# US 9,751,774 B2 · Cesium borosilicate compound, nonlinear optical crystal of cesium borosilicate, and preparation method therefor and use thereof

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- Number: US 9,751,774 B2
- Document ID: US9751774B2
- Status: Granted
- Kind: B2
- Application number: 14/426,094
- Filed: 2013-05-31
- Published: 2015-08-13
- Granted: 2017-09-05
- Earliest claimed: 2012-11-13
- Assignees: The Xinjian Technical Institute oh Physics & Chemistry, Chinese Academy of Sciences
- Applicants: The Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences
- Inventors: Shilie Pan; Hongping Wu; Hongwei Yu
- Web page: https://patentgrep.com/patent/US9751774B2

## CPC

- C01D 17/003: {Compounds of alkali metals}
- C01D 17/00: Rubidium, caesium or francium compounds
- C30B 9/12: Salt solvents, e.g. flux growth
- C30B 11/003: {Heating or cooling of the melt or the crystallised material}
- C30B 29/22: Complex oxides
- G02F 1/3551: {Crystals}
- C01B 35/10: Compounds containing boron and oxygen (C01B35/06 takes precedence)
- C01P 2002/70: defined by measured X-ray, neutron or electron diffraction data
- C01D: COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides C01B17/22; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia and cyanogen, containing nitrogen and other non-metals C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; phosphides C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

The present invention relates to a cesium borosilicate compound, a nonlinear optical crystal of cesium borosilicate, and a preparation method therefor and a use thereof. The cesium borosilicate compound has a chemical formula of Cs2B4SiO9 and a molecular weight of 481.15, and is prepared using a solid phase method. The nonlinear optical crystal of the cesium borosilicate compound has a chemical formula of Cs2B4SiO9 and a molecular weight of 481.15, does not have a center of symmetry, belongs to the tetragonal system with space group I4 and unit-cell parameters a=6.731(3) Å, c=9.871(9) Å and V=447.2(5) Å3, and has a wide transmittance range. The shortest ultraviolet cutoff edge is smaller than 190 nm, the frequency doubling effect of the crystal is 4.6 KDP, and the crystal is grown by a high-temperature solution spontaneous crystallization method and a flux method. The crystal has advantages of high growth rate, being transparent and inclusion free, low cost having a wide transmittance range, high hardness, good mechanical property, being crack resistant and not prone to deliquescence, being easy to process and store, and the like. The crystal is widely applied to manufacturing of nonlinear optical devices such as frequency doubling generators, frequency up-converters, frequency down-converters or optical parametric oscillators.

## Claims

### Claim 1

A cesium borosilicate compound, wherein the compound has a chemical formula of Cs2B4SiO9 with a molecular weight of 481.15.

### Claim 2 (depends on 1)

A method for preparing the cesium borosilicate compound according to claim 1, wherein the method is conducted according to the following steps of:
a. a Cs-containing compound, a B-containing compound and a Si-containing compound are mixed uniformly at a molar ratio of Cs:B:Si=2:4:1, grinded, loaded into a Φ100 mm×100 mm open type corundum crucible and then compressed tightly; the corundum crucible is placed into a muffle furnace, which is heated slowly to a temperature of 550° C., held at this temperature for 24 hours and then cooled down to room temperature; the mixture is taken out, grinded once again and then put back to the muffle furnace, which is heated to 650° C., held at this temperature for 24 hours and then cooled down to room temperature; the mixture is taken out, grinded for the third time and then put back to the muffle furnace, which is further heated to 700-900° C. and held at this temperature for 3-96 hours; the mixture is taken out and grinded to obtain the single-phase polycrystalline powder of a Cs2B4SiO9 compound;
b. the obtained single-phase polycrystalline powder of the Cs2B4SiO9 compound is mixed with a fluxing agent at a molar ratio of 1:0.5-10 and then loaded into a Φ80 mm×80 mm open type platinum crucible; the platinum crucible is heated to a temperature ranging from 630° C. to 900° C. and held at this temperature range for 5-80 hours to obtain a mixed melting liquid; the temperature is then decreased to 610-835° C. and further decreased to room temperature at a temperature-decreasing rate of 1-10° C./h, allowing for spontaneous crystallization to obtain a Cs2B4SiO9 seed crystal;
c. crystals are grown in the mixed melting liquid: the obtained Cs2B4SiO9 seed crystal is attached onto a seed crystal rod for forming the seed crystal from the top of a crystal growing furnace; the seed crystal is preheated on the surface of the mixed melting liquid for 10 minutes, and then immersed underneath the liquid surface so that the seed crystal is remelted in the mixed melting liquid; the temperature is kept for 30 minutes, and decreased rapidly to a temperature ranging from 610° C. to 745° C.;
d. the temperature is further decreased at a rate of 2° C./day and the seed crystal rod is rotated at a rotation rate of 10 rpm; after the crystal stops growing, the crystal is drawn out of the liquid surface and cooled down to room temperature at a rate of 5-50° C./h to obtain the cesium borosilicate compound, the cesium borosilicate compound being a colorless and transparent large-size nonlinear optical crystal of Cs2B4SiO9;
said fluxing agent is Cs2CO3, a Cs2CO3—H3BO3 system, a PbO—H3BO3 system, or a Cs2CO3—PbO system.

### Claim 3 (depends on 2)

The method according to claim 2, wherein said Cs-containing compound is Cs2CO3, CsNO3, Cs2O, CsOH, CsHCO3 or Cs2C2O4; said Si-containing compound is SiO2; said B-containing compound is H3BO3 or B2O3.

### Claim 4 (depends on 2)

The method according to claim 2, wherein the molar ratio of Cs2CO3 to H3BO3 is 1-5:1-3 in said Cs2CO3-H3BO3 system; the molar ratio of PbO to H3BO3 is 1-5:1-3 in said PbO-H3BO3 system; and the molar ratio of Cs2CO3 to PbO is 1-5:0.2-3 in said Cs2CO3—PbO system.

### Claim 5 (depends on 1)

A method for preparing the cesium borosilicate compound according to claim 1, wherein the method is conducted according to the following steps of:
a. a Cs-containing compound, a B-containing compound and a Si-containing compound are mixed uniformly at a molar ratio of Cs:B:Si=2:4:1, loaded into a Φ80 mm×80 mm open type platinum crucible; the platinum crucible is heated to a temperature ranging from 630° C. to 900° C. and held at this temperature range for 5-80 hours to obtain a mixed melting liquid; the temperature is then decreased to 610-835° C. and further decreased to room temperature at a temperature-decreasing rate of 1-10° C./h, allowing for spontaneous crystallization to obtain a Cs2B4SiO9 seed crystal;
b. crystals are grown in the mixed melting liquid: the obtained Cs2B4SiO9 seed crystal is attached onto a seed crystal rod for forming the seed crystal from the top of a crystal growing furnace; the seed crystal is preheated on the surface of the mixed melting liquid for 10 minutes, and then immersed underneath the liquid surface so that the seed crystal is remelted in the mixed melting liquid; the temperature is kept for 30 minutes, and decreased rapidly to a temperature ranging from 610° C. to 745° C.;
c. the temperature is further decreased at a rate of 2° C./day and the seed crystal rod is rotated at a rotation rate of 10 rpm; after the crystal stops growing, the crystal is drawn out of the liquid surface and cooled down to room temperature at a rate of 5-50° C./h to obtain the cesium borosilicate compound, the cesium borosilicate compound being a colorless and transparent large-size nonlinear optical crystal of Cs2B4SiO9;
said fluxing agent is Cs2CO3, a Cs2CO3-H3BO3 system, a PbO-H3BO3 system, or a Cs2CO3—PbO system.

### Claim 6 (depends on 5)

The method according to claim 5, wherein said Cs-containing compound is Cs2CO3, CsNO3, Cs2O, CsOH, CsHCO3 or Cs2C2O4; said Si-containing compound is SiO2; said B-containing compound is H3BO3 or B2O3.

### Claim 7 (depends on 5)

The method according to claim 5, wherein the molar ratio of Cs2CO3 to H3BO3 is 1-5:1-3 in said Cs2CO3-H3BO3 system; the molar ratio of PbO to H3BO3 is 1-5:1-3 in said PbO-H3BO3 system; and the molar ratio of Cs2CO3 to PbO is 1-5:0.2-3 in said Cs2CO3—PbO system.

### Claim 8

A cesium borosilicate nonlinear optical crystal, wherein the crystal has a chemical formula of Cs2B4SiO9 with a molecular weight of 481.15; has no symmetric center; belongs to an tetragonal system; has a space group of 14 with unit cell parameters of a=6.731(3) Å, c=9.871(9) Å, V=447.2(5) Å3; has a wide transmittance range with a shortest UV cut-off edge lower than 190 nm; has a powder frequency-doubling effect of 4.6 KDP.

### Claim 9 (depends on 8)

A method for preparing the cesium borosilicate nonlinear optical crystal according to claim 8, wherein the method is conducted according to the following steps of:
a. a Cs-containing compound, a B-containing compound and a Si-containing compound are mixed uniformly at a molar ratio of Cs:B:Si=2:4:1, grinded, loaded into a Φ100 mm×100 mm open type corundum crucible and then compressed tightly; the corundum crucible is placed into a muffle furnace, which is heated slowly to a temperature of 550° C., held at this temperature for 24 hours and then cooled down to room temperature; the mixture is taken out, grinded once again and then put back to the muffle furnace, which is heated to 650° C., held at this temperature for 24 hours and then cooled down to room temperature; the mixture is taken out, grinded for the third time and then put back to the muffle furnace, which is further heated to 700-900° C. and held at this temperature for 3-96 hours; the mixture is taken out and grinded to obtain the single-phase polycrystalline powder of a Cs2B4SiO9 compound;
b. the obtained single-phase polycrystalline powder of the Cs2B4SiO9 compound is mixed with a fluxing agent at a molar ratio of 1:0.5-10 and then loaded into a Φ80 mm×80 mm open type platinum crucible; the platinum crucible is heated to a temperature ranging from 630° C. to 900° C. and held at this temperature range for 5-80 hours to obtain a mixed melting liquid; the temperature is then decreased to 610-835° C. and further decreased to room temperature at a temperature-decreasing rate of 1-10° C./h, allowing for spontaneous crystallization to obtain a Cs2B4SiO9 seed crystal;
c. crystals are grown in the mixed melting liquid: the obtained Cs2B4SiO9 seed crystal is attached onto a seed crystal rod for forming the seed crystal from the top of a crystal growing furnace; the seed crystal is preheated on the surface of the mixed melting liquid for 10 minutes, and then immersed underneath the liquid surface so that the seed crystal is remelted in the mixed melting liquid; the temperature is kept for 30 minutes, and decreased rapidly to a temperature ranging from 610° C. to 745° C.;
d. the temperature is further decreased at a rate of 2° C./day and the seed crystal rod is rotated at a rotation rate of 10 rpm; after the crystal stops growing, the crystal is drawn out of the liquid surface and cooled down to room temperature at a rate of 5-50° C./h to obtain the cesium borosilicate nonlinear optical crystal, the cesium borosilicate nonlinear optical crystal being a colorless and transparent large-size nonlinear optical crystal of Cs2B4SiO9;
said fluxing agent is Cs2CO3, a Cs2CO3—H3BO3 system, a PbO—H3BO3 system, or a Cs2CO3—PbO system.

### Claim 10 (depends on 9)

The method according to claim 9, wherein said Cs-containing compound is Cs2CO3, CsNO3, Cs2O, CsOH, CsHCO3 or Cs2C2O4; said Si-containing compound is SiO2; said B-containing compound is H3BO3 or B2O3.

### Claim 11 (depends on 9)

The method according to claim 9, wherein the molar ratio of Cs2CO3 to H3BO3 is 1-5:1-3 in said Cs2CO3—H3BO3 system; the molar ratio of PbO to H3BO3 is 1-5:1-3 in said PbO—H3BO3 system; and the molar ratio of Cs2CO3 to PbO is 1-5:0.2-3 in said Cs2CO3—PbO system.

### Claim 12 (depends on 8)

A method for preparing the cesium borosilicate nonlinear optical crystal according to claim 8, wherein the method is conducted according to the following steps of:
a. a Cs-containing compound, a B-containing compound and a Si-containing compound are mixed uniformly at a molar ratio of Cs:B:Si=2:4:1, loaded into a Φ80 mm×80 mm open type platinum crucible; the platinum crucible is heated to a temperature ranging from 630° C. to 900° C. and held at this temperature range for 5-80 hours to obtain a mixed melting liquid; the temperature is then decreased to 610-835° C. and further decreased to room temperature at a temperature-decreasing rate of 1-10° C./h, allowing for spontaneous crystallization to obtain a Cs2B4SiO9 seed crystal;
b. crystals are grown in the mixed melting liquid: the obtained Cs2B4SiO9 seed crystal is attached onto a seed crystal rod for forming the seed crystal from the top of a crystal growing furnace; the seed crystal is preheated on the surface of the mixed melting liquid for 10 minutes, and then immersed underneath the liquid surface so that the seed crystal is remelted in the mixed melting liquid; the temperature is kept for 30 minutes, and decreased rapidly to a temperature ranging from 610° C. to 745° C.;
c. the temperature is further decreased at a rate of 2° C./day and the seed crystal rod is rotated at a rotation rate of 10 rpm; after the crystal stops growing, the crystal is drawn out of the liquid surface and cooled down to room temperature at a rate of 5-50° C./h to obtain the cesium borosilicate nonlinear optical crystal, the cesium borosilicate nonlinear optical crystal being a colorless and transparent large-size nonlinear optical crystal of Cs2B4SiO9;
said fluxing agent is Cs2CO3, a Cs2CO3-H3BO3 system, a PbO-H3BO3 system, or a Cs2CO3—PbO system.

### Claim 13 (depends on 12)

The method according to claim 12, wherein said Cs-containing compound is Cs2CO3, CsNO3, Cs2O, CsOH, CsHCO3 or Cs2C2O4; said Si-containing compound is SiO2; said B-containing compound is H3BO3 or B2O3.

### Claim 14 (depends on 12)

The method according to claim 12, wherein the molar ratio of Cs2CO3 to H3BO3 is 1-5:1-3 in said Cs2CO3-H3BO3 system; the molar ratio of PbO to H3BO3 is 1-5:1-3 in said PbO-H3BO3 system; and the molar ratio of Cs2CO3 to PbO is 1-5:0.2-3 in said Cs2CO3—PbO system.