Compound lead fluorinated phosphate and lead fluorinated phosphate nonlinear optical frequency doubling crystal and preparation method and use thereof

Abstract

The invention discloses a lead fluoride phosphate compound and a lead fluoride phosphate nonlinear optical frequency doubling crystal, and a preparation method and application thereof, belonging to the technical field of nonlinear optical frequency doubling crystals. The lead fluoride phosphate compound has a chemical formula of PbPO3F and a molecular weight of 305.16, and is prepared by a solid phase synthesis method or a solution method; the lead fluoride phosphate nonlinear optical frequency doubling crystal has a chemical formula of PbPO3F and a molecular weight of 305.16, belongs to an orthorhombic crystal system, has a space group of Cc, unit cell parameters of #imgabs0##imgabs1#α=90°, β=126.0920(10)°, γ=90°, and a unit cell volume of #imgabs2#. The frequency doubling effect of the crystal is about 1.8 times that of KDP, and the ultraviolet cutoff edge is lower than 240nm, so the crystal can be used as a short-wavelength nonlinear optical frequency doubling in an all-solid-state laser.

Description

Technical Field

[0001] The invention belongs to the technical field of nonlinear optical frequency doubling crystals, and in particular relates to a compound lead fluorinated phosphate and a lead fluorinated phosphate nonlinear optical frequency doubling crystal, and a preparation method and application thereof. Background Art

[0002] Ultraviolet nonlinear optical frequency-doubling crystals can use their frequency conversion properties to convert near-infrared, visible and other band lasers into ultraviolet lasers, and have important application value in the fields of medicine, communication, scientific research, etc. As we all know, the currently practical short-wavelength nonlinear optical frequency-doubling crystals are KBe2BO3F2 (KBBF) crystals, BaB2O4 (BBO) and LiB3O5 (LBO) invented by Chinese scientists. However, these crystals have defects such as difficulty in growing large-sized crystals and small birefringence, which limit their application to a certain extent. Therefore, the preparation and synthesis of new short-wavelength nonlinear optical frequency-doubling crystal materials with excellent comprehensive performance is of great significance and practical value. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a lead phosphate fluoride compound and a lead phosphate fluoride nonlinear optical frequency doubling crystal and a preparation method and use thereof. The lead phosphate fluoride compound of the present invention has a chemical formula of PbPO3F and a molecular weight of 305.16. The lead phosphate fluoride compound is prepared by a solid phase reaction method or a solution method.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A compound, lead fluorinated phosphate, has the chemical formula PbPO3F and a molecular weight of 305.16.

[0006] The present invention also provides a method for preparing the compound lead fluorinated phosphate, which is prepared by a solid phase synthesis method or a solution method;

[0007] When the solid phase synthesis method is used for preparation, the steps are as follows: weighing a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mixing them uniformly, heating to 300-600°C under vacuum or inert atmosphere, and keeping the temperature constant for 24-120 hours to obtain a compound of fluorinated lead phosphate (PbPO3F);

[0008] When the solution method is used for preparation, the steps are as follows: weigh a Pb-containing compound, a P-containing compound and a F-containing compound in a molar ratio of Pb:P:F=1:1:1, mix them, add a solvent, place them in a dry, ventilated and light-proof place to evaporate the solvent for 24-120 hours, and then filter the filtrate to obtain the compound PbPO3F.

[0009] Preferably, in the preparation method of the compound lead fluoride phosphate, when the solid phase synthesis method is adopted, the Pb-containing compound is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2; it should be noted that (NH4)2PO3F contains both P and F. When (NH4)2PO3F is used as the raw material, it can be considered that the compounds containing P and F are added at the same time, the same below.

[0010] When the solution method is adopted, the Pb-containing compound is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, the F-containing compound is PbF2, and the solvent is deionized water, ethanol or acetone.

[0011] The present invention also provides a lead fluorinated phosphate nonlinear optical frequency doubling crystal, the chemical formula of the crystal is PbPO3F, the molecular weight is 305.16, it belongs to the monoclinic system, the space group is Cc, and the unit cell parameters are α=90°,β=126.0920(10)°,γ=90°,the unit cell volume is

[0012] The present invention also provides a method for preparing the lead fluorinated phosphate nonlinear optical frequency doubling crystal, which grows the crystal by a melt method, a vacuum packaging method, a hydrothermal method or a room temperature solution volatilization method;

[0013] When the melt method is used to grow crystals, the following steps are included:

[0014] a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mix them evenly, raise the temperature to 300-600°C under vacuum or inert atmosphere, and keep the temperature constant for 24-120 hours to obtain PbPO3F polycrystalline powder;

[0015] b. The PbPO3F polycrystalline powder obtained in step a is heated to 500-900° C. under vacuum or inert atmosphere and kept at this temperature for 10-120 hours to obtain a mixed melt;

[0016] c. Cooling the mixed melt obtained in step b to 300° C. at a rate of 0.1-2° C. / h, and then cooling to room temperature at a rate of 5-10° C. / h to obtain PbPO3F seed crystals;

[0017] d. Growing crystals in the mixed melt by the pulling method: fixing the PbPO3F seed crystal obtained in step c on a seed crystal rod, placing the PbPO3F seed crystal from the top of the mixed melt obtained in step b, applying a crystal rotation of 2-20 rpm through a crystal growth controller, pulling the seed crystal at a speed of 1-10 mm / day, and cooling at a rate of 0.1-10°C / h. After the crystal growth stops, the lead fluorinated phosphate nonlinear optical frequency doubling crystal (PbPO3F nonlinear optical frequency doubling crystal) is obtained;

[0018] Or the crystal is grown in the mixed melt by the kyber growth method: the PbPO3F seed crystal obtained in step c is fixed on the seed crystal rod, the PbPO3F seed crystal is placed from the top of the mixed melt obtained in step b, the temperature is lowered at a rate of 0.1-10°C / h, the crystal is grown for 5-15 hours, the crystal is lifted but does not leave the liquid surface to continue growing, and this is repeated until the crystal growth stops, and the PbPO3F nonlinear optical frequency doubling crystal is obtained;

[0019] Or a crystal is grown in a mixed melt by a crucible lowering method: the PbPO3F seed crystal obtained in step c is placed at the bottom of the crucible, and the PbPO3F polycrystal prepared in step a is placed in the crucible, and then the crucible is sealed, the temperature of the growth furnace is raised to 550-750°C, and the temperature is kept constant for 10-120 hours, the position of the crucible is adjusted to make the PbPO3F seed crystal slightly melted, and then the crucible is lowered at a rate of 1-10 mm / day, and at the same time, the growth temperature is kept unchanged, or the temperature is lowered to 350°C at a cooling rate of 3°C / h, and after the growth is completed, the temperature is quickly lowered to room temperature at a rate of 5-10°C / h, so as to obtain the PbPO3F nonlinear optical frequency doubling crystal;

[0020] When the vacuum packaging method is used to grow crystals, the following steps are included:

[0021] a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mix them evenly, raise the temperature to 400-600°C under vacuum or inert atmosphere, and keep the temperature constant for 24-120 hours to obtain PbPO3F polycrystalline powder;

[0022] b. The PbPO3F polycrystalline powder obtained in step a is mixed evenly with a co-solvent at a molar ratio of 0-1:0.1-6, and the mixture is placed in a quartz tube, sealed and placed in a muffle furnace, heated to 500-800°C, kept at a constant temperature for 5-120 hours, then cooled to 350°C at a rate of 0.1-3°C / h, and then cooled to room temperature at a rate of 5-10°C / h, to obtain the PbPO3F nonlinear optical frequency doubling crystal;

[0023] When the hydrothermal method is used to grow crystals, the following steps are included:

[0024] a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mix them evenly, raise the temperature to 400-600°C under vacuum or inert atmosphere, and keep the temperature constant for 24-120 hours to obtain PbPO3F polycrystalline powder;

[0025] b. The PbPO3F polycrystalline powder obtained in step a is dissolved in deionized water, and the incompletely dissolved mixture is subjected to ultrasonic treatment at a temperature of 60° C. to allow the mixture to be fully mixed and dissolved, and the pH value is adjusted to 2-6 with HF and NH3·H2O to obtain a mixed solution;

[0026] c. Transfer the mixed solution obtained in step b into the inner lining of a high-pressure reactor, and tighten and seal the reactor;

[0027] d. placing the high-pressure reactor in a constant temperature box, raising the temperature to 100-300° C., maintaining the temperature for 5-8 days, and then cooling the temperature down to room temperature at a rate of 5-20° C. / day, thereby obtaining the PbPO3F nonlinear optical frequency doubling crystal;

[0028] When the room temperature solution volatilization method is used to grow crystals, the following steps are included:

[0029] a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound in a molar ratio of Pb:P:F=1-2:1-3:1-2, mix them evenly, and dissolve them in a solution to obtain a mixed solution. Place the mixed solution in a glass container, seal it with weighing paper, place it in a static environment, pierce a plurality of small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and leave it at room temperature for 5-20 days;

[0030] b. Waiting for the solution in step a to grow crystal particles at the bottom of the container until the size of the crystal particles no longer changes significantly, thereby obtaining seed crystals;

[0031] c. Select the one with better quality in step b (transparent area larger than 1*1cm 2 The seed crystal with a thickness greater than 0.5 cm is suspended in the mixed solution obtained in step b and allowed to stand and grow at room temperature for 10-30 days to obtain the PbPO3F nonlinear optical frequency doubling crystal.

[0032] Preferably, in the preparation method of the fluorinated lead phosphate nonlinear optical frequency doubling crystal, when the crystal is grown by the melt method, the Pb-containing compound in step a is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2;

[0033] When the vacuum packaging method is used to grow the crystal, the Pb-containing compound in step a is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2; the cosolvent in step b is PbF2, H3PO4 or P2O5;

[0034] When the crystal is grown by hydrothermal method, the Pb-containing compound in step a is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2;

[0035] When the room temperature solution volatilization method is used to grow crystals, the Pb-containing compound in step a is Pb(NO3)2, PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2; the static environment in step a refers to an environment without shaking, pollution, or air convection;

[0036] The present invention also provides the use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal in preparing the 1064nm fundamental frequency light output by the Nd:YAG laser for double-frequency and triple-frequency harmonic light output.

[0037] The present invention also provides the use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal in preparing a short-wavelength frequency doubling light output of 266nm.

[0038] The present invention also provides the use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal in preparing a frequency doubling generator, an up or down frequency converter or an optical parametric oscillator.

[0039] Compared with the prior art, the present invention has the following advantages and technical effects:

[0040] (1) In the present invention, by using a large-sized crucible or container and extending the crystal growth period, a correspondingly large-sized PbPO3F nonlinear optical frequency doubling crystal can be obtained. During the growth process of the PbPO3F nonlinear optical frequency doubling crystal, the crystal is easy to grow, transparent and without wrapping, and has the advantages of fast growth rate, low cost, and easy acquisition of large-sized crystals.

[0041] (2) The preparation method of the present invention can be used to obtain a large-sized PbPO3F nonlinear optical frequency doubling crystal. According to the crystallographic data of the crystal, the crystal blank is oriented, the crystal is cut according to the required angle, thickness and cross-sectional size, and the light-transmitting surface of the crystal is polished, and it can be used as a nonlinear optical device. The PbPO3F nonlinear optical frequency doubling crystal has a light transmission band of about 240nm, and has the advantages of stable physical and chemical properties (the crystal quality and mass do not change significantly within 2 months exposed to air at room temperature) and is not easy to deliquesce (no deliquesce occurs within 2 months exposed to air at room temperature). BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0043] Figure 1 The powder XRD spectrum of the compound PbPO3F in Example 1 of the present invention;

[0044] Figure 2 : is a unit cell structure diagram of the PbPO3F nonlinear optical frequency doubling crystal in Example 6 of the present invention;

[0045] Figure 3 This is a working principle diagram of a nonlinear optical device made using the PbPO3F nonlinear optical frequency doubling crystal of the present invention, wherein 1 is a laser, 2 is an emitted light beam, 3 is a PbPO3F nonlinear optical frequency doubling crystal, 4 is an output light beam, and 5 is a filter. DETAILED DESCRIPTION

[0046] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0047] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0048] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0049] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0050] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0051] In the present invention, unless otherwise specified, room temperature is 25±2°C.

[0052] All raw materials and equipment used in the embodiments of the present invention are commercially available.

[0053] The embodiment of the present invention provides a compound lead fluoride phosphate, the chemical formula of which is PbPO3F and the molecular weight is 305.16.

[0054] The embodiment of the present invention also provides a method for preparing the compound lead fluorinated phosphate, which is prepared by a solid phase synthesis method or a solution method;

[0055] When the solid phase synthesis method is adopted for preparation, the steps are as follows: weighing a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mixing them evenly, loading them into a platinum crucible, placing them in a muffle furnace under vacuum or inert atmosphere, heating them to 300-600°C, and keeping the temperature constant for 24-120 hours to obtain a compound of fluorinated lead phosphate (PbPO3F), wherein the Pb-containing compound is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2;

[0056] When the solution method is used for preparation, the steps are as follows: weigh a Pb-containing compound, a P-containing compound and a F-containing compound in a molar ratio of Pb:P:F=1:1:1, mix them, add a solvent, place them in a dry, ventilated and light-proof place to evaporate the solvent, the evaporation time is 24-120 hours, and then filter the filtrate to obtain the compound PbPO3F, the Pb-containing compound is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, the F-containing compound is PbF2, and the solvent is deionized water, ethanol or acetone.

[0057] The embodiment of the present invention also provides a lead fluorinated phosphate nonlinear optical frequency doubling crystal, the chemical formula of the crystal is PbPO3F, the molecular weight is 305.16, belongs to the monoclinic system, the space group is Cc, and the unit cell parameters are α=90°,β=126.0920(10)°,γ=90°,the unit cell volume is

[0058] In an embodiment of the present invention, a method for preparing the lead fluorinated phosphate nonlinear optical frequency doubling crystal is also provided, wherein the crystal is grown by a melt method, a vacuum packaging method, a hydrothermal method or a room temperature solution volatilization method;

[0059] When the melt method is used to grow crystals, the following steps are included:

[0060] a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound in a molar ratio of Pb:P:F=1:1:1, mix them evenly, put them into a platinum crucible, place them in a muffle furnace under vacuum or inert atmosphere, heat them to 300-600°C, and keep the temperature constant for 24-120 hours to obtain a PbPO3F polycrystalline powder, wherein the Pb-containing compound is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2;

[0061] b. The PbPO3F polycrystalline powder obtained in step a is placed in a platinum crucible, placed in a muffle furnace under vacuum or inert atmosphere, heated to 500-900° C., and kept at this temperature for 10-120 hours to obtain a mixed melt;

[0062] c. Cooling the mixed melt obtained in step b to 300° C. at a rate of 0.1-2° C. / h, and then cooling to room temperature at a rate of 5-10° C. / h to obtain PbPO3F seed crystals;

[0063] d. Growing crystals in the mixed melt by the pulling method: fixing the PbPO3F seed crystal obtained in step c on a seed crystal rod, placing the PbPO3F seed crystal from the top of the mixed melt obtained in step b, applying a crystal rotation of 2-20 rpm through a crystal growth controller, pulling the seed crystal at a speed of 1-10 mm / day, and cooling at a rate of 0.1-10°C / h. After the crystal growth stops, the lead fluorinated phosphate nonlinear optical frequency doubling crystal (PbPO3F nonlinear optical frequency doubling crystal) is obtained;

[0064] Or the crystal is grown in the mixed melt by the kyber growth method: the PbPO3F seed crystal obtained in step c is fixed on the seed crystal rod, the PbPO3F seed crystal is placed from the top of the mixed melt obtained in step b, the temperature is lowered at a rate of 0.1-10°C / h, the crystal is grown for 5-15 hours, the crystal is lifted but does not leave the liquid surface to continue growing, and this is repeated until the crystal growth stops, and the PbPO3F nonlinear optical frequency doubling crystal is obtained;

[0065] Or a crystal is grown in a mixed melt by a crucible lowering method: the PbPO3F seed crystal obtained in step c is placed at the bottom of the crucible, and the PbPO3F polycrystal prepared in step a is placed in the crucible, and then the crucible is sealed, the temperature of the growth furnace is raised to 550-750°C, and the temperature is kept constant for 10-120 hours, the position of the crucible is adjusted to make the PbPO3F seed crystal slightly melted, and then the crucible is lowered at a rate of 1-10 mm / day, and at the same time, the growth temperature is kept unchanged, or the temperature is lowered to 350°C at a cooling rate of 3°C / h, and after the growth is completed, the temperature is quickly lowered to room temperature at a rate of 5-10°C / h, so as to obtain the PbPO3F nonlinear optical frequency doubling crystal;

[0066] When the vacuum packaging method is used to grow crystals, the following steps are included:

[0067] a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mix them evenly, put them into a platinum crucible, place them in a muffle furnace under vacuum or inert atmosphere, heat them to 400-600°C, and keep the temperature constant for 24-120 hours to obtain PbPO3F polycrystalline powder, wherein the Pb-containing compound is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2;

[0068] b. The PbPO3F polycrystalline powder obtained in step a is mixed evenly with a co-solvent at a molar ratio of 0-1:0.1-6 (the molar number of the PbPO3F polycrystalline powder is not 0), and the mixture is placed in a quartz tube, sealed and placed in a muffle furnace, heated to 500-800°C, kept at a constant temperature for 5-120 hours, then cooled to 350°C at a rate of 0.1-3°C / h, and then cooled to room temperature at a rate of 5-10°C / h, to obtain the PbPO3F nonlinear optical frequency doubling crystal, wherein the co-solvent is PbF2, H3PO4 or P2O5;

[0069] When the hydrothermal method is used to grow crystals, the following steps are included:

[0070] a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound in a molar ratio of Pb:P:F=1:1:1, mix them evenly, raise the temperature to 400-600°C under vacuum or inert atmosphere, and keep the temperature constant for 24-120 hours to obtain PbPO3F polycrystalline powder, wherein the Pb-containing compound is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2;

[0071] b. The PbPO3F polycrystalline powder obtained in step a is dissolved in deionized water, and the incompletely dissolved mixture is subjected to ultrasonic treatment at a temperature of 60° C. to allow the mixture to be fully mixed and dissolved, and the pH value is adjusted to 2-6 with HF and NH3·H2O to obtain a mixed solution;

[0072] c. Transfer the mixed solution obtained in step b into the inner liner of the autoclave, and tighten and seal the autoclave;

[0073] d. placing the high-pressure reactor in a constant temperature box, raising the temperature to 100-300° C., maintaining the temperature for 5-8 days, and then cooling the temperature down to room temperature at a rate of 5-20° C. / day, thereby obtaining the PbPO3F nonlinear optical frequency doubling crystal;

[0074] When the room temperature solution volatilization method is used to grow crystals, the following steps are included:

[0075] a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound in a molar ratio of Pb:P:F=1-2:1-3:1-2, mix them evenly, and dissolve them in a solution to obtain a mixed solution. Place the mixed solution in a clean glass container, seal it with weighing paper, and place it in a static environment without shaking, pollution, or air convection. Punch a number of small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and let it stand at room temperature for 5-20 days. The Pb-containing compound is Pb(NO3)2, PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2;

[0076] b. Waiting for the solution in step a to grow crystal particles at the bottom of the container until the size of the crystal particles no longer changes significantly, thereby obtaining seed crystals;

[0077] c. Select the one with better quality in step b (transparent area larger than 1*1cm 2 , with a thickness greater than 0.5 cm), suspending the seed crystal in the mixed solution obtained in step b, and letting it stand and grow at room temperature for 10-30 days to obtain the PbPO3F nonlinear optical frequency doubling crystal,

[0078] The present invention also provides the use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal in preparing the 1064nm fundamental frequency light output by the Nd:YAG laser for double-frequency and triple-frequency harmonic light output.

[0079] The present invention also provides the use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal in preparing a short-wavelength frequency doubling light output of 266nm.

[0080] The present invention also provides the use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal in preparing a frequency doubling generator, an up or down frequency converter or an optical parametric oscillator.

[0081] In the preparation method of the fluorinated lead phosphate nonlinear optical frequency doubling crystal of the embodiment of the present invention, the container used in the preparation process is a platinum crucible, an iridium crucible, a ceramic crucible, a quartz tube, a conical flask, a beaker, and a hydrothermal kettle lined with a polytetrafluoroethylene liner or a stainless steel liner equipped with a platinum sleeve. When the container is a quartz tube, it needs to be evacuated before sealing to avoid the volatilization of the raw materials during the reaction and the explosion of the quartz tube. When the container is a conical flask or a beaker, the container must be cleaned with acid first, then rinsed with deionized water, and dried.

[0082] The technical solution of the present invention is further illustrated by the following embodiments.

[0083] Example 1

[0084] According to the reaction formula: Pb(NO3)2+(NH4)2PO3F→PbPO3F+2NH4NO3, the compound PbPO3F is synthesized by solid phase reaction method:

[0085] Pb(NO3)2 and (NH4)2PO3F were mixed uniformly in a molar ratio of 1:1, loaded into a platinum crucible, placed in a muffle furnace, heated to 450°C under vacuum conditions, and kept at this temperature for 48 hours to obtain a polycrystalline powder of the compound PbPO3F.

[0086] The powder XRD spectrum of the compound PbPO3F in Example 1 of the present invention is shown in Figure 1 .

[0087] Example 2

[0088] According to the reaction formula: PbO+PbF2+2H3PO4→2PbPO3F+3H2O, the compound PbPO3F is synthesized by solid phase reaction method:

[0089] PbO, H3PO4 and PbF2 were mixed evenly in a molar ratio of 1:2:1, loaded into a platinum crucible, placed in a muffle furnace, heated to 300°C in an inert atmosphere, and kept at this temperature for 120 hours to obtain a polycrystalline powder of the compound PbPO3F.

[0090] Example 3

[0091] According to the reaction formula: PbO+PbF2+P2O5→2PbPO3F, the compound PbPO3F is synthesized by solid phase reaction method:

[0092] PbO, PbF2 and P2O5 were mixed uniformly in a molar ratio of 1:1, loaded into a platinum crucible, placed in a muffle furnace, heated to 600°C in an inert atmosphere, and kept at this temperature for 24 hours to obtain a polycrystalline powder of the compound PbPO3F.

[0093] Example 4

[0094] According to the reaction formula: Pb(NO3)2+(NH4)2PO3F→PbPO3F+2NH4NO3, the compound PbPO3F is synthesized by solution method:

[0095] Pb(NO3)2 and (NH4)2PO3F are uniformly mixed in a molar ratio of 1:1, and deionized water is added to prepare a saturated solution. The solution is placed in a dry, ventilated and light-proof place to evaporate the solvent for 48 hours, and then the filtrate is filtered to obtain a polycrystalline powder of the compound PbPO3F.

[0096] Example 5

[0097] According to the reaction formula: PbO+PbF2+2H3PO4→2PbPO3F+3H2O, the compound PbPO3F is synthesized by solution method:

[0098] PbO, H3PO4 and PbF2 were mixed evenly in a molar ratio of 1:2:1, and deionized water with a volume twice that of phosphoric acid was added. The mixture was placed in a dry, ventilated and dark place to evaporate the solvent for 120 hours, and then the filtrate was filtered to obtain a polycrystalline powder of the compound PbPO3F.

[0099] Example 6

[0100] PbPO3F nonlinear optical frequency doubling crystals were grown using the melt method:

[0101] a. The compound PbPO3F polycrystalline powder prepared in Example 1 was placed in a platinum crucible, placed in a muffle furnace, heated to 600° C. under vacuum conditions, and maintained at this temperature for 80 hours to obtain a mixed melt;

[0102] b. The mixed melt was slowly cooled to 300°C at a rate of 0.1°C / h, and then rapidly cooled to room temperature at a rate of 5°C / h to obtain PbPO3F seed crystals;

[0103] c. Grow crystals in the mixed melt by the pulling method: Fix the obtained PbPO3F seed crystal on the seed crystal rod, place the PbPO3F seed crystal from the top of the mixed melt, apply 2 rpm crystal rotation through the crystal growth controller, pull the seed crystal at a speed of 1 mm / day, cool it at a rate of 0.1°C / h, and after the crystal growth stops, a PbPO3F nonlinear optical frequency doubling crystal with a size of 18 mm×15 mm×10 mm is obtained.

[0104] The unit cell structure diagram of the PbPO3F nonlinear optical frequency doubling crystal in the embodiment of the present invention is shown in Figure 2 , we can know that the chemical formula of the crystal is PbPO3F, the molecular weight is 305.16, it belongs to the monoclinic system, the space group is Cc, and the unit cell parameters are α=90°,β=126.0920(10)°,γ=90°,the unit cell volume is

[0105] Example 7

[0106] PbPO3F nonlinear optical frequency doubling crystals were grown using the melt method:

[0107] a. The compound PbPO3F polycrystalline powder prepared in Example 5 was placed in a platinum crucible, placed in a muffle furnace, heated to 600° C. in an inert atmosphere, and kept at this temperature for 10 hours to obtain a mixed melt;

[0108] b. Slowly cooling the obtained mixed melt to 300° C. at a rate of 1° C. / h, and then rapidly cooling to room temperature at a rate of 8° C. / h to obtain PbPO3F seed crystals;

[0109] c. Grow crystals from the mixed melt by the Czochralski method: Fix the obtained PbPO3F seed crystal on the seed crystal rod, place the PbPO3F seed crystal from the top of the mixed melt, apply a crystal rotation of 10 rpm through the crystal growth controller, pull the seed crystal at a speed of 5 mm / day, cool it at a rate of 5°C / h, and after the crystal growth stops, a PbPO3F nonlinear optical frequency doubling crystal with a size of 15 mm×10 mm×10 mm is obtained.

[0110] Example 8

[0111] PbPO3F nonlinear optical frequency doubling crystals were grown using the melt method:

[0112] a. The compound PbPO3F polycrystalline powder prepared in Example 4 was placed in a platinum crucible, placed in a muffle furnace under an inert atmosphere, heated to 600° C., and maintained at this temperature for 50 hours to obtain a mixed melt;

[0113] b. The obtained mixed melt was slowly cooled to 300° C. at a rate of 1° C. / h, and then rapidly cooled to room temperature at a rate of 8° C. / h to obtain PbPO3F seed crystals;

[0114] c. Grow crystals in the mixed melt using the kyberysis method: Fix the obtained PbPO3F seed crystal on the seed crystal rod, lower the PbPO3F seed crystal from the top of the mixed melt, cool it down at a rate of 0.1℃ / h, let the crystal grow for 5 hours, slowly lift the crystal but do not leave the liquid surface, continue to grow, and repeat this process. After the crystal growth stops, a PbPO3F nonlinear optical frequency doubling crystal with a size of 20mm×15mm×12mm is obtained.

[0115] Example 9

[0116] PbPO3F nonlinear optical frequency doubling crystals were grown using the melt method:

[0117] a. The polycrystalline powder of the compound PbPO3F prepared in Example 6 was placed in a platinum crucible, placed in a muffle furnace under vacuum conditions, heated to 800° C., and kept at this temperature for 100 hours to obtain a mixed melt;

[0118] b. The obtained mixed melt was slowly cooled to 300°C at a rate of 2°C / h, and then rapidly cooled to room temperature at a rate of 10°C / h to obtain PbPO3F seed crystals;

[0119] c. Grow crystals in the mixed melt by the crucible lowering method: Place the obtained PbPO3F seed crystal at the bottom of a platinum crucible, then place the compound PbPO3F polycrystalline powder prepared in Example 6 into the platinum crucible, and then seal the platinum crucible, raise the growth furnace temperature to 750°C, keep the temperature constant for 10 hours, adjust the position of the platinum crucible to make the seed crystal slightly melted, then lower the crucible at a rate of 1 mm / day, and cool it to 350°C at a cooling rate of 3°C / h. After the growth is completed, quickly cool it to room temperature at a rate of 10°C / h to obtain a PbPO3F nonlinear optical frequency doubling crystal with a size of 20 mm×16 mm×13 mm.

[0120] Example 10

[0121] Growing PbPO3F nonlinear optical frequency doubling crystal using vacuum packaging method:

[0122] The compound PbPO3F polycrystalline powder prepared in Example 2 and the auxiliary solvent PbF2 were placed in a quartz tube of Φ40 mm in a molar ratio of 1:3, and the quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature, placed in a muffle furnace, heated to 650 ° C, kept constant for 5 hours, then cooled to 350 ° C at a rate of 0.1 ° C / h, and then quickly cooled to room temperature at a rate of 8 ° C / h, to obtain a PbPO3F nonlinear optical frequency doubling crystal with a size of 4mm × 4mm × 2mm.

[0123] Embodiment 11

[0124] Hydrothermal growth of lead fluorinated phosphate nonlinear optical frequency doubling crystals:

[0125] a. The compound PbPO3F polycrystalline powder prepared in Example 3 was dissolved in deionized water, and the incompletely dissolved mixture was subjected to ultrasonic treatment at a temperature of 60° C. to allow it to be fully mixed and dissolved; the pH value was adjusted to 3 with HF and NH3·H2O to obtain a mixed solution;

[0126] b. Transfer the obtained mixed solution into the liner of a clean, pollution-free autoclave with a volume of 100 mL, and tighten and seal the autoclave;

[0127] c. Place the autoclave in a constant temperature box, raise the temperature to 150°C, keep the temperature constant for 8 days, and then cool it down to room temperature at a rate of 5°C / day to obtain a PbPO3F nonlinear optical frequency doubling crystal with a size of 5mm×3mm×2mm.

[0128] Example 12

[0129] Growing lead fluorinated phosphate nonlinear optical frequency doubling crystals using room temperature solution method:

[0130] a. Put the PbPO3F polycrystalline powder obtained in Example 1 into a clean glass container, add 20 mL of deionized water, and then perform ultrasonic treatment to fully mix and dissolve it. Adjust the pH value of the solution to 3 with HF and NH3·H2O, and filter with filter paper to obtain a mixed solution.

[0131] b. Place the obtained mixed solution in a clean conical flask, seal it with weighing paper, place it in a static environment without shaking, pollution, or air convection, pierce several small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and leave it at room temperature for 5 days;

[0132] c. Wait for the solution to grow crystal particles at the bottom of the container until the size of the crystal particles no longer changes significantly, thereby obtaining seed crystals;

[0133] d. Select a seed crystal with good quality, suspend it in the mixed solution prepared in step a, and let it stand and grow at room temperature for 30 days to obtain a PbPO3F nonlinear optical frequency doubling crystal with a size of 10 mm×8 mm×6 mm.

[0134] Example 13

[0135] The same as Example 12, except that the growth time in step d is 10 days, and a PbPO3F nonlinear optical frequency doubling crystal with a size of 15 mm×10 mm×10 mm is obtained.

[0136] Embodiment 14

[0137] Hydrothermal growth of lead fluorinated phosphate nonlinear optical frequency doubling crystals:

[0138] a. The polycrystalline powder of the compound PbPO3F prepared in Example 4 was dissolved in deionized water, and the incompletely dissolved mixture was subjected to ultrasonic treatment at a temperature of 60° C. to allow it to be fully mixed and dissolved; the pH value was adjusted to 6 with HF and NH3·H2O to obtain a mixed solution;

[0139] b. Transfer the obtained mixed solution into the liner of a clean, pollution-free autoclave with a volume of 100 mL, and tighten and seal the autoclave;

[0140] c. Place the autoclave in a constant temperature box, raise the temperature to 300°C, keep the temperature constant for 5 days, and then cool it down to room temperature at a rate of 20°C / day to obtain a PbPO3F nonlinear optical frequency doubling crystal with a size of 18mm×15mm×12mm.

[0141] Embodiment 15

[0142] Growing PbPO3F nonlinear optical frequency doubling crystal using vacuum packaging method:

[0143] The compound PbPO3F polycrystalline powder prepared in Example 2 and the co-solvent H3PO4 were placed in a quartz tube of Φ40 mm in a molar ratio of 1:6, and the quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature, placed in a muffle furnace, heated to 800 ° C, kept at a constant temperature for 40 hours, then cooled to 350 ° C at a rate of 3 ° C / h, and then quickly cooled to room temperature at a rate of 5 ° C / h, to obtain a PbPO3F nonlinear optical frequency doubling crystal with a size of 10mm × 10mm × 5mm.

[0144] Example 16

[0145] Growing PbPO3F nonlinear optical frequency doubling crystal using vacuum packaging method:

[0146] The compound PbPO3F polycrystalline powder prepared in Example 3 and the auxiliary solvent P2O5 were placed in a quartz tube of Φ40 mm in a molar ratio of 1:0.1, and the quartz tube was evacuated to a vacuum degree of 1×10 -3 Pa, sealed at high temperature, placed in a muffle furnace, heated to 500 ° C, kept at a constant temperature for 120 hours, then cooled to 350 ° C at a rate of 0.1 ° C / h, and then quickly cooled to room temperature at a rate of 10 ° C / h, to obtain a PbPO3F nonlinear optical frequency doubling crystal with a size of 10mm × 10mm × 8mm.

[0147] Embodiment 17

[0148] PbPO3F nonlinear optical frequency doubling crystals were grown using the melt method:

[0149] a. The PbPO3F polycrystalline powder prepared in Example 6 was placed in a platinum crucible, placed in a muffle furnace under an inert atmosphere, heated to 500° C., and kept at this temperature for 10 hours to obtain a mixed melt;

[0150] b. The obtained mixed melt was slowly cooled to 300°C at a rate of 0.1°C / h, and then rapidly cooled to room temperature at a rate of 5°C / h to obtain PbPO3F seed crystals;

[0151] c. Grow crystals in the mixed melt by the crucible descent method: Place the obtained PbPO3F seed crystal at the bottom of a platinum crucible, then place the compound PbPO3F polycrystalline powder prepared in Example 6 into the platinum crucible, and then seal the platinum crucible, raise the growth furnace temperature to 550°C, keep the temperature constant for 120 hours, adjust the position of the platinum crucible to make the seed crystal slightly melted, and then lower the crucible at a rate of 10 mm / day to keep the temperature constant. After the growth is completed, quickly lower it to room temperature at a rate of 5°C / h to obtain a PbPO3F nonlinear optical frequency doubling crystal with a size of 10 mm×10 mm×5 mm.

[0152] Embodiment 18

[0153] PbPO3F nonlinear optical frequency doubling crystals were grown using the melt method:

[0154] a. The compound PbPO3F polycrystalline powder prepared in Example 4 was placed in a platinum crucible, placed in a muffle furnace under an inert atmosphere, heated to 800° C., and kept at this temperature for 100 hours to obtain a mixed melt;

[0155] b. The obtained mixed melt was slowly cooled to 300° C. at a rate of 1° C. / h, and then rapidly cooled to room temperature at a rate of 6° C. / h to obtain PbPO3F seed crystals;

[0156] c. Grow crystals in the mixed melt using the kyberysis method: Fix the obtained PbPO3F seed crystal on the seed crystal rod, lower the PbPO3F seed crystal from the top of the mixed melt, cool it down at a rate of 10℃ / h, let the crystal grow for 5 hours, slowly lift the crystal but do not leave the liquid surface, continue to grow, and repeat this process. After the crystal growth stops, a PbPO3F nonlinear optical frequency doubling crystal with a size of 15mm×12mm×10mm is obtained.

[0157] Test Example 1

[0158] Figure 3 The working principle diagram of the nonlinear optical device made by using the PbPO3F nonlinear optical frequency doubling crystal of the present invention (taking the PbPO3F nonlinear optical frequency doubling crystal prepared in Example 7 as an example), wherein 1 is a laser, 2 is an emitted light beam, 3 is a PbPO3F nonlinear optical frequency doubling crystal, 4 is an output light beam, and 5 is a filter. The PbPO3F nonlinear optical frequency doubling crystal obtained in Example 7 is processed in a matching direction, and the PbPO3F nonlinear optical frequency doubling crystal ... Figure 3 As shown, it is placed at the position of the PbPO3F nonlinear optical frequency doubling crystal 3. At room temperature, a Q-switched Nd:YAG laser is used as the light source. The incident wavelength is 1064nm. The infrared light beam 2 with a wavelength of 1064nm emitted by the Q-switched Nd:YAG laser 1 is incident on the PbPO3F nonlinear optical frequency doubling crystal 3 to generate a green frequency doubling light 4 with a wavelength of 532nm. The output intensity after the filter 5 is about 1.8 times that of KH2PO4 (KDP) under the same conditions. The ultraviolet cutoff edge is lower than 240nm, which can be used as a short-wavelength nonlinear optical frequency doubling in all-solid-state lasers.

[0159] Test Example 2

[0160] Same test process as test example 1 ( Figure 3 ), a KDP filter is added at the outlet of the Q-Nd:YAG laser, and the incident wavelength is a green laser of 532nm. The incident light enters the PbPO3F nonlinear optical frequency doubling crystal 3 to generate a frequency doubling light 4 with a wavelength of 266nm. The output intensity after passing through the filter 5 is about 0.5 times that of BaB2O4 under the same conditions, and can be used as a short-wavelength, ultraviolet nonlinear optical frequency doubling in all-solid-state lasers.

[0161] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A lead fluorinated phosphate nonlinear optical frequency doubling crystal, characterized in that: The chemical formula of the crystal is PbPO3F, the molecular weight is 305.16, it belongs to the monoclinic system, the space group is Cc, and the unit cell parameters are α=90°,β=126.0920(10)°,γ=90°,the unit cell volume is 2. A method for preparing the lead fluorinated phosphate nonlinear optical frequency doubling crystal according to claim 1, characterized in that: Growing crystals by melt method, vacuum encapsulation method, hydrothermal method or room temperature solution evaporation method; When the melt method is used to grow crystals, the following steps are included: a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mix them evenly, raise the temperature to 300-600°C under vacuum or inert atmosphere, and keep the temperature constant for 24-120 hours to obtain PbPO3F polycrystalline powder; b. The PbPO3F polycrystalline powder obtained in step a is heated to 500-900° C. under vacuum or inert atmosphere and kept at this temperature for 10-120 hours to obtain a mixed melt; c. Cooling the mixed melt obtained in step b to 300° C. at a rate of 0.1-2° C. / h, and then cooling to room temperature at a rate of 5-10° C. / h to obtain PbPO3F seed crystals; d. Growing crystals in the mixed melt by the Czochralski method: fixing the PbPO3F seed crystal obtained in step c on a seed crystal rod, placing the PbPO3F seed crystal from the top of the mixed melt obtained in step b, applying a crystal rotation of 2-20 rpm through a crystal growth controller, pulling the seed crystal at a speed of 1-10 mm / day, and cooling at a rate of 0.1-10°C / h. After the crystal growth stops, the lead fluorinated phosphate nonlinear optical frequency doubling crystal is obtained; Or the crystal is grown in the mixed melt by the pyrolysis method: the PbPO3F seed crystal obtained in step c is fixed on the seed crystal rod, the PbPO3F seed crystal is placed from the top of the mixed melt obtained in step b, the temperature is lowered at a rate of 0.1-10°C / h, the crystal is grown for 5-15 hours, the crystal is lifted but does not leave the liquid surface to continue growing, and this is repeated until the crystal growth stops, and the lead fluorinated phosphate nonlinear optical frequency doubling crystal is obtained; Or a crystal is grown in a mixed melt by a crucible lowering method: the PbPO3F seed crystal obtained in step c is placed at the bottom of the crucible, and the PbPO3F polycrystal prepared in step a is placed in the crucible, and then the crucible is sealed, the temperature of the growth furnace is raised to 550-750°C, and the temperature is kept constant for 10-120 hours, the position of the crucible is adjusted to make the PbPO3F seed crystal slightly melted, and then the crucible is lowered at a rate of 1-10 mm / day, and at the same time, the growth temperature is kept unchanged, or the temperature is lowered to 350°C at a cooling rate of 3°C / h, and after the growth is completed, the temperature is quickly lowered to room temperature at a rate of 5-10°C / h, so as to obtain the lead fluorinated phosphate nonlinear optical frequency doubling crystal; When the vacuum packaging method is used to grow crystals, the following steps are included: a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mix them evenly, raise the temperature to 400-600°C under vacuum or inert atmosphere, and keep the temperature constant for 24-120 hours to obtain PbPO3F polycrystalline powder; b. The PbPO3F polycrystalline powder obtained in step a is mixed evenly with a co-solvent at a molar ratio of 0-1:0.1-6, and the mixture is placed in a quartz tube, sealed and placed in a muffle furnace, heated to 500-800°C, kept at a constant temperature for 5-120 hours, then cooled to 350°C at a rate of 0.1-3°C / h, and then cooled to room temperature at a rate of 5-10°C / h, to obtain the lead fluorinated phosphate nonlinear optical frequency doubling crystal; When the hydrothermal method is used to grow crystals, the following steps are included: a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound at a molar ratio of Pb:P:F=1:1:1, mix them evenly, raise the temperature to 400-600°C under vacuum or inert atmosphere, and keep the temperature constant for 24-120 hours to obtain PbPO3F polycrystalline powder; b. The PbPO3F polycrystalline powder obtained in step a is dissolved in deionized water, and the incompletely dissolved mixture is subjected to ultrasonic treatment at a temperature of 60° C. to allow the mixture to be fully mixed and dissolved, and the pH value is adjusted to 2-6 with HF and NH3·H2O to obtain a mixed solution; c. Transfer the mixed solution obtained in step b into the inner lining of a high-pressure reactor, and tighten and seal the reactor; d. placing the high-pressure reactor in a constant temperature box, raising the temperature to 100-300° C., maintaining the temperature for 5-8 days, and then cooling the temperature down to room temperature at a rate of 5-20° C. / day, thereby obtaining the lead fluorinated phosphate nonlinear optical frequency doubling crystal; When the room temperature solution volatilization method is used to grow crystals, the following steps are included: a. Weigh a Pb-containing compound, a P-containing compound and a F-containing compound in a molar ratio of Pb:P:F=1-2:1-3:1-2, mix them evenly, and dissolve them in a solution to obtain a mixed solution. Place the mixed solution in a glass container, seal it with weighing paper, place it in a static environment, pierce a plurality of small holes in the seal to adjust the evaporation rate of water in the aqueous solution, and leave it at room temperature for 5-20 days; b. Waiting for the solution in step a to grow crystal particles at the bottom of the container until the size of the crystal particles no longer changes significantly, thereby obtaining seed crystals; c. Select the seed crystal with better quality in step b, suspend it in the mixed solution prepared in step b, and let it stand and grow at room temperature for 10-30 days to obtain the lead fluorinated phosphate nonlinear optical frequency doubling crystal.

3. The method for preparing the lead fluorinated phosphate nonlinear optical frequency doubling crystal according to claim 2, characterized in that: When the crystal is grown by the melt method, the Pb-containing compound in step a is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2; When the vacuum packaging method is used to grow the crystal, the Pb-containing compound in step a is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2; the cosolvent in step b is PbF2, H3PO4 or P2O5; When the crystal is grown by hydrothermal method, the Pb-containing compound in step a is PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2; When the room temperature solution volatilization method is used to grow crystals, the Pb-containing compound in step a is Pb(NO3)2, PbO, PbF2 or Pb(NO3)2, the P-containing compound is H3PO4, P2O5 or (NH4)2PO3F, and the F-containing compound is PbF2; the static environment in step a refers to an environment without shaking, pollution, and air convection.

4. Use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal according to claim 1 in preparing the 1064nm fundamental frequency light output by Nd:YAG laser for double-frequency and triple-frequency harmonic light output.

5. Use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal according to claim 1 in preparing a short-wavelength frequency doubling light output of 266 nm.

6. Use of the lead fluorinated phosphate nonlinear optical frequency doubling crystal according to claim 1 in preparing a frequency doubling generator, an up or down frequency converter or an optical parametric oscillator.

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