WO2007028326A1

WO2007028326A1 - LARGE-SIZE KBe2(BO3)F3 CRYSTAL, ITS PREPARATION METHOD AND FREQUENCY CONVERTER BY USING IT

Info

Publication number: WO2007028326A1
Application number: PCT/CN2006/002275
Authority: WO
Inventors: Ning Ye; Dingyuan Tang
Original assignee: Fujian Institute Of Research Of The Structure Of Matter, Chinese Academy Sciences
Priority date: 2005-09-06
Filing date: 2006-09-04
Publication date: 2007-03-15
Also published as: CN1928167B; CN1928167A

Abstract

Large-size KBe2(BO3)F2 crystal, its hydro thermal method and frequency converter by using it are disclosed and directed to synthetic crystal field. Selected mineralising agents in said hydrothermal method are hydroxide or carbonate or halide or borate or boric acid or any combination of them. The present hydrothermal method completely overcomes the layering growth tendency, realizes blocky crystal growth with crystal face, an the resulted thickness exceeds 5mm.

Description

Large-size potassium borofluoride potassium crystal, preparation method thereof and inverter parts

Technical field

The invention relates to the field of artificial crystals, in particular to a large-sized potassium borofluoride potassium crystal, a preparation method thereof and a frequency converter member. Background technique

The molecular formula of potassium fluoroborate is KBe ₂ (B0 ₃ )F ₂ , abbreviated as KBBF. Trigonal crystal system, space group R32, point group D _3. The main non-linearly active anion group in the crystal lattice is a (B0 ₃ ) planar triangular group aligned perpendicularly to the crystallographic C axis, and the (Be0 ₃ F) tetrahedral group is passed between the (B0 ₃ ) groups. A common oxygen atom is bonded to form (Be ₂ B0 ₃ F ₂ ): a two-dimensional layered structure, and the layer is connected to the layer by an ionic bond of K to the F atom in the layer.

The structural characteristics of KBBF determine that it is an excellent deep UV doubling crystal. It has a multiplication factor of 0.49 pm/V, a birefringence of 0.07, and a crystal UV absorption edge of 165 nm. BBF is currently the only crystal that can achieve direct multiplier to produce laser output below 200 nm. The frequency doubling effect of KBBF crystal can produce high quality deep ultraviolet laser, which is very good in laser medical, spectroscopy, semiconductor lithography. Important application. '

The layered structure of KBBF also determines its layered growth habits. If the growth method is not properly selected, the crystal grows slowly along the C-axis of the crystallography, and the crystal is not easily grown. At present, KBBF crystals are grown by high-temperature molten salt method. The layered growth habit is very serious, and the crystals cannot grow long. The complete KBBF crystal grown by molten salt method has a maximum thickness of no more than 2 mm. Due to the limited thickness, the crystal cannot be cut at the phase matching angle. In order to make a frequency doubling device, prism coupling technology must be used, that is, a thin film KBBF crystal is sandwiched between two prisms to form a prism coupling device, and the process is complicated, and since the crystal is too thin, the frequency conversion efficiency cannot be improved, which is extremely large. Limits the practical use of KBBF' crystals.

The main technical problems in KBBF crystal growth and application are: Crystal layer growth habits are serious, crystals cannot grow long, and the crystals are too thin to be processed into phase-doubling devices by phase matching angle cutting. In the prior art, KBBF crystals are grown by a high-temperature molten salt method, and the thickness of the KBBF crystal grown by the method cannot exceed 2 mm, which brings great difficulty to practical applications. There is currently no hydrothermal growth. KBBF crystals are reported. Summary of the invention It is an object of the present invention to provide a method for hydrothermally growing large size KBBF single crystals.

Another object of the present invention is to provide a KBBF single crystal prepared by hydrothermal method.

It is still another object of the present invention to provide a frequency doubling device comprising a KBBF crystal of the present invention cut at a phase matching angle.

In particular, the present invention provides the following aspects:

A method for preparing a potassium borofluoride silicate crystal, the method comprising the steps of:

The potassium borofluoride potassium polycrystalline raw material or single crystal raw material is grown in the presence of an aqueous solution of a seed crystal and a mineralizer at 250 to 500 ° C, 100 to 3000 atmospheres for 240 hours to 2400 hours.

2. The method according to item 1, wherein the mineralizer is selected from the group consisting of hydroxides, carbonates, halides, borates, boric acids or a mixture of two or more thereof.

3. The method of item 2, wherein the hydroxide is selected from the group consisting of: sodium hydroxide, potassium hydroxide or lithium hydroxide.

4. The method of item 2, wherein the carbonate is selected from the group consisting of: sodium carbonate or potassium carbonate or lithium carbonate.

5. The method of item 2, wherein the halide is selected from the group consisting of sodium fluoride, potassium fluoride, lithium fluoride, sodium chloride, potassium chloride or lithium chloride.

6. The method according to item 2, wherein the borate is selected from the group consisting of sodium borate, potassium borate or lithium borate.

7. The method according to item 1, wherein the concentration of the aqueous mineralizer solution is from 0.01 M to 8 M.

8. The method according to item 1, wherein the potassium borofluoride potassium polycrystalline raw material is (A) polycrystal obtained by mixing KBF ₄ , BeO and B ₂ 0 ₃ and sintering at 750 ° C for 24 hours. The raw material, and the single crystal raw material is a KBBF single crystal grown by a molten salt method using a KBBF polycrystalline raw material synthesized by Aj.

9. The method of item 2, wherein the mineralizer is a mixture of potassium fluoride and boric acid.

10. The method according to item 9, wherein in the aqueous solution, the potassium fluoride concentration ranges from 0.1 M to 6 M, and the boric acid concentration ranges from 0.01 M to 2 M. ·

11. The method of item 2, wherein the mineralizer is potassium fluoride.

12. The method according to item 11, wherein the concentration of the potassium fluoride in the aqueous solution ranges from 0.1 M to 6 M.

A potassium fluoroborate crystal obtained by the production method of the item 1, wherein the potassium borofluoride crystal has a thickness of more than 2 mm.

14. A frequency converter component made of the potassium fluoroborate silicate crystal of item 13. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of an autoclave employed in the process of the present invention.

Figure 2 is a photograph of the crystal of potassium borofluoride silicate prepared in Example 10.

Fig. 3 is an X-ray diffraction spectrum of potassium borofluoride silicate crystals prepared in Example 10. detailed description

The hydrothermal method is a method in which crystals are grown under high temperature and high pressure in the presence of a mineralizer using water as a solvent. The KBBF crystal was grown by hydrothermal method, which overcomes the lamellar growth habit of the crystal. The crystal realizes a block-like growth of crystal plane with a crystal thickness exceeding 5 mm. The crystal can be cut into a frequency doubling device in a phase matching angular direction. It paved the way for its large-scale use and industrialization.

The following is a specific technical solution: Put the compressed KBBF polycrystalline raw material or single crystal raw material into the double temperature zone autoclave shown in Figure 1, and add an aqueous solution containing a mineralizer, which may be hydroxide or carbon. An acid salt or a halide or a borate or boric acid or a mixture of any combination thereof, and the like. For example, the hydroxide may be sodium hydroxide, potassium hydroxide, lithium hydroxide or the like; the carbonate may be sodium carbonate, potassium carbonate, lithium carbonate, etc.; the halide may be sodium fluoride, potassium fluoride, lithium fluoride And sodium chloride, potassium chloride, lithium chloride, etc.; the borate may be sodium borate, potassium borate, lithium borate or the like. The mineralizer concentration ranges from 0.01 M to 8 M in molarity. For example, a mineralizer is an aqueous potassium fluoride solution, and a potassium fluoride concentration ranges from 0.1 M to 6 M; for example, a mineralizer is a mixed aqueous solution of potassium fluoride and boric acid, and the potassium fluoride concentration ranges from 0.1 M to 6 M, The boric acid concentration ranges from 0.01 M to 2 M. Then insert the inner baffle to fix the seed crystal frame. Tighten the plug. The autoclave was placed in a heating furnace.

In the double temperature zone autoclave shown in Fig. 1, 1 is a heat preservation barrel; 2 is a plug; 3 is a KBBF seed crystal; 4 is a kettle; 5 is an upper temperature zone;

The heating temperature range is 250-500 ° C, the ffi force range is 100-3000 atmospheres; the solvent zone (lower temperature zone) and the growth zone (upper temperature zone) maintain a certain temperature difference, and the temperature difference ranges from 10-100 °C. The growth cycle is 10-100 days. After the end of the growth, the temperature is lowered and the kettle is opened. After the crystal is taken out, it is cut at a certain phase matching angle and processed into a frequency doubling device. '

The KBBF polycrystalline material can be obtained by the following method: BeO, 3⁄4B0 ₃ and KBF ₄ ' are uniformly mixed according to the molar ratio BeO:H ₃ B0 ₃ :KBF ₄ =6: l:3, and then sintered at 750 ° C for 24 hours. That is, KBBF polycrystalline raw materials are obtained. KBBF single crystal raw materials can be obtained by the following methods: KBBF, KF and B ₂ 0 _{3 are} uniformly mixed according to the molar ratio of BBF:KF:B ₂ 0 ₃ =1:5:1, and charged into a platinum crucible at 750 The mixture was melted at ° C, and then the melt was slowly lowered to room temperature at a rate of 2 ° C per day, and the soluble flux was washed away with water to obtain a sheet-like KBBF single crystal raw material. Compared with the prior art, the present invention hydrothermally grows KBBF crystals, completely overcomes the lamellar growth habit of crystals, and the crystal realizes a block-like growth with crystal faces having a crystal thickness of more than 2 mm, preferably 5 mm or more. It is preferably 5 mm to 15 mm. The crystal can be cut into a frequency doubling device in a phase matching angular direction. It paved the way for its large-scale use and industrialization. Example

Example 1

Take KBF ₄ (1.90 g), BeO (0.75 g) and B ₂ O ₃ (0.35 g) as raw materials, grind and mix well, put them into a white gold crucible, sinter at 750 ° C for 24 hours, take them out and press them into a tablet press. sheet.

The compressed KBBF polycrystalline material was placed in an autoclave having a volume of 37 ml, and 31 ml of a sodium hydroxide aqueous solution having a molar concentration of 1 M was added. Hang the seed crystal, tighten the plug and place it in the heating furnace.

The upper temperature zone of the heating furnace is heated to 380 ° C, and the lower temperature zone is heated to 400 ° C, and the temperature is maintained for 60 days. Then cool down and open the kettle. A KBBF single crystal having a thickness of 5 mm is longer than the seed crystal. A photograph of the obtained potassium borofluoride silicate crystal is shown in Fig. 2, and the obtained X-ray diffraction spectrum of potassium borofluoride silicate crystal is shown in Fig. 3. Example 2:

31 ml of a potassium fluoride aqueous solution having a molar concentration of 0.8 M was used as a mineralizer, and the incubation time was 30 days, and the rest of the procedure was as described in Example 1. A KBBF single crystal having a thickness of 5 mm was obtained. Example 3:

31 ml of a sodium chloride aqueous solution having a molar concentration of 1 M was used as a mineralizer aqueous solution; the upper temperature zone of the heating furnace was heated to 450 ° C, and the lower temperature zone was heated to 500 ° C for 30 days; the rest of the procedure was as follows. A KBBF single crystal having a thickness of 5 mm was obtained. Example 4:

The autoclave with a volume of 37 ml was used, and 31 ml of a potassium chloride aqueous solution having a molar concentration of 6 M was added as a mineralizer aqueous solution; the upper temperature zone of the heating furnace was heated to 350 ° C, and the lower temperature zone was heated to 380 ° C, and the temperature was constant. 30 days; the rest of the process is referred to in Example 1. A KBBF single crystal having a thickness of 5 mm was obtained. An autoclave having a volume of 37 ml was used, and 31 ml of a 2 M aqueous solution of sodium fluoride was added as a mineralizer aqueous solution. Warm the upper temperature zone of the furnace to 250. C, the lower temperature zone is heated to 300 ° C, constant temperature for 60 days. The rest of the process is referred to in Example 1. A KBBF single crystal having a thickness of 5 mm was obtained. Example 6

An autoclave having a volume of 37 ml was used, and 31 ml of a lithium carbonate aqueous solution having a molar concentration of 1 M was added. The upper temperature zone of the heating furnace was heated to 400 ° C, and the temperature in the lower temperature zone was raised to 430 ° C, and the temperature was kept constant for 30 days. The rest of the process is referred to in Example 1. A KBBF single crystal having a thickness of 5 mm was obtained. Example 7

Take KBF ₄ (2.90 g), BeO (1.15 g) and H ₃ BO ₃ (0.95 g) as raw materials; use an autoclave with a volume of 32 ml, and add 26 ml of a 2 M potassium borate aqueous solution as a mineralizer. Aqueous solution; The temperature in the upper temperature zone of the heating furnace is raised to 420 ° C, and the temperature in the lower temperature zone is raised to 450 ° ά constant temperature for 30 days. The rest of the process is referred to in Example 1. A KBBF single crystal having a thickness of 5 mm was obtained. 'Example 8:

An autoclave having a volume of 37 ml was used, and 29 ml of a mixed aqueous solution of 0.8 M potassium fluoride and 0.3 M boric acid was added as a mineralizer aqueous solution. The upper temperature zone of the heating furnace is heated to 400 ° C, and the temperature in the lower temperature zone is raised to 420 ° C, and the temperature is kept constant for 30 days. The rest of the process is referred to in Embodiment 1. A KBBF single crystal having a thickness of 6 mm was obtained to be longer than the seed crystal. Example 9

The KBBF single crystal blank grown in Example 8 was cut into cubes of 3 x 3 x 3 mm, one of which was parallel to the light passing direction. The light passing direction is at an angle of about 66° to the crystallographic C axis of the crystal. The two faces perpendicular to the light passing direction are the light passing faces. Polish the clear surface. That is, a six-fold frequency device is fabricated. A laser beam extending at a wavelength of 355 nm is incident on the KBBF six-frequency device to produce a laser output having a wavelength of 177.3. Example 10

The KBBF single crystal blank grown in Example 8 was cut into cubes of 3 x 3 x 3 mm, one of which was parallel to the light passing direction. The light passing direction is at an angle of about 36 to the crystallographic C axis of the crystal. Vertical to the direction of light The two faces are the clear side. Polish the clear surface. That is, a quadruple frequency device is fabricated. A laser beam having a wavelength of 532 nm is incident on the KBBF quadruple frequency device, that is, a laser output having a wavelength of 266 is generated. Example 11:

The KBBF single crystal blank grown in Example 8 was cut into cubes of 3 x 3 x 3 mm, one of which was parallel to the light passing direction. The light passing direction is at an angle of about 47° to the crystallographic C axis of the crystal. The two faces perpendicular to the light passing direction are the light passing faces. Polish the clear surface. That is, a five-fold frequency device is fabricated. A laser beam extending at a wavelength of 532 nm and a wavelength of 355 nm is incident on the KBBF five-frequency device, producing a laser output having a wavelength of 213 nm. Example 12:

The KBBF single crystal blank grown in Example 8 was cut into cubes of 3 x 3 x 3 mm, one of which was parallel to the light passing direction. The light passing direction is at an angle of about 27° to the crystallographic C axis of the crystal. The two faces perpendicular to the light passing direction are the light passing faces. Polish the clear surface. That is, a parametric device with a pump source of 355 nm is fabricated. A laser beam having a wavelength of 355 nm is incident on the KBBF parametric device, and the crystal is rotated to change the angle of the crystal light to the incident light to obtain a laser output having a wavelength tuning range of about 400 nm to 2 μm.

Claims

Rights request

A method for preparing a potassium borofluoride silicate crystal, the method comprising the steps of: in the presence of an aqueous solution of a mineralizer, a potassium fluoroborate polycrystalline raw material or a single crystal raw material at 250-500 ° C,

It is grown for 240 hours to 2400 hours at 100-3000 atmospheres.

2. The method of claim 1 wherein said mineralizer is selected from the group consisting of: hydroxides, carbonates, halides, borates, boric acids, or mixtures of two or more thereof.

3. A method according to claim 2 wherein said hydroxide is selected from the group consisting of: sodium hydroxide, potassium hydroxide or lithium hydroxide.

4. The method of claim 2, wherein the carbonate is selected from the group consisting of: sodium carbonate or potassium carbonate or lithium carbonate.

5. The method of claim 2, wherein the halide is selected from the group consisting of sodium fluoride, potassium fluoride, lithium fluoride, sodium chloride, potassium chloride or lithium chloride.

6. The method of claim 2, wherein the borate is selected from the group consisting of: sodium borate, potassium borate or lithium borate.

7. The method of claim 1 wherein the aqueous mineralizer solution has a concentration of from 0.01 M to 8 M.

8. The method according to claim 1, wherein the potassium borofluoride potassium polycrystalline raw material is (A) obtained by mixing KBF ₄ , BeO and B ₂ 0 ₃ and sintering at 750 ° C for 24 hours. The crystal raw material, and the single crystal raw material ^ is a KBBF polycrystalline raw material synthesized by (A), and a KBBF single crystal grown by a molten salt method.

9. The method of claim 2 wherein the mineralizer is a mixture of potassium fluoride and boric acid. '

10. The method according to claim 9, wherein the potassium fluoride concentration in the aqueous solution ranges from 0.1 M to 6 M, and the boric acid concentration ranges from 0.01 M to 2 M.

11. The method of claim 2 wherein the mineralizer is potassium fluoride.

12. The method according to claim 11, wherein the concentration of the potassium fluoride in the aqueous solution is in the range of

0.1M to 6M.

A crystal of potassium borofluoride silicate obtained by the production method of claim 1, wherein the potassium borofluoride crystal has a thickness of more than 2 mm.

A transducer device made of the potassium borofluoride silicate crystal of claim 13.