent Zn2HgP2S8 infrared nonlinear optical crystal;

[0023] The crucible descent method for growing crystals is specifically performed in the following steps:

[0024] a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5Pa vacuum degree, melt-seal, put into a program-controlled muffle furnace, heat to 600-630°C at a rate of 15-18°C / h, carry out solid phase reaction, and cool to room temperature at a rate of 3-5°C / h to obtain a compound of sulfur, phosphorus, mercury and zinc, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5;

[0025] b. Place the sulfur, phosphorus, mercury and zinc compounds obtained in step a into a quartz tube with a length of 20 cm and a diameter of 35 mm, and evacuate the quartz tube to 10 -3 -10 -5 Pa vacuum degree is achieved and then melt-sealed; the sealed quartz tube is placed in a programmed temperature-controlled Bridgman furnace, and the temperature is slowly increased to 650-700°C at a heating rate of 15-30°C / h, and kept warm for 30-50h. After the raw materials are completely melted, the vertical crucible is lowered at a speed of 0.3-0.8mm / h, and crystal growth is carried out during the descending process of the Bridgman furnace. The growth cycle is 14-35 days. After the growth is completed, continuous annealing is carried out at a speed of 10-25°C / h until it is cooled to room temperature to obtain a Zn2HgP2S8 infrared nonlinear optical crystal.

[0026] The sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal is used in preparing infrared-band laser frequency conversion crystals, infrared electro-optical devices, infrared communication devices or infrared laser guidance devices.

[0027] The Zn2HgP2S8 compound of the present invention can be prepared according to the following chemical reaction formula:

[0028] (1)2Zn+Hg+2P+8S=Zn2HgP2S8;

[0029] (2)2ZnS+Hg+2P+5S=Zn2HgP2S8;

[0030] (3) 2Zn+Hg+P2S5+3S=Zn2HgP2S8;

[0031] (4) 2ZnS+HgS+P2S5=Zn2HgP2S8.

[0032] By using the method for preparing the sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal described in the present invention, a centimeter-sized Zn2HgP2S8 infrared nonlinear optical crystal can be obtained; by using a large-sized crucible and extending the growth period, a correspondingly larger-sized Zn2HgP2S8 infrared nonlinear optical crystal 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 present invention further provides a nonlinear optical device. The nonlinear optical device comprises the above-mentioned Zn2HgP2S8 nonlinear optical crystal. The Zn2HgP2S8 nonlinear optical crystal 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 that of the incident electromagnetic radiation after at least one beam of incident electromagnetic radiation passes through at least one Zn2HgP2S8 nonlinear optical crystal.

[0035] During the growth process of preparing the Zn2HgP2S8 nonlinear optical crystal by the present invention, the crystal is easy to grow and is transparent without wrapping, and has the advantages of fast growth speed, low cost, easy acquisition of larger-sized crystals, etc. The obtained Zn2HgP2S8 nonlinear optical crystal and device have the advantages of large nonlinear optical effect, wide light transmission band, large hardness, good mechanical property, not easy to break and deliquesce, easy processing and storage, etc. The Zn2HgP2S8 nonlinear optical crystal can be used to make infrared nonlinear optical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of the present invention. Zn, Hg and P are tetracoordinated with S atoms in the crystal structure. ZHPS has a typical three-dimensional (3D) defective diamond-like structure, in which three types of tetrahedrons composed of Zn2HgS8 layers and pseudo layers constructed by PS4 are arranged in parallel along the c direction, and the two layers are connected to each other by sharing S atoms.

[0037] Figure 2 Schematic diagram of the SHG effect of the present invention. In the particle size range of 180-214 220 μm, Zn2HgP2S8 exhibits a medium-sized NLO response, which is about 1.1 times that of the benchmark AgGaS2.

[0038] Figure 3 A working principle diagram of a typical nonlinear optical device made for the present invention, wherein 1 is a laser, 2 is a convex lens, 3 is a Zn2HgP2S8 nonlinear optical crystal after crystal post-processing and optical processing, 4 is a prism, and 5 is a filter. DETAILED DESCRIPTION

[0039] 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.

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Example 1

[0042] According to the chemical reaction formula 2Zn+Hg+2P+8S=Zn2HgP2S 8， The compound Zn2HgP2S8 was prepared by high temperature solid phase method, and the specific operation was carried out according to the following steps:

[0043] 0.101 g Zn, 0.154 g Hg, 0.048 g P and 0.197 g S were weighed and mixed evenly in a molar ratio of 2:1:2:8 under vacuum. The mixture was placed in a clean graphite crucible. The graphite crucible was placed in a quartz tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was pumped to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, heat it to 630°C at a rate of 20°C / h, and keep it warm for 35h to obtain the polycrystalline powder of the compound Zn2HgP2S8.

[0044] Example 2

[0045] The compound Zn2HgP2S8 is prepared by a high temperature solid phase method according to the chemical reaction formula 2ZnS+Hg+2P+6S=Zn2HgP2S8. The specific operation is carried out according to the following steps:

[0046] 0.195 g ZnS, 0.201 g Hg, 0.062 g P and 0.192 g S were weighed and mixed evenly in an inert atmosphere at a molar ratio of 2:1:2:6. The mixture was placed in a clean graphite crucible. The graphite crucible was placed in a quartz tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, heat it to 650°C at a rate of 18°C / h, and keep it warm for 32h to obtain the polycrystalline powder of the compound Zn2HgP2S8.

[0047] Example 3

[0048] The compound Zn2HgP2S8 is prepared by a high temperature solid phase method according to the chemical reaction formula 2Zn+Hg+P2S5+3S=Zn2HgP2S8. The specific operation is carried out according to the following steps:

[0049] 0.121 g Zn, 0.185 g Hg, 0.205 g P2S5 and 0.089 g S were weighed and mixed evenly in a molar ratio of 2:1:1:3 under vacuum conditions. The mixture was placed in a clean graphite crucible. The graphite crucible was placed in a quartz tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, heat it to 640°C at a rate of 19°C / h, and keep it warm for 28h to obtain the polycrystalline powder of the compound Zn2HgP2S8.

[0050] Example 4

[0051] The compound Zn2HgP2S8 is prepared by a high temperature solid phase method according to the chemical reaction formula 2ZnS+HgS+P2S5=Zn2HgP2S8. The specific operation is carried out according to the following steps:

[0052] 0.180 g ZnS, 0.215 g HgS and 0.205 g P2S5 were weighed and mixed evenly in an inert atmosphere at a molar ratio of 2:1:1. The mixture was placed in a clean graphite crucible. The graphite crucible was placed in a quartz tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, heat it to 670°C at a rate of 24°C / h, and keep it warm for 35h to obtain the polycrystalline powder of the compound Zn2HgP2S8.

[0053] Example 5

[0054] The Zn2HgP2S8 infrared nonlinear optical crystal was prepared by high temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0055] The Zn2HgP2S8 polycrystalline powder obtained in Example 1 was placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, heat it to 600℃ at a rate of 20℃ / h, keep it at that temperature for 50h, and then cool it to room temperature at a cooling rate of 4℃ / h to obtain a quartz tube with a size of 0.25×4.08×6.15mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0056] Example 6

[0057] The Zn2HgP2S8 infrared nonlinear optical crystal was prepared by high temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0058] The Zn2HgP2S8 polycrystalline powder obtained in Example 2 was placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-sealed; then the sealed quartz tube was placed in a program-controlled muffle furnace, heated to 615°C at a rate of 22°C / h, kept at that temperature for 45h, and then cooled to room temperature at a cooling rate of 6°C / h to obtain a quartz tube with a size of 0.39×3.98×6.10mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0059] Example 7

[0060] The Zn2HgP2S8 infrared nonlinear optical crystal was prepared by high temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0061] The Zn2HgP2S8 polycrystalline powder obtained in Example 3 was placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, heat it to 625℃ at a rate of 26℃ / h, keep it warm for 60h, and then cool it to room temperature at a cooling rate of 7℃ / h to obtain a quartz tube with a size of 0.22×4.20×6.36mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0062] Example 8

[0063] The Zn2HgP2S8 infrared nonlinear optical crystal was prepared by high temperature melt spontaneous crystallization method. The specific operation is carried out according to the following steps:

[0064] The Zn2HgP2S8 polycrystalline powder obtained in Example 4 was placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-sealed; then the sealed quartz tube was placed in a program-controlled muffle furnace, heated to 630°C at a rate of 32°C / h, kept warm for 55h, and then cooled to room temperature at a cooling rate of 5°C / h to obtain a quartz tube with a size of 0.18×4.56×6.08mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0065] Example 9

[0066] The Zn2HgP2S8 infrared nonlinear optical crystal was prepared by chemical vapor transport method. The specific operation was carried out according to the following steps:

[0067] The Zn2HgP2S8 polycrystalline powder obtained in Example 1 was placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled tube furnace growth device, slowly heat it to 655℃, keep it constant for 58 hours, and slowly cool it to room temperature at a rate of 3.5℃ / h. During this period, the vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal is carried out through a horizontal gradient temperature field; after the quartz tube is completely cooled, it is cut to obtain a quartz tube with a size of 0.98×3.58×5.08mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0068] Example 10

[0069] The Zn2HgP2S8 infrared nonlinear optical crystal was prepared by chemical vapor transport method. The specific operation was carried out according to the following steps:

[0070] The Zn2HgP2S8 polycrystalline powder obtained in Example 2 was placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled tube furnace growth device, slowly heat it to 650℃, keep it constant for 68 hours, and slowly cool it to room temperature at a rate of 5℃ / h. During this period, the vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal is carried out through a horizontal gradient temperature field; after the quartz tube is completely cooled, it is cut open to obtain a quartz tube with a size of 1.32×4.38×6.51mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0071] Embodiment 11

[0072] The Zn2HgP2S8 infrared nonlinear optical crystal was prepared by chemical vapor transport method. The specific operation was carried out according to the following steps:

[0073] The Zn2HgP2S8 polycrystalline powder obtained in Example 3 was placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled tube furnace growth device, slowly heat it to 663℃, keep it constant for 70 hours, and slowly cool it to room temperature at a rate of 3℃ / h. During this period, the vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal is carried out through a horizontal gradient temperature field; after the quartz tube is completely cooled, it is cut open to obtain a quartz tube with a size of 0.82×4.62×6.08mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0074] Example 12

[0075] The Zn2HgP2S8 infrared nonlinear optical crystal was prepared by chemical vapor transport method. The specific operation was carried out according to the following steps:

[0076] The Zn2HgP2S8 polycrystalline powder obtained in Example 4 was placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled tube furnace growth device, slowly heat it to 678℃, keep it constant for 70 hours, and slowly cool it to room temperature at a rate of 6℃ / h. During this period, the vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal is carried out through a horizontal gradient temperature field; after the quartz tube is completely cooled, it is cut open to obtain a quartz tube with a size of 1.92×3.93×6.58mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0077] Example 13

[0078] The flux growth method is used to prepare the Zn2HgP2S8 infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0079] The compound Zn2HgP2S8 polycrystalline powder obtained in Example 1 and the flux ZnCl2 were mixed in a mass ratio of 1:3 and placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, slowly heat it to 618℃, keep it in a constant temperature for 65h, and then slowly cool it to room temperature at a rate of 6℃ / h. During this period, the vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal is carried out through a horizontal gradient temperature field; after the quartz tube is completely cooled, it is cut to obtain a size of 0.82×4.46×6.33mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0080] Embodiment 14

[0081] The flux growth method is used to prepare the Zn2HgP2S8 infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0082] The compound Zn2HgP2S8 polycrystalline powder obtained in Example 2 and the flux ZnCl2 were mixed in a mass ratio of 1:3.5 and placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, slowly heat it to 632℃, keep it in a constant temperature for 45h, and then slowly cool it to room temperature at a rate of 4℃ / h. During this period, the vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal is carried out through a horizontal gradient temperature field; after the quartz tube is completely cooled, it is cut to obtain a quartz tube with a size of 0.98×4.13×6.27mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0083] Embodiment 15

[0084] The flux growth method is used to prepare the Zn2HgP2S8 infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0085] The compound Zn2HgP2S8 polycrystalline powder obtained in Example 3 and the flux ZnCl2 were mixed in a mass ratio of 1:4 and placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, slowly heat it to 643℃, and react at a constant temperature for 55h, and then slowly cool it to room temperature at a rate of 6.5℃ / h. During this period, the vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal is carried out through a horizontal gradient temperature field; after the quartz tube is completely cooled, it is cut to obtain a quartz tube with a size of 0.61×4.33×6.65mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0086] Example 16

[0087] The flux growth method is used to prepare the Zn2HgP2S8 infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0088] The compound Zn2HgP2S8 polycrystalline powder obtained in Example 4 and the flux ZnCl2 were mixed in a mass ratio of 1:4.5 and placed in a quartz tube with a length of 20 cm and a diameter of 35 mm. The quartz tube was evacuated to 10 -3 -10 -5Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled muffle furnace, slowly heat it to 650℃, keep it in a constant temperature for 45h, and then slowly cool it to room temperature at a rate of 5.5℃ / h. During this period, the vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal is carried out through a horizontal gradient temperature field; after the quartz tube is completely cooled, it is cut open to obtain a quartz tube with a size of 0.63×4.89×6.97mm 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0089] Embodiment 17

[0090] The crucible descent method is used to prepare the Zn2HgP2S8 infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0091] The Zn2HgP2S8 polycrystalline powder obtained in Example 1 was placed in a quartz tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled Bridgman furnace, heat it to 650℃ at a rate of 15℃ / h, and keep it warm for 35h; then vertically descend the crucible at a speed of 0.35mm / h, and the crystal grows during the descent of the Bridgman furnace. The growth cycle is 16 days. After the growth is completed, annealing is continued at a rate of 20℃ / h until it cools to room temperature, and a crystal with a size of 0.39×4.42×6.28mm is obtained. 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0092] Embodiment 18

[0093] The crucible descent method is used to prepare the Zn2HgP2S8 infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0094] The Zn2HgP2S8 polycrystalline powder obtained in Example 2 was placed in a quartz tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled Bridgman furnace, heat it to 665℃ at a rate of 20℃ / h, and keep it warm for 45h; then vertically descend the crucible at a speed of 0.5mm / h, and the crystal grows during the descent of the Bridgman furnace. The growth cycle is 20 days. After the growth is completed, annealing is continued at a rate of 18℃ / h until it cools to room temperature, and a crystal with a size of 0.60×4.98×6.58mm is obtained. 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0095] Embodiment 19

[0096] The crucible descent method is used to prepare the Zn2HgP2S8 infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0097] The Zn2HgP2S8 polycrystalline powder obtained in Example 3 was placed in a quartz tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled Bridgman furnace, heat it to 670℃ at a rate of 25℃ / h, and keep it warm for 48h; then descend the crucible vertically at a speed of 0.6mm / h, and the crystal grows during the descent of the Bridgman furnace. The growth cycle is 25 days. After the growth is completed, annealing is continued at a rate of 22℃ / h until it cools to room temperature, and a crystal with a size of 0.15×4.03×6.22mm is obtained. 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0098] Embodiment 20

[0099] The crucible descent method is used to prepare the Zn2HgP2S8 infrared nonlinear optical crystal. The specific operation is carried out in the following steps:

[0100] The Zn2HgP2S8 polycrystalline powder obtained in Example 4 was placed in a quartz tube with a length of 24 cm and a diameter of 12 mm. The quartz tube was evacuated to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; then put the sealed quartz tube into a program-controlled Bridgman furnace, heat it to 675℃ at a rate of 30℃ / h, and keep it warm for 50h; then descend the crucible vertically at a speed of 0.7mm / h, and the crystal grows during the descent of the Bridgman furnace. The growth cycle is 30 days. After the growth is completed, annealing is continued at a rate of 25℃ / h until it cools to room temperature, and a crystal with a size of 0.66×4.32×6.55mm is obtained. 3 Sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal.

[0101] Embodiment 21

[0102] After testing, the Zn2HgP2S8 infrared nonlinear optical crystal prepared in Example 5-20 belongs to the orthorhombic system, the space group is Aea2, the nonlinear optical crystal does not have a symmetry center, and the unit cell parameters are: α=β=γ=90°, Z=4. The crystal has good frequency doubling effect and the light transmission range is 0.3-17μm; Figure 1 It is a schematic diagram of the structure of Zn2HgP2S8 nonlinear optical crystal;

[0103] The Zn2HgP2S8 crystals obtained in Example 5-20 are not easy to break or deliquesce, and are easy to cut, polish and store. Figure 3 At the position marked 3 in the device shown, at room temperature, a Q-switched Ho:Tm:Cr:YAG laser is used as the light source, the incident wavelength is 2090nm infrared light, and the output wavelength is 1045nm double frequency light. The laser intensity output by the Zn2HgP2S8 crystal is 1.1 times that of AgGaS2 under the same conditions;

[0104] Attached Figure 3 This is a working principle diagram of a typical nonlinear optical device made of the Zn2HgP2S8 nonlinear optical crystal of the present invention, wherein 1 is a laser, 2 is a convex lens, 3 is a Zn2HgP2S8 nonlinear optical crystal after crystal post-processing and optical processing, 4 is a prism, and 5 is a filter; the laser beam emitted by the laser 1 is incident on the Zn2HgP2S8 single crystal 3 through the convex lens 2, and the generated outgoing laser beam passes through the prism 4 and the filter 5, thereby obtaining the required laser beam.

[0105] The devices made of the Zn2HgP2S8 nonlinear optical crystal of the present invention are frequency doubling generators, up and down frequency converters, optical parametric oscillators, optical parametric amplifiers, etc.

Claims

1. A sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal, characterized in that The crystal chemical formula is Zn2HgP2S8, the molecular weight is 649.79 g / mol, it is an orthorhombic system, and belongs to the non-central space group: Aea 2, the unit cell parameters are: a=16.2706(12) Å, b=7.9266(7) Å, c=9.0620(7) Å, α=β=γ=90°, Z=4.

2. The method for preparing the sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal according to claim 1, characterized in that: The method uses a high temperature melt spontaneous crystallization method, a chemical vapor transport method, a flux method or a crucible descent method to grow crystals; The high temperature melt spontaneous crystallization method for growing crystals is specifically performed in the following steps: a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, melt-seal, put into a program-controlled muffle furnace, heat to 600-630°C at a rate of 15-18°C / h, carry out solid phase reaction, and cool to room temperature at a rate of 3-5°C / h to obtain a compound of sulfur, phosphorus, mercury and zinc, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5; b. Put the compound sulfur, phosphorus, mercury and zinc polycrystalline powder obtained in step a into a quartz tube with a length of 20 cm and a diameter of 35 mm, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; put the sealed quartz tube into a program-controlled muffle furnace, and heat it to 600-630°C at a heating rate of 20-35°C / h, and react at a constant temperature for 26-98 hours, and then cool it to room temperature at a cooling rate of 2-8°C / hour to make it spontaneously crystallize to obtain Zn2HgP2S8 infrared nonlinear optical crystal; The chemical vapor transport method for growing Zn2HgP2S8 nonlinear optical crystals is specifically performed in the following steps: a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, melt-seal, put into a program-controlled muffle furnace, heat to 600-630°C at a rate of 15-18°C / h, carry out solid phase reaction, and cool to room temperature at a rate of 3-5°C / h to obtain a compound of sulfur, phosphorus, mercury and zinc, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5; b. Put the compound sulfur, phosphorus, mercury and zinc powder obtained in step a into a quartz tube with a length of 20 cm and a diameter of 35 mm, and evacuate the quartz tube to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; put the sealed quartz tube into a tube furnace growth device, slowly heat it to 650-680°C, and after constant temperature reaction for 30-95 hours, slowly cool it to room temperature at 3-8°C / h, and perform vapor phase transmission growth of Zn2HgP2S8 nonlinear optical crystal through a horizontal gradient temperature field, with a growth cycle of 12-45 days, to obtain Zn2HgP2S8 infrared nonlinear optical crystal; The flux method for growing Zn2HgP2S8 nonlinear optical crystals is specifically performed in the following steps: a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, melt-seal, put into a program-controlled muffle furnace, heat to 600-630°C at a rate of 15-18°C / h, carry out solid phase reaction, and cool to room temperature at a rate of 3-5°C / h to obtain a compound of sulfur, phosphorus, mercury and zinc, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5; b. Mix the sulfur, phosphorus, mercury and zinc powder obtained in step a with the flux ZnCl2 in a mass ratio of 1:0.5-4.50, put them into a quartz tube with a length of 20 cm and a diameter of 35 mm, and use a vacuum pump to evacuate the quartz tube to 10 -3 -10 -5 Pa vacuum degree, and then melt-seal; put the sealed quartz tube into a program-controlled muffle furnace, heat it to 610-650℃, keep the temperature constant for 30-68 h, and then cool it down to room temperature at a cooling rate of 2-9℃ / h to obtain a light green transparent Zn2HgP2S8 infrared nonlinear optical crystal; The crucible descent method for growing crystals is specifically performed in the following steps: a. Mix Zn source material, Hg source material, P source material and elemental S evenly in a molar ratio of 1.8-2.5:1:2:7.5-8.5, put them into a clean graphite crucible, put the graphite crucible into a quartz tube, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree, melt-seal, put into a program-controlled muffle furnace, heat to 600-630°C at a rate of 15-18°C / h, carry out solid phase reaction, and cool to room temperature at a rate of 3-5°C / h to obtain a compound of sulfur, phosphorus, mercury and zinc, wherein the Zn source material is Zn, ZnCl2, ZnS or ZnI2; the Hg source material is Hg, Hg2Cl2 or HgS; the P source material is P or P2S5; b. Place the sulfur, phosphorus, mercury and zinc compounds obtained in step a into a quartz tube with a length of 20 cm and a diameter of 35 mm, and use a vacuum pump to pump the quartz tube to 10 -3 -10 -5 Pa vacuum degree is achieved and then melt-sealed; the sealed quartz tube is placed in a programmed temperature-controlled Bridgman furnace, and the temperature is slowly increased to 650-700°C at a heating rate of 15-30°C / h, and kept warm for 30-50h. After the raw materials are completely melted, the vertical crucible is lowered at a speed of 0.3-0.8mm / h, and crystal growth is carried out during the descending process of the Bridgman furnace. The growth cycle is 14-35 days. After the growth is completed, continuous annealing is carried out at a speed of 10-25°C / h until it is cooled to room temperature to obtain a Zn2HgP2S8 infrared nonlinear optical crystal.

3. Use of the sulfur-phosphorus-mercury-zinc infrared nonlinear optical crystal as claimed in claim 1 in the preparation of infrared band laser frequency conversion crystals, infrared electro-optical devices, infrared communication devices or infrared laser guidance devices.

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