(19)
(11)EP 3 620 555 A1

(12)EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(43)Date of publication:
11.03.2020 Bulletin 2020/11

(21)Application number: 17904829.3

(22)Date of filing:  10.07.2017
(51)Int. Cl.: 
C30B 29/10  (2006.01)
C30B 17/00  (2006.01)
C30B 9/12  (2006.01)
C30B 7/04  (2006.01)
G02F 1/355  (2006.01)
C30B 15/00  (2006.01)
C30B 11/00  (2006.01)
C30B 7/10  (2006.01)
C01B 35/12  (2006.01)
(86)International application number:
PCT/CN2017/092331
(87)International publication number:
WO 2018/184312 (11.10.2018 Gazette  2018/41)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
MA MD

(30)Priority: 03.04.2017 CN 201710215337

(71)Applicant: Xinjiang Technical Institute Of Physics&Chemistry, Chinese Academy Of Sciences
Urumqi, Xinjiang 830011 (CN)

(72)Inventors:
  • PAN, Shilie
    Urumqi Xinjiang 830011 (CN)
  • WANG, Xuefei
    Urumqi Xinjiang 830011 (CN)
  • ZHANG, Fangfang
    Urumqi Xinjiang 830011 (CN)
  • WANG, Ying
    Urumqi Xinjiang 830011 (CN)

(74)Representative: Hanna Moore + Curley 
Garryard House 25/26 Earlsfort Terrace
Dublin 2, D02 PX51
Dublin 2, D02 PX51 (IE)

  


(54)COMPOUND CESIUM FLUOROBORATE, NON-LINEAR OPTICAL CRYSTAL OF CESIUM FLUOROBORATE, PREPARATION METHOD THEREFOR AND USE THEREOF


(57) The present disclosure provides a compound of cesium fluorooxoborate, a nonlinear optical crystal of cesium fluorooxoborate, and a method of preparation and use thereof. The compound has a chemical formula of CsB4O6F and a molecular weight of 291.15. It has a crystal structure, which is prepared by a solid-state synthesis method or a vacuum encapsulation method. The crystal has a chemical formula of CsB4O6F and a molecular weight of 291.15. It belongs to an orthorhombic crystal system, with a space group of Pna21, crystal cell parameters of α = 7.9241 Å, b = 11.3996 Å, c = 6.6638 Å, and α = β = γ = 90°, and a unit cell volume of 601.95 Å3. The crystal has a frequency-multiplied effect that is about 2 times that of KH2PO4 (KDP), and a UV absorption edge shorter than 190 nm. A melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method is used to grow the crystal of CsB4O6F. The crystal is not deliquescent in air and has a good chemical stability, and therefore can be used in all-solid-state lasers as a UV or deep-ultraviolet nonlinear optical crystal.




Description

TECHNICAL FIELD



[0001] The present invention relates to a compound of cesium fluorooxoborate, CsB4O6F, a nonlinear optical crystal of CsB4O6F, and a method of preparation and use thereof.

BACKGROUND OF THE INVENTION



[0002] As a kind of important components of all-solid-state lasers, nonlinear optical crystals have always been widely concerned both at home and abroad. After half a century's researches, a series of nonlinear optical crystals with excellent properties have been found. Typical nonlinear optical crystals used in the visible light region include KTiOPO4 (KTP), KH2PO4 (KDP), etc. Nonlinear optical crystals used in the ultraviolet region that have been industrialized include LiB3O5 (LBO), CsB3O5 (CBO), CsLiB6O10 (CLBO), BaB2O4 (BBO), etc. However, KBe2BO3F2 (KBBF) is the only available crystal that can apply in the deep-ultraviolet region below 200 nm. The application of KBBF is restricted due to its long growth period highly toxic element Be and layer growth habit, etc. Therefore, it is necessary to explore new deep-ultraviolet nonlinear optical crystals with better performances.

[0003] The inventors developed a compound of ammonium fluorooxoborate, NH4B4O6F, and a nonlinear optical crystal of NH4B4O6F in previous studies, as described in the patent application No. 201611128283.3. The main differences between the present invention and NH4B4O6F is that the NH4+ is linked to the anion group by a hydrogen bond in NH4B4O6F, while the Cs+ is linked to the anion group by an ionic bond in CsB4O6F, resulting in completely different structures and growth habits, as well as different key parameters of the growth process, crystal properties, and the like between CsB4O6F and NH4B4O6F.

SUMMARY OF THE INVENTION



[0004] An object of the present invention is to provide a compound of cesium fluorooxoborate, which has a chemical formula of CsB4O6F and a molecular weight of 291.15 and is prepared by solid-state reaction or vacuum encapsulation method.

[0005] Another object of the present invention is to provide a nonlinear optical crystal of cesium fluorooxoborate, which has a chemical formula of CsB4O6F and a molecular weight of 291.15. The crystal belongs to an orthorhombic crystal system, with the space group of Pna21, unit cell parameters of α = 7.9241 Å, b = 11.3996 Å, c = 6.6638 Å, and α = β = y = 90°, and a unit cell volume of 601.95 Å3.

[0006] Yet another object of the present invention is to provide a method for preparing the nonlinear optical crystal of CsB4O6F, comprising growing the crystal by a melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method.

[0007] Yet another object of the present invention is to provide the utilities of the nonlinear optical crystal of CsB4O6F.

[0008] The present invention provides a compound of cesium fluorooxoborate with the chemical formula of CsB4O6F and the molecular weight of 291.15.

[0009] In the method for preparing the compound of cesium fluorooxoborate as described herein, the compound is prepared by a solid-state synthesis method or a vacuum encapsulation method.

[0010] The solid-state synthesis method for preparing the compound of cesium fluorooxoborate comprises the steps of:
mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously with the molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4.

[0011] The vacuum encapsulation method for preparing the compound of cesium fluorooxoborate comprises the steps of:
mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a Φ40 mm quartz tube; vacuumizing the quartz tube to a vacuum degree of 1×10-3 Pa, and sealing it with high temperature; then placing the quartz tube in a muffle furnace, and increasing the temperature to 350-600 °C at a rate of 10-50 °C for 3-96 hours, to give the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4.

[0012] Provided herein is a nonlinear optical crystal of cesium fluorooxoborate. The crystal has a chemical formula of CsB4O6F with molecular weight of 291.15. The crystal belongs to an orthorhombic crystal system, with the space group of Pna21, unit cell parameters of α=7.9241Å, b=11.3996Å, c=6.6638Å, and α=β=γ=90°, and a unit cell volume of 601.95Å3.

[0013] In the method of preparing the nonlinear optical crystal of cesium fluorooxoborate as described herein, the crystal is grown by a melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method.

[0014] The melt method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:
  1. a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give a polycrystal powder of the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4;
  2. b) filling the resultant polycrystal powder of the compound of CsB4O6F into a clean platinum crucible; placing the platinum crucible in a muffle furnace, and increasing the temperature to 400-700 °C at a rate of 20-40 °C/h for 7-15 hours, to give a melt; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4;
  3. c) decreasing the temperature of the melt from step b) to 400-590 °C at a rate of 0.1-5 °C/h, to 300-440 °C at a rate of 0.2-2 °C/h, and further to 30 °C at a rate of 3-15 °C/h, to give a seed crystal of CsB4O6F; and
  4. d) growing the crystal in the melt of the compound by the Czochralski method, comprising
    fixing the seed crystal obtained from step c) onto a seed crystal rod; lowering the seed crystal to 1 mm above the liquid surface from the top of a crystal growing furnace for the melt prepared in step b), and preheating it for 5-60 minutes; then immersing the seed crystal in the liquid at 1-5 mm below the surface; rotating the crystal at 2-30 rpm by a crystal growth controller and controlling the temperature to saturate the melt; lifting the seed crystal at a rate of 1-3 mm/day while keeping the temperature constant; upon completion of the crystal growth, pulling the crystal on the seed crystal rod, and decreasing the temperature to 300-440 °C at a rate of 0.2-2 °C/h, and further to 30 °C at a rate of 3-15 °C/h, to obtain the nonlinear optical crystal of CsB4O6F;
    alternatively, growing the crystal in the melt of the compound by the Kyropoulos method, comprising
    fixing the seed crystal obtained from step c) onto a seed crystal rod; lowering the seed crystal to 1 mm above the liquid surface from the top of a crystal growing furnace for the melt prepared in step b), and preheating it for 5-60 minutes; then immersing the seed crystal in the liquid at 1-5 mm below the surface; decreasing the temperature at a rate of 0.1-0.7 °C/h; 3-10 hours later, lifting the seed crystal by 1-2 mm, and further decreasing the temperature at a rate of 0.1-0.7 °C/h; upon completion of the crystal growth, pulling the crystal on the seed crystal rod, and decreasing the temperature to 300-440 °C at a rate of 0.2-2 °C/h, and further to 30 °C at a rate of 3-15 °C/h, to obtain the nonlinear optical crystal of CsB4O6F;
    alternatively, growing the crystal in the melt of the compound by the Bridgeman-Stockbarger method, comprising
    placing the seed crystal prepared in step c) at the bottom of a crucible, then adding the polycrystal compound of CsB4O6F prepared in step a) to the crucible; sealing the platinum crucible, and increasing the temperature of the growing furnace to 500-700 °C for 7-15 hours; adjusting the position of the crucible such that the seeding temperature is 500-625 °C; then lowering the crucible at a rate of 1-10 mm/day while keeping the growth temperature constant; upon completion of the growth, decreasing the temperature to 300-440 °C at a rate of 0.2-2 °C/h, and further to 30 °C at a rate of 3-15 °C/h; and removing the platinum crucible, to obtain the nonlinear optical crystal of CsB4O6F.


[0015] The high temperature solution method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:
  1. a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give a polycrystal powder of the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4;
  2. b) mixing the polycrystal powder of the compound of CsB4O6F obtained from step a) homogeneously with a fluxing agent at a molar ratio of 1:0.1-0.5; then filling the mixture into a clean platinum crucible, and increasing the temperature to 400-700 °C at a rate of 35-45 °C/h for 7-15 hours, to give a meltsolution; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; the B-containing compound is H3BO3, B2O3 or CsBF4; and the fluxing agent is CsF, H3BO3, B2O3, PbO or PbF2;
  3. c) preparation of a seed crystal: placing the meltsolution prepared in step b) into a single crystal furnace, and then decreasing the temperature to 350-610 °C at a rate of 0.1-5 °C/h, to 300-385 °C at a rate of 0.2-0.6 °C/h, and further to 30 °C at a rate of 3-10 °C/h, to give a seed crystal of CsB4O6F; and
  4. d) growth of a crystal: fixing the resultant seed crystal of CsB4O6F onto a seed crystal rod; lowering the seed crystal to 1 mm above the liquid surface from the top of a crystal growing furnace for the meltsolution prepared in step b), and preheating it for 10-25 minutes; contacting the seed crystal with the liquid surface, and decreasing the temperature at a rate of 0.1-2 °C/h; upon completion of the crystal growth, pulling the crystal away from the surface of the solution, and then decreasing the temperature to 30 °C at a rate of 3-10 °C/h, to obtain the nonlinear optical crystal of CsB4O6F.


[0016] The vacuum encapsulation method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:
  1. a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C at a rate of 10-50 °C for 3-96 hours, to give a polycrystal powder of the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4; and
  2. b) mixing the polycrystal powder of the compound of CsB4O6F obtained from step a) homogeneously with a fluxing agent at a molar ratio of 1:0.1-1; then filling the mixture into a quartz tube, and increasing the temperature to 400-700 °C at a rate of 10-50 °C/h for 3-96 hours; then decreasing the temperature to 330-450 °C at a rate of 0.5-1.5 °C/day, and further to 30 °C at a rate of 2-5 °C/h; and cutting the quartz tube to obtain the nonlinear optical crystal of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF, CsBF4 or HF; the B-containing compound is H3BO3, B2O3 or CsBF4; and the fluxing agent is CsF, H3BO3, B2O3, PbO or PbF2.


[0017] The hydrothermal method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:
  1. a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give a polycrystal powder product of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CH3COOCs; the F-containing compound is CsF or HF; and the B-containing compound is H3BO3 or B2O3;
  2. b) dissolving the polycrystal powder of the compound of CsB4O6F obtained from step a) in 5-30 mL of deionized water, and sonicating the incompletely dissolved mixture at a temperature of 20-50 °C for 5-30 minutes to allow for sufficient mixing and dissolution;
  3. c) transferring the mixed solution obtained from step b) into the lining of a clean, pollution-free high pressure reactor with a volume of 100 mL, and tightening and sealing the reactor; and
  4. d) placing the high pressure reactor in a thermostat, increasing the temperature to 150-350 °C at a rate of 5-50 °C/h for 3-15 days, and then decreasing the temperature to room temperature at a rate of 5-30 °C/day, to obtain the nonlinear optical crystal of CsB4O6F.


[0018] The room temperature solution method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:
  1. a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give a polycrystal powder product of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CH3COOCs; the F-containing compound is CsF or HF; and the B-containing compound is H3BO3 or B2O3;
  2. b) placing the polycrystal powder of the compound of CsB4O6F obtained from step a) in a clean glass container, to which 20-100 mL of deionized water is added, followed by ultrasonication for 5-60 minutes to allow for sufficient mixing and dissolution, and then adjusting the pH of the solution to 8-11 by addition of HF or CsOH;
  3. c) sealing the container containing the solution in step b) with weighing paper, and placing it in a static environment without shaking, pollution and air convection; controlling the evaporation rate at 0.2-2 mL/day by piercing the seal; and setting it aside for 5-20 days at room temperature;
  4. d) obtaining a seed crystal upon completion of the growth when the size of the crystal particles grown at the bottom of the container from the solution in step c) is no longer changed significantly; and
  5. e) filtering the remaining solution through qualitative filter paper to filter out grains and other impurities from the solution; selecting the seed crystal of better quality, fixing it with a platinum wire and suspending it in the filtered solution; controlling the evaporation rate at 0.2-2 mL/day by piercing the seal, and setting it aside for growth for 5-20 days at room temperature, to obtain the nonlinear optical crystal of CsB4O6F.


[0019] The present invention provides the utilities of the nonlinear optical crystal of cesium fluorooxoborate in the manufacture of an Nd:YAG laser that outputs a fundamental frequency light of 1064 nm for the second, third, fourth, fifth or sixth harmonic generation laser output.

[0020] The present invention provides the utilities of the nonlinear optical crystal of cesium fluorooxoborate in the production of a deep-ultraviolet frequency-multiplied light output of below 200 nm.

[0021] The present invention provides the utilities of the nonlinear optical crystal of the compound of cesium fluorooxoborate in the manufacture of a frequency multiplication generator, a frequency up or down converter or an optical parametric oscillator.

[0022] In the method of preparing the nonlinear optical crystal of cesium fluorooxoborate according to the present invention, the polycrystal powder of cesium fluorooxoborate for use in the preparation of the melt or mixed solution can also be replaced by raw materials which are directly weighed; that is, the Cs-containing compound, B-containing compound and F-containing compound can be weighed and mixed homogeneously at a molar ratio of Cs: B: F = 0.5-2: 3-5: 0.5-2; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4.

[0023] In the method for preparing the nonlinear optical crystal of cesium fluorooxoborate according to the present invention, the container used during the preparation is a platinum crucible, iridium crucible, ceramic crucible, quartz tube, conical flask, beaker, or hydrothermal reactor lined with polytetrafluoroethylene or lined with stainless steel with a platinum sleeve. When the container is a quartz tube, vacuumization is required before sealing to avoid burst of the quartz tube resulting from volatilization of the raw materials in the reaction. When the container is a conical flask or beaker, it needs to be washed with an acid, rinsed with deionized water, and air-dried.

[0024] In the method of preparing the nonlinear optical crystal of cesium fluorooxoborate according to the present invention, the resistance furnace used during the preparation is a muffle furnace or drying cabinet.

[0025] With the method for preparing the nonlinear optical crystal of cesium fluorooxoborate according to the present invention, a centimeter-sized nonlinear optical crystal of CsB4O6F can be obtained. When a large-sized crucible or container is used and the growth cycle of the crystal is prolonged, a corresponding large-sized nonlinear optical crystal of CsB4O6F can be obtained. During the growth of the nonlinear optical crystal of CsB4O6F, the crystal is easy to grow up without inclusions and has high transparency, and has the advantages of high growth rate, low cost, easy to obtain large-sized crystals, and so on.

[0026] The large-sized nonlinear optical crystal of CsB4O6F obtained by the method for preparing the nonlinear optical crystal of cesium fluorooxoborate according to the present invention can be used as a nonlinear optical device by orienting the raw crystal based on the crystallographic data of the crystal, cutting the crystal according to the desired angle, thickness and sectional size, and polishing the transmission surface of the crystal. The nonlinear optical crystal of CsB4O6F has the advantages of a wide transparent region, stable physical and chemical properties, a high mechanical hardness, being hard to break and deliquesce, being easy to cut, polish and preserve, and so on.

BRIEF DESCRIPTION OF THE DRAWINGS



[0027] 

Fig. 1 shows a powder XRD pattern of the compound of CsB4O6F of the present invention, which is consistent with the theoretical XRD pattern, demonstrating the presence of the compound of CsB4O6F.

Fig. 2 shows the structure of the CsB4O6F crystal of the present invention.

Fig. 3 illustrates the operating principle of the nonlinear optical device made of the CsB4O6F crystal of the present invention, wherein 1 represents a laser, 2 represents an emitted beam, 3 represents a CsB4O6F crystal, 4 represents an outgoing beam, and 5 represents a filter.


DETAILED DESCRIPTION OF THE INVENTION



[0028] The present invention is further described with reference to the following Examples. It should be understood that the present invention is not limited to the Examples illustrated below, and any improvement made on the basis of the invention is not contrary to the spirit of the present invention. The raw materials and equipments used herein are all commercially available unless otherwise indicated.

Example 1: Preparation of a compound



[0029] The compound of CsB4O6F was synthesized by the solid-state synthesis method based on the reaction equation CsF+2B2O3→CsB4O6F.

[0030] CsF and B2O3 were mixed homogeneously at a molar ratio of 1:3. CsF and H3BO3 were mixed homogeneously at a molar ratio of 2:5. The mixtures were filled into a clean, pollution-free platinum crucible with a volume of 28 mL. The temperature was then increased to 350 °C for 96 hours, to obtain the compound of CsB4O6F.

Example 2: Preparation of a compound



[0031] The compound of CsB4O6F was synthesized by the solid-state reaction method based on the reaction equation CsF+4H3BO3→CsB4O6F+6H2O↑.

[0032] CsF and H3BO3 were mixed homogeneously at a molar ratio of 2:5, and filled into a clean, pollution-free platinum crucible with a volume of 28 mL. The temperature was then increased to 600 °C for 3 hours, to obtain the compound of CsB4O6F.

Example 3: Preparation of a compound



[0033] The compound of CsB4O6F was synthesized by the solid-state reaction method based on the reaction equation 12CsHCO3 + 4CsBF4 → CsB4O6F + 15CsF + 6H2O↑ + 12CO2↑.

[0034] CsHCO3 and CsBF4 were mixed homogeneously at a molar ratio of 2:3, and filled into a platinum crucible. The platinum crucible was placed in a muffle furnace, and the temperature was then increased to 450 °C for 56 hours, to obtain the compound of CsB4O6F.

Example 4: Preparation of a compound



[0035] The compound of CsB4O6F was synthesized by the solid-state reaction method based on the reaction equation 6Cs2CO3 + 4CsBF4 → CsB4O6F + 15CsF + 6CO2↑.

[0036] Cs2CO3 and CsBF4 were mixed homogeneously at a molar ratio of 2:3, and filled into a platinum crucible. The platinum crucible was placed in a muffle furnace, and the temperature was then increased to 460 °C for 96 hours, to obtain the compound of CsB4O6F.

Example 5: Preparation of a compound



[0037] The compound of CsB4O6F was synthesized by the solid-state synthesis method based on the reaction equation 12CsNO3 + 4CsBF4 → CsB4O6F + 15CsF + 6N2O5.

[0038] CsNO3 and CsBF4 were mixed homogeneously at a molar ratio of 2:3, and filled into a platinum crucible. The platinum crucible was placed in a muffle furnace, and the temperature was then increased to 470 °C for 96 hours, to obtain the compound of CsB4O6F.

Example 6: Preparation of a compound



[0039] The compound of CsB4O6F was synthesized by the vacuum encapsulation method based on the reaction equation CsF+2B2O3→CsB4O6F.

[0040] CsF and B2O3 were mixed homogeneously at a molar ratio of 1:3, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and vacuum encapsulated with a flame gun. The quartz tube was placed in a muffle furnace, and the temperature was then increased to 350 °C at a rate of 50 °C for 96 hours. The quartz tube was opened after the temperature was decreased to room temperature, to obtain the compound of CsB4O6F.

Example 7: Preparation of a compound



[0041] The compound of CsB4O6F was synthesized by the vacuum encapsulation method based on the reaction equation CsF+4H3BO3→CsB4O6F+6H2O↑.

[0042] CsF and B2O3 were mixed homogeneously at a molar ratio of 2:5, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and vacuum encapsulated with a flame gun. The quartz tube was placed in a muffle furnace, and the temperature was then increased to 600 °C at a rate of 10 °C for 96 hours. The quartz tube was opened after the temperature was decreased to room temperature, to obtain the compound of CsB4O6F.

Example 8: Preparation of a compound



[0043] The compound of CsB4O6F was synthesized by the vacuum encapsulation method based on the reaction equation 12CsHCO3 + 4CsBF4 → CsB4O6F + 15CsF + 6H2O↑ + 12CO2↑.

[0044] CsHCO3 and CsBF4 were mixed homogeneously at a molar ratio of 2:3, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and sealed at an elevated temperature. Then, the quartz tube was placed in a muffle furnace, and the temperature was increased to 470 °C at a rate of 6 °C/h for 72 hours, to obtain the compound of CsB4O6F.

Example 9: Preparation of a compound



[0045] The compound of CsB4O6F was synthesized by the vacuum encapsulation method based on the reaction equation 6Cs2CO3 + 4CsBF4 → CsB4O6F + 15CsF + 6CO2↑.

[0046] Cs2CO3 and CsBF4 were mixed homogeneously at a molar ratio of 2:3, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and sealed at an elevated temperature. Then, the quartz tube was placed in a muffle furnace, and the temperature was increased to 460 °C at a rate of 5 °C/h for 72 hours, to obtain the compound of CsB4O6F.

Example 10: Preparation of a compound



[0047] The compound of CsB4O6F was synthesized by the vacuum encapsulation method based on the reaction equation 12CsNO3 + 4CsBF4 → CsB4O6F + 15CsF + 6N2O5.

[0048] CsNO3 and CsBF4 were mixed homogeneously at a molar ratio of 2:3, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and sealed at an elevated temperature. Then, the quartz tube was placed in a muffle furnace, and the temperature was increased to 450 °C at a rate of 4 °C/h for 72 hours, to obtain the compound of CsB4O6F.

Example 11: Synthesis of a nonlinear optical crystal of CsB4O6F by the high temperature solution method



[0049] The compound of CsB4O6F obtained in accordance with Example 1 was mixed homogeneously with CsF as a fluxing agent at a molar ratio of 1:0.1, and filled into a clean platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was then increased to 400 °C at a rate of 35 °C/h for 7 hours, to give a mixedsolution.

[0050] Preparation of a seed crystal: the mixed solution as prepared was placed in a single crystal furnace, and the temperature was decreased to 350 °C at a rate of 0.1 °C/h, to 300 °C at a rate of 0.2 °C/h, and further to 30 °C at a rate of 3 °C/h, to give a seed crystal of CsB4O6F.

[0051] Growth of a crystal: the seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the mixed solution as prepared, and preheated for 10 minutes. Then, the seed crystal was contacted with the liquid surface, and the temperature was decreased at a rate of 0.1 °C/h. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 30 °C at a rate of 3 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 12 mm×13 mm×16 mm.

Example 12: Synthesis of a nonlinear optical crystal of CsB4O6F by the high temperature solution method



[0052] The compound of CsB4O6F obtained in accordance with Example 2 was mixed with PbF2 as a fluxing agent at a molar ratio of 1:0.5. The mixture was placed in a single crystal growing furnace, and the temperature was then increased to 700 °C at a rate of 45 °C/h for 15 hours, to give a mixed solution.

[0053] Preparation of a seed crystal: the solution as prepared was placed in a single crystal furnace, and the temperature was decreased to 610 °C at a rate of 5 °C/h, to 385 °C at a rate of 0.6 °C/h, and further to 30 °C at a rate of 10 °C/h, to give a seed crystal of CsB4O6F.

[0054] Growth of a crystal: the seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the mixed solution as prepared, and preheated for 25 minutes. Then, the seed crystal was contacted with the liquid surface, and the temperature was decreased at a rate of 2 °C/h. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 30 °C at a rate of 10 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 15 mm×17 mm×18 mm.

Example 13: Synthesis of a nonlinear optical crystal of CsB4O6F by the high temperature solution method.



[0055] The compound of CsB4O6F obtained in accordance with Example 3 was mixed with B2O3 as a fluxing agent at a molar ratio of 1:0.5, and filled into a clean platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was increased to 690 °C at a rate of 40 °C/h for 10 hours, to give a mixed solution.

[0056] Preparation of a seed crystal: the mixed solution as prepared was placed in the single crystal furnace, and the temperature was decreased to 580 °C at a rate of 3 °C/h, to 330 °C at a rate of 0.6 °C/h, and further to 30 °C at a rate of 8 °C/h, to give a seed crystal of CsB4O6F.

[0057] Growth of a crystal: the seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the mixed solution as prepared, and preheated for 20 minutes. Then, the seed crystal was contacted with the liquid surface, and the temperature was decreased at a rate of 0.3 °C/h. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 30 °C at a rate of 8 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 12 mm×15 mm×19 mm.

Example 14: Synthesis of a nonlinear optical crystal of CsB4O6F by the high temperature solution method



[0058] The compound of CsB4O6F obtained in accordance with Example 4 was mixed with PbO as a fluxing agent at a molar ratio of 1:0.2, and filled into a platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was then increased to 660 °C at a rate of 35 °C/h for 8 hours, to give a mixed solution.

[0059] Preparation of a seed crystal: the solution as prepared was placed in a single crystal furnace, and the temperature was decreased to 575 °C at a rate of 2 °C/h, to 380 °C at a rate of 0.2 °C/h, and further to 30 °C at a rate of 7 °C/h, to give a seed crystal of CsB4O6F.

[0060] Growth of a crystal: the seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the mixed solution as prepared, and preheated for 25 minutes. Then, the seed crystal was contacted with the liquid surface, and the temperature was decreased at a rate of 0.1 °C/h. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 30 °C at a rate of 7 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 10 mm×12 mm×15 mm.

Example 15: Synthesis of a nonlinear optical crystal of CsB4O6F by the high temperature solution method



[0061] The raw materials were weighed at a molar ratio of CsF:H3BO3=1:4, and mixed with H3BO3 as a fluxing agent at a molar ratio of 1:0.4. The mixture was filled into a platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was then increased to 665 °C at a rate of 37 °C/h for 7 hours, to give a mixed solution.

[0062] Preparation of a seed crystal: the mixed solution as prepared was placed in a single crystal furnace, and the temperature was decreased to 570 °C at a rate of 2.4 °C/h, to 385 °C at a rate of 0.15 °C/h, and further to 30 °C at a rate of 7.5 °C/h, to give a seed crystal of CsB4O6F.

[0063] Growth of a crystal: the seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the mixed solution as prepared, and preheated for 20 minutes. Then, the seed crystal was contacted with the liquid surface, and the temperature was decreased at a rate of 0.15 °C/h. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was further decreased to 30 °C at a rate of 7.5 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 13 mm×14 mm×16 mm.

Example 16: Growth of a CsB4O6F crystal by the vacuum encapsulation method



[0064] The compound of CsB4O6F obtained in accordance with Example 6 was mixed with B2O3 as a fluxing agent at a molar ratio of 1:0.1, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and vacuum encapsulated with a flame gun. The quartz tube was placed in a muffle furnace, and the temperature was increased to 400 °C at a rate of 10 °C/h for 3 hours. Then, the temperature was decreased to 330 °C at a rate of 0.5 °C/day, and further to 30 °C at a rate of 2 °C/h. The quartz tube was cut apart to obtain a nonlinear optical crystal of CsB4O6F with a size of 13 mm×16 mm×21 mm.

Example 17: Growth of a CsB4O6F crystal by the vacuum encapsulation method



[0065] The compound of CsB4O6F obtained in accordance with Example 7 was mixed with CsF as a fluxing agent at a molar ratio of 1:1, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and vacuum encapsulated with a flame gun. The quartz tube was placed in a muffle furnace, and the temperature was increased to 700 °C at a rate of 50 °C/h for 96 hours. Then, the temperature was decreased to 450 °C at a rate of 1.5 °C/day, and further to 30 °C at a rate of 5 °C/h. The quartz tube was cut apart to obtain a nonlinear optical crystal of CsB4O6F with a size of 15 mm×18 mm×23 mm.

Example 18: Growth of a CsB4O6F crystal by the vacuum encapsulation method



[0066] The compound of CsB4O6F obtained in accordance with Example 8 was mixed with H3BO3 as a fluxing agent at a molar ratio of 1:0.3, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and vacuum encapsulated with a flame gun. The quartz tube was placed in a muffle furnace, and the temperature was increased to 500 °C at a rate of 35 °C/h for 50 hours. Then, the temperature was decreased to 430 °C at a rate of 0.5 °C/day, and further to 30 °C at a rate of 4 °C/h. The quartz tube was cut apart to obtain a nonlinear optical crystal of CsB4O6F with a size of 14 mm×16 mm×17 mm.

Example 19: Growth of a CsB4O6F crystal by the vacuum encapsulation method



[0067] The compound of CsB4O6F obtained in accordance with Example 9 was mixed with PbO as a fluxing agent at a molar ratio of 1:0.4, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and vacuum encapsulated with a flame gun. The quartz tube was placed in a muffle furnace, and the temperature was increased to 520 °C at a rate of 32 °C/h for 52 hours. Then, the temperature was decreased to 435 °C at a rate of 0.8 °C/day, and further to 30 °C at a rate of 4.5 °C/h. The quartz tube was cut apart to obtain a nonlinear optical crystal of CsB4O6F with a size of 14 mm×16 mm×17 mm.

Example 20: Growth of a CsB4O6F crystal by the vacuum encapsulation method



[0068] The raw materials were weighed according to CsF:H3BO3=1:4. The compound of CsB4O6F thus obtained was mixed with PbF2 as a fluxing agent at a molar ratio of 1:0.5, and filled into a Φ40 mm quartz tube. The quartz tube was vacuumized to a vacuum degree of 1×10-3 Pa, and vacuum encapsulated with a flame gun. The quartz tube was placed in a muffle furnace, and the temperature was increased to 510 °C at a rate of 37 °C/h for 96 hours. Then, the temperature was decreased to 445 °C at a rate of 1.2 °C/day, and further to 30 °C at a rate of 3.5 °C/h. The quartz tube was cut apart to obtain a nonlinear optical crystal of CsB4O6F with a size of 14 mm×16 mm×17 mm.

Example 21: Synthesis of a nonlinear optical crystal of CsB4O6F by the Czochralski method.



[0069] The compound of CsB10O6F obtained in accordance with Example 10 was filled into a clean platinum crucible. The platinum crucible was placed in a muffle furnace, and the temperature was increased to 700 °C at a rate of 40 °C/h for 15 hours, to give a melt.

[0070] The temperature of the melt obtained above was decreased to 590 °C at a rate of 5 °C/h, to 440 °C at a rate of 2 °C/h, and further to 30 °C at a rate of 15 °C/h, to give a seed crystal of CsB4O6F.

[0071] The seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the melt as prepared, and preheated for 5 minutes. The seed crystal was then immersed in the liquid at 5 mm below the surface, and rotated at 30 rpm by a crystal growth controller. The melt was saturated by controlling the temperature, and the seed crystal was lifted at a rate of 3 mm/day while the temperature was kept constant. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 440 °C at a rate of 2 °C/h, and further to 30 °C at a rate of 15 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 12 mm×15 mm×16 mm.

Example 22: Synthesis of a nonlinear optical crystal of CsB4O6F by the Czochralski method



[0072] The compound of CsB2O6F obtained in accordance with Example 2 was filled into a platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was increased to 400 °C at a rate of 20 °C/h for 7 hours, to give a melt.

[0073] The temperature of the melt obtained above was decreased to 400 °C at a rate of 0.1 °C/h, to 300 °C at a rate of 0.2 °C/h, and further to 30 °C at a rate of 3 °C/h, to give a seed crystal of CsB4O6F.

[0074] The seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the melt as prepared, and preheated for 5 minutes. The seed crystal was then immersed in the liquid at 1 mm below the surface, and rotated at 2 rpm by a crystal growth controller. The melt was saturated by controlling the temperature, and the seed crystal was lifted at a rate of 1 mm/day while the temperature was kept constant. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 300 °C at a rate of 0.2 °C/h, and further to 30 °C at a rate of 3 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 11 mm×14 mm×15 mm.

Example 23: Synthesis of a nonlinear optical crystal of CsB4O6F by the Czochralski method



[0075] The raw materials were weighed according to CsF:H3BO3=1:4, and filled into a clean platinum crucible. The platinum crucible was placed in a muffle furnace, and the temperature was increased to 650 °C at a rate of 30 °C/h for 12 hours, to give a melt.

[0076] The temperature of the melt obtained above was decreased to 580 °C at a rate of 4 °C/h, to 440 °C at a rate of 1 °C/h, and further to 30 °C at a rate of 6 °C/h, to give a seed crystal of CsB4O6F.

[0077] The Seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the melt as prepared, and preheated for 15 minutes. The seed crystal was then immersed in the liquid at 3 mm below the surface, and rotated at 8 rpm by a crystal growth controller. The melt was saturated by controlling the temperature, and the seed crystal was lifted at a rate of 3 mm/day while the temperature was kept constant. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 440 °C at a rate of 1 °C/h, and further to 30 °C at a rate of 6 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 17 mm×19 mm×20 mm.

Example 24: Growth of a CsB4O6F crystal by the Bridgman-Stockbarger Method



[0078] The compound of CsB4O6F obtained in accordance with Example 4 was filled into a platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was increased to 700 °C at a rate of 20 °C/h for 15 hours, to give a melt.

[0079] The temperature of the melt obtained above was decreased to 590 °C at a rate of 5 °C/h, to 440 °C at a rate of 2 °C/h, and further to 30 °C at a rate of 15 °C/h. The platinum crucible was removed to give a seed crystal of CsB4O6F.

[0080] The seed crystal obtained above was placed at the bottom of the platinum crucible, and then the compound of CsB4O6F obtained was also placed in the platinum crucible. The platinum crucible was sealed and placed in a Bridgman-Stockbarger furnace, and the temperature was increased to 700 °C for 15 hours. The position of the platinum crucible was adjusted such that the seeding temperature was 625 °C. Then, the platinum crucible was lowered at a rate of 10 mm/day while the growth temperature was kept constant. Upon completion of the growth, the temperature was decreased to 440 °C at a rate of 2 °C/h, and further to 30 °C at a rate of 15 °C/h. The platinum crucible was removed to obtain a nonlinear optical crystal of CsB4O6F with a size of 18 mm×23 mm×24 mm.

Example 25: Growth of a CsB4O6F crystal by the Bridgman-Stockbarger Method



[0081] The compound of CsB5O6F obtained in accordance with Example 5 was filled into a platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was increased to 675 °C at a rate of 40 °C/h for 7 hours, to give a melt.

[0082] The temperature of the melt obtained above was decreased to 575 °C at a rate of 0.1 °C/h, to 380 °C at a rate of 1.5 °C/h, and further to 30 °C at a rate of 12 °C/h. The platinum crucible was removed to give a seed crystal of CsB4O6F.

[0083] The seed crystal obtained above was placed at the bottom of the platinum crucible, and then the compound of CsB4O6F obtained was also placed in the platinum crucible. The platinum crucible was sealed and placed in a Bridgman-Stockbarger furnace, and the temperature was then increased to 500 °C for 7 hours. The position of the platinum crucible was adjusted such that the seeding temperature was 500 °C. Then, the platinum crucible was lowered at a rate of 1 mm/day while the growth temperature was kept constant. Upon completion of the growth, the temperature was decreased to 300 °C at a rate of 0.2 °C/h, and further to 30 °C at a rate of 3 °C/h. The platinum crucible was removed to obtain a nonlinear optical crystal of CsB4O6F with a size of 19 mm×22 mm×23 mm.

Example 26: Growth of a CsB4O6F crystal by the Bridgman-Stockbarger Method



[0084] The raw materials were weighed according to CsF:B2O3=1:2, and filled into a platinum crucible. The platinum crucible was placed in a muffle furnace, and the temperature was increased to 680 °C at a rate of 30 °C/h for 24 hours, to give a melt.

[0085] The temperature of the melt obtained above was decreased to 570 °C at a rate of 3 °C/h, to 350 °C at a rate of 1 °C/h, and further to 30 °C at a rate of 15 °C/h. The platinum crucible was removed to give a seed crystal of CsB4O6F.

[0086] The seed crystal obtained above was placed at the bottom of the platinum crucible, and then the compound of CsB4O6F obtained was also placed in the platinum crucible. The platinum crucible was sealed and placed in a Bridgman-Stockbarger furnace, and the temperature was increased to 680 °C for 12 hours. The position of the platinum crucible was adjusted such that the seeding temperature was 550 °C. Then, the platinum crucible was lowered at a rate of 5 mm/day while the growth temperature was kept constant. Upon completion of the growth, the temperature was decreased to 350 °C at a rate of 1 °C/h, and further to 30 °C at a rate of 15 °C/h. The platinum crucible was removed to obtain a nonlinear optical crystal of CsB4O6F with a size of 15 mm×16 mm×23 mm.

Example 27: Synthesis of a nonlinear optical crystal of CsB4O6F by the Kyropoulos method.



[0087] The compound of CsB2O6F obtained in accordance with Example 2 was filled into a platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was increased to 630 °C at a rate of 40 °C/h for 18 hours, to give a melt.

[0088] The temperature of the melt obtained above was decreased to 565 °C at a rate of 5 °C/h, to 380 °C at a rate of 2 °C/h, and further to 30 °C at a rate of 8 °C/h, to give a seed crystal of CsB4O6F.

[0089] The seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the melt as prepared, and preheated for 60 minutes. The seed crystal was then immersed in the liquid at 5 mm below the surface, and the temperature was decreased at a rate of 0.7 °C/h. 3 hours later, the seed crystal was lifted by 2 mm. The temperature was further decreased at a rate of 0.7 °C/h. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 440 °C at a rate of 2 °C/h, and further to 30 °C at a rate of 15 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 4 mm×6 mm×9 mm.

Example 28: Synthesis of a nonlinear optical crystal of CsB4O6F by the Kyropoulos method



[0090] The compound of CsB3O6F obtained in accordance with Example 3 was filled into a platinum crucible. The platinum crucible was placed in a single crystal growing furnace, and the temperature was increased to 640 °C at a rate of 20 °C/h for 24 hours, to give a melt.

[0091] The temperature of the melt obtained above was decreased to 560 °C at a rate of 6 °C/h, to 390 °C at a rate of 1.8 °C/h, and further to 30 °C at a rate of 3.5 °C/h, to give a seed crystal of CsB4O6F.

[0092] The crystal was grown in the melt of the compound by the Kyropoulos method as below. The seed crystal of CsB4O6F obtained above was fixed on a seed crystal rod. The seed crystal was lowered to 1 mm above the liquid surface from the top of a crystal growing furnace containing the melt as prepared, and preheated for 5 minutes. The seed crystal was then immersed in the liquid at 1 mm below the surface, and the temperature was decreased at a rate of 0.1 °C/h. 10 hours later, the seed crystal was lifted by 1 mm, and the temperature was further decreased at a rate of 0.1 °C/h. Upon completion of the crystal growth, the crystal on the seed crystal rod was pulled out, and the temperature was decreased to 300 °C at a rate of 0.2 °C/h, and further to 30 °C at a rate of 3 °C/h, to obtain a nonlinear optical crystal of CsB4O6F with a size of 13 mm×18 mm×24 mm.

Example 29: Synthesis of a nonlinear optical crystal of CsB4O6F by the room temperature solution method



[0093] The compound of CsB4O6F obtained in accordance with Example 1 was put into a clean glass container, to which 100 mL of deionized water was added. Then, ultrasonication was performed for 5 minutes to allow for sufficient mixing and dissolution. Then, the pH of the solution was adjusted to 8 by addition of HF or CsOH.

[0094] The container containing the solution was sealed with weighing paper and placed in a static environment without shaking, pollution and air convection. The evaporation rate was controlled at 2 mL/day by piercing the seal, and the solution was set aside for 5 days.

[0095] Crystal particles were grown at the bottom of the container from the solution. Upon completion of the growth when the size of the crystal particles was no longer changed significantly, a seed crystal was obtained.

[0096] The remaining solution was filtered with qualitative filter paper to filter out grains and other impurities from the solution. The seed crystal of better quality was selected, fixed with a platinum wire and suspended in the filtered solution. The evaporation rate was controlled at 2 mL/day by piercing the seal. The solution was set aside for 30 days at room temperature, to obtain a nonlinear optical crystal of CsB4O6F with a size of 8 mm×14 mm×17 mm.

Example 30: Synthesis of a nonlinear optical crystal of CsB4O6F by the room temperature solution method



[0097] The raw materials were weighed according to CsF:B2O3=1:2, and put into a clean glass container, to which 20 mL of deionized water was added. Then, ultrasonication was performed for 30 minutes to allow for sufficient mixing and dissolution. Then, the pH of the solution was adjusted to 11 by addition of HF or CsOH.

[0098] The container containing the solution was sealed with weighing paper and placed in a static environment without shaking, pollution and air convection. The evaporation rate was controlled at 0.2 mL/day by piercing the seal, and the solution was set aside for 20 days.

[0099] Crystal particles were grown at the bottom of the container from the solution. Upon completion of the growth when the size of the crystal particles was no longer changed significantly, a seed crystal was obtained.

[0100] The remaining solution was filtered with qualitative filter paper to filter out grains and other impurities from the solution. The seed crystal was fixed with a platinum wire and suspended in the filtered solution. The evaporation rate was controlled at 0.2 mL/day by piercing the seal. The solution was set aside for 30 days at room temperature, to obtain a nonlinear optical crystal of CsB4O6F with a size of 4 mm×8 mm×9 mm.

Example 31: Synthesis of a nonlinear optical crystal of CsB4O6F by the hydrothermal method



[0101] The compound of CsB4O6F obtained in accordance with Example 1 was added to 5 mL of deionized water. The incompletely dissolved mixture was sonicated at a temperature of 20 °C for 5 minutes to allow for sufficient mixing.

[0102] The mixed solution was transferred into the lining of a clean, pollution-free high pressure reactor with a volume of 100 mL, and the reactor was tightened and sealed.

[0103] The high pressure reactor was placed in a thermostat, and the temperature was increased to 350 °C at a rate of 50 °C/h for 3 days. Then, the temperature was decreased to room temperature at a rate of 5 °C/day. The high pressure reactor was opened to obtain a nonlinear optical crystal of CsB4O6F with a size of 8 mm×9 mm×15 mm.

Example 32: Synthesis of a nonlinear optical crystal of CsB4O6F by the hydrothermal method



[0104] The raw materials were weighed according to CsF:H3BO3=1:4, and added to 30 mL of deionized water. The incompletely dissolved mixture was sonicated at a temperature of 50 °C for 30 minutes to allow for sufficient mixing.

[0105] The mixed solution was transferred into the lining of a clean, pollution-free high pressure reactor with a volume of 100 mL, and the reactor was tightened and sealed.

[0106] The high pressure reactor was placed in a thermostat, and the temperature was increased to 150 °C at a rate of 5 °C/h for 15 days. Then, the temperature was decreased to room temperature at a rate of 30 °C/day. The high pressure reactor was opened to obtain a nonlinear optical crystal of CsB4O6F with a size of 22 mm×24 mm×27 mm.

Example 33: Synthesis of a nonlinear optical crystal of CsB4O6F by the hydrothermal method.



[0107] The compound of CsB4O6F obtained in accordance with Example 2 was added to 8 mL of deionized water. The incompletely dissolved mixture was sonicated at a temperature of 45 °C for 30 minutes to allow for sufficient mixing.

[0108] The mixture was transferred into the lining of a clean, pollution-free high pressure reactor with a volume of 100 mL, and the reactor was tightened and sealed.

[0109] The high pressure reactor was placed in a thermostat, and the temperature was increased to 330 °C at a rate of 40 °C/h for 10 days. Then, the temperature was decreased to room temperature at a rate of 8 °C/day. The high pressure reactor was opened to obtain a nonlinear optical crystal of CsB4O6F with a size of 12 mm×18 mm×20 mm.

Example 34:



[0110] The CsB4O6F crystal obtained from any one of Examples 1-33 was processed in the phase-matched direction and was arranged in the position of 3 as shown in Fig. 3. At room temperature, a Q switched Nd:YAG laser was used as the light source with an fundamental wavelength of 1064 nm. The Q switched Nd:YAG laser 1 emitted an infrared beam 2 with a wavelength of 1064 nm onto the CsB4O6F single crystal 3, producing a green frequency-multiplied light with a wavelength of 532 nm, with an output intensity that is about 2 times that of KDP under the equivalent condition.

Example 35:



[0111] The CsB4O6F crystal obtained from any one of Examples 1-33 was processed in the phase-matched direction, and was arranged in the position of 3 as shown in Fig. 3. At room temperature, a Q switched Nd:YAG laser was used as the light source with an incident wavelength of 532 nm. The Q switched Nd:YAG laser 1 emitted an infrared beam 2 with a wavelength of 532 nm onto the CsB4O6F single crystal 3, producing a frequency-multiplied light with a wavelength of 266 nm, with an output intensity that is about 0.5 times that of BBO under the equivalent condition.

Example 36:



[0112] The CsB4O6F crystal obtained from any one of Examples 1-33 was processed in the phase-matched direction, and was arranged in the position of 3 as shown in Fig. 3. At room temperature, a Q switched Nd:YAG laser was used as the light source with an incident wavelength of 355 nm. The Q switched Nd:YAG laser 1 emitted an infrared beam 2 with a wavelength of 355 nm onto the CsB4O6F single crystal 3. An output of a deep-ultraviolet frequency-multiplied light with a wavelength of 177.3 nm could be observed.


Claims

1. A compound of cesium fluorooxoborate, wherein a chemical formula of the compound is CsB4O6F, and a molecular weight of the compound is 291.15.
 
2. A method for preparing a compound of cesium fluorooxoborate of claim 1, wherein the compound is prepared by a solid-state synthesis method or a vacuum encapsulation method;
the said solid-state synthesis method for preparing of the compound of cesium fluorooxoborate comprises the steps of:

mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4; and

the said vacuum encapsulation method for preparing the compound of cesium fluorooxoborate,

mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a Φ40 mm quartz tube; vacuumizing the quartz tube to a vacuum degree of 1×10-3 Pa, and sealing it at a high temperature; then placing the quartz tube in a muffle furnace, and increasing the temperature to 350-600 °C at a rate of 10-50 °C for 3-96 hours, to give the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4.


 
3. A nonlinear optical crystal of cesium fluorooxoborate, wherein a chemical formula of the crystal is CsB4O6F and a molecular weight of the crystal is 291.15, and the crystal belongs to an orthorhombic crystal system, with a space group of Pna21, crystal cell parameters of α=7.9241Å, b=11.3996Å, c=6.6638Å, and α=β=γ=90°, and a unit cell volume of 601.95Å3.
 
4. A method for preparing the nonlinear optical crystal of cesium fluorooxoborate of claim 3, wherein the crystal is grown by a melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method; wherein the melt method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:

a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give a polycrystal powder of the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4;

b) filling the resultant polycrystal powder of the compound of CsB4O6F into a clean platinum crucible; placing the platinum crucible in a muffle furnace, and increasing the temperature to 400-700 °C at a rate of 20-40 °C/h for 7-15 hours, to give a melt; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4;

c) decreasing the temperature of the melt from step b) to 400-590 °C at a rate of 0.1-5 °C/h, to 300-440 °C at a rate of 0.2-2 °C/h, and further to 30 °C at a rate of 3-15 °C/h, to give a seed crystal of CsB4O6F; and

d) growing the crystal in the melt of the compound by the Czochralski method, comprising
fixing the seed crystal obtained from step c) onto a seed crystal rod; lowering the seed crystal to 1 mm above the liquid surface from the top of a crystal growing furnace for the melt prepared in step b), and preheating it for 5-60 minutes; then immersing the seed crystal in the liquid at 1-5 mm below the surface; rotating the crystal at 2-30 rpm by a crystal growth controller and controlling the temperature to saturate the melt; lifting the seed crystal at a rate of 1-3 mm/day while keeping the temperature constant; upon completion of the crystal growth, pulling the crystal on the seed crystal rod, and decreasing the temperature to 300-440 °C at a rate of 0.2-2 °C/h, and further to 30 °C at a rate of 3-15 °C/h, to obtain the nonlinear optical crystal of CsB4O6F;
alternatively, growing the crystal in the melt of the compound by the Kyropoulos method, comprising
fixing the seed crystal obtained from step c) onto a seed crystal rod; lowering the seed crystal to 1 mm above the liquid surface from the top of a crystal growing furnace for the melt prepared in step b), and preheating it for 5-60 minutes; then immersing the seed crystal in the liquid at 1-5 mm below the surface; decreasing the temperature at a rate of 0.1-0.7 °C/h; 3-10 hours later, lifting the seed crystal by 1-2 mm, and further decreasing the temperature at a rate of 0.1-0.7 °C/h; upon completion of the crystal growth, pulling the crystal on the seed crystal rod, and decreasing the temperature to 300-440 °C at a rate of 0.2-2 °C/h, and further to 30 °C at a rate of 3-15 °C/h, to obtain the nonlinear optical crystal of CsB4O6F;
alternatively, growing the crystal in the melt of the compound by the Bridgeman-Stockbarger method, comprising
placing the seed crystal prepared in step c) at the bottom of a crucible, then adding the polycrystal compound of CsB4O6F prepared in step a) to the crucible; sealing the platinum crucible, and increasing the temperature of the growing furnace to 500-700 °C for 7-15 hours; adjusting the position of the crucible such that the seeding temperature is 500-625 °C; then lowering the crucible at a rate of 1-10 mm/day while keeping the growth temperature constant; upon completion of the growth, decreasing the temperature to 300-440 °C at a rate of 0.2-2 °C/h, and further to 30 °C at a rate of 3-15 °C/h; and removing the platinum crucible, to obtain the nonlinear optical crystal of CsB4O6F;

the high temperature solution method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:

a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2 to obtain a mixture; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give a polycrystal powder of the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4;

b) mixing the polycrystal powder of the compound of CsB4O6F obtained from step a) homogeneously with a fluxing agent at a molar ratio of 1:0.1-0.5; then filling the mixture into a clean platinum crucible, and increasing the temperature to 400-700 °C at a rate of 35-45 °C/h for 7-15 hours, to give a mixed solution; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; the B-containing compound is H3BO3, B2O3 or CsBF4; and the fluxing agent is CsF, H3BO3, B2O3, PbO or PbF2;

c) preparation of a seed crystal: placing the mixed solution prepared in step b) into a single crystal furnace, and then decreasing the temperature to 350-610 °C at a rate of 0.1-5 °C/h, to 300-385 °C at a rate of 0.2-0.6 °C/h, and further to 30 °C at a rate of 3-10 °C/h, to give a seed crystal of CsB4O6F; and

d) growth of a crystal: fixing the resultant seed crystal of CsB4O6F onto a seed crystal rod; lowering the seed crystal to 1 mm above the liquid surface from the top of a crystal growing furnace for the mixed solution prepared in step b), and preheating it for 10-25 minutes; contacting the seed crystal with the liquid surface, and decreasing the temperature at a rate of 0.1-2 °C/h; upon completion of the crystal growth, pulling the crystal away from the surface of the solution, and then decreasing the temperature to 30 °C at a rate of 3-10 °C/h, to obtain the nonlinear optical crystal of CsB4O6F;

the vacuum encapsulation method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:

a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C at a rate of 10-50 °C for 3-96 hours, to give a polycrystal powder of the compound of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF or CsBF4; and the B-containing compound is H3BO3, B2O3 or CsBF4; and

b) mixing the polycrystal powder of the compound of CsB4O6F obtained from step a) homogeneously with a fluxing agent at a molar ratio of 1:0.1-1; then filling the mixture into a quartz tube, and increasing the temperature to 400-700 °C at a rate of 10-50 °C/h for 3-96 hours; then decreasing the temperature to 330-450 °C at a rate of 0.5-1.5 °C/day, and further to 30 °C at a rate of 2-5 °C/h; and cutting the quartz tube to obtain the nonlinear optical crystal of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CsBF4; the F-containing compound is CsF, CsBF4 or HF; the B-containing compound is H3BO3, B2O3 or CsBF4; and the fluxing agent is CsF, H3BO3, B2O3, PbO or PbF2;

the hydrothermal method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:

a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give a polycrystal powder product of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CH3COOCs; the F-containing compound is CsF or HF; and the B-containing compound is H3BO3 or B2O3;

b) dissolving the polycrystal powder of the compound of CsB4O6F obtained from step a) in 5-30 mL of deionized water, and sonicating the incompletely dissolved mixture at a temperature of 20-50 °C for 5-30 minutes to allow for sufficient mixing and dissolution;

c) transferring the mixed solution obtained from step b) into the lining of a clean, pollution-free high pressure reactor with a volume of 100 mL, and tightening and sealing the reactor; and

d) placing the high pressure reactor in a thermostat, increasing the temperature to 150-350 °C at a rate of 5-50 °C/h for 3-15 days, and then decreasing the temperature to room temperature at a rate of 5-30 °C/day, to obtain the nonlinear optical crystal of CsB4O6F;

and
the room temperature solution method for growing the nonlinear optical crystal of cesium fluorooxoborate comprises the following steps:

a) mixing a Cs-containing compound, a B-containing compound and an F-containing compound homogeneously at a molar ratio of Cs:B:F=0.5-2:3-5:0.5-2; filling the mixture into a platinum crucible; then placing the platinum crucible in a muffle furnace, and increasing the temperature to 350-600 °C for 3-96 hours, to give a polycrystal powder product of CsB4O6F; wherein the Cs-containing compound is Cs2CO3, CsNO3, CsHCO3, CsF or CH3COOCs; the F-containing compound is CsF or HF; and the B-containing compound is H3BO3 or B2O3;

b) placing the polycrystal powder of the compound of CsB4O6F obtained from step a) in a clean glass container, to which 20-100 mL of deionized water is added, followed by ultrasonication for 5-60 minutes to allow for sufficient mixing and dissolution, and then adjusting the pH of the solution to 8-11 by addition of HF or CsOH;

c) sealing the container containing the solution in step b) with weighing paper, and placing it in a static environment without shaking, pollution and air convection; controlling the evaporation rate at 0.2-2 mL/day by piercing the seal; and setting it aside for 5-20 days at room temperature;

d) obtaining a seed crystal upon completion of the growth when the size of the crystal particles grown at the bottom of the container from the solution in step c) is no longer changed significantly; and

e) filtering the remaining solution through qualitative filter paper to filter out grains and other impurities from the solution; selecting the seed crystal of better quality, fixing it with a platinum wire and suspending it in the filtered solution; controlling the evaporation rate at 0.2-2 mL/day by piercing the seal, and setting it aside for growth for 5-20 days at room temperature, to obtain the nonlinear optical crystal of CsB4O6F.


 
5. Use of the nonlinear optical crystal of cesium fluorooxoborate of claim 3 in the manufacture of an Nd:YAG laser that outputs a fundamental frequency light of 1064 nm for the second, third, fourth, fifth or sixth harmonic generation laser output.
 
6. Use of the nonlinear optical crystal of cesium fluorooxoborate of claim 3 in the production of a deep-ultraviolet frequency-multiplied light below 200 nm.
 
7. Use of the nonlinear optical crystal of the compound of cesium fluorooxoborate of claim 3 in the manufacture of a frequency multiplication generator, a frequency up or down converter or an optical parametric oscillator.
 




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REFERENCES CITED IN THE DESCRIPTION



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Patent documents cited in the description