CN105506743B - Li6Cd5Sn4Se16Nonlinear optical crystal and its preparation method and use - Google Patents

Abstract

The present invention relates to a Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal, its preparation method and application; the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal does not have a symmetry center, belongs to an orthorhombic crystal system, and its space group is Pna2 ₁ , and its unit cell parameters are: α=β=γ=90°; the nonlinear optical crystal is grown by the high-temperature melt spontaneous crystallization method or the crucible drop method; the nonlinear optical crystal is growing, and the crystal is easy to grow and transparent without wrapping, and has a faster growth rate , low cost, easy to obtain large-sized crystals and other advantages; the nonlinear optical crystal has a wide light transmission band, high hardness, good mechanical properties, not easy to break and deliquesce, easy to process and store, etc.; the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystals can be used to make nonlinear optical devices.

Description

A kind of Li6Cd5Sn4Se16 nonlinear optical crystal and its preparation method and application

technical field

The invention belongs to the field of nonlinear optical crystals, preparation and application, in particular to a nonlinear optical crystal of Li ₆ Cd ₅ Sn ₄ Se ₁₆ (Li ₆ Cd ₅ Sn ₄ Se ₁₆ single crystal) and the SnGa ₄ Se ₇ single crystal The preparation method of the crystal and the application of the Li ₆ Cd ₅ Sn ₄ Se ₁₆ single crystal in the manufacture of nonlinear optical devices.

Background technique

Crystals with nonlinear optical effects are called nonlinear optical crystals. Here nonlinear optical effects refer to effects such as frequency doubling, sum frequency, difference frequency, and parametric amplification. Nonlinear optical effects are only possible in crystals that do not have a center of symmetry. 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 by nonlinear optical devices, so as to obtain more useful wavelengths of laser light, so that the laser can be used more widely. According to the different application bands of materials, they can be divided into three categories: ultraviolet region, visible and near-infrared region, and mid-infrared region nonlinear optical materials. Nonlinear optical crystal materials in the visible and ultraviolet regions can already meet the requirements of practical applications; for example, KTP (KTiOPO ₄ ), BBO (β-SnB 2 O 4 ), BBO (β-SnB ₂ O ₄ ), and LBO (LiB ₃ O ₅ ) crystals; BBO, LBO, and CBO (CsB ₃ O ₅ ) are available for practical use in triple frequency (355nm) crystals. The development of nonlinear crystals in the infrared band is relatively slow; the materials in the infrared region are mostly ABC ₂ -type chalcopyrite structure semiconductor materials, such as AgGaQ ₂ (Q=S, Se, Te), and the optical damage threshold of infrared nonlinear crystals Too low and crystal growth is difficult, which directly affects the actual use. The mid-infrared band nonlinear optical crystal has important applications in the field of optoelectronics. For example, it can extend the near-infrared band laser (such as 1.064μm) to the mid-infrared region by means of optical parametric oscillation or optical parametric amplification; Frequency doubling of important lasers in the region (such as CO ₂ laser, 10.6 μm), which is of great significance for obtaining continuously adjustable wavelength lasers. Therefore, searching for new infrared nonlinear optical crystal materials with excellent performance has become a difficult point and one of the frontier directions in the field of nonlinear optical materials research.

We studied the crystal structure of Li ₆ Cd ₅ Sn ₄ Se ₁₆ for the first time and found that Li ₆ Cd ₅ Sn ₄ Se ₁₆ has nonlinear optical properties.

Contents of the invention

The purpose of the present invention is to provide a Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal.

Another object of the present invention is to provide a preparation method of Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal.

Another object of the present invention is to provide the use of Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal.

Technical scheme of the present invention is as follows:

The Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal provided by the present invention, the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal does not have a symmetry center, belongs to an orthorhombic crystal system, and its space group is Pna2 ₁ . The cell parameters are: α=β=γ=90°.

The preparation method of the Li _{6 Cd 5 Sn 4 Se 16 nonlinear optical crystal provided by the present invention is to grow the Li 6 Cd 5 Sn 4 Se 16 nonlinear optical crystal by} a high-temperature melt spontaneous crystallization method, and the steps are as follows:

Heat the powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound or the mixture mixed according to the molar ratio Li:Cd:Sn:Se=6:5:4:16 to melt to obtain a high-temperature melt, and in the high-temperature melt state Keep at low temperature for 24-96 hours, and then cool down to room temperature at a cooling rate of 1-10°C/hour to obtain Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystals;

The preparation of the powdery Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound is as follows:

After mixing Li source material, Cd source material, Sn source material and Se simple substance according to the ratio of molar ratio Li:Cd:Sn:Se=6:5:4:16, heating to 800-1050°C for chemical synthesis to obtain The chemical formula is Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound, which is crushed and ground to obtain powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound;

The Li source material is simple lithium or lithium selenide;

The Cd source material is simple cadmium or cadmium selenide:

_The Sn4 source material is tin simple substance or tin diselenide.

The chemical synthesis is a solid phase reaction.

The powdery Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound is prepared according to the following reaction formula:

(1) 6Li+5Cd+4Sn+16Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(2) 3Li ₂ Se+5Cd+4Sn+13Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(3) 6Li+5CdSe+4Sn+11Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(4) 6Li+5Cd+4SnSe ₂ +8Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(5) 3Li ₂ Se+5CdSe+4SnSe ₂ ＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

Another preparation method of the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal provided by the present invention is to grow the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal by the crucible descent method, and the steps are as follows:

Put the powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound or the mixture mixed according to the molar ratio Li:Cd:Sn:Se=6:5:4:16 into the crystal growth device, raise the temperature until the raw materials are melted, and wait until the raw materials are completely After melting, the crystal growth device descends vertically at a speed of 0.1-10 mm/h, and performs Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal growth during the descent of the crystal growth device to obtain Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystals; Its growth cycle is 5-20 days;

The preparation of the powdery Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound is as follows:

After mixing Li source material, Cd source material, Sn source material and Se simple substance according to the ratio of molar ratio Li:Cd:Sn:Se=6:5:4:16, heating to 800-1050°C for chemical synthesis to obtain The chemical formula is Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound, which is crushed and ground to obtain powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound;

The Li source material is simple lithium or lithium selenide;

The Cd source material is simple cadmium or cadmium selenide:

_The Sn4 source material is tin simple substance or tin diselenide.

The Li ₆ Cd ₅ Sn ₄ Se ₁₆ is prepared according to the following chemical reaction formula:

(1) 6Li+5Cd+4Sn+16Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(2) 3Li ₂ Se+5Cd+4Sn+13Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(3) 6Li+5CdSe+4Sn+11Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(4) 6Li+5Cd+4SnSe ₂ +8Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(5) 3Li ₂ Se+5CdSe+4SnSe ₂ =Li ₆ Cd ₅ Sn ₄ Se ₁₆ .

The above two methods can be used to obtain Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystals with a size of centimeters; use a large-sized crucible and prolong the growth period, and correspondingly larger-sized Li ₆ Cd ₅ Sn ₄ Se can be obtained ₁₆ nonlinear optical crystals.

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 transparent surface of the crystal is polished, then it can be used as a nonlinear optical device. The Li ₆ Cd ₅ Sn ₄ Se ₁₆ non-linear The linear optical crystal has the advantages of stable physical and chemical properties, high hardness, good mechanical properties, not easy to break, not easy to deliquescence, easy to process and store; for this reason, the present invention further provides Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal The use of the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal is used to prepare a nonlinear optical device, and the nonlinear optical device includes passing at least one beam of incident electromagnetic radiation through at least one piece of the Li ₆ Cd ₅ Sn ₄ Se ₁₆ non-linear A device that produces at least one output radiation having a frequency different from that of the incident electromagnetic radiation after a linear optical crystal.

The compound of Li ₆ Cd ₅ Sn ₄ Se ₁₆ of the present invention, the nonlinear optical crystal of the compound and its preparation method and use have the following effects:

In the growth of the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal, the crystal is easy to grow and transparent without wrapping, and has the advantages of fast growth, low cost, and easy to obtain larger-sized crystals; the obtained Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal has a relatively wide light transmission band, high hardness, good mechanical properties, not easy to break and deliquesce, easy to process and store; the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical Crystals can be used to make nonlinear optical devices.

Description of drawings

Fig. 1 is a working principle diagram of a typical nonlinear optical device made of Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal of the present invention, wherein 1 is a laser, 2 is an incident laser beam, and 3 is a laser beam after passing through the crystal. The treated and optically processed Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal, 4 is the generated outgoing laser beam, and 5 is a filter.

Fig. 2 is a schematic diagram of the structure of Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal.

detailed description

Example 1, Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystals were prepared by high-temperature melt spontaneous crystallization method:

Weigh 2.785 grams of Li ₂ Se, 9.568 grams of CdSe and 11.065 grams of SnSe ₂ (i.e. Li ₂ Se:CdSe:SnSe ₂ =0.03mol:0.05mol:0.04mol), mix them evenly, and put them into a Φ12mm×20mm quartz glass tube In the process, vacuumize to 10 ^-3 Pa, seal it with an oxyhydrogen flame, place it in a tubular growth furnace, raise it to 900°C, keep the temperature constant for 72 hours, slowly cool down to room temperature at a rate of 5°C/h, and turn off the tubular growth Furnace; after the quartz tube is cooled, it can be cut to obtain transparent Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystals.

Example 2, preparing Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystals using the crucible drop method:

Weigh 0.417 grams of Li, 5.621 grams of Cd, 4.748 grams of Sn and 12.634 grams of Se (Li:Cd:Sn:Se = 0.06mol:0.05mol:0.04mol:0.16mol), after uniform mixing, put it into a Φ20mm×30mm quartz In the glass tube, after evacuating to 10 ^-3 Pa, seal it with an oxyhydrogen flame and place it in a crystal growth furnace, raise it to 900°C to melt the raw material, and after the raw material is completely melted, the growth device will operate at a speed of 0.1-10mm/hour vertical drop; after the crystal growth is completed, the growth device takes 20 hours to cool down to room temperature, and a transparent Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystal is obtained.

After testing, the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal prepared in the above-mentioned examples 1-2 belongs to the orthorhombic crystal system, the space group is Pna2 ₁ , and its unit cell parameters are: α=β=γ=90°, Z=7, Density: 5.453g/cm ³ , with frequency doubling effect; Figure 2 is a schematic structural diagram of the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal.

Example 3:

The Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystal obtained in Example 1-2 is not easily broken, easy to cut, polish and store, and does not deliquesce; the Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystal obtained in Example 1-2 is placed in At the position where the device label shown in accompanying drawing 1 is 3, at room temperature, use a Q-switched Ho:Tm:Cr:YAG laser as a light source, the incident wavelength is infrared light of 2090nm, and the output wavelength is frequency-doubled light of 1045nm. Laser intensity is comparable to that of AgGaSe ₂ .

Accompanying drawing 1 is to adopt Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optics crystals of the present invention to make a kind of typical working principle figure of nonlinear optical device, wherein 1 is laser device, 2 is incident laser beam, 3 is warp crystal Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal after post-processing and optical processing, 4 is the outgoing laser beam generated, 5 is a filter; the incident laser beam 2 is emitted by the laser 1 and enters Li ₆ Cd ₅ Sn ₄ Se ₁₆ single crystal 3, the generated outgoing laser beam 4 passes through the filter 5 to obtain the required laser beam;

The device made by using the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal of the present invention can be a frequency multiplication generator, an up/down frequency converter, and an optical parametric oscillator. Optical parametric amplifier, etc.

It should be noted that the present invention can also directly use powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound to prepare Li ₆ Cd ₅ Sn ₄ Se ₁₆ single crystal: preparation of powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound: Li source Material, Cd source material, Sn ₄ source material and Se simple substance are mixed uniformly according to the ratio of molar ratio Li:Cd:Sn ₄ :Se=7:4.5:4:16, and then heated to 800-1050°C for chemical synthesis to obtain the chemical formula Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound, crushed and ground to obtain powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound; the chemical synthesis method of the present invention is preferably a solid phase reaction method; Li ₆ Cd ₅ Sn ₄ of the present invention Se ₁₆ compound can be prepared by following reaction formula:

(1) 6Li+5Cd+4Sn+16Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(2) 3Li ₂ Se+5Cd+4Sn+13Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(3) 6Li+5CdSe+4Sn+11Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(4) 6Li+5Cd+4SnSe ₂ +8Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

(5) 3Li ₂ Se+5CdSe+4SnSe ₂ ＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ;

The Li source material in the preparation of the above powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound and its nonlinear chemical crystal can be lithium element or lithium selenide; the Cd source material can be cadmium element or cadmium selenide; the Sn ₄ source material can be It is tin elemental or tin diselenide.

Claims (7)

1. A Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal, the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal does not have a symmetry center, belongs to an orthorhombic crystal system, and its space group is Pna2 ₁ , and its crystal The cell parameters are: α=β=γ=90°. 2. a kind of preparation method of Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystals described in claim 1, it is high temperature melt spontaneous crystallization method growth Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystals, its steps are : Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound or a mixture of Li source material, Cd source material, Sn source material and Se simple substance mixed according to the molar ratio Li:Cd:Sn:Se=6:5:4:16 is heated to Melt to obtain a high-temperature melt, and keep the high-temperature melt for 24-96 hours, and then cool down to room temperature at a cooling rate of 1-10°C/hour to obtain Li ₆ Cd ₅ Sn ₄ Se ₁₆ crystals; The powdery Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound was prepared as follows: After mixing Li source material, Cd source material, Sn source material and Se simple substance according to the molar ratio of Li:Cd:Sn:Se=6:5:4:16, heating to 800-1050°C for chemical synthesis to obtain The chemical formula is Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound, which is crushed and ground to obtain powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound; The Li source material is simple lithium or lithium selenide; The Cd source material is simple cadmium or cadmium selenide; The Sn source material is tin simple substance or tin diselenide. 3. The preparation method of Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal according to claim 2, characterized in that said chemical synthesis is a solid phase reaction. 4. by the preparation method of Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystals described in claim 2, it is characterized in that, powdery Li ₆ Cd ₅ Sn ₄ Se ₁₆ compounds are prepared by following reaction formula: (1) 6Li+5Cd+4Sn+16Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ; (2) 3Li ₂ Se+5Cd+4Sn+13Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ; (3) 6Li+5CdSe+4Sn+11Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ; (4) 6Li+5Cd+4SnSe ₂ +8Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ; (5) 3Li ₂ Se+5CdSe+4SnSe ₂ =Li ₆ Cd ₅ Sn ₄ Se ₁₆ . 5. A preparation method of Li _{6 Cd 5 Sn 4 Se 16 nonlinear optical crystal according to claim 1, which is growing Li 6 Cd 5 Sn 4 Se 16 nonlinear optical crystal by} crucible descent method, and the steps are as follows: Put the Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound or the mixture mixed according to the molar ratio Li:Cd:Sn:Se=6:5:4:16 into the crystal growth device, raise the temperature until the raw material melts, and wait until the raw material is completely melted , the crystal growth device drops vertically at a speed of 0.1-10mm/h, and Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystals are grown during the descent of the crystal growth device to obtain Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystals ; Its growth cycle is 5-20 days; The preparation of powdery Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound is as follows: After mixing Li source material, Cd source material, Sn source material and Se simple substance according to the molar ratio of Li:Cd:Sn:Se=6:5:4:16, heating to 800-1050°C for chemical synthesis to obtain The chemical formula is Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound, which is crushed and ground to obtain powdered Li ₆ Cd ₅ Sn ₄ Se ₁₆ compound; The Li source material is simple lithium or lithium selenide; The Cd source material is simple cadmium or cadmium selenide; The Sn source material is tin simple substance or tin diselenide. 6. The method for preparing Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal according to claim 5, characterized in that the Li ₆ Cd ₅ Sn ₄ Se ₁₆ is prepared according to the following chemical reaction formula: (1) 6Li+5Cd+4Sn+16Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ; (2) 3Li ₂ Se+5Cd+4Sn+13Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ; (3) 6Li+5CdSe+4Sn+11Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ; (4) 6Li+5Cd+4SnSe ₂ +8Se＝Li ₆ Cd ₅ Sn ₄ Se ₁₆ ; (5) 3Li ₂ Se+5CdSe+4SnSe ₂ =Li ₆ Cd ₅ Sn ₄ Se ₁₆ . 7. The use of the Li _{6 Cd 5 Sn 4 Se 16 nonlinear optical crystal according to claim 1, characterized in that the Li 6 Cd 5 Sn 4 Se 16 nonlinear optical crystal is} used to prepare nonlinear optical devices, The prepared nonlinear optical device includes a device for generating at least one beam of output radiation whose frequency is different from that of the incident electromagnetic radiation after passing at least one beam of incident electromagnetic radiation through at least one piece of the Li ₆ Cd ₅ Sn ₄ Se ₁₆ nonlinear optical crystal.