A trivalent luminescent ion doped rare earth fluoride laser crystal regulated by a divalent alkaline earth ion and preparation and application thereof

Abstract

The application relates to a trivalent luminescent ion doped rare earth fluoride laser crystal regulated by divalent alkaline earth ions and preparation and application thereof. The laser crystal is expressed as xR, yMe: MF3, 0.001 <= x <= 0.3, 0.01 <= y <= 0.2; R, Me and M all represent metal elements, R is at least any one of Nd, Pr, Er, Tm, Ho, Dy or Eu, Me is at least any one of Mg, Ca, Sr or Ba, and M is at least any one of Y, Lu, Sc, Gd or La. The laser crystal is grown by a temperature gradient method, and the steps are as follows: RF3, MeF2 and MF3 raw materials are weighed, mixed, loaded into a crucible and grinded; the laser crystal is obtained by slow cooling growth in a vacuum atmosphere. The laser crystal can accelerate the application process of visible light new band continuous and ultrafast lasers, the application shows very wide fluorescent bands in the visible orange red and deep red light bands and new emission wavelengths, the problem of narrow fluorescent bands of current praseodymium ion doped laser crystals can be solved, and the development of visible light new bands is promoted.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of laser materials, in particular to a rare earth fluoride laser crystal doped with trivalent luminescent ions regulated by divalent alkaline earth ions and preparation and application thereof. BACKGROUND

[0002] Visible light band lasers have great application needs in the fields of display, communication, sodium beacon, biomedicine, atomic optical clock, high-end manufacturing, etc. The emergence of high-efficiency blue pump sources (such as InGaN laser diodes and frequency-doubled optical pump semiconductor lasers (2ω-OPSL)) greatly promotes the development of visible light band laser output of rare earth ion doped media. At present, visible light rare earth ions mainly concentrate on Pr 3+ , Dy 3+ , Tb 3+ and Sm 3+ , etc. Among them, the absorption cross section of Pr 3+ ion at 445 nm, 468 nm and 486 nm reaches 10 -19 cm 2 order of magnitude, 3 the fluorescence lifetime of the upper level P0 is about tens of microseconds, and the absorption peaks at 445 nm and 468 nm are very consistent with the emission wavelengths of InGaN laser diode pump sources and 2ω-OPSL pump sources respectively. Compared with other rare earth ions, Pr 3+ has a large number of radiation transitions, and the light emission range almost covers the red, orange, green and blue light of the visible light band. The Pr:LiYF4 full solid-state continuous laser output is nearly 10W, and the highest laser output slope efficiency is as high as 60%, and the Pr:LiYF4 at 639 nm waveband is the first to obtain practical application. Therefore, Pr 3+ doped laser material is the most potential visible light band laser material at present.

[0003] The inventor's previous patents have provided some related visible band laser materials, for example:

[0004] Patent CN115102022A relates to a praseodymium ion doped fluorine aluminum calcium lithium type visible band ultrafast laser crystal and a growth method and application thereof. The chemical formula of the ultrafast laser crystal is Pr x LiM 1-xNF6, wherein x ranges from 0.003 to 0.03, M is at least one of Mg, Ca, Sr or Ba or a combination of two, and N is at least one of Al, Sc or Ga. The Pr ion-doped fluorocalcium-lithium type visible band ultrafast laser crystal is grown by a crucible lowering method, including the following steps: weighing PrF3, LiF, MF and NF raw materials in stoichiometric ratio, mixing uniformly, and then loading into a crucible; placing the crucible in an inert atmosphere, heating and melting, removing impurities, and then lowering to grow, after the growth is completed, lowering to room temperature, to obtain a Pr ion-doped fluorocalcium-lithium type visible band ultrafast laser crystal; the ultrafast laser crystal is applied to accelerate visible band all-solid-state femtosecond ultrafast laser; the application exhibits a very wide fluorescence band in the visible orange-red and deep red light band, which can solve the problem of narrow fluorescence band of Pr ion-doped laser crystal. Patent CN116145254A provides a rare earth ion-doped disordered high-entropy fluoride ultrafast laser crystal and a preparation method and application thereof. The disordered high-entropy laser crystal is represented by Pr:CaSrBaF6, Pr:M1M2CaSrBaF 12 , wherein the doping range of praseodymium (Pr) ions is 0.003-0.05 (M1, M2 are one of Y, La, Lu, Gd, Sc and other trivalent non-luminescent ions). The doped rare earth luminescent ions are not limited to Pr ions, but also include other luminescent ions such as Yb, Nd, Er, Ho, Tm, Dy, Tb, etc. The crystal is represented by Pr:CaSrBaF6, Pr:M1M2CaSrBaF 12 , compared with other fluorides, has a more disordered local structure, can realize 3 H6 and 3 F2, 3 F3 and 3 F4 are close to the lower energy level merging and overlapping, achieving the effect of overlapping and non-uniform broadening of fluorescence spectrum; the crystal material of the application can realize ultra-wide band emission of Pr ion-doped laser crystal in the visible band, solve the problem of narrow fluorescence band of Pr ion-doped laser crystal, and accelerate the research and development of all-solid-state femtosecond ultrafast laser in the visible band and its application in biological medicine and optical communication.

[0005] At present, ultrafast pulse laser has the characteristics of ultra-short response time and high peak power, and it is obvious that the next step of development is visible light band laser, but the current Pr 3+ The fluorescence spectrum of each visible light channel of the laser crystal is generally narrow (half peak width FWHM is about 0.7-3 nm), so it is difficult to realize LD pumped all-solid-state femtosecond ultrafast laser, and this bottleneck problem also seriously restricts the commercialization process of visible light band femtosecond laser. SUMMARY

[0006] The present application aims to overcome the defects of the prior art and provide a trivalent luminescent ion doped rare earth fluoride laser crystal regulated by divalent alkaline earth ions and preparation and application thereof.

[0007] The rare earth fluoride laser crystal material doped with praseodymium ions and regulated by divalent alkaline earth ions provided by the present application exhibits a very wide fluorescence band in the visible orange red and deep red light bands under the excitation of a blue light diode, and can solve the problem of narrow fluorescence band of the praseodymium ion doped laser crystal, and can accelerate the research and application process of visible band full solid state femtosecond ultrafast laser.

[0008] The rare earth fluoride can be grown in a large size, has a weak lattice field and low phonon energy, and is also suitable as a Pr 3+ ion doped substrate material. 3+ The LaF3 crystal has a melting point of 1493 DEG C, is hexagonal, and has a space group of P63 / mcm. - The LaF3 crystal has a melting point of 1493 DEG C, is hexagonal, and has a space group of P63 / mcm. 3+ The LaF3 crystal has a melting point of 1493 DEG C, is hexagonal, and has a space group of P63 / mcm. 3+ The LaF3 crystal has a melting point of 1493 DEG C, is hexagonal, and has a space group of P63 / mcm.

[0009] The present application can be achieved by the following technical solutions.

[0010] The present application can be achieved by the following technical solutions.

[0011] Further, the R is preferably Pr, the Me is preferably Sr, and the M is preferably La. More preferably, the chemical formula of the laser crystal is xPr, ySr:LaF3, wherein x is in the range of 0.001<=x<=0.3, and y is in the range of 0.01<=y<=0.2. More preferably, the chemical formula of the laser crystal is preferably 0.6%Pr, 5%Sr:LaF3.

[0012] The LaF3 crystal belongs to a tetragonal system, and in addition to having a lower phonon energy and a higher 5d energy level position, can greatly reduce the non-radiative transition probability caused by multi-phonon relaxation and the absorption of the upper energy level excited state of the laser caused by the low 5d energy level position. The inventors have noticed that Pr 3+ two groups of lower energy levels of ions 3 H6 and 3 F2, 3 F3 and 3 F4 energy level positions are very close, such as in a LiYF4 substrate, 3 H6 and 3 F2 and 3 F3 and 3 F4 energy levels are 255cm -1 and 232cm -1 -1 respectively. By replacing the trivalent La 2+ ion with an aliovalent alkaline earth ion Me 3+ (Me=Mg, Ca, Sr, Ba), with the incorporation of the Sr 2+ ion, the lower the local symmetry, the more serious the lattice distortion, the greater the energy level splitting, the enhanced local disorder, and the truly formed La 3+ / Sr 2+ -Pr 3+ disordered mixed compound fluoride, so as to realize 3 H6 and 3 F2, 3 F3 and 3 F4 similar lower energy level merging and overlapping, and achieve the effect of overlapping and non-uniform broadening of the fluorescence spectrum. Thus, the key scientific problem of the narrow (half peak width FWHM 0.7-3nm) fluorescence spectrum of the existing Pr 3+ doped crystal is solved, and in combination with the research of the visible light band femtosecond laser technology, it is expected to realize the full solid-state femtosecond ultrafast laser output.

[0013] The second technical scheme of the present application provides a preparation method of a rare earth fluoride laser crystal doped with a trivalent luminescent ion regulated by a divalent alkaline earth ion, and the crystal is grown by using a temperature gradient method, including the following steps:

[0014] (1) Material preparation: weigh the raw materials of RF3, MeF2 and MF3 according to the stoichiometric ratio, mix uniformly, then load into a crucible, and grind;

[0015] (2) Crystal growth: Put the crucible in high vacuum atmosphere, heat the material, remove impurities, then start the slow cooling process for crystal growth, after the growth is completed, it is cooled to room temperature, and a rare earth fluoride laser crystal doped with divalent alkali earth ions and praseodymium ions is obtained.

[0016] Further, the purity of the RF3, MeF2 and MF3 raw materials in step (1) is 5N purity, and the state is single crystal particles or powder; the grinding time is 40-60 min.

[0017] Further, the vacuum atmosphere in step (2) is rough vacuum and fine vacuum by mechanical pump and molecular pump, and the vacuum degree is kept below 8 Pa during the whole crystal growth process.

[0018] Further, the heating of the material in step (2) generally refers to fully melting the solid material by increasing the temperature, so as to convert the raw material into the desired molten state. The impurity removal refers to the process of removing impurities in the raw material or generated during the chemical reaction; the impurities are other trace components other than the desired components in the raw material, including water vapor, inclusions, bubbles, etc.

[0019] Further, the heating rate in step (2) is 200-300℃ / h, and the temperature is increased to 1500℃, and the temperature is kept constant at 1500℃ for 5-8h after the temperature is increased to 1500℃.

[0020] Further, the slow cooling process in step (2) is to decrease from 1500℃ to 1350℃ at a rate of 1.5℃ / h.

[0021] Further, after the growth is completed (slow cooling process) in step (2), the temperature is decreased from 1350℃ to room temperature at a rate of 30-50℃ / h.

[0022] In some specific embodiments of the present application, the RF3 is selected from PrF3, the MeF2 is selected from SrF2, and the MF3 is selected from LaF3, and the specific embodiments include the following steps:

[0023] (1) The PrF3, SrF2 and LaF3 raw materials are weighed according to the stoichiometric ratio, mixed uniformly, and then loaded into a crucible;

[0024] (2) Put the crucible in high vacuum atmosphere, heat the material, remove impurities, then decrease to grow, after the growth is completed, it is cooled to room temperature, and a lanthanum fluoride visible band ultrafast laser crystal co-doped with trivalent praseodymium ions and divalent strontium ions is obtained.

[0025] The third technical solution of the present application provides an application of the praseodymium ion doped rare earth fluoride laser crystal regulated by the divalent alkaline earth ions as described above, which is used as a laser gain medium of a full solid-state visible light ultrafast laser to accelerate the full solid-state femtosecond ultrafast laser in a visible waveband.

[0026] Compared with the prior art, the present application has at least the following improvements and beneficial effects:

[0027] (1) In some specific embodiments provided by the present application, the LaF3 crystal is selected to belong to the tetragonal system, which has lower phonon energy and higher 5d energy level position, can greatly reduce the non-radiative transition probability caused by multi-phonon relaxation, and can reduce the laser upper energy level excitation state absorption caused by the low 5d energy level position. In addition, the heterovalent alkaline earth ion Sr 2+ is replaced to obtain an xPr,yMe:LaF3 (Me=Mg, Ca, Sr, Ba, etc., 0.001≤x≤0.3, 0.01≤y≤0.2) crystal. With the incorporation of the Sr 2+ ion, the local symmetry is lower, the lattice distortion is more serious, the energy level splitting is larger, the local disorder is enhanced, and the La 3+ / Sr 2+ -Pr 3+ mixed compound fluoride with disordered distribution is formed, so that 3 H6 and 3 F2, 3 F3 and 3 F4 lower energy levels are merged and overlapped, the effect of overlapping and non-uniform broadening of the fluorescence spectrum is achieved, and the key scientific problem of narrow fluorescence spectrum (half peak width FWHM 0.7-3nm) of the existing Pr 3+ doped crystal is solved. Combined with the research on femtosecond laser technology in the visible waveband, the full solid-state femtosecond ultrafast laser output is expected to be realized;

[0028] (2) In some specific embodiments provided by the present application, the xPr,yMe:LaF3 (Me=Mg, Ca, Sr, Ba, etc., 0.001≤x≤0.3, 0.01≤y≤0.2) crystal can realize a wider fluorescence band in the visible waveband than the existing xPr:LaF3 (0.001≤x≤0.3) and is more expected to realize the laser material of the full solid-state femtosecond laser output.

[0029] (3) The crystal material of the present application can accelerate the research and application process of the visible waveband full solid-state femtosecond ultrafast laser, and can be applied to the fields of laser display, optical communication, deep water detection and biological medical treatment, etc. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 0.6% Pr, 5% Sr:LaF3 prepared for Examples 1 and 23； 0.6%Pr, 8%Sr:LaF3 sample under 444 nm light excitation; wherein (A) represents: the full fluorescence spectrum of the crystal in the visible light band, (B) represents: the local fluorescence spectrum of the crystal in the red-orange light band;

[0031] Figure 2 0.6%Pr, 8%Sr:LaF3 sample under 444 nm light excitation; wherein (A) represents: the full fluorescence spectrum of the crystal in the visible light band, (B) represents: the local fluorescence spectrum of the crystal in the red-orange light band; 3； 0.6%Pr, 8%Sr:LaF3 sample under 444 nm light excitation; wherein (A) represents: the full fluorescence spectrum of the crystal in the visible light band, (B) represents: the local fluorescence spectrum of the crystal in the red-orange light band; 3 Lifetime of P0 energy level, (B) represents: Example 1: 0.6%Pr, 5%Sr:LaF3 crystal 3 Lifetime of P0 energy level; (C) represents: Example 2: 0.6%Pr, 8%Sr:LaF3 crystal 3 Lifetime of P0 energy level. DETAILED DESCRIPTION

[0032] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be described in detail below in conjunction with specific embodiments. It should be pointed out that the following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all belong to the protection scope of the present application.

[0033] All raw materials of the present application have no special restrictions on their sources, and can be purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0034] All raw materials are purchased from Shanghai Aladdin Biochem Technology Co., Ltd.

[0035] A rare earth fluoride laser crystal doped with trivalent luminescent ions regulated by divalent cations (a rare earth fluoride laser crystal doped with praseodymium ions regulated by divalent alkaline earth ions) has a chemical formula of xR, yMe:MF3, wherein x ranges from 0.001 to 0.3, y ranges from 0.01 to 0.2, R is one of Nd, Pr, Er, Tm, Ho, Dy and Eu, Me is one of Mg, Ca, Sr and Ba, and M is one of Y, Lu, Sc, Gd or La. The rare earth fluoride laser crystal is represented by Pr, Sr:LaF3, and is grown by a temperature gradient method, which mainly includes the following steps:

[0036] (1) PrF3, SrF2 and LaF3 single crystal particles or powders with 5N purity are used as raw materials, and the required mass of each raw material is calculated according to the stoichiometric ratio and accurately weighed.

[0037] (2) The weighed raw material powder is thoroughly ground to mix uniformly, and then is loaded into a graphite crucible and covered with a lid; the grinding is performed in an agate mortar for 40-60 min; the ground raw material is placed into the graphite crucible and covered with a crucible lid to prevent the mass volatilization of the raw material and the entry of an oxygen environment.

[0038] (3) The loaded graphite crucible is placed in a hot field to perform vacuum pumping to a vacuum degree of less than 8 Pa, and is heated to ensure complete melting of the raw material and completion of impurity removal, and then is slowly cooled to perform crystal growth, after which the temperature is reduced to room temperature, and then the crystal is taken out. The vacuum pumping is performed by rough vacuum pumping through a mechanical pump and fine vacuum pumping through a molecular pump, and the entire crystal growth process is performed under high vacuum. The heating rate to ensure complete melting of the raw material and completion of impurity removal is 200-300 ℃ / h, and the temperature is raised to 1500 ℃, and after the temperature is raised to 1500 ℃, the temperature is kept constant for 5-8 h. The slow cooling process is to slowly reduce the temperature at a rate of 1.5 ℃ / h, and the temperature is reduced from 1500 ℃ to 1350 ℃, and the temperature interval of the temperature reduction is 150 ℃. After the slow cooling growth is completed, the temperature is rapidly reduced from 1350 ℃ to room temperature at a rate of 30-50 ℃ / h.

[0039] The rare earth fluoride laser crystal provided by the application can accelerate the research and application process of full solid-state visible light new waveband and femtosecond ultrafast laser. Based on the above steps, the following specific embodiments are provided:

[0040] Embodiment 1

[0041] The 0.6% Pr, 5% Sr:LaF3 crystal is grown by the temperature gradient method, and is prepared by the following method:

[0042] The 0.6% Pr, 5% Sr:LaF3 crystal is grown by the temperature gradient method, and is prepared by the following method:

[0043] The fluorescence spectrum test (the results are shown in Figure 1 and Figure 2) and spectral calculations (fitting the fluorescence full width at half maximum using Origin software), for 3 P0→ 3 H6 3 P0→ 3 F2 and 3 P0→ 3 F3+ 3 The full width at half maximum (FWHM) of the F4 transition are 18.4 nm, 8.22 nm, and 11.2 nm, respectively, which are improvements compared to the FWHM of pure Pr:LaF3 (15.3 nm, 6.86 nm, and 5.78 nm). The emission peak gradually broadens from the original double peaks and multiple sharp peaks to a smooth emission band, truly forming the LaF3 emission band. 3+ / Sr 2+ -Pr 3+ The disordered, mixed-type complex fluoride should contain praseodymium ions. 3 H6 and 3 F2 and 3 F3 and 3 The result of energy level merging and overlapping at F4 levels is a wide fluorescence band, which is very beneficial for the output of ultrafast femtosecond lasers.

[0044] Example 2

[0045] 0.6% Pr, 8% Sr:LaF3 crystals were grown using a temperature gradient method, specifically prepared by the following method:

[0046] 0.6%Pr,8%Sr:LaF3 crystals were grown using a temperature gradient method. 150g of raw material (weighed according to the stoichiometric ratio in the chemical formula) was placed in a graphite crucible, which was then covered and the furnace was evacuated to below 8 Pa. The temperature was then increased to approximately 1500℃ at a rate of 200℃ / h and held at this temperature for 8 hours until the raw material was completely melted and impurities were thoroughly removed. The temperature was then slowly decreased from 1500℃ to 1350℃ at a rate of 1.5℃ / h, during which crystal growth continued. After the slow cooling growth was complete, the temperature was rapidly reduced from 1350℃ to room temperature at a rate of 30℃ / h. The entire growth process was carried out under high vacuum, and the crystal was then removed. A 0.6%Pr,8%Sr:LaF3 crystal with good optical quality was obtained.

[0047] Fluorescence spectroscopy was performed (results are shown in...). Figure 1 and Figure 2 ) and spectral calculations (fitting the fluorescence full width at half maximum using Origin software), for 3 P0→ 3 H6 3 P0→ 3 F2 and 3 P0→ 3 F3+ 3The half-widths of F4 transitions are 16.5 nm, 8.06 nm, and 11.6 nm, respectively, which are higher than the half-widths of 15.3 nm, 6.86 nm, and 5.78 nm of pure Pr:LaF3. 3 The P0 level lifetime is 44.0 μs.

[0048] Comparative Example 1

[0049] The 0.6% Pr:LaF3 crystal (i.e., not doped with Sr) was grown by the temperature gradient method in the following manner:

[0050] The 0.6% Pr:LaF3 crystal was grown by the temperature gradient method in the following manner: 150 g of raw materials (weighed according to the stoichiometric ratio in the chemical formula) were placed in a graphite crucible, and then a crucible cover was placed on the crucible. The crucible was placed in a furnace and vacuumized to below 8 Pa. The temperature was then raised to about 1500 °C at a rate of 200 °C / h, and the temperature was kept constant for 8 h to completely melt the raw materials and sufficiently remove impurities. Then, the temperature was slowly lowered from 1500 °C to 1350 °C at a rate of 1.5 °C / h, and the crystal was grown during the slow cooling process. After the slow cooling and growth were completed, the temperature was rapidly lowered to room temperature at a rate of 30 °C / h. The entire growth process was performed under high vacuum, and then the crystal was removed. A piece of 0.6% Pr:LaF3 crystal with good optical quality was obtained.

[0051] The fluorescence spectrum (results shown in Figure 1 and Figure 2 ) and spectral calculation (Origin software was used to fit the fluorescence half-width) were performed on the 3 P0→ 3 H6, 3 P0→ 3 F2, and 3 P0→ 3 F3+ 3 F4 transitions, and the half-widths were 15.3 nm, 6.86 nm, and 5.78 nm, respectively. The 0.6% Pr:LaF3 sample was excited by 444 nm light, and the 640 nm emission peak corresponded to 3 The P0 level lifetime was 49.3 μs.

[0052] As shown in Figure 1 , the room temperature fluorescence spectra of the 0.6% Pr, 5% Sr:LaF3 sample and the 0.6% Pr, 8% Sr:LaF3 sample prepared in Examples 1-2, and the 0.6% Pr:LaF3 sample prepared in Comparative Example 1 can be seen. The two crystals provided in Examples 1-2 have 3 H6and 3 F2orange-red light bands and 3 F3and 3The emission bands of F4 deep red light band are compared with single-doped Pr:LaF3, and both have certain improvement.

[0053] As Figure 2 The fluorescence lifetime spectra of 640 nm emission peak under 444 nm light excitation of 0.6%Pr, 5%Sr:LaF3 sample (b) and 0.6%Pr, 8%Sr:LaF3 sample (c) prepared in Examples 1-2, and 0.6%Pr:LaF3 sample (a) prepared in Comparative Example 1 are shown. 3 The lifetime of P0 energy level is 45.6 μs, and the lifetime of P0 energy level of 0.6%Pr, 8%Sr:LaF3 sample 3 The lifetime of P0 energy level is 44.0 μs, and the lifetime of P0 energy level of 0.6%Pr:LaF3 sample 3 The lifetime of P0 energy level is 49.3 μs.

[0054] Example 3

[0055] The 0.6%Pr, 5%Ca:LaF3 crystal is grown by temperature gradient method, and is prepared by the following method:

[0056] The 0.6%Pr, 5%Ca:LaF3 crystal is grown by temperature gradient method, and is prepared by the following method:

[0057] Through fluorescence spectrum test, it can be found that the emission band width in orange-red light band and deep red light band is increased compared with that of 0.6%Pr:LaF3.

[0058] Example 4

[0059] The 0.6%Pr, 5%Ca:LaF3 crystal is grown by temperature gradient method, and is prepared by the following method:

[0060] A 0.6%Pr, 5%Ba:LaF3 crystal is grown by a temperature gradient method. 150g of raw material is put into a graphite crucible, then a crucible cover is put on, the furnace is vacuumized, vacuumization is performed to below 8Pa, then the temperature is raised to about 1500°C at a rate of 200°C / h, the temperature is kept constant for 8h until the raw material is completely melted and impurities are sufficiently removed, then the temperature is slowly lowered from 1500°C to 1350°C at a rate of 1.5°C / h, and the crystal is grown in the process of slow temperature lowering. After the slow temperature lowering growth is completed, the temperature is quickly lowered to room temperature at a rate of 30°C / h, the whole growth process is performed under high vacuum, and then the crystal is taken out. A 0.6%Pr, 5%Ba:LaF3 crystal with good optical quality is obtained.

[0061] It is found by fluorescence spectrum test that the emission bandwidth in the orange-red light band and the deep red light band is increased compared with that of the 0.6%Pr:LaF3.

[0062] Example 5

[0063] A 0.6%Pr, 5%Sr:Y 0.5 Gd 0.5 F3 crystal is grown by a temperature gradient method, and is prepared by the following method:

[0064] A 0.6%Pr, 5%Sr:Y 0.5 Gd 0.5 F3 crystal is grown by a temperature gradient method. 150g of raw material is put into a graphite crucible, then a crucible cover is put on, the furnace is vacuumized, vacuumization is performed to below 8Pa, then the temperature is raised to about 1250°C at a rate of 200°C / h, the temperature is kept constant for 8h until the raw material is completely melted and impurities are sufficiently removed, then the temperature is slowly lowered from 1500°C to 1350°C at a rate of 1.5°C / h, and the crystal is grown in the process of slow temperature lowering. After the slow temperature lowering growth is completed, the temperature is quickly lowered to room temperature at a rate of 30°C / h, the whole growth process is performed under high vacuum, and then the crystal is taken out. A 0.6%Pr, 5%Sr:Y 0.5 Gd 0.5 F3 crystal is obtained.

[0065] It is found by fluorescence spectrum test that the emission bandwidth in the orange-red light band and the deep red light band is increased compared with that of the 0.6%Pr:LaF3.

[0066] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any person skilled in the art can modify or change the above disclosed technical content into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made on the basis of the technical essence of the present application to the above embodiments still belongs to the protection scope of the technical scheme of the present application.

Claims

1. A rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions, characterized in that, The chemical composition of the laser crystal is expressed as xR,yMe:MF3, where x ranges from 0.001 to 0.3 and y ranges from 0.01 to 0.

2. R is Pr, Me is at least one of Mg, Ca, Sr or Ba, and M is La.

2. The rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions according to claim 1, characterized in that, The chemical formula of the laser crystal is xPr,ySr:LaF3, where x ranges from 0.001 to 0.3 and y ranges from 0.01 to 0.

2.

3. The rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions according to claim 2, characterized in that, The chemical formula of the laser crystal is 0.6%Pr,5%Sr:LaF3.

4. The method for preparing a rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions as described in any one of claims 1 to 3, characterized in that, Crystal growth using the temperature gradient method includes the following steps: (1) Material preparation: Weigh RF3, MeF2 and MF3 raw materials according to the stoichiometric ratio, mix them evenly, and then put them into a crucible and grind them; (2) Crystal growth: The crucible is placed in a high vacuum atmosphere, heated to melt the material and remove impurities, and then a slow cooling process is started to grow the crystal. After the growth is completed, the temperature is lowered to room temperature to obtain a rare earth fluoride laser crystal doped with divalent alkaline earth ions and praseodymium ions.

5. The method for preparing a rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions according to claim 4, characterized in that, The RF3, MeF2 and MF3 raw materials mentioned in step (1) have a purity of 5N and are in the form of single crystal particles or powder; the grinding time is 40-60 min.

6. The method for preparing a rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions according to claim 4, characterized in that, The vacuum atmosphere described in step (2) is as follows: the vacuum level is maintained below 8 Pa throughout the entire crystal growth process.

7. The method for preparing a rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions according to claim 4, characterized in that, The heating rate in step (2) is 200-300℃ / h, and the temperature is raised to 1500℃. After the temperature is raised to 1500℃, it is kept constant for 5-8 hours.

8. The method for preparing a rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions according to claim 4, characterized in that, The slow cooling procedure in step (2) is as follows: the temperature is reduced from 1500℃ to 1350℃ at a rate of 1.5℃ / h.

9. The method for preparing a rare-earth fluoride laser crystal doped with divalent alkaline earth ions and controlled by trivalent luminescent ions according to claim 4, characterized in that, After the slow cooling growth described in step (2) is completed, the temperature is reduced from 1350℃ to room temperature at a rate of 30-50℃ / h.

10. The application of a rare-earth fluoride laser crystal doped with divalent alkaline earth ions to regulate trivalent luminescent ions as described in any one of claims 1 to 3, characterized in that, As a laser gain medium for all-solid-state visible ultrafast lasers, it is used to accelerate all-solid-state femtosecond ultrafast lasers in the visible band.

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