34 results about "Fluoride crystals" patented technology

The present invention provides a all-solid-state laser that directly emits 486.1 nm blue laser based on a praseodymium-doped fluoride crystal. The laser includes an excitation source, a focusing system, a laser resonator, and a laser gain medium crystal. The excitation source is a laser diode laser that emits laser with a central wavelength of 440 - 445 nm; the laser resonator is composed of an input mirror and an output mirror coated with a film system for realizing blue laser; the laser gain medium crystal is a fluoride crystal doped with praseodymium ions. By using the Pr 3+ ion 3 P0→ 3 H4 energy level transition to directly emit 486.1 nm wavelength blue laser, the signal-to-noise ratio of the laser can be improved. The blue laser fabricated by the present invention has the advantages of simple and compact structure, high stability, good monochromaticity, small volume, low power consumption, etc. And by means of Q-switching, a high peak power blue laser pulse output can be obtained, which can meet the requirements of high power and high integration miniaturized blue lasers for ocean exploration and underwater communication.

The present invention provides defect-controlled fluoride crystals, a method for producing the same, and the use thereof. These fluoride crystals contain at least a rare earth element RE (RE is at least one element selected from the group consisting of cerium (Ce), praseodymium (Pr), lanthanum (La), and neodymium (Nd)), fluorine (F), and hydrogen (H), and have the same crystal structure as crystals represented by CeF3. A method for producing fluoride crystals according to the present invention comprises growing crystals from a raw material containing a rare earth element RE and a raw material containing fluorine (F) by a solvothermal method in the presence of at least one mineralizer selected from the group consisting of mineralizers containing an alkali metal element and / or an alkaline earth metal element, acid mineralizers, and mineralizers containing a normal salt.

The utility model discloses a temperature field for fluoride crystal growth, and particularly relates to the technical field of crystal growth, which comprises a processing table, a rotating unit arranged on the processing table, a support frame arranged on the rotating unit, a lifting unit arranged on the support frame, and a hanging bracket arranged at the lifting position of the lifting unit, a positioning barrel is fixedly connected to the upper surface of the machining table, a fluoride hearth group is arranged in the positioning barrel and comprises a plurality of longitudinally stacked crystal growth hearths, a positioning rod and a positioning groove which are inserted in a matched mode are arranged between every two adjacent crystal growth hearths, and graphite heaters used for heating fluoride crystal growth are arranged on the inner walls of the crystal growth hearths. The utility model solves the technical problems that the maintenance cost is increased due to the damage of the hearth because the hearth for the current thermal field is mostly of an integrated structure, and the thermal field for the crystal growth of fluoride crystals is relatively high in construction difficulty and is inconvenient to transfer and transport at the same time.

The present invention provides applications of rare earth ion-doped alkaline earth metal fluoride crystals, including applications in solid-state lasers, laser imaging, environmental detection, satellite guidance, information storage, or underwater detection. The rare earth ion-doped alkaline earth metal fluoride comprises a matrix crystal and dysprosium ions or Dy / RE co-doped ions doped in the cation lattice of the matrix crystal, wherein the RE comprises at least one of Tm, Pr, and Sm; the matrix crystal comprises calcium strontium fluoride or barium fluoride crystals. The crystals employed in the present invention have low phonon energy and high fluorescence quantum efficiency. The introduction of calcium improves the stability of the crystals; the Dy / RE co-doping enhances energy level transfer. The crystals employed in the present invention have an absorption wavelength range of 250 to 600 nm. Upon excitation with ultraviolet or blue light, they can produce a broad emission spectrum spanning the violet to orange wavelength range, making them ideal working materials for direct pumping of semiconductor lasers.

The invention relates to a single-cavity Tm-Ho co-doped fluoride crystal dual-frequency Kerr lens mode-locked laser, which belongs to the technical field of optics, and comprises a pumping source for emitting pumping light, a convergent lens, four plano-concave reflectors and a plane output mirror, a natural birefringence bonding gain crystal is installed between the first plane-concave cavity mirror and the second plane-concave cavity mirror. According to the invention, an auxiliary mode locking crystal with an adjustable thickness is arranged between the third plano-concave cavity mirror and the fourth plano-concave cavity mirror, and the crystal has a very high nonlinear refractive index coefficient, has very high transmittance in a 2-micron wave band, and is very suitable for 2-micron laser mode locking. By combining the Kerr self-focusing effects of the Tm, Ho: LLF / YLF bonding crystal and the ZnS crystal and optimizing the lengths of the two matrix gain crystals, the resonant cavity has different optical lengths for the two cross-polarized lasers, so that the output of the double-repetition-frequency mode-locked pulse laser with the wave band of 2 microns based on the Kerr lens effect can be realized.

The invention discloses a closed growth method of a high-purity laser-damage-resistant fluoride crystal, and relates to the technical field of crystal growth. The preparation method comprises the following steps: treating fluoride powder with an HF solution, and performing F2 high-temperature roasting purification; growing crystals in a Bridgman furnace under the assistance of a uniform magnetic field with proper intensity; and finally, processing the crystal by using CF4 and O2 mixed gas plasma to eliminate crystal surface damage and form a fluorine-rich passivation layer. Heat convection in the melt can be inhibited through assistance of the magnetic field, the crystallization process is kept stable, the impurity content and dislocation density of the crystal can be effectively reduced, the laser damage resistance of the crystal is improved, and the method is suitable for the high-end optical field.

A preparation device for a center-shaped fluoride optical crystal comprises a graphite crucible, a graphite shaped piece is arranged at the center of the graphite crucible, the length direction of the graphite shaped piece is parallel to the height direction of the graphite crucible, a first connection structure is arranged at one end of the graphite shaped piece, a second connection structure is arranged in the graphite crucible, and the first connection structure and the second connection structure are detachably connected. The present invention utilizes the characteristics that the fluoride optical crystal material and the graphite material are non-wettable and the thermal expansion coefficient is relatively large. The present invention aims at the demand for fluoride optical crystals with complex geometric structures, and according to the growth characteristics of fluoride crystals, proposes a method for growing shaped crystals, which can realize one-time molding of fluoride crystals with shaped geometric structures, and can directly grow fluoride optical crystals with shaped geometric structures in the center, thereby avoiding the subsequent cumbersome crystal processing process, greatly reducing the difficulty of crystal processing, and improving the crystal utilization rate and yield rate.

The invention relates to a multi-crucible vacuum descending furnace device for fluoride crystal growth, which comprises a furnace body with a vacuum inner cavity, the side wall, close to the top, of the furnace body is provided with an air exhaust pipeline communicated with the vacuum inner cavity, and the bottom wall of the furnace body is provided with an air inlet for filling the vacuum inner cavity with protective atmosphere; two heaters are symmetrically arranged on the two opposite side walls in the furnace body, a plurality of crucibles are arranged between the two heaters in the furnace body in a lifting mode, a plurality of driving assemblies are arranged at the bottom of the furnace body and correspond to the crucibles to drive the crucibles to ascend and descend, each driving assembly independently controls ascending and descending, and every two adjacent crucibles are separated through a carbon felt partition plate. The carbon felt partition plates divide the vacuum inner cavity into a plurality of independent hot areas with the number equal to that of the crucibles. According to the invention, multiple crucibles can realize synchronous crystal growth, the crystal growth aperture and length can be freely regulated and controlled, the crystal growth device is suitable for synchronous growth of multiple crystals with medium and small apertures, a relatively high growth speed can be maintained, and the feeding amount can be effectively increased under the condition of multiple crucibles.

The invention relates to a method for realizing bonding growth of rare earth doped fluoride and pure fluoride crystals, and belongs to the technical field of crystal growth. Aiming at the technical problems of high requirement on polishing quality of a pre-bonding surface, sudden change of refractive index of a bonding interface, limited bonding area and the like in the existing crystal bonding method, one of a pure fluoride host crystal or a rare earth doped fluoride crystal is selected as a seed crystal; then weighing and mixing the raw materials according to the stoichiometric ratio of another bonded crystal component, pressing the raw materials into a raw material block, finally putting the seed crystal and the raw material block into a crucible in sequence, and realizing the bonding growth of the rare earth doped fluoride and pure fluoride crystal by adopting a temperature gradient method or a Bridgman-Stockbarger method. And finally obtaining the composite crystal formed by bonding the pure fluoride crystal and the rare earth ion doped fluoride crystal. According to the composite crystal grown by the method, sudden change of the refractive index at the bonding interface is avoided, the preparation cost of the composite crystal element is reduced, and the laser performance of the bonding gain element is improved.

Provided is a fluoride crystal containing, on a mass basis, 2-420 ppm of Mg and at least 300 ppm and 55% (5.5 × 105 ppm or less) of Sr.

An adaptive annealing crucible for large-size fluoride crystals includes: a crucible base having an inner ring located radially inward, an outer ring located radially outward, and a lower adaptive layer connecting the inner and outer rings; a crucible lid having an inner ring located radially inward, an outer ring located radially outward, and an upper adaptive layer connecting the inner and outer rings; an inner crucible cylinder composed of multiple segmented structures, movably and vertically disposed between the inner ring of the base and the inner ring of the lid; and the inner cylinder being capable of radial expansion and contraction; and a guiding structure for defining the direction of expansion and contraction of the inner cylinder. This invention solves the problem that crystals cannot freely expand and contract during annealing, resulting in the inability to release stress within the crystal.

The invention relates to a rare earth doped alkaline earth fluoride / alkaline earth fluoride bonded crystal and a preparation method thereof. The preparation method of the rare earth doped alkaline earth fluoride / alkaline earth fluoride bonding crystal comprises the following steps: (1) polishing and cleaning a bonding surface to prepare a pre-bonding piece of a rare earth doped alkaline earth fluoride RE: MF2 crystal and an alkaline earth fluoride MF2 crystal; (2) placing the pre-bonding piece of the RE: MF2 crystal and the pre-bonding piece of the MF2 crystal on an optical cement leaning body in the direction that the bonding surfaces are oppositely attached to each other, heating, and applying pressure to enable the bonding surfaces of the two crystals to tightly abut against each other to obtain a crystal optical cement pre-bonding piece; and (3) fixing the crystal optical cement pre-bonding piece, applying pressure of 0.2-5 MPa perpendicular to the bonding surface again through a stainless steel spring, embedding the crystal optical cement pre-bonding piece by adopting MF2 crystal powder, and carrying out heat treatment in a muffle furnace at the temperature of 400-650 DEG C to obtain the rare earth doped alkaline earth fluoride / alkaline earth fluoride bonding crystal.

The invention discloses a weighing method diameter control system of a laser crystal single crystal growth furnace. The weighing method diameter control system comprises a seed crystal weighing unit, a crucible heating unit, a high-precision voltage detector and a PLC (Programmable Logic Controller) crystal growth control system, the seed crystal weighing unit can monitor weight data of a seed crystal rod and a seed crystal in real time, and outputs the weight data to the high-precision voltage detector through an analog voltage signal; the high-precision voltage detector is used for measuring a voltage value output by the seed crystal weighing unit, converting a real-time change value of the weight of the crystal and judging the growth trend of the crystal of the seeding part of the crystal; the PLC crystal growth control system reads weight change data detected by the high-precision voltage detector, calculates a real-time crystal diameter feedback value, designs an ADC diameter control algorithm, adjusts the heater power of the crucible heating unit through target diameter and feedback diameter parameters, intervenes in real-time temperature change of crystal growth in the furnace, and controls the temperature of the furnace. And full-automatic diameter control of the diameter of the fluoride crystal is realized.

This invention provides a thorium-doped fluoride crystal, its preparation method, and a solid-state nuclear optical clock using the thorium-doped fluoride. The thorium-doped fluoride crystal uses SrF2, LiF, BaF2, and LiF+BaF2 as matrix materials, respectively, and ThF4 as a dopant material. Single crystals of Th:SrF2, Th:LiF, Th:BaF2, and Th:BaLiF3 are obtained through a melt growth process according to a pre-set molar percentage of the raw materials. The thorium-doped fluoride crystal of this invention has a low melting point and simple composition, which is beneficial for achieving high-quality crystal growth. It has an extremely wide band gap, high transmittance in the vacuum ultraviolet band, and a high Th doping concentration, which helps reduce absorption loss and background luminescence in the nuclear transition emission band, and is beneficial for the excitation and detection of nuclear transition signals. It can be used as a preferred material for applications based on… 229 A solid-state nuclear optical clock based on the transition of the Th atom nucleus.

This invention belongs to the field of rare-earth luminescent materials and optical sensing technology, specifically disclosing an upconversion temperature probe excited by NIR-I, its preparation method, and its application. The probe includes a matrix core material, which is a fluoride crystal; and dopant ions, specifically holmium ions (Ho) doped into the matrix core material. 3+ Ho 3+ As the sole luminescent center, it is excited by a near-infrared I light source with a wavelength of 880-920 nm to generate Ho. 3+ Characteristic green upconversion luminescence and red upconversion luminescence. This invention employs the aforementioned NIR-I excited upconversion temperature probe, its preparation method, and its application, utilizing Ho... 3+ The unique energy level competition mechanism of ions enables high-sensitivity temperature measurement over a wide temperature range, and the temperature measurement signal is unaffected by fluctuations in excitation power.

The invention discloses a polishing tool and a fluoride crystal ball cover machining process, the polishing tool comprises a grinding tool, a clamp and a polishing leather, the grinding tool comprises an upper grinding tool and a lower grinding tool which are matched with each other, the clamp is arranged at the edge of the upper grinding tool, the polishing leather and a ball cover are fixed through the clamp, and the polishing leather is arranged between the upper grinding tool and the ball cover. And ball cover machining of the high-purity fluoride crystal is achieved through ball opening, accurate grinding and application of a polishing tool. The implementation process has the advantages of reliable machining process, high machining efficiency and the like.

The invention discloses a Czochralski method fluoride crystal growth control method and device, and the method comprises the following steps: S1, adding a fluorinating agent into a fluoride raw material, and drying to form a pretreated raw material; relates to the technical field of fluoride crystal growth. Seed crystals are heated at a first heating rate, the initial processing stress of the seed crystals is released firstly, and the thermal expansion difference between the surface layer and the core part of the seed crystals is constructed through the two-stage heating rate difference of segmented annealing; forming a fine grain strengthening layer on the surface of the seed crystal in a gas quenching manner of spraying inert gas to the surface of the seed crystal and maintaining the temperature difference between the surface of the seed crystal and the core part of the seed crystal, so that the surface of the seed crystal generates pressure stress and the core part of the seed crystal forms a uniform stress field; and the pretreated seed crystal with small axial stress gradient, low axial elongation and improved surface hardness is obtained after stepped cooling, so that the problems of high-temperature deformation, tensile failure and cracking of the seed crystal caused by concentrated internal stress or insufficient surface strength in the traditional process are solved.

The application discloses an explosion-proof window structure and a preparation method and application thereof, relates to the technical field of explosion-proof window structures, and comprises the following steps: mixing inorganic nano-particles modified with perfluoropolyether to prepare a composite functional coating; spraying the composite functional coating onto the surface of a fluoride crystal to prepare a light-transmitting element; and assembling the light-transmitting element with a sealing assembly, a mounting and fixing assembly, a flange frame and a protective cover to obtain an explosion-proof window structure. The window structure improves the explosion-proof performance of the light-transmitting element through the physical structure and the performance enhancement of the light-transmitting element, maintains the excellent light-transmitting property of the light-transmitting element, and has wide application value.

The invention discloses a fluoride crystal bar processing machine tool, and relates to the technical field of semiconductor material processing, a cutting assembly in the machine tool comprises a base, a carborundum line arranged on the base, and a fixing frame arranged on the base; the adjusting assembly comprises a motor, a screw rod connected with the motor, a sliding block connected with the screw rod, a connecting rod connected with the sliding block, an adjusting frame arranged on the fixing frame, an adjusting rod arranged on the adjusting frame and a rotating block arranged on the adjusting rod. The feeding assembly comprises a mounting frame, a moving seat arranged on the mounting frame, a clamp arranged on the moving seat and an inclined frame arranged on the mounting frame. The cutting path of the crystal bar can be changed from a straight line to a controllable curved surface through the adjusting assembly, which is crucial to machining of optical crystal elements needing specific curved surface shapes, and the machining capacity of a machine tool is greatly expanded.

The invention discloses a novel fluoride crystal pulling thermal field. A novel fluoride crystal pulling thermal field comprises a thermal field body, bottom heating supporting legs are fixed to a bottom heat preservation structure of the thermal field body, and the bottom heating supporting legs are detachably connected with a bottom heater; the bottom heating supporting legs are positioned on the periphery of the graphite shaft; the bottom heat preservation structure is sleeved with a lower soaking cylinder, the lower soaking cylinder is located on the periphery of the bottom heater, and the side heater is located on the periphery of the lower soaking cylinder. The interior of the heat preservation cavity is divided up and down through a filter graphite supporting ring, a filtering assembly and an upper soaking cylinder which are arranged inside and outside are installed above the filter graphite supporting ring, the top of the filtering assembly is sleeved with a flow guide cylinder, the top of the flow guide cylinder is higher than the top of the filtering assembly, and air holes are formed in the upper soaking cylinder; and the filter graphite supporting ring is erected above the lower soaking cylinder and is provided with an air guide pipe which is butted and communicated with the upper cavity. According to the invention, the stability and quality of fluoride crystal pulling are realized.

This invention relates to the field of crystal detection technology, specifically to a method for detecting the dislocation density of fluoride crystals, particularly suitable for the dislocation density analysis of calcium fluoride crystals. The method comprises: (1) pre-treating the surface of the fluoride crystal to be tested; (2) corroding the surface of the fluoride crystal to be tested using a corrosion mixture solution, followed by termination of corrosion, wherein the corrosion mixture solution is used to form corrosion pits on the surface of the fluoride crystal to be tested; (3) observing the surface of the fluoride crystal to be tested, counting the number of corrosion pits in the fluoride crystal to be tested, and calculating the dislocation density of the fluoride crystal to be tested based on the number of corrosion pits, wherein the corrosion pits are corrosion pits with dislocation characteristics among the corrosion pits.

The invention belongs to the technical field of single crystal optical fiber growth, and relates to a method for growing a rare earth ion doping concentration gradient distribution composite single crystal optical fiber by using a laser heating base (LHPG) method by taking a thermal bonding crystal as a source rod. The preparation method comprises the following steps: adopting a thermal bonding crystal with a sandwich structure as a source rod, and growing a composite single crystal optical fiber with rare earth ion doping concentration in gradient distribution by using a laser heating base method; wherein the thermal bonding crystal takes a pure fluoride crystal as two end parts and a rare earth ion doped fluoride crystal as the middle part, or takes a pure garnet type oxide crystal as two end parts and a rare earth ion doped garnet type oxide crystal as the middle part. The diameter phi of the grown composite single crystal optical fiber can reach 0.2-2.0 mm, the growth speed can reach 10-150 mm / h, and the grown single crystal optical fiber can be used in the fields of solid laser, radiation detection and the like.

This application relates to the field of fluoride-containing wastewater treatment technology, and particularly to a system and method for recovering fluorides from fluoride-containing wastewater. The system includes a raw material zone, a sedimentation zone, and a detection zone. The raw material zone includes a first feeding unit for storing the fluoride-containing wastewater and a second feeding unit for storing a precipitant solution. The sedimentation zone includes a sedimentation chamber, and the detection zone includes a detection chamber, the bottom of which is connected to the top of the sedimentation chamber. Fluoride seed crystals are present in the sedimentation chamber. The first feeding unit delivers the fluoride-containing wastewater to the bottom of the sedimentation chamber, and the second feeding unit delivers the precipitant solution to the bottom of the sedimentation chamber. The fluoride-containing wastewater and the precipitant solution mix to form a mixed solution, which then reacts on the surface of the fluoride seed crystals to form fluoride crystals. The detection chamber is used by an operator to detect the fluoride content and turbidity in the mixed solution and to discharge the supernatant. When the reaction is complete, the fluoride crystals in the sedimentation chamber are removed. This system for recovering fluorides from fluoride-containing wastewater exhibits high fluoride recovery efficiency and quality.

The utility model discloses a fixing device for polishing fluoride crystal bars, which comprises a crystal bar disc and cover plates, the crystal bar disc comprises a disc, the outer edge of the disc is provided with a plurality of grooves, the grooves are used for placing crystal bars, and one groove at least corresponds to one cover plate; the cover plate is arranged corresponding to the grooves, the cover plate comprises a main body and second bulges arranged corresponding to the grooves, the end parts of the two sides of the main body are connected with the disc, and the crystal bars in the corresponding grooves are locked through the cover plate. During use, a crystal bar is placed in the groove, the bottom face of the crystal bar slightly exceeds the crystal bar disc, after positioning is completed, the crystal bar is fixed through glue injection, the opening of the groove is covered with the cover plate to be locked, and then the crystal bar and the crystal bar disc can form a whole to be fixed to a polishing machine to polish the end of the crystal bar. The fixing device for polishing the fluoride crystal bar further has the advantages that the polishing process is stable, the stress point height in the crystal bar machining process is reduced, materials are saved, and machining is flexible.

This invention belongs to the field of fluoride crystal annealing technology, specifically relating to an annealing crucible and annealing method for fluoride crystals. The annealing crucible includes: an outer crucible; and an inner crucible disposed inside the outer crucible. The inner crucible has multiple through holes and is used to place the fluoride crystal and a protective material. The protective material covers the fluoride crystal to prevent direct contact between the fluoride crystal and the inner crucible and air. A gap layer is provided between the inner and outer crucibles to fill with fragmented crystal material. The annealing crucible can selectively allow at least a portion of the protective material to overflow into the gap layer along the through holes. The "double-layer crucible" structure of this invention, combining the outer crucible and the through-hole inner crucible, provides a buffer space for the expansion of the fluoride crystal during annealing, effectively reducing the axial and radial temperature gradients of the crystal, generating a more uniform annealing environment, and allowing the internal stress of the crystal to be released slowly.

To provide defect-controlled fluoride crystals, methods for producing the same, and their applications. [Solution] The fluoride crystal of the present invention contains cesium (Cs), rare earth element RE, and fluorine (F), and has the general formula CsRE2F 7-x The inorganic crystal represented by (where x satisfies 0 ≤ x ≤ 0.5) contains at least hydrogen (H). The present invention relates to a method for producing fluoride crystals, which involves growing crystals by solvothermal method from a raw material containing a rare earth element RE and a raw material containing a fluorine element (F) in the presence of a mineralizing agent containing at least cesium element (Cs).

The invention discloses an optical property prediction method of a fluoride laser crystal based on deep learning, which belongs to the technical field of deep learning and material science and comprises the following steps: constructing a source domain data set of the fluoride crystal with a crystal stability label, and training a source domain model by taking structural parameters and a chemical formula of the fluoride crystal as input to obtain a source domain model; obtaining a crystal stability prediction model; the constructed optical property prediction model comprises a feature extractor and a detection head which are connected in sequence, and the feature extractor is a structure branch GNN and a component branch CoTAN in the crystal stability prediction model; the detection head is used for mapping the features extracted by the feature extractor into a prediction result of the optical properties of the crystal; and inputting the obtained structure parameters and the chemical formula of the fluoride laser crystal to be predicted into the optical property prediction model to obtain an optical property prediction result. According to the method, the crystal stability prediction model is introduced into the optical property prediction process through transfer learning, the problem of scarcity of crystal optical data is solved, and the model prediction precision is improved.

The invention relates to a center heating fluoride multi-crucible descent method crystal growth thermal field which comprises a furnace body provided with a vacuum inner cavity, a side peripheral heating body and a center heating body which are independently controlled are arranged in the vacuum inner cavity, and the side peripheral heating body is cylindrical and covers the periphery of the center heating body. The central heating body is arranged at the central position of the side peripheral heating body and is also located at the central position of the vacuum inner cavity, at least one arc-shaped crucible is arranged between the side peripheral heating body and the central heating body in the peripheral direction of the side peripheral heating body, and the crucible can be an integral annular crucible and is provided with a plurality of growth notches; the crucible can also be an annular crucible formed by splicing a plurality of groups of independent arc-shaped crucibles and is used for preparing a plurality of groups of fluoride crystals, and a descending mechanism for driving the crucible to ascend and descend is arranged in the furnace body. The crucible is arranged in the space between the central heating body and the side heating body, and the inner side and the outer side of the crucible are heated by the central heater and the side heater respectively, so that the temperatures of the front, back, left and right sides of the crucible are uniform, and low-cost and large-batch preparation of fluoride crystals is realized.

The present application relates to a kind of rare earth doped alkaline earth fluoride / alkaline earth fluoride bonded crystal and its preparation method.The preparation method of the rare earth doped alkaline earth fluoride / alkaline earth fluoride bonded crystal includes the following steps:(1) polishing, cleaning preparation rare earth doped alkaline earth fluoride RE:MF2 Crystal and alkaline earth fluoride MF2 Crystal pre-bonding piece of bonding surface;(2) RE:MF2 Crystal and MF2 Crystal pre-bonding piece is placed on the optical cement body with the direction of bonding surface opposite to each other with heat, pressure is applied to make the bonding surface of two crystals closely abut, obtain crystal optical cement pre-bonding piece;(3) crystal optical cement pre-bonding piece is fixed and by stainless steel spring perpendicular to bonding surface again 0.2-5MPa is applied pressure, MF2 Crystal powder is used to embed the crystal optical cement pre-bonding piece, heat treatment is carried out in muffle furnace at 400-650 ℃ temperature, obtain the rare earth doped alkaline earth fluoride / alkaline earth fluoride bonded crystal.