Device and method for determining polarization axis of birefringent laser crystal

Abstract

The present application provides a device and method for determining the polarization axis of a birefringent laser crystal. The device comprises: a pump component, a pump light polarization component, a laser crystal carrier, a fluorescence polarization component, a fluorescence shaping component, a fluorescence detection component, and a display and determination component, which are sequentially arranged along an optical path. The pump component provides pump light; the pump light polarization component adjusts the pump light into polarized pump light; the birefringent laser crystal generates fluorescence; the fluorescence polarization component transmits the fluorescence in a target polarization direction; the fluorescence processing component processes the fluorescence into a beam of preset size and intensity; the fluorescence detection component converts the detected fluorescence into fluorescence information through photoelectric conversion; and the display and determination component displays the fluorescence information and determines the polarization direction of the birefringent laser crystal based on the fluorescence information. In the present application, the polarization absorption characteristics of the birefringent laser crystal can be used to determine the polarization axis of the laser crystal, thereby quickly and effectively adjusting the polarization axis of the laser crystal.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and in particular to a device and method for determining the polarization axis of a birefringent laser crystal. Background Art

[0002] To support subsequent laser applications such as nonlinear transformation and laser amplification, laser light is typically required to be polarized at a specific angle, such as horizontal, vertical, or other. For birefringent laser crystals that directly excite linearly polarized light, the polarization axis of the crystal is also typically required to be maintained at a specific angle.

[0003] In the laser side pump module, since the pump source or reflective cavity is ring-shaped, in order to ensure uniform absorption of the pump light, the laser crystal is usually designed as a round rod. Since the laser crystal is installed inside the side pump module, its polarization axis is difficult to observe and locate, and it requires repeated adjustments to approach a specific direction. In addition, the existing adjustment method requires taking the side pump module and laser crystal out of the resonant cavity each time, adjusting the angle and fixing the position of the laser crystal, and then putting the side pump module back into the resonant cavity to align and optimize the side pump module and the resonant cavity. It can be seen that the existing method has cumbersome adjustment steps, cannot determine the angle deviation, and requires that the optimal value be achieved each time the resonant cavity is restored, which requires a high level of debugging. Summary of the Invention

[0004] The purpose of this application is to provide a device and method for determining the polarization axis of a birefringent laser crystal.

[0005] In a first aspect, the present application provides a device for determining the polarization axis of a birefringent laser crystal, comprising:

[0006] The pump component, pump light polarization component, laser crystal carrier, fluorescence polarization component, fluorescence shaping component, fluorescence detection component and display judgment component are arranged in sequence along the optical path; wherein,

[0007] The laser crystal carrier is used to carry the birefringent laser crystal to be detected, and the birefringent laser crystal is rotatable;

[0008] The pump component is used to provide pump light for the birefringent laser crystal to be detected;

[0009] The pump light polarization component is used to adjust the pump light provided by the pump component into polarized pump light, wherein the polarized pump light is linearly polarized light in a target polarization direction; the birefringent laser crystal generates fluorescence under the action of the polarized pump light;

[0010] The fluorescence polarization component is used to pass fluorescence with a target polarization direction;

[0011] The fluorescence processing component is used to process the fluorescence into a light beam of preset size and intensity so as to form an image on the fluorescence detection component;

[0012] The fluorescence detection component is used to convert the detected fluorescence into fluorescence information through photoelectric conversion;

[0013] The display and judgment component is used to display the fluorescence information and judge the polarization direction of the birefringent laser crystal according to the fluorescence information.

[0014] In some embodiments of the present application, the pump component includes a pump source and a first beam shaping unit;

[0015] The pump source is used to provide pump light to the birefringent laser crystal using an end-face pumping method;

[0016] The first beam shaping unit is used to converge the pump light into a preset size to increase the intensity of the pump light, and the focus of the shaped pump light is located inside the birefringent laser crystal.

[0017] In some embodiments of the present application, the pump source is a semiconductor laser diode pump source.

[0018] In some embodiments of the present application, the pump light polarization component is a polarization beam splitter prism, a polarizer, or a lens positioned at a Brewster angle.

[0019] In some embodiments of the present application, the laser crystal carrier includes a heat dissipation component for dissipating heat from the birefringent laser crystal.

[0020] In some embodiments of the present application, the fluorescence polarization component is a polarization beam splitter prism, a polarizer, or a lens positioned at the Brewster angle.

[0021] In some embodiments of the present application, the fluorescence processing component includes a second beam shaping unit and an attenuation unit;

[0022] The second beam shaping unit is used to process the fluorescence into a beam of a preset size;

[0023] The attenuation unit is used to attenuate the fluorescence into a light beam with a light intensity less than a preset light intensity.

[0024] In some embodiments of the present application, the second beam shaping unit uses a spherical mirror or an aspherical mirror.

[0025] In some embodiments of the present application, the fluorescence detection component is a CCD camera.

[0026] A second aspect of the present application provides a method for determining the polarization axis of a birefringent laser crystal, based on the device for determining the polarization axis of a birefringent laser crystal described in the first aspect. The method comprises:

[0027] The pump component provides pump light to the birefringent laser crystal to be detected;

[0028] The pump light polarization component adjusts the pump light provided by the pump component into polarized pump light, wherein the polarized pump light is linearly polarized light in a target polarization direction; the birefringent laser crystal generates fluorescence under the action of the polarized pump light;

[0029] The fluorescence polarization component passes the fluorescence in the target polarization direction;

[0030] The fluorescence processing component processes the fluorescence into a light beam of preset size and intensity so as to form an image on the fluorescence detection component;

[0031] The fluorescence detection component converts the detected fluorescence into fluorescence information through photoelectric conversion;

[0032] The display and judgment component displays the fluorescence information and judges the polarization direction of the birefringent laser crystal according to the fluorescence information.

[0033] Compared with the prior art, the present application provides a device for determining the polarization axis of a birefringent laser crystal, comprising: a pump component, a pump light polarization component, a laser crystal carrier, a fluorescence polarization component, a fluorescence shaping component, a fluorescence detection component, and a display and determination component, which are sequentially arranged along an optical path; the pump component provides pump light for a birefringent laser crystal to be detected; the pump light polarization component adjusts the pump light provided by the pump component into polarized pump light, wherein the polarized pump light is linearly polarized light in a target polarization direction; the birefringent laser crystal generates fluorescence under the action of the polarized pump light; the fluorescence polarization component passes the fluorescence in the target polarization direction; the fluorescence processing component processes the fluorescence into a light beam of preset size and intensity for imaging on the fluorescence detection component; the fluorescence detection component converts the detected fluorescence into fluorescence information through photoelectric conversion; the display and determination component displays the fluorescence information and determines the polarization direction of the birefringent laser crystal based on the fluorescence information. In the present application, after the birefringent laser crystal absorbs linearly polarized pump light, the threshold and intensity of fluorescence generated in different axes are inconsistent. The above-mentioned polarization absorption characteristics of the birefringent laser crystal can be used to determine the polarization axis of the laser crystal, thereby quickly and effectively adjusting the polarization axis of the laser crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0035] Figure 11 shows an axial schematic diagram of a birefringent laser crystal provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of an existing resonant cavity method for adjusting the polarization direction of a crystal is shown;

[0037] Figure 3 A structural diagram of a device for determining the polarization axis of a birefringent laser crystal provided in an embodiment of the present application is shown;

[0038] Figure 4 shows the polarization absorption spectrum of the Nd:YLF crystal provided in the examples of the present application;

[0039] Figure 5 A flow chart of a method for determining the polarization axis of a birefringent laser crystal provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0040] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0041] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which this application belongs.

[0042] In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0043] by Figure 1 Taking the birefringent laser crystal shown in the figure as an example, the a-axis is the cutting direction, which is also the direction of laser light transmission. The b-axis is the direction of σ-polarized light, and the c-axis is the direction of π-polarized light. Assuming that the designed laser requires π-polarized light, the polarization direction is along the dotted line in the figure. Therefore, the c-axis of the laser crystal needs to be rotated in the crystal plane perpendicular to the a-axis to the dotted line direction. All subsequent rotations mentioned in this application refer to rotations in the crystal plane perpendicular to the a-axis.

[0044] At present, the method for rotating the polarization direction of a rod-shaped laser crystal is to build a resonant cavity containing a polarizer. The schematic diagram of the principle is shown in the figure below. Figure 2 As shown, the polarizer angle must be adjusted to the desired polarization direction. The laser crystal angle must be rotated until the resonator output power reaches maximum. This adjustment method requires removing the side pump module and laser crystal from the resonator each time. After adjusting the angle, the laser crystal's position must be fixed. The side pump module must then be placed back into the resonator to align and optimize the side pump module and resonator. This cumbersome adjustment process makes it impossible to determine angle deviations. Furthermore, the resonator must always be restored to its optimal value, requiring a high level of debugging expertise.

[0045] The embodiments of the present application provide a device for determining the polarization axis of a birefringent laser crystal and a method for determining the polarization axis of a birefringent laser crystal, which are described below with reference to the accompanying drawings.

[0046] Please refer to Figure 3 , which shows the structure of a device for determining the polarization axis of a birefringent laser crystal provided by an embodiment of the present application. As shown in the figure, the determination device includes: a pump component 10, a pump light polarization component 20, a laser crystal carrier 30, a fluorescence polarization component 40, a fluorescence shaping component 50, a fluorescence detection component 60, and a display determination component 70, which are sequentially arranged along the optical path. Of course, the determination device may also include other devices or components, and this application does not limit this.

[0047] The laser crystal carrier 30 is used to carry the birefringent laser crystal to be tested. The birefringent laser crystal is rotatably positioned on the laser crystal carrier 30. The birefringent laser crystals to be tested primarily include various types of birefringent laser crystals doped with active ions such as Nd ions and Yb ions, such as Nd:YVO4, Nd:YLF, Nd:KGW, and Nd:LYSO. After absorbing pump light, the laser crystal emits linearly polarized light, with the polarization direction aligned along the axial direction of the crystal. Fluorescence emitted from different axes may have different wavelengths, or they may have the same wavelength but different emission cross-sections. To prevent damage from overheating after absorbing strong pump energy, heat dissipation of the laser crystal should be considered. Therefore, in practical applications, the laser crystal carrier 30 is also equipped with a heat dissipation component to dissipate heat from the birefringent laser crystal. Conductive cooling or liquid convection cooling, which are both more effective, can be used. To reduce errors, a crystal heat dissipation system used in subsequent actual lasers can be employed, such as one incorporated into the laser side pump module.

[0048] The pumping component 10 is used to provide pump light to the birefringent laser crystal to be tested. Specifically, the pumping component 10 includes a pump source and a first beam shaping unit. The pump source can be used for actual lasers or for testing, and specifically, a semiconductor laser diode pump source can be used. The pump source uses end-face pumping to provide pump light to the birefringent laser crystal. The first beam shaping unit focuses the pump light into a preset size to increase the intensity of the pump light. The focus of the shaped pump light is located within the birefringent laser crystal. The first beam shaping unit can utilize a spherical mirror or an aspherical mirror, for example.

[0049] The pump light polarization component 20 adjusts the pump light provided by the pump component 10 into polarized pump light. This polarized pump light is linearly polarized light in a target polarization direction. The aforementioned birefringent laser crystal can generate fluorescence under the action of the polarized pump light passing through the pump light polarization component 20. The target polarization direction can be σ-polarized light or π-polarized light. In practical applications, the pump light polarization component 20 can be a device with polarization and recovery functions to adjust the pump light into linearly polarized light in a specific polarization state and recover the residual pump light. The pump light polarization component 20 can be configured as a polarization beam splitter, a polarizer, a lens positioned at the Brewster angle, or other polarization-generating device.

[0050] After absorbing the polarized pump light, the birefringent laser crystal carried by the laser crystal carrier 30 excites linearly polarized light, and the polarization direction of the light is along the axial direction of the crystal. The fluorescence of different axes may have different wavelengths, or the same wavelength but different emission cross-sections.

[0051] The fluorescence polarization component 40 can detect the polarization direction of the fluorescence by passing the fluorescence in the target polarization direction. The fluorescence polarization component 40 can be configured as a polarization beam splitter prism, a polarizer, a lens placed at the Brewster angle, or other devices capable of generating polarization.

[0052] Fluorescence processing unit 50 processes the fluorescence into a beam of appropriate size (emission angle) and intensity for imaging on fluorescence detection unit 60, facilitating observation of changes in the light spot. Fluorescence detection unit 60 converts the detected fluorescence into fluorescence information through photoelectric conversion and transmits it to display and judgment unit 70, which displays the fluorescence information and determines the polarization direction of the birefringent laser crystal based on the fluorescence information. Specifically, fluorescence detection unit 60 may be a CCD camera.

[0053] Specifically, the fluorescence processing component 50 includes a second beam shaping unit and an attenuation unit. The second beam shaping unit processes the fluorescence into a beam of a preset size; the attenuation unit attenuates the fluorescence to a beam with a light intensity lower than a preset intensity. In practical applications, the size and intensity of the fluorescence may be too large to be detected and displayed by a CCD camera. Therefore, the size and intensity of the fluorescence can be adjusted to facilitate observation of the spot changes on the CCD.

[0054] Specifically, the second beam shaping unit may be a spherical mirror or an aspherical mirror. To achieve the collimation effect, a single lens may be used, or two or more lenses may be used.

[0055] The display judgment component 70 can be a computer device that can accurately judge the polarization axis of the laser crystal based on the fluorescence information generated by the birefringent laser crystal. Alternatively, the user can judge the polarization axis of the laser crystal based on the fluorescence information displayed on the display judgment component 70.

[0056] This application utilizes the fact that a birefringent laser crystal produces fluorescence of varying intensities under the action of polarized pump light, thereby correspondingly determining the orientation of the different crystal axes of the laser crystal. This allows the crystal's polarization direction to be rotated to a specified angle to meet the polarization state requirements of subsequent optical paths. The device for determining the polarization axis of a birefringent laser crystal in this application makes the polarization axis of the birefringent laser crystal observable and repeatable, enabling rapid and accurate angle alignment.

[0057] To facilitate understanding, the following specific examples are provided.

[0058] Example 1

[0059] The goal is to have the Nd:YLF side pump module output horizontally polarized π-polarized light, where the laser crystal is an a-axis cut Nd:YLF crystal.

[0060] like Figure 4 As shown in the figure, the absorption coefficient of the Nd:YLF crystal for pump light at around 796nm with polarization parallel to the optical axis is about three times that for pump light polarized perpendicular to the optical axis. For pump light at 792nm, the absorption coefficient reaches more than ten times.

[0061] like Figure 3 As shown, pump component 10 provides 792nm pump light, and pump light polarization component 20 uses a horizontally polarized pump light polarizer. Laser crystal carrier 30 carries a rod-shaped Nd:YLF crystal, which is mounted within the side pump module. Fluorescence polarization component 40 is a horizontally polarized fluorescence polarizer. The remaining components remain unchanged.

[0062] After the pump light passes through a horizontal pump light polarizer, it becomes horizontally polarized light and is pumped into the laser crystal, while polarized light in other directions is extracted and recycled. After the laser crystal absorbs the polarized pump light, it generates radiation, and its fluorescence is shaped and displayed on the fluorescence detection component 60. A horizontal fluorescence polarizer is used to verify that the fluorescence is π-polarized light parallel to the c-axis. When the c-axis of the rotating laser crystal is parallel to the horizontal polarization, the threshold for detecting fluorescence by the fluorescence detection component 60 is the lowest, and the fluorescence intensity detected by the fluorescence detection component 60 is the highest under the same pump intensity. In this way, the c-axis direction of the laser crystal can be determined, and its axial position can be fixed unchanged. When it is placed in a real laser resonant cavity, horizontally polarized π-polarized light can be generated.

[0063] Example 2

[0064] The goal is to have the Nd:YLF side pump module output horizontally polarized σ-polarized light, where the laser crystal is an a-axis cut Nd:YLF crystal.

[0065] like Figure 3 As shown, the pump light polarization component 20 is a vertically polarized pump light polarizer, the fluorescence polarization component 40 is a horizontally polarized fluorescence polarizer, and the other components are the same as those in the first embodiment.

[0066] The 792nm pump light is vertically polarized after passing through a vertically polarized pump light polarizer. When the laser crystal's c-axis is vertical and its b-axis is horizontal, the generated fluorescence is vertically π-polarized light. After passing through a horizontally polarized fluorescence polarizer, it is largely reflected, and the fluorescence detected by the fluorescence detection component 60 is minimal. At this point, the crystal's axis is fixed, and when placed in a true laser resonant cavity, it generates horizontally polarized σ-polarized light.

[0067] Example 3

[0068] This application also applies to laser crystals with square cross-sections. When the axial marking of the laser crystal is incorrect or cannot be determined, it is also necessary to accurately determine the axial direction of the laser crystal.

[0069] A square, a-axis-cut Nd:YVO4 crystal is mounted in a copper crystal holder. Heat is conducted away from the holder to ensure the crystal's temperature does not exceed its critical temperature. At 808nm pump light, the laser crystal's absorption coefficient along the c-axis is approximately four times greater than that along the a-axis. The goal is to obtain vertically polarized, π-polarized light.

[0070] like Figure 3 As shown, the pump component 10 provides 808nm pump light, the pump light polarization component 20 is a vertically polarized pump light polarizer, the laser crystal carrier 30 carries the end-pumped Nd:YVO4 crystal and the mounting base, the fluorescence polarization component 40 is a vertically polarized fluorescence polarizer, and the other components remain unchanged.

[0071] When the Nd:YVO4 crystal absorbs vertically polarized pump light, absorption is strongest along the c-axis, initially stimulating π-polarized light. When the laser crystal's c-axis is parallel to the vertical direction, the fluorescence intensity measured on the fluorescence detection component 60 is maximum and the threshold is lowest. At this point, the axial direction of the laser crystal can be determined: the vertical direction is the c-axis, and the horizontal direction is the a-axis. The threshold refers to the pump light intensity that stimulates fluorescence.

[0072] This application utilizes the polarization absorption characteristics of birefringent laser crystals, that is, the threshold and intensity of fluorescence generated in different axes of the crystal after absorbing linearly polarized pump light are inconsistent, to determine the polarization axis of the laser crystal, thereby quickly and effectively adjusting the polarization axis of the laser crystal so that the polarized light generated can be adjusted in any specified direction within the crystal plane.

[0073] Based on the device for determining the polarization axis of a birefringent laser crystal provided in the above embodiment, the present application also provides a method for determining the polarization axis of a birefringent laser crystal, please refer to Figure 5 , which shows a flow chart of a method for determining the polarization axis of a birefringent laser crystal provided by an embodiment of the present application. As shown in the figure, the method includes:

[0074] Step S101: a pumping component provides pumping light to a birefringent laser crystal to be detected;

[0075] Step S102: the pump light polarization component adjusts the pump light provided by the pump component into polarized pump light, wherein the polarized pump light is linearly polarized light in a target polarization direction; the birefringent laser crystal generates fluorescence under the action of the polarized pump light;

[0076] Step S103: The fluorescence polarization component passes the fluorescence in the target polarization direction;

[0077] Step S104: The fluorescence processing component processes the fluorescence into a light beam of preset size and intensity so as to form an image on the fluorescence detection component;

[0078] Step S105: The fluorescence detection component converts the detected fluorescence into fluorescence information through photoelectric conversion;

[0079] Step S106: the display and judgment component displays the fluorescence information and judges the polarization direction of the birefringent laser crystal according to the fluorescence information.

[0080] The method for determining the polarization axis of a birefringent laser crystal provided in an embodiment of the present application is based on the same inventive concept as the device for determining the polarization axis of a birefringent laser crystal provided in the aforementioned embodiment of the present application and has the same beneficial effects.

[0081] It should be noted that the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0082] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0083] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interface, the indirect coupling or communication connection of the device or unit can be electrical, mechanical or other forms.

[0084] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0085] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0086] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and description of the present application.

Claims

1. A device for determining the polarization axis of a birefringent laser crystal, characterized in that: include: The pump component, pump light polarization component, laser crystal carrier, fluorescence polarization component, fluorescence processing component, fluorescence detection component and display judgment component are arranged in sequence along the optical path; wherein, The laser crystal carrier is used to carry the birefringent laser crystal to be detected, and the birefringent laser crystal is rotatable; the laser crystal carrier includes a heat dissipation component for dissipating heat from the birefringent laser crystal; The pump component is used to provide pump light for the birefringent laser crystal to be detected; the pump component includes a pump source and a first beam shaping unit; the pump source is used to provide pump light to the birefringent laser crystal using an end-face pumping method; the first beam shaping unit is used to focus the pump light into a preset size to increase the intensity of the pump light, and the focus of the shaped pump light is located inside the birefringent laser crystal; The pump light polarization component is used to adjust the pump light provided by the pump component into polarized pump light, wherein the polarized pump light is linearly polarized light in a target polarization direction; the birefringent laser crystal generates fluorescence under the action of the polarized pump light; The fluorescence polarization component is used to pass fluorescence with a target polarization direction; The fluorescence processing component is used to process the fluorescence into a light beam of preset size and intensity so as to form an image on the fluorescence detection component; The fluorescence detection component is used to convert the detected fluorescence into fluorescence information through photoelectric conversion; The display and judgment component is used to display the fluorescence information and judge the polarization direction of the birefringent laser crystal according to the fluorescence information.

2. The device for determining the polarization axis of a birefringent laser crystal according to claim 1, wherein: The pump source is a semiconductor laser diode pump source.

3. The device for determining the polarization axis of a birefringent laser crystal according to claim 1, wherein: The pump light polarization component is a polarization beam splitter prism, a polarizer or a lens placed at a Brewster angle.

4. The device for determining the polarization axis of a birefringent laser crystal according to claim 1, wherein: The fluorescence polarization component is a polarization beam splitter prism, a polarizer or a lens positioned at a Brewster angle.

5. The device for determining the polarization axis of a birefringent laser crystal according to claim 1, wherein: The fluorescence processing component includes a second beam shaping unit and an attenuation unit; The second beam shaping unit is used to process the fluorescence into a beam of a preset size; The attenuation unit is used to attenuate the fluorescence into a light beam with a light intensity less than a preset light intensity.

6. The device for determining the polarization axis of a birefringent laser crystal according to claim 5, wherein: The second beam shaping unit adopts a spherical mirror or an aspherical mirror.

7. The device for determining the polarization axis of a birefringent laser crystal according to claim 1, wherein: The fluorescence detection component is a CCD camera.

8. A method for determining the polarization axis of a birefringent laser crystal, based on the device for determining the polarization axis of a birefringent laser crystal according to any one of claims 1 to 7, characterized in that: The method comprises: The pump component provides pump light to the birefringent laser crystal to be detected; The pump light polarization component adjusts the pump light provided by the pump component into polarized pump light, wherein the polarized pump light is linearly polarized light in a target polarization direction; the birefringent laser crystal generates fluorescence under the action of the polarized pump light; The fluorescence polarization component passes the fluorescence in the target polarization direction; The fluorescence processing component processes the fluorescence into a light beam of preset size and intensity so as to form an image on the fluorescence detection component; The fluorescence detection component converts the detected fluorescence into fluorescence information through photoelectric conversion; The display and judgment component displays the fluorescence information and judges the polarization direction of the birefringent laser crystal according to the fluorescence information.

Images