Internal liquid-cooled laser crystal assembly of medical lasers

Abstract

This disclosure discloses an internal liquid-cooled laser crystal assembly for a medical laser. One specific embodiment of this internal liquid-cooled laser crystal assembly includes a rectangular slab laser crystal and a fixing device for clamping the slab laser crystal. The contact surface between the fixing device and the slab laser crystal is sealed at the edge. The slab laser crystal has coolant channels parallel to the clamping direction, arranged in two rows along the crystal thickness direction. The thickness of the slab laser crystal and the spacing between two adjacent coolant channels in the same row have a first preset relationship, and the thickness of the coolant channels has a second preset relationship. The slab laser crystal has two optically grade polished surfaces, respectively coated with antireflection films for the pump light and the emitted laser, as light-transmitting end faces. The fixing device has a liquid passage hole. By creating coolant channels within the slab laser crystal, the risk of crystal wavefront distortion is reduced. This improves the energy stability of the laser output.

Description

Technical Field

[0001] The embodiments disclosed herein relate to the field of medical laser technology, and more specifically to the internal liquid-cooled laser crystal assembly of a medical laser. Background Technology

[0002] With the rapid development of laser technology, lasers have been widely used in surgical procedures. Surgical lasers require high stability in laser output energy, and the heat dissipation effect of the laser's gain medium is a key factor determining its performance. Currently, commonly used lasers employ a copper heat sink soldering heat dissipation solution, where a large portion of the gain medium is bonded to the surface of a copper heat sink using indium soldering, relying on the coolant within the heat sink's internal channels for heat conduction.

[0003] However, when using commonly used lasers, the following technical problems often arise: The thermal expansion coefficients of copper heat sinks and laser crystals differ significantly. During the process of using copper heat sinks to dissipate heat from laser crystals, the two will generate internal stress due to inconsistent thermal deformation, which in turn causes wavefront distortion of the crystal, resulting in poor energy stability of the output laser.

[0004] The information disclosed in this background section is only intended to enhance the understanding of the background of the present disclosure concept, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The summary portion of this disclosure is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description portion. This summary portion is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0006] Some embodiments of this disclosure propose an internal liquid-cooled laser crystal assembly for a medical laser to address one or more of the technical problems mentioned in the background section above.

[0007] Some embodiments of this disclosure provide an internal liquid-cooled laser crystal assembly for a medical laser. The internal liquid-cooled laser crystal assembly includes a slab laser crystal and a fixing device. The fixing device clamps the slab laser crystal, and the edges of the contact surfaces between the fixing device and the slab laser crystal are sealed. The slab laser crystal has a rectangular slab structure. Coolant channels are formed on the slab laser crystal, and the direction of the coolant channels is parallel to the clamping direction of the fixing device. The coolant channels are arranged in two rows along the thickness direction of the slab laser crystal, and the coolant channels in the same row are evenly distributed along the length direction of the slab laser crystal. The spacing between two adjacent coolant channels in the same row is in a first preset relationship with the thickness of the slab laser crystal. The diameter of the coolant channels is in a second preset relationship with the thickness of the slab laser crystal. Both light-transmitting end faces of the slab laser crystal are optically polished and are coated with anti-reflection films for the pump light and the emitted laser, respectively. The fixing device has liquid passage holes that match the coolant channels inside.

[0008] Optionally, the above-mentioned slab laser crystal has a three-layer bonded structure along the thickness direction, consisting of a first undoped crystal layer, a doped crystal layer, and a second undoped crystal layer from one side to the other.

[0009] Optionally, the thickness of the first undoped crystal layer and the second undoped crystal layer are equal.

[0010] Optionally, both the coolant flow channels and the coolant passages are filled with coolant.

[0011] Optionally, the coolant is one or more of pure water, Freon, liquid nitrogen, and ethylene glycol.

[0012] Optionally, the aforementioned internal liquid-cooled laser crystal assembly further includes a pump source, a first cavity mirror, and a second cavity mirror; the first cavity mirror and the second cavity mirror are respectively disposed on both sides of the aforementioned slab laser crystal; the pump source is disposed on one side of the aforementioned first cavity mirror.

[0013] Optionally, the surface of the first cavity mirror is coated with a reflective film for the emitted laser, and the surface of the second cavity mirror is coated with a partially transmissive film for the emitted laser.

[0014] Optionally, the coolant flow channels are created through the following steps: three-dimensional coordinate calibration of the crystal to be processed to obtain a calibrated crystal, wherein the calibrated crystal is obtained through the following steps: in response to completing the reference plane selection process for the crystal to be processed, laser scanning is performed on the crystal to obtain a three-dimensional scanning model of the crystal; the origin of the three-dimensional scanning model of the crystal is set to obtain a crystal coordinate system; the coordinate axes of the crystal coordinate system are calibrated to obtain a standard coordinate system; the flow channel positioning marking process is performed on the three-dimensional scanning model of the crystal in the standard coordinate system to obtain a positioning marked crystal; the hole position coordinates of the positioning marked crystal are generated to obtain the three-dimensional coordinates of each coolant flow channel; based on the three-dimensional coordinates of each coolant flow channel, the crystal to be processed is solidly marked to obtain a calibrated crystal; the drilling positions of the calibrated crystal are laser-penetrated to obtain a crystal with through holes; the inner walls of the through holes on the crystal with through holes are laser-polished to obtain the slab laser crystal.

[0015] Some embodiments of this disclosure provide an internal liquid-cooled laser crystal assembly for a medical laser, which can improve the energy stability of the laser output. Specifically, the reason for the poor energy stability of most laser outputs is that commonly used lasers generally employ a copper heat sink soldering heat dissipation scheme. This involves bonding a large portion of the gain medium to the surface of a copper heat sink using indium soldering, relying on the coolant in the internal channels of the heat sink for heat conduction. However, during the heat dissipation process using a copper heat sink for the laser crystal, the inconsistent thermal deformation between the two generates internal stress, leading to wavefront distortion of the crystal and resulting in poor energy stability of the output laser. Based on this, some embodiments of this disclosure provide an internal liquid-cooled laser crystal assembly for a medical laser. The internal liquid-cooled laser crystal assembly includes a slab laser crystal and a fixing device. The fixing device clamps the slab laser crystal, and the edges of the contact surfaces between the fixing device and the slab laser crystal are sealed. The slab laser crystal has a rectangular slab structure. Coolant channels are formed on the slab laser crystal, and the direction of the coolant channels is parallel to the clamping direction of the fixing device. The coolant channels are arranged in two rows along the thickness direction of the slab laser crystal, and the coolant channels in the same row are evenly distributed along the length direction of the slab laser crystal. The spacing between two adjacent coolant channels in the same row is in a first preset relationship with the thickness of the slab laser crystal. The diameter of the coolant channels is in a second preset relationship with the thickness of the slab laser crystal. Both light-transmitting end faces of the slab laser crystal are optically polished and coated with anti-reflection films for the pump light and the emitted laser light, respectively. The fixing device has internal cooling holes that match the coolant channels. By directly creating coolant channels within the slab laser crystal, which serves as the gain medium, cooling is achieved directly from within the crystal, reducing the risk of internal stress and wavefront distortion. This improves the energy stability of the laser output. Attached Figure Description

[0016] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements are not necessarily drawn to scale.

[0017] Figure 1 This is a schematic diagram of the internal liquid-cooled laser crystal assembly of a medical laser according to some embodiments of this disclosure in an assembled state; Figure 2 This is a schematic diagram of the slab laser crystal structure of the internal liquid-cooled laser crystal assembly of a medical laser according to some embodiments of this disclosure. Detailed Implementation

[0018] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0019] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0020] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0021] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0022] The names of messages or information exchanged between multiple devices in the embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of such messages or information.

[0023] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is a schematic diagram of the internal liquid-cooled laser crystal assembly of a medical laser in an assembled state, according to some embodiments of this disclosure. Figure 1 It includes a first cavity mirror 1, a fixing device 2, a pump source 3, a second cavity mirror 4, and a slab laser crystal 5. It should be noted that... Figure 1 The arrows shown emanating from the pump source 3 represent the laser output direction and are not the physical hardware structure of the internal liquid-cooled laser crystal assembly of the medical laser in some embodiments of this disclosure.

[0025] Figure 2 This is a schematic diagram of the slab laser crystal structure of the internal liquid-cooled laser crystal assembly of a medical laser according to some embodiments of this disclosure. Figure 2 It includes a first undoped crystal layer 6, a doped crystal layer 7, a second undoped crystal layer 8, and a coolant flow channel 9.

[0026] In some embodiments, the internal liquid-cooled laser crystal assembly may include a slab laser crystal 5 and a fixing device 2. The fixing device 2 can clamp the slab laser crystal 5, and the edges of the contact surfaces between the fixing device 2 and the slab laser crystal 5 can be sealed. The fixing device 2 may be two block-shaped structures fixed to the laser housing with screws; its material is not specifically limited. The sealing structure may be a silicone sealing ring embedded in the clamping surface of the fixing device 2 to prevent coolant leakage from the contact surface. The slab laser crystal 5 may be a rectangular slab structure. The length, width, and thickness ratio of this rectangular slab structure can be designed according to the cavity size of the medical laser; it is not specifically limited here, as long as it facilitates stable installation and bidirectional light transmission. Coolant channels 9 may be formed on the slab laser crystal 5, and the direction of the coolant channels 9 may be parallel to the clamping direction of the fixing device 2 clamping the slab laser crystal 5. The parallel direction of the coolant channels 9 facilitates the flow of coolant from the fixing device 2 into the interior of the slab laser crystal 5. The aforementioned coolant channels 9 can be arranged in two rows along the thickness direction of the slab laser crystal 5, and the coolant channels 9 in the same row can be evenly distributed along the length direction of the slab laser crystal 5. The design of two rows of coolant channels 9 increases the contact area between the coolant and the slab laser crystal 5, and the evenly distributed coolant channels 9 improve the temperature uniformity of different regions of the crystal. The distance between two adjacent coolant channels 9 in the same row can be in a first preset relationship with the thickness of the slab laser crystal 5. Specifically, the distance between two adjacent coolant channels 9 in the same row can be greater than one-third of the thickness of the slab laser crystal 5. This spacing setting can maintain the structural strength of the slab laser crystal 5 while ensuring the heat dissipation area, reducing the risk of cracking during processing or use. The diameter of the aforementioned coolant channels 9 can be in a second preset relationship with the thickness of the slab laser crystal 5. Specifically, the diameter of the aforementioned coolant channels 9 can be less than one-third of the thickness of the slab laser crystal 5. Limiting the diameter of the coolant channels 9 can reduce the risk of the effective gain area of ​​the crystal being reduced due to excessively thick channels. Both light-transmitting end faces of the aforementioned slab laser crystal 5 can be optically polished surfaces, and each can be coated with an anti-reflection film for the pump light and the emitted laser. The surface roughness of the optically polished surface can be less than 0.01 μm. The anti-reflection film can be designed for specific wavelengths of pump light and emitted laser to reduce light reflection loss at the end faces and improve laser output efficiency. The interior of the aforementioned fixing device 2 can have a liquid passage hole matching the aforementioned coolant flow channel 9. This liquid passage hole can be a channel for transporting coolant into the interior of the aforementioned slab laser crystal 5.The diameter of the aforementioned liquid passage hole can be the same as the diameter of the aforementioned coolant flow channel 9, and its position can be aligned with the port of the aforementioned coolant flow channel 9, for connecting to an external coolant circulation system to realize the input and output of coolant.

[0027] Optionally, such as Figure 2 As shown, the aforementioned slab laser crystal 5 can have a three-layer bonded structure along its thickness direction, consisting of a first undoped crystal layer 6, a doped crystal layer 7, and a second undoped crystal layer 8, sequentially arranged from one side to the other. The first undoped crystal layer 6 and the second undoped crystal layer 8 can be pure crystalline materials, while the doped crystal layer 7 can be a crystalline material doped with active ions, for example, the active ions could be Nd³⁺. + Yb³ + Rare earth ions are present. The three-layer bonded structure can be achieved through thermal bonding. The doped crystal layer 7 mentioned above is the core gain region for laser generation, while the undoped crystal layer can protect the doped layer and reduce end-face thermal damage.

[0028] Optionally, such as Figure 2 As shown, the thicknesses of the first undoped crystal layer 6 and the second undoped crystal layer 8 can be equal. This allows for a more uniform stress distribution in the thickness direction of the slab laser crystal 5, reducing crystal deformation caused by differences in thermal expansion coefficients.

[0029] Optionally, both the coolant channel 9 and the liquid passage hole can be filled with coolant. The coolant can continuously circulate within the coolant channel 9 and the liquid passage hole to remove the heat generated by the slab laser crystal 5 during operation and maintain the crystal's temperature stability.

[0030] Optionally, the coolant can be one or more of pure water, Freon, liquid nitrogen, and ethylene glycol. Pure water can be used for room temperature heat dissipation, which is low in cost and pollution-free; Freon has a high thermal conductivity and can be used for medium and low temperature heat dissipation; liquid nitrogen can be used for ultra-low temperature heat dissipation and is suitable for medical laser equipment with extremely high temperature control precision requirements; ethylene glycol can be mixed with pure water to lower the freezing point of the coolant and is suitable for lasers in low-temperature environments.

[0031] Optionally, such as Figure 1As shown, the aforementioned internal liquid-cooled laser crystal assembly may further include a pump source 3, a first cavity mirror 1, and a second cavity mirror 4. The first cavity mirror 1 and the second cavity mirror 4 may be respectively disposed on both sides of the slab laser crystal 5. The first cavity mirror 1 and the second cavity mirror 4 may be arranged parallel to the light-transmitting end face of the slab laser crystal 5, and the three together constitute a laser resonant cavity. The pump source 3 may be disposed on one side of the first cavity mirror 1. The pump source 3 may be a semiconductor laser, and its output pump light can pass through the first cavity mirror 1 and be incident on the slab laser crystal 5 to excite doped ions to generate population inversion, thereby generating laser light.

[0032] Optionally, the surface of the first cavity mirror 1 can be coated with a reflective film for the emitted laser, and the surface of the second cavity mirror 4 can be coated with a partially transmissive film for the emitted laser. The reflective film of the first cavity mirror 1 can have a reflectivity of over 99% for the emitted laser, used to reflect the laser back to the resonant cavity for multiple amplifications. The partially transmissive film of the second cavity mirror 4 can have a transmittance of 10% to 30% for the emitted laser, used to allow a portion of the laser to be output from the resonant cavity, forming a laser beam that can be used for medical surgery. The laser reflected back to the resonant cavity by the second cavity mirror 4 can maintain stimulated emission amplification of the laser, while optimizing the beam quality and energy stability of the output laser.

[0033] Optionally, the above-mentioned coolant flow channels are opened by the following steps: The first step is to perform three-dimensional coordinate calibration on the crystal to be processed, obtaining a calibrated crystal. This three-dimensional coordinate calibration refers to the process of locating the opening position of the coolant flow channel. The calibrated crystal can be obtained through the following steps: Step one involves selecting a reference surface for the crystal to be processed, followed by laser scanning to obtain a 3D scanning model of the crystal. This reference surface selection process involves choosing a flat, light-transmitting end face of the crystal as the reference surface. This reference surface can serve as a reference for subsequent coordinate calibration. In practice, a 3D laser scanner can be used to scan the crystal, covering its entire surface, to obtain a 3D scanning model of the crystal.

[0034] Step two involves setting the origin of the coordinate system on the 3D scanning model of the crystal to obtain the crystal coordinate system. This origin setting can be achieved by selecting a point on the 3D scanning model of the crystal as the origin. In practice, CAD software can be used to set the origin of the coordinate system on the 3D scanning model of the crystal. For example, UG software can be used to set the origin of the coordinate system on the 3D scanning model of the crystal.

[0035] Step three involves calibrating the crystal coordinate system to obtain a standard coordinate system. This calibration process involves using an edge of the crystal to be processed as a reference to calibrate the X, Y, and Z axes of the crystal coordinate system, while ensuring that all three axes are perpendicular to each other. The calibrated crystal coordinate system is the standard coordinate system.

[0036] Step four: Perform flow channel positioning and marking processing on the crystal 3D scanning model in a standard coordinate system to obtain a positioned and marked crystal. The flow channel positioning and marking processing refers to the process of marking the positions of the coolant flow channels in the standard coordinate system according to a preset flow channel distribution rule. The crystal 3D scanning model after completing the flow channel positioning and marking processing is the positioned and marked crystal.

[0037] Step five involves generating hole position coordinates on the positioning marker crystal to obtain the three-dimensional coordinates of each coolant flow channel. This hole position coordinate generation process refers to generating corresponding three-dimensional coordinates for each flow channel marker on the positioning marker crystal. These three-dimensional coordinates can include the start-point coordinates, end-point coordinates, and hole diameter of each coolant flow channel. These three-dimensional coordinates can be imported into the control system of the laser drilling equipment to provide positional references for subsequent drilling operations.

[0038] Step six: Based on the three-dimensional coordinates of each coolant flow channel, perform solid marking processing on the crystal to be processed to obtain the calibrated crystal. The aforementioned solid marking processing can refer to the process of using a laser marking machine to mark the specific location of each flow channel hole on the surface of the crystal to be processed according to the positional information contained in the three-dimensional coordinates of the hole.

[0039] The second step involves laser penetration treatment of the calibrated crystal at the drilling locations, resulting in a crystal with through holes. This laser penetration treatment can refer to the drilling process using a femtosecond laser drilling machine. The calibrated crystal after drilling is then the crystal with through holes. The through holes in this crystal form the prototype of the coolant flow channels. In practice, the femtosecond laser drilling machine can be controlled to start from one side of the calibrated crystal and drill perpendicularly through the calibrated holes to the other side.

[0040] The third step involves laser polishing the inner walls of the through-holes in the crystal to obtain a slab laser crystal. This laser polishing process refers to using laser polishing equipment to perform a circular scanning polishing of the inner walls of the through-holes in the crystal. In practice, the laser polishing equipment can be controlled to perform a circular scanning polishing of the inner walls of the through-holes in the crystal to obtain a slab laser crystal. This laser polishing process reduces the flow resistance of the coolant in the coolant channels, while also improving the smoothness of the inner walls of the coolant channels and reducing the adhesion of residual impurities. It should be noted that this process of first 3D modeling and calibration, and then solid marking and drilling, can improve the drilling accuracy of the coolant channels in medical laser crystals, mainly in the mass production process. Specifically, the reuse of digital models can improve the consistency of mass production and increase assembly efficiency.

[0041] In addressing the technical problems mentioned above, the laser ablation system for corneal endothelial cell transplantation, specifically for the application scenario, often presents the following technical challenge: poor laser operation precision. Considering the specific requirements of this application scenario—adapting to the temperature sensitivity of corneal endothelial cells, meeting the low mechanical stress requirements of the laser lens, and achieving micron-level precision positioning at the ablation interface—we have decided to adopt the following solution: Optionally, the slab laser crystal 5 may also be provided with a precision temperature control channel. This precision temperature control channel can be distributed within the inner region of the light-transmitting end face of the slab laser crystal 5, and it can communicate with the liquid passage in the fixing device 2. The aperture of the precision temperature control channel can be smaller than the aperture of the coolant channel. This precision temperature control channel can be used for precise temperature control of the core area of ​​the laser output. Further precise control of the thermal stress of the slab laser crystal 5 through the precision temperature control channel can improve the control over the stability of the output laser. The fixing device 2 may be provided with a proportional regulating valve and a platinum resistance temperature sensor. The proportional regulating valve can be an electromagnetic proportional regulating valve used to control the flow rate of the coolant. The platinum resistance temperature sensor can be used to monitor the temperature of the slab laser crystal 5 in real time. The probe end of the temperature sensor can be embedded inside the light-transmitting end face of the slab laser crystal 5, and the proportional regulating valve can be configured to adjust the coolant flow rate in the precision temperature control channel based on the feedback signal from the platinum resistance temperature sensor. For example, when the proportional control valve receives a feedback signal from the platinum resistance temperature sensor indicating a 0.1°C increase in crystal temperature, it can increase the coolant flow rate by 1%. The clamping surface of the fixing device 2 can have an array of adsorption holes, which can communicate with a built-in miniature vacuum pump. The diameter of the adsorption holes can be 0.1mm to 0.3mm, without specific limitation. Each adsorption hole can be surrounded by a soft rubber suction cup. The array of adsorption holes can be evenly distributed on the clamping surface of the fixing device 2. The miniature vacuum pump provides negative pressure, and the slab laser crystal 5 is fixed by adsorption force, replacing the traditional mechanical clamping method, thereby reducing the mechanical pressure inside the slab laser crystal 5. The contact area between the slab laser crystal 5 and the fixing device 2 can be covered with a diamond-like carbon coating. The diamond-like carbon coating can improve the wear resistance and thermal conductivity of the contact area, while reducing frictional damage between the fixing device 2 and the slab laser crystal 5. Positioning reference marks can be engraved on the light-transmitting end face of the slab laser crystal 5. The aforementioned positioning reference marks can be cross-shaped or circular grooves, with a line width of 5μm~10μm and a depth of 2μm~5μm, used to provide reference points for subsequent laser positioning. The aforementioned fixing device 2 can be equipped with a microscopic vision positioning component that matches the aforementioned positioning reference marks. The aforementioned microscopic vision positioning component can include an industrial camera and a microscope lens, which can be used to identify the positioning reference marks on the light-transmitting end face of the aforementioned slab laser crystal 5 and determine the position of the aforementioned slab laser crystal 5. The aforementioned pump light source 3 can be equipped with a dynamic beam shaper at its light-emitting end, and the aforementioned dynamic beam shaper can be communicatively connected to the aforementioned microscopic vision positioning component. The aforementioned dynamic beam shaper can include a control board and a spatial light modulator and optical lens group, both communicatively connected to the aforementioned control board.The aforementioned dynamic beam shaper can receive the positioning reference mark deviation data transmitted by the aforementioned microscopic visual positioning component, and adjust the phase, direction, or spot shape of the pump beam in real time to calibrate the incident position of the pump beam. The dynamic beam shaper can be configured to adjust the incident position of the pump beam in real time according to the displayed position of the positioning reference mark. For example, during a laser ablation procedure for corneal endothelial cell transplantation, the aforementioned microscopic visual positioning component can first photograph the positioning reference mark, compare the positioning reference mark with the system's preset reference coordinates, and calculate the deviation value between the current actual position of the lens and the preset position, assuming an X-axis offset of +3μm and a Y-axis offset of -2μm. The aforementioned microscopic visual positioning component can transmit this deviation data to the aforementioned dynamic beam shaper in real time. The spatial light modulator built into the aforementioned dynamic beam shaper receives the instruction and adjusts the phase distribution of the pump beam, allowing the incident position of the pump beam to synchronously compensate for the X-axis offset of -3μm and the Y-axis offset of +2μm. The adjusted pump beam can be precisely projected onto the boundary between diseased endothelial cells and healthy matrix, achieving micron-level ablation. Simultaneously, the aforementioned microscopic vision components can continuously monitor the marked position, enabling dynamic closed-loop adjustment. In summary, by adjusting the incident position of the pump beam, the pump light can be more precisely incident on the gain region of the aforementioned slab laser crystal 5, improving the efficiency and stability of the output laser.

[0042] The above-mentioned optional embodiments, as an inventive point of this disclosure, solve the technical problem of "poor operating accuracy of lasers". The specific factors leading to poor operating accuracy of lasers are as follows: First, the heat generated during the operation of the slab laser crystal cannot be precisely controlled, and temperature fluctuations cause thermal deformation of the crystal, resulting in laser output optical path deviation; second, traditional mechanical clamping methods apply uneven stress to the crystal, causing minute deformation and further aggravating optical path deviation; third, minute displacements during crystal installation or operation cannot be monitored and compensated in real time, leading to misalignment of the pump beam incident position with the preset gain region. Solving these factors can improve the operating accuracy of the laser. To achieve this effect, this disclosure also provides a slab laser crystal assembly structure integrating precision temperature control, low-stress fixing, and positioning compensation functions. On one hand, precise temperature control of the crystal is achieved through the linkage of a precision temperature control channel, a proportional regulating valve, and a platinum resistance temperature sensor. Simultaneously, negative pressure adsorption replaces mechanical clamping, and a diamond-like carbon coating reduces contact friction and stress, lowering the risk of optical path deviation caused by crystal deformation. On the other hand, by using a microscopic vision positioning component to identify the crystal positioning reference mark, positional deviations are captured in real time, and the incident position of the pump beam is adjusted by a dynamic beam shaper to achieve micron-level deviation compensation. This improves the operating accuracy of the laser.

[0043] In addressing the technical issue of poor laser operation precision, the application scenario—laser ablation systems for corneal endothelial cell transplantation in school-aged children—often presents the following challenges: poor safety of the laser equipment. To meet the specific requirements of this application scenario—real-time monitoring of corneal endothelial cell activity during surgery, individualized adaptation to different patients' corneal curvatures, dynamic adjustment of laser energy during the ablation process, and maintaining high reliability under high-frequency use—we have decided to adopt the following solution: Optionally, a miniature Raman spectroscopy probe can be installed on the aforementioned fixation device 2, and the miniature Raman spectroscopy probe can communicate with the temperature sensor built into the fixation device 2. The miniature Raman spectroscopy probe can be a Raman probe. This probe can emit laser light of a specific wavelength towards the target tissue, collect the Raman spectral signal scattered by the tissue, and analyze the spectral characteristics to determine the activity state of corneal endothelial cells in real time, providing a basis for dynamic control of laser energy and reducing the risk of irreversible cell damage during surgery. The detection end of the miniature Raman spectroscopy probe can be installed at the laser output end of the laser. This location facilitates the collection of Raman spectral signals from the target tissue. The fixation device 2 can be equipped with a corneal curvature sensing component, and this component can communicate with the dynamic beam shaper. The corneal curvature sensing component can be a non-contact optical sensor, which can be used to measure the curvature data of the patient's cornea in real time. The aforementioned dynamic beam shaper may further include an achromatic collimator and a polarization controller, with the exit surface of the achromatic collimator coaxially aligned with the incident surface of the polarization controller. The achromatic collimator can calibrate the diverging beam of the pump light source 3 into parallel light, and the polarization controller can adjust the polarization direction of the beam. Coaxial alignment of the two improves the stability of the beam transmission process. The dynamic beam shaper can be configured to adjust the focusing depth and spot shape of the pump beam based on feedback signals from the corneal curvature sensing component. For example, the corneal curvature sensing component can first scan the patient's corneal surface, assuming the collected curvature data indicates that the corneal curvature radius in the lesion area is 0.8 mm smaller than that in the normal area, and exhibits an irregular astigmatic shape. The aforementioned corneal curvature sensing component can transmit the curvature data to the aforementioned dynamic beam shaper, which calculates compensation parameters accordingly. These compensation parameters are assumed to adjust the focusing depth of the pump beam by 12 μm towards the corneal stroma, while simultaneously adjusting the circular spot to an elliptical spot to accommodate astigmatism. The adjusted beam can be focused at the boundary between the diseased endothelium and the healthy stroma, reducing the risk of spot diffusion due to irregular curvature or damage to the posterior elastic layer of the cornea due to excessive focusing. The doped crystal layer 7 of the aforementioned slab laser crystal 5 can be a gradient-doped structure, with the doping concentration linearly transitioning from the central region to the edge region. For example, the doping concentration of the gradient-doped structure can linearly decrease from 0.8 at.% at the center to 0.2 at.% at the edge, to make the gain distribution within the aforementioned slab laser crystal 5 more uniform and improve the quality of the laser beam. The aforementioned pump source 3 can be configured to dynamically adjust its output power based on feedback signals from the aforementioned micro Raman spectroscopy probe and the aforementioned temperature sensor. For example, when the Raman spectroscopy probe detects that the crystal stress is greater than a preset value, or the temperature sensor detects that the temperature is higher than a preset value, the pump source can automatically reduce the output power by 10%, reducing the risk of the above-mentioned slab laser crystal 5 being damaged due to overheating or excessive stress.A backup gas pump can be installed on one side of the aforementioned miniature vacuum pump, and the output interfaces of the miniature vacuum pump and the backup gas pump can be connected in parallel to the circuit of the adsorption orifice via a three-way valve. The three-way valve can realize automatic switching between the main pump and the backup gas pump. When the miniature vacuum pump fails, the backup gas pump can start immediately to maintain the negative pressure of the adsorption orifice and ensure the clamping stability of the slab laser crystal 5.

[0044] The above-mentioned optional embodiments, as an inventive point of this disclosure, solve the technical problem of "poor safety in the use of laser equipment". The specific factors leading to poor safety in the use of laser equipment are as follows: First, the lack of real-time monitoring methods for intraoperative corneal endothelial cell activity makes it impossible to detect cell damage risks in a timely manner; second, the failure to adjust beam parameters according to the differences in corneal curvature among different patients easily causes burns to non-target areas; third, the inability to dynamically control laser energy during the dissection process, and continuous constant power easily leads to lens overheating or irreversible damage to endothelial cells; fourth, the lack of redundancy in the negative pressure clamping system, which easily leads to clamping failure and surgical interruption when the equipment is used frequently. Solving these factors can improve the safety of laser equipment use. To achieve this effect, this disclosure also provides a laser safety control component integrating activity monitoring, individualized adaptation, dynamic energy regulation, and redundancy backup functions. Cell activity is monitored through a micro Raman spectroscopy probe linked with a temperature sensor; a corneal curvature sensing component, in conjunction with a dynamic beam shaper, achieves individualized adjustment of the spot shape and focusing depth; the pump light source dynamically adjusts its output power based on feedback signals; and a backup air pump is configured to ensure stable operation of the clamping system. This improves the safety of using laser equipment.

[0045] In addressing the aforementioned technical problems in the process of adopting technical solutions, the application scenario—the laser welding system for ossicle reconstruction—often presents the following technical issue: the laser can cause collateral damage to the ear. Considering the following requirements for this application scenario: adapting to varying laser energy levels based on different ossicle materials and thicknesses, facilitating the collection of thermal debris during laser welding, and minimizing interference from the micro-vibrations and electromagnetic radiation of the laser equipment on the cochlear hair cells, we have decided to adopt the following solution: Optionally, the pump light source 3 may have a built-in wavelength switching component, which can communicate with an external ossicle ultrasonic thickness measurement probe. The wavelength switching component may include multiple laser diodes of different wavelengths. The ossicle ultrasonic thickness measurement probe can measure the thickness and material density of the ossicles in real time. The wavelength switching component can be configured to automatically adjust the wavelength and energy density of the output beam of the pump light source 3 based on the real-time measured ossicle thickness data. Specifically, for the thicker malleus, the wavelength switching component can select a beam with a shorter wavelength and higher energy density; for the thinner stapes, it can select a beam with a longer wavelength and lower energy density, adapting to the welding requirements of different ossicles. For example, in reconstructive laser welding surgery for patients with congenital ossicular chain malformation, an external ossicular ultrasonic thickness probe measures the malleus body thickness to be 0.8 mm, which is considered a relatively thick ossicular component. In this case, the wavelength switching component automatically selects a short-wavelength beam of 1064 nm and adjusts the energy density to 120 J / cm², ensuring sufficient laser energy to fuse the dense bone of the malleus and form a strong weld surface. When the stapes footplate thickness is detected to be 0.2 mm, which is a thin and brittle component, the wavelength switching component can switch to a long-wavelength beam of 1550 nm and reduce the energy density to 30 J / cm², completing the welding while reducing the risk of perforating the stapes footplate or damaging the surrounding vestibular membrane structure due to excessive energy. A negative pressure adsorption component can be installed on the aforementioned fixation device 2, and the adsorption port of the adsorption component can be coaxially aligned with the laser beam path. The negative pressure adsorption component can include a cylindrical adsorption port and a miniature vacuum generator, and the adsorption port and the miniature vacuum generator can be connected via a pipe. The aforementioned negative pressure adsorption component can capture micro-nano thermal debris generated by laser welding using negative pressure suction, reducing the risk of debris irritating the middle ear mucosa or damaging the cochlear structure. The inner wall of the adsorption port can be coated with an electrostatic adsorption coating for electrostatic capture of micro-nano debris. This electrostatic adsorption coating can be a conductive polymer coating, which generates an electrostatic field when energized, improving debris collection efficiency. The aforementioned negative pressure adsorption component can be connected to a graded filtration and collection component, which can sequentially include a sintered titanium filter, a nanofiber filter membrane, and an electrostatic dust collection chamber. The sintered titanium filter can filter larger debris particles; the nanofiber filter membrane can filter finer particles; and the electrostatic dust collection chamber can store the collected finer particles. By intercepting debris of different particle sizes at each stage, the wear of individual filter components can be reduced, extending the overall component's lifespan and reducing the cost of frequent parts replacement. A piezoelectric ceramic active vibration damping platform can be installed between the aforementioned fixing device 2 and the aforementioned negative pressure adsorption component. This piezoelectric ceramic active vibration damping platform can incorporate a triaxial accelerometer, a piezoelectric ceramic actuator, and a controller. The aforementioned piezoelectric ceramic active vibration damping platform can be configured to drive the piezoelectric ceramic to generate reverse vibration based on the vibration signals collected in real time.The aforementioned triaxial accelerometer can collect the vibration direction and amplitude of the equipment in real time, while the aforementioned piezoelectric ceramic actuator can generate a reverse vibration wave to cancel out the equipment's vibration. For example, assuming the laser equipment generates a micro-vibration with an X-axis amplitude of 5μm and a frequency of 100Hz during operation, the triaxial accelerometer captures this vibration signal in real time and transmits it to the controller. The controller can then calculate the reverse compensation parameters to drive the piezoelectric ceramic actuator to generate a reverse vibration wave with an amplitude of 5μm and a frequency of 100Hz, thus canceling each other out. This ultimately reduces the vibration amplitude transmitted to the surgical area, lowering the risk of vibration damage to the patient's cochlear hair cells. Both the aforementioned pump light source 3 and the aforementioned negative pressure adsorption component can employ a double-layer electromagnetic shielding structure. The inner layer of the aforementioned double-layer electromagnetic shielding structure can be a permalloy shielding layer, and the outer layer can be a conductive silver nano-coating. The aforementioned permalloy shielding layer refers to a protective layer made of permalloy, which has high shielding effectiveness against low-frequency electromagnetic radiation; the aforementioned conductive silver nano-coating has good shielding effect against high-frequency electromagnetic radiation. The aforementioned permalloy shielding layer can be grounded through a grounding terminal. The grounding terminal can guide the electromagnetic radiation collected by the shielding layer to the ground, reducing electromagnetic radiation leakage and protecting sensitive tissues such as the cochlear hair cells from electromagnetic interference.

[0046] The above-mentioned optional embodiments, as an inventive point of this disclosure, solve the technical problem of "lasers causing collateral damage to the ear". The specific factors leading to collateral damage to the ear from lasers are as follows: First, the laser energy parameters cannot be adapted to the thickness and material differences of different ossicles, easily resulting in weak welding of thick ossicles and penetration of thin ossicles, while also damaging surrounding fragile tissues such as the vestibular window membrane; second, the micro-nano-level thermal debris generated by laser welding cannot be effectively collected, and residual debris can irritate the middle ear mucosa, causing inflammation, or enter the cochlea and damage hair cells; third, the micro-vibrations and electromagnetic radiation generated by the operation of laser equipment lack effective shielding measures, directly damaging cochlear hair cells that are highly sensitive to vibration and radiation. If the above factors are solved, the collateral damage to the ear caused by lasers can be reduced. To achieve this effect, this disclosure also provides a laser component integrating differentiated energy regulation, residue-free collection of micro-nano debris, and dual shielding functions for vibration and electromagnetic radiation. Laser energy is adapted through a wavelength switching component linked with an ultrasonic thickness gauge probe; a negative pressure adsorption component works with a graded filtration module to collect debris; a piezoelectric ceramic active vibration damping platform counteracts equipment micro-vibrations; and a double-layer electromagnetic shielding structure blocks high and low frequency electromagnetic radiation. This reduces collateral damage to the ear caused by the laser.

[0047] Some embodiments of this disclosure provide an internal liquid-cooled laser crystal assembly for a medical laser, which can improve the energy stability of the laser output. Specifically, the reason for the poor energy stability of most laser outputs is that commonly used lasers generally employ a copper heat sink soldering heat dissipation scheme. This involves bonding a large portion of the gain medium to the surface of a copper heat sink using indium soldering, relying on the coolant in the internal channels of the heat sink for heat conduction. However, during the heat dissipation process using a copper heat sink for the laser crystal, the inconsistent thermal deformation between the two generates internal stress, leading to wavefront distortion of the crystal and resulting in poor energy stability of the output laser. Based on this, some embodiments of this disclosure provide an internal liquid-cooled laser crystal assembly for a medical laser. The internal liquid-cooled laser crystal assembly includes a slab laser crystal and a fixing device. The fixing device clamps the slab laser crystal, and the edges of the contact surfaces between the fixing device and the slab laser crystal are sealed. The slab laser crystal has a rectangular slab structure. Coolant channels are formed on the slab laser crystal, and the direction of the coolant channels is parallel to the clamping direction of the fixing device. The coolant channels are arranged in two rows along the thickness direction of the slab laser crystal, and the coolant channels in the same row are evenly distributed along the length direction of the slab laser crystal. The spacing between two adjacent coolant channels in the same row is in a first preset relationship with the thickness of the slab laser crystal. The diameter of the coolant channels is in a second preset relationship with the thickness of the slab laser crystal. Both light-transmitting end faces of the slab laser crystal are optically polished and coated with anti-reflection films for the pump light and the emitted laser light, respectively. The fixing device has internal cooling holes that match the coolant channels. By directly creating coolant channels within the slab laser crystal, which serves as the gain medium, cooling is achieved directly from within the crystal, reducing the risk of internal stress and wavefront distortion. This improves the energy stability of the laser output.

[0048] The above description is merely a selection of preferred embodiments of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. An internal liquid-cooled laser crystal assembly for a medical laser, characterized in that, The internal liquid-cooled laser crystal assembly includes a slab laser crystal and a fixing device, wherein... The fixing device clamps the slab laser crystal, and the edge of the contact surface between the fixing device and the slab laser crystal is sealed. The slab laser crystal has a rectangular slab structure; The slab laser crystal has coolant channels, and the direction of the coolant channels is parallel to the clamping direction of the fixing device. The coolant channels are arranged in two rows along the thickness direction of the slab laser crystal, and the coolant channels in the same row are evenly distributed along the length direction of the slab laser crystal. The spacing between two adjacent coolant channels in the same row is related to the thickness of the slab laser crystal by a first preset relationship; The diameter of the coolant flow channel and the thickness of the slab laser crystal are in a second preset relationship; Both light-transmitting end faces of the slab laser crystal are optically polished surfaces, and are respectively coated with anti-reflection films for the pump light and the emitted laser. The fixing device has a liquid passage hole inside that matches the coolant flow channel.

2. The internal liquid-cooled laser crystal assembly of the medical laser according to claim 1, characterized in that, The slab laser crystal has a three-layer bonded structure along its thickness direction, consisting of a first undoped crystal layer, a doped crystal layer, and a second undoped crystal layer, sequentially from one side to the other.

3. The internal liquid-cooled laser crystal assembly of the medical laser according to claim 2, characterized in that, The first undoped crystal layer and the second undoped crystal layer have the same thickness.

4. The internal liquid-cooled laser crystal assembly of the medical laser according to claim 1, characterized in that, Both the coolant flow channel and the liquid passage are filled with coolant.

5. The internal liquid-cooled laser crystal assembly of the medical laser according to claim 4, characterized in that, The coolant is one or more of pure water, Freon, liquid nitrogen, and ethylene glycol.

6. The internal liquid-cooled laser crystal assembly of the medical laser according to claim 1, characterized in that, The internal liquid-cooled laser crystal assembly also includes a pump source, a first cavity mirror, and a second cavity mirror; The first cavity mirror and the second cavity mirror are respectively disposed on both sides of the slab laser crystal; The pump light source is located on one side of the first cavity mirror.

7. The internal liquid-cooled laser crystal assembly of the medical laser according to claim 6, characterized in that, The surface of the first cavity mirror is coated with a reflective film for the emitted laser, and the surface of the second cavity mirror is coated with a partially transmissive film for the emitted laser.

8. The internal liquid-cooled laser crystal assembly of the medical laser according to claim 1, characterized in that, The coolant flow channel is opened by the following steps: The crystal to be processed is calibrated in three dimensions to obtain a calibrated crystal, wherein the calibrated crystal is obtained through the following steps: In response to the completion of the reference plane selection process for the crystal to be processed, the crystal to be processed is laser-scanned to obtain a three-dimensional scanning model of the crystal; The origin of the coordinate system is set for the three-dimensional scanning model of the crystal to obtain the crystal coordinate system; The crystal coordinate system is calibrated to obtain a standard coordinate system; The crystal three-dimensional scanning model is subjected to flow channel positioning marking processing in the standard coordinate system to obtain a positioning marked crystal; The hole position coordinates of the positioning marker crystal are generated to obtain the three-dimensional coordinates of each coolant flow channel; The crystal to be processed is marked based on the three-dimensional coordinates of each coolant flow channel to obtain the calibrated crystal. The calibrated crystal is subjected to laser penetration processing at the drilling positions to obtain a crystal with through holes; The inner wall of the through hole on the crystal with through hole is laser polished to obtain the slab laser crystal.

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