Tellurate crystal, growth method therefor, and use thereof

Abstract

The present disclosure relates to tellurite crystals, growing methods of the same, and applications thereof; the crystals a chemical formula of MTe.sub.3O.sub.8, wherein M=Ti, Zr, Hf, which belongs to an Ia-3 space group of a cubic crystal system, wherein a transmittance waveband ranges from visible light to infrared light, with a transparency ≥70%. According to the present disclosure, a growing method of a tellurite crystal is provided, wherein the crystal may be grown using a flux method, a Czochralski method, or a Bridgman-Stockbarger method. The tellurite crystals may be used as an acousto-optic crystal for fabricating an optical modulation device. The present disclosure takes the lead internationally in growing the tellurite single crystals, the size and quality of which sufficiently meet the demands of practical applications of the tellurite single crystals.

Claims

1. A growing method of a tellurite crystal having a chemical formula of MTe.sub.3O.sub.8, wherein M=Ti, Zr, Hf, which belongs to an Ia-3 space group of a cubic crystal system, and wherein a transmittance waveband ranges from visible light to infrared light, with a transparency ≥70%, wherein the crystal is grown using a flux method, the growing method comprising steps of: (1) compounding raw materials MO.sub.2 (M=Ti, Zr, Hf) and TeO.sub.2 according to an MTe.sub.3O.sub.8 stoichiometric ratio, homogeneously mixing and tableting, sintering at 500° C.˜650° C. for 20˜40 h, cooling, grinding, and then sintering at 600˜700° C. for 20˜40 h, obtaining a pure-phase tellurite polycrystal; adding the pure-phase tellurite polycrystal to a flux system, then obtaining a crystal growth material; or, compounding raw materials MO.sub.2 (M=Ti, Zr, Hf) and TeO.sub.2 according to an MTe.sub.3O.sub.8 stoichiometric ratio, directly adding them to the flux system, homogeneously mixing, thereby obtaining a crystal growth material; wherein the flux system is selected from one of the following substances, but not limited thereto: (a) TeO.sub.2; (b) A.sub.2CO.sub.3—TeO.sub.2 (A=Li, Na, K, Rb or/and Cs), wherein the mole ratio between M.sub.2CO.sub.3 and TeO.sub.2 is 2: (1˜5); (c) MoO.sub.3; (d) B.sub.2O.sub.3; (e) PbO—B.sub.2O.sub.3; wherein the mole ratio between the tellurite and the flux system is 1: (1˜5); (2) putting the crystal growth material obtained in step (1) in a platinum crucible, heating to melt it completely, stirring homogeneously, cooling to facilitate the crystal to be nucleated spontaneously and to grow to obtain a tellurite seed crystal; putting the crystal growth material obtained in step (1) in a platinum crucible, heating to melt it completely, stirring homogeneously, cooling to a saturation point of the solution, feeding the tellurite seed crystal to perform crystal transformation, cooling to facilitate the crystal to grow; wherein a temperature range for the crystal growth is 750˜900° C., and a cooling rate is 0.01˜5° C./h.

2. The growing method of the tellurite crystal of claim 1, wherein a cooling procedure during growing of the tellurite crystal in step (2) comprises: cooling to 750˜850° C. at a rate of 0.01˜4° C./h with a growth period: 5˜70 days.

3. The growing method of the tellurite crystal of claim 1, wherein a grown tellurite single crystal has a length ≥20 mm and a thickness ≥10 mm.

4. The growing method of the tellurite crystal of claim 1, wherein in the step (1), a rare earth element material Re.sub.2O.sub.3, the MO.sub.2 (M=Ti, Zr, Hf), and the TeO.sub.2 are compounded together according to a certain proportion, obtaining a rare earth element-doped crystal growth material, and growth through the step (2) results in a rare earth element-doped tellurite crystal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an experimental X-ray powder diffraction pattern of a titanium tellurite polycrystal grown according to embodiment 1 of the present disclosure and a standard X-ray powder diffraction pattern obtained from theoretical calculation (a denotes the experimental X-ray powder diffraction pattern, and b denotes the result obtained from the theoretical calculation);

(2) FIG. 2 is a picture of a titanium tellurite seed crystal prepared according to Embodiment 1;

(3) FIG. 3 is a picture of a titanium tellurite single crystal prepared according to Embodiment 2;

(4) FIG. 4 is a picture of a titanium tellurite single crystal prepared according to Embodiment 3;

(5) FIG. 5 is a picture of a titanium tellurite single crystal prepared according to Embodiment 4;

(6) FIG. 6 is an operating schematic diagram of typical acousto-optic crystal Q switching;

(7) FIG. 7 is an operating schematic diagram of a typical laser crystal;

(8) FIG. 8 is an operating schematic diagram of a typical laser self-Q switching crystal;

(9) where 1, 7, 12 represent a laser diode, 2, 8, 13 represent a focusing system, 3, 14 represent a concave mirror, 4 represents Nd:YVO.sub.4/Nd:YAG laser crystal, 5 represents a TiTe.sub.3O.sub.8 acousto-optic medium, 6, 9, 11, 16 represent a planar mirror, 10 represents Yb: TiTe.sub.3O.sub.8 laser crystal; 15 represents a Yb: TiTe.sub.3O.sub.8 laser self-Q switching crystal.

DETAILED DESCRIPTION OF EMBODIMENTS

(10) Hereinafter, the technical solution according to the present disclosure is further illustrated with reference to the preferred embodiments, but not limited thereto.

Embodiment 1: Growth of Titanium Tellurite Seed Crystal

(11) Compounding the raw materials TiO.sub.2 and TeO.sub.2 according to the TiTe.sub.3O.sub.8 stoichiometric ratio, adding them to a flux system Li.sub.2CO.sub.3—TeO.sub.2 (the Li.sub.2CO.sub.3:TeO.sub.2 mole rate is 2:3), where the mole rate between the titanium tellurite and the flux system is 1:3, placing them into a platinum crucible with a volume of Φ50 mm×70 mm, rapidly heating to 980° C. to completely melt the raw materials, homogeneously stirring; sinking a platinum rod and performing crystal transformation, slowly cooling to the saturation point of the solution, wherein the cooling rate is 0.55° C./h and the growth period is 5 days; pulling up a seed crystal rod to obtain an orange-colored polycrystal (as shown in FIG. 2). The experimental X-ray powder diffraction pattern is tested to be coincident with the result derived from theoretical computation (as shown in FIG. 1), indicating that what is obtained is the titanium tellurite crystal of a cubic crystal system, where a small crystal of good quality is selected therefrom as a seed crystal for a crystal with a relatively large growth size.

Embodiment 2: Growth of Titanium Tellurite Single Crystal

(12) Compounding the raw materials TiO.sub.2 and TeO.sub.2 according to the TiTe.sub.3O.sub.8 stoichiometric ratio, adding them to a flux system Li.sub.2CO.sub.3—TeO.sub.2 (the Li.sub.2CO.sub.3:TeO.sub.2 mole rate is 2:3), where the mole rate between the titanium tellurite and the flux system is 1:3, placing them into a platinum crucible with a volume of Φ50 mm×70 mm, rapidly heating to 980° C. to completely melt the raw materials, homogeneously stirring; slowly cooling to the saturation point of the solution; performing crystal growth with the small crystal obtained in Embodiment 1 as the seed crystal, wherein the cooling rate is 0.25° C./h and the growth period is 10 days, thereby obtaining an orange-colored bulky single crystal (as shown in FIG. 3). Testing on the experimental X-ray powder diffraction pattern shows a coincidence with the result derived from theoretical computation, indicating that what is obtained is the titanium tellurite crystal of the cubic crystal system.

(13) The titanium tellurite single crystal obtained from embodiment 2 is orientation-processed into a wafer of a desired size; testing of its transmittance spectrum shows that it has a wide transmittance waveband (480˜6000 nm).

(14) The crystal is placed in the air for 6 months, without deliquescence or decomposition, indicating that the physical and chemical properties of the crystal are stable.

Embodiment 3: Growth of Titanium Tellurite Single Crystal

(15) Compounding the raw materials TiO.sub.2 and TeO.sub.2 according to the TiTe.sub.3O.sub.8 stoichiometric ratio, adding them to a flux system Li.sub.2CO.sub.3—TeO.sub.2 (the Li.sub.2CO.sub.3:TeO.sub.2 mole rate is 2:3), where the mole rate between the titanium tellurite and the flux system is 1:3, placing them into a platinum crucible with a volume of Φ50 mm×70 mm, rapidly heating to 980° C. to completely melt the raw materials, homogeneously stirring; slowly cooling to the saturation point of the solution; performing crystal growth with a crystal along [100] direction as the seed crystal, wherein the cooling rate is 0.06° C./h and the growth period is 20 days, thereby obtaining orange-colored bulky single crystal (as shown in FIG. 4). Testing on the experimental X-ray powder diffraction pattern shows a coincidence with the result derived from theoretical computation, indicating that what is obtained is the titanium tellurite crystal of the cubic crystal system.

Embodiment 4: Growth of Titanium Tellurite Single Crystal

(16) Compounding the raw materials TiO.sub.2 and TeO.sub.2 according to the TiTe.sub.3O.sub.8 stoichiometric ratio, adding them to a flux system TeO.sub.2, where the mole rate between the titanium tellurite and the flux system is 1:3, placing them into a platinum crucible with a volume of Φ50 mm×70 mm, rapidly heating to 980° C. to completely melt the raw materials, homogeneously stirring; slowly cooling to the saturation point of the solution; performing crystal growth with a crystal along [100] direction as the seed crystal, wherein the cooling rate is 0.05° C./h and the growth period is 40 days, thereby obtaining a bulky single crystal (as shown in FIG. 5). Testing on the experimental X-ray powder diffraction pattern shows a coincidence with the result derived from theoretical computation, indicating that what is obtained is the titanium tellurite crystal of the cubic crystal system.

Embodiment 5: Growth of Yb: TiTe.SUB.3.O.SUB.8 .Single Crystal

(17) Compounding the raw materials TiO.sub.2 and TeO.sub.2 according to the TiTe.sub.3O.sub.8 stoichiometric ratio, adding them together with Yb.sub.2O.sub.3 to a flux system TeO.sub.2, wherein the mole rate between Yb.sub.2O.sub.3 and the flux system is 0.05:1, and the mole rate between the titanium tellurite and the flux system is 1:3; placing them into a platinum crucible with a volume of Φ50 mm×70 mm, rapidly heating to 1100° C. to completely melt the raw materials, homogeneously stirring; slowly cooling to the saturation point of the solution; performing crystal growth with a crystal along [100] direction as the seed crystal, wherein the cooling rate is 0.04° C./h and the growth period is 50 days, thereby obtaining a Yb: TiTe.sub.3O.sub.8 bulky single crystal.

Embodiment 6: Application of Titanium Tellurite Single Crystal as Acousto-Optic Crystal

(18) The operating schematic diagram of fabricating an acousto-optic Q switching device using the titanium tellurite single crystal grown according to embodiment 3 is shown in FIG. 6. 1 represents a laser diode, whose output light is focused by a focusing system 2 onto the Nd: YVO4/Nd:YAG laser crystal 3. The resonant cavity employs a plano-concave structure, and the acousto-optic medium 5 employs a titanium tellurite single crystal.

Embodiment 7: Application of Using the Yb: TiTe.SUB.3.O.SUB.8 .Single Crystal as the Laser Crystal

(19) The operating schematic diagram of fabricating a laser device using the Yb: TiTe.sub.3O.sub.8 single crystal grown according to embodiment 5 is shown in FIG. 7. 7 represents a laser diode, whose output light is focused by a focusing system 8 onto the Yb: TiTe.sub.3O.sub.8 laser crystal 10.

Embodiment 8: Application of Using the Yb: TiTe.SUB.3.O.SUB.8 .Single Crystal as the Laser Self-Q Switching Crystal

(20) The operating schematic diagram of fabricating a laser self-Q switching crystal using the Yb: TiTe.sub.3O.sub.8 single crystal grown according to embodiment 5 is shown in FIG. 8. 12 represents a laser diode, whose output light is focused by a focusing system 13 onto the Yb: TiTe.sub.3O.sub.8 laser self-Q switching crystal 15. The resonant cavity employs a plano-concave structure.

Embodiment 9: Growth of Zirconium Tellurite Single Crystal

(21) Compounding the raw materials ZrO.sub.2 and TeO.sub.2 according to the ZrTe.sub.3O.sub.8 stoichiometric ratio, adding them to a flux system TeO.sub.2, where the mole rate between the zirconium tellurite and the flux system is 1:4, placing them into a platinum crucible with a volume of Φ50 mm×70 mm, rapidly heating to completely melt the raw materials, stirring sufficiently homogeneously; cooling slowly to the saturation point of the solution; performing crystal growth with a crystal along [100] direction as the seed crystal, wherein the cooling rate is 0.02° C./h and the growth period is 40 days, thereby obtaining a zirconium tellurite single crystal. Testing of the experimental X-ray powder diffraction pattern shows a coincidence with the result derived from theoretical computation, indicating that what is obtained is a zirconium tellurite crystal of the cubic crystal system.

Embodiment 10: Growth of Hafnium Tellurite Single Crystal

(22) Compounding the raw materials HfO.sub.2 and TeO.sub.2 according to the HfTe.sub.3O.sub.8 stoichiometric ratio, adding them to a flux system Li.sub.2CO.sub.3—TeO.sub.2 (the Li.sub.2CO.sub.3:TeO.sub.2 mole rate is 2:3), where the mole rate between hafnium tellurite and the flux system is 1:4, placing them into a platinum crucible with a volume of Φ50 mm×70 mm, rapidly heating to completely melt the raw materials, stirring sufficiently and homogeneously; slowly cooling to the saturation point of the solution; performing crystal growth with a crystal along [100] direction as the seed crystal, wherein the cooling rate is 0.02° C./h and the growth period is 60 days, thereby obtaining a hafnium tellurite single crystal. Testing of the experimental X-ray powder diffraction pattern shows a coincidence with the result derived from theoretical computation, indicating that what is obtained is a hafnium Tellurite crystal of the cubic crystal system.