Medical microchip laser with continuously adjustable pulse width and energy

Abstract

Embodiments of the present disclosure disclose a medical microchip laser with continuous adjustable pulse width and energy. A specific embodiment of the medical microchip laser comprises a pump light generating assembly, a bonded crystal microchip, and a crystal translation assembly, wherein the pump light generating assembly is installed in a front position of the bonded crystal microchip; the bonded crystal microchip is fixedly installed on the crystal translation assembly; the bonded crystal microchip is an integrated bonded structure, comprising a first wedge-shaped crystal piece and a second wedge-shaped crystal piece which are of the same structure but different materials, and a gain crystal piece; the first and second wedge-shaped crystal pieces are both prismatic structures with wedge-shaped inclined surfaces; the gain crystal piece is a cuboid structure, and the gain crystal piece and the first wedge-shaped crystal piece are fixedly bonded through a planar end surface, and the first and second wedge-shaped crystal pieces are fixedly bonded through the wedge-shaped inclined surfaces. The bonding of the two wedge-shaped crystal pieces can continuously change the light passing thickness of the saturable absorber. The embodiment can improve the stability of the output beam quality.

Description

Technical Field

[0001] Embodiments of this disclosure relate to the field of medical laser equipment technology, specifically to medical microchip lasers with continuously adjustable pulse width and energy. Background Technology

[0002] Microchip lasers, with their compact structure and excellent beam quality, have been widely used in delicate microsurgical procedures in fields such as otolaryngology and ophthalmology. According to domestic ophthalmological clinical statistics, the number of newly diagnosed patients with pathological vitreous opacities in my country exceeds 3 million annually. Among these, the annual growth rate of patients undergoing laser ablation for vitreous opacities exceeds 15%, and over 60% of these patients also have high myopia or age-related degenerative fundus diseases. These patients have lower tolerance to eye tissues and a more urgent need for precise adaptation of laser treatment parameters. In the clinical application of precision ophthalmic surgery, the volume, location, and tissue toughness of vitreous opacities vary among patients. Clinical procedures typically require continuous adjustment of the single-pulse energy within the range of 0.1mJ to 2mJ, while matching the corresponding pulse width within the range of 1ns to 10ns, to reduce the risk of thermal accumulation and mechanical damage to the peripheral retina and lens.

[0003] However, when using commonly used microchip lasers, the following technical problems often arise: Currently used microchip lasers have a fixed transmittance length for the saturable absorber after crystal bonding. This means that current microchip lasers can only achieve small-range energy adjustments by regulating the pump power, and cannot achieve synchronous pulse width adjustment, making it difficult to adapt to the precise treatment needs of patients with different conditions. Furthermore, currently used microchip lasers are prone to unstable output and large energy fluctuations in the low-energy output range, resulting in poor applicability and beam quality 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 a medical microchip laser with continuously tunable pulse width and energy to address one or more of the technical problems mentioned in the background section above.

[0007] Some embodiments of this disclosure provide a medical microchip laser with continuously adjustable pulse width and energy. The medical microchip laser includes a pump light generating component, a bonding crystal microchip, and a crystal translation component. The pump light generating component is mounted in front of the bonding crystal microchip. The bonding crystal microchip is fixedly mounted on the crystal translation component. The bonding crystal microchip is an integral bonding structure and includes a gain crystal sheet, a first wedge-shaped crystal sheet, and a second wedge-shaped crystal sheet bonded sequentially. The first wedge-shaped crystal sheet and the second wedge-shaped crystal sheet have the same structure but are made of different materials. Both the first and second wedge-shaped crystal sheets are prism structures with wedge-shaped bevels. The gain crystal sheet has a cuboid structure, and one planar end face of the gain crystal sheet is bonded and fixed to the planar end face of the first wedge-shaped crystal sheet, and the wedge-shaped bevel of the first wedge-shaped crystal sheet is bonded and fixed to the wedge-shaped bevel of the second wedge-shaped crystal sheet.

[0008] Optionally, the first wedge-shaped crystal sheet and the second wedge-shaped crystal sheet are bonded together to form a cuboid structure.

[0009] Optionally, the light-transmitting end face of the gain crystal wafer away from the bonding surface is coated with a first dielectric film; the light-transmitting end face of the second wedge-shaped crystal wafer away from the bonding surface is coated with a second dielectric film.

[0010] Optionally, the pump light generating component includes a laser diode, an optical fiber coupler, and a focusing lens group; the laser diode is mounted at the input end of the optical fiber coupler; the output end of the optical fiber coupler and the input end of the focusing lens group are coaxially arranged along the same optical axis, and the output optical axis of the focusing lens group is perpendicular to the light-transmitting end face of the bonding crystal microplate.

[0011] Optionally, the surface of the input lens of the aforementioned focusing lens group is coated with an anti-reflection film corresponding to the wavelength of the laser emitted by the aforementioned laser diode.

[0012] Optionally, the crystal translation assembly includes a translation stage and a crystal clamping fixture; the crystal clamping fixture is fixedly connected to the non-light-transmitting side of the bonded crystal micro-wafer, and the crystal clamping fixture is fixedly installed on the moving end of the translation stage; the translation direction of the translation stage is perpendicular to the light-transmitting direction of the bonded crystal micro-wafer.

[0013] Optionally, the type of translation stage mentioned above is at least one of a manual translation stage and an electric translation stage.

[0014] Optionally, the aforementioned medical microchip laser further includes a housing, a built-in optical reference platform, and a multi-channel heat dissipation fin assembly; the housing is integrally die-cast from aluminum alloy and has mounting feet at the bottom; the mounting feet are inlaid with rubber shock-absorbing pads; the built-in optical reference platform is integrally milled with the bottom surface of the housing; the pump light generating component and the crystal translation component are both fixed to the upper surface of the built-in optical reference platform; the multi-channel heat dissipation fin assembly is integrally formed on the outer walls of opposite sides of the housing; the root of the multi-channel heat dissipation fin assembly is thermally connected to the side of the built-in optical reference platform; the translation stage of the crystal translation component has limiting blocks at both ends, and the side wall of the housing has an optical path calibration reference hole parallel to the translation direction of the translation stage, with a quartz glass plate inlaid in the optical path calibration reference hole.

[0015] Some embodiments of this disclosure provide a medical microchip laser with continuously adjustable pulse width and energy, which can achieve synchronous adjustment of the pulse energy and pulse width of the output laser, thereby improving the stability of the output beam quality. Specifically, the reason for the poor beam quality stability of most microchip lasers is that currently commonly used microchip lasers cannot synchronously adjust the energy and pulse width through the crystal structure, and can only forcibly change the parameters by adjusting the pump power. However, excessively high pump power will cause a severe thermal lensing effect in the gain medium, leading to resonant cavity mode distortion. Based on this, some embodiments of this disclosure provide a medical microchip laser with continuously adjustable pulse width and energy. The medical microchip laser includes a pump light generating component, a bonding crystal microchip, and a crystal translation component. The pump light generating component is mounted in front of the bonding crystal microchip. The bonding crystal microchip is fixedly mounted on the crystal translation component. The bonding crystal microchip is an integral bonding structure and includes a gain crystal chip, a first wedge crystal chip, and a second wedge crystal chip bonded sequentially. The first wedge crystal chip and the second wedge crystal chip have the same structure but different materials. Both the first wedge crystal chip and the second wedge crystal chip are prism structures with wedge-shaped bevels. The gain crystal chip has a cuboid structure, and one planar end face of the gain crystal chip is bonded and fixed to the planar end face of the first wedge crystal chip, and the wedge-shaped bevel of the first wedge crystal chip is bonded and fixed to the wedge-shaped bevel of the second wedge crystal chip. By using a crystal translation component positioned perpendicular to the light transmission direction, the bonded crystal microplate is translated to continuously change the light transmission thickness of the saturable absorber. Without adjusting the pump power or changing the cavity length, the pulse energy and pulse width of the output laser are simultaneously controlled, reducing the risk of thermal lensing effects in the gain medium and resonant cavity mode distortion. This improves the stability of the output beam quality. 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 structure of a medical microchip laser with continuously adjustable pulse width and energy according to some embodiments of this disclosure; Figure 2 A top view of a medical microchip laser with continuously adjustable pulse width and energy 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 structure of a medical microchip laser with continuously adjustable pulse width and energy according to some embodiments of this disclosure. Figure 1 It includes a pump light generating component 1, a crystal translation component 2, a gain crystal 3, a first wedge crystal 4, and a second wedge crystal 5.

[0025] Figure 2 A top view of a medical microchip laser with continuously adjustable pulse width and energy according to some embodiments of this disclosure. Figure 2 It includes a pump light generating component 1, a crystal translation component 2, a gain crystal 3, a first wedge crystal 4, and a second wedge crystal 5.

[0026] In some embodiments, the aforementioned medical microchip laser with continuously adjustable pulse width and energy may include a pump light generating component 1, a bonded crystal microchip, and a crystal translation component 2. The pump light generating component 1 may be mounted in front of the bonded crystal microchip. The pump light generating component 1 provides a pump source for the medical microchip laser, providing energy input for the laser oscillation process. For example, the pump light generating component 1 may be a laser diode, without specific limitation. The bonded crystal microchip may be fixedly mounted on the crystal translation component 2. The bonded crystal microchip may be the optical resonator unit of the medical microchip laser, capable of laser gain amplification and passive Q-switched pulse output. The bonded crystal microchip may be an integral bonding structure and may include a gain crystal chip 3, a first wedge-shaped crystal chip 4, and a second wedge-shaped crystal chip 5 bonded sequentially. The wedge shape may refer to a triangular or quadrangular prism structure with a right-angled triangle or trapezoidal top surface. The first wedge-shaped crystal chip 4 and the second wedge-shaped crystal chip 5 may be crystal chips with the same structure but different materials. For example, the first wedge-shaped crystal sheet 4 can be made of pure YAG crystal material, and the second wedge-shaped crystal sheet 5 can be made of Cr. 4+The two different YAG crystal materials can respectively perform optical path compensation and passive Q-switching functions. Both the first wedge-shaped crystal plate 4 and the second wedge-shaped crystal plate 5 can be prism structures with wedge-shaped bevels. The wedge-shaped bevel can refer to the side face corresponding to the hypotenuse of the right triangle or the inclined leg of the right trapezoid in a triangular or quadrangular prism with a right-angled triangle or trapezoid as its top face. The wedge-shaped bevel can serve as the bonding contact surface between the two wedge-shaped crystals, enabling them to be bonded and fixed together. The gain crystal plate 3 can be a cuboid structure, and one planar end face of the gain crystal plate 3 can be bonded and fixed to the planar end face of the first wedge-shaped crystal plate 4, while the wedge-shaped bevel of the first wedge-shaped crystal plate 4 can be bonded and fixed to the wedge-shaped bevel of the second wedge-shaped crystal plate 5. For example, the gain crystal plate 3 can be made of Nd:YAG crystal material, which can achieve population inversion under pump light excitation, providing gain for laser output. The aforementioned bonding and fixing can be accomplished using a bonding process, enabling the formation of adhesive-free, low-loss optical connections between different crystal sheets. Specifically, this bonding process can refer to a process where two crystals are first bonded together at room temperature using van der Waals forces, followed by high-temperature heat treatment in an inert atmosphere (e.g., 1000–1300°C) to allow interfacial atoms to diffuse and form covalent / ionic bonds.

[0027] Optionally, such as Figure 1 and Figure 2 As shown, the first wedge-shaped crystal sheet 4 and the second wedge-shaped crystal sheet 5, after being bonded together, can form a cuboid structure. The total thickness of the cuboid structure can remain constant, ensuring that the total optical path length remains consistent regardless of the translational position of the two bonded crystals. The external dimensions of the cuboid structure can match the external dimensions of the gain crystal sheet 3, ensuring that the overall shape of the bonded crystal micro-sheet remains regular.

[0028] Optionally, the light-transmitting end face of the gain crystal 3 away from the bonding surface can be coated with a first dielectric film. The light-transmitting end face of the second wedge-shaped crystal 5 away from the bonding surface can be coated with a second dielectric film. Both the first and second dielectric films can be multilayer optical dielectric film systems. The first dielectric film can enhance the transmission of pump light and provide high reflectivity to the output laser of the medical microchip laser. The second dielectric film can partially transmit the output laser of the medical microchip laser. For example, when the pump light wavelength is 808 nm and the output laser wavelength is 1064 nm, the first and second dielectric films can be 20-layer film systems formed by alternating stacks of tantalum pentoxide and silicon dioxide, and 10-layer film systems formed by alternating stacks of tantalum pentoxide and silicon dioxide, respectively. The first dielectric film has a transmittance of ≥95% for 808 nm pump light and a reflectivity of ≥99.8% for 1064 nm fundamental frequency laser. The second dielectric film has a transmittance of 15% and a reflectance of 85% for a 1064nm fundamental frequency laser. The first dielectric film and the second dielectric film together can constitute the resonant cavity mirror of a medical microchip laser, providing optical feedback conditions for laser oscillation.

[0029] Optionally, the pump light generating component 1 may include a laser diode, a fiber coupler, and a focusing lens group. The laser diode can be the pump source of the medical microchip laser, capable of emitting pump light of a fixed wavelength. The laser diode can be mounted at the input end of the fiber coupler. The fiber coupler can perform beam shaping and transmission of the pump light emitted by the laser diode, optimizing the beam quality of the pump light. The output end of the fiber coupler can be coaxially arranged with the input end of the focusing lens group along the same optical axis. The focusing lens group can focus the pump light output from the fiber coupler, focusing it into the interior of the gain crystal 3. The output optical axis of the focusing lens group can be perpendicular to the light-transmitting end face of the bonded crystal microchip, allowing the pump light to be incident perpendicularly onto the light-transmitting end face of the bonded crystal microchip, improving the coupling efficiency of the pump light.

[0030] Optionally, the surface of the input lens of the aforementioned focusing lens group can be coated with an antireflection film corresponding to the wavelength of the laser emitted by the laser diode. The antireflection film can be a multilayer optical dielectric film system, capable of reducing the reflection loss of the pump light on the lens surface and improving the transmittance of the pump light. Specifically, the antireflection film can be a multilayer dielectric film system using alternating stacks of tantalum pentoxide and silicon dioxide, directly deposited on the incident surface of the input lens of the aforementioned focusing lens group using a vacuum electron beam evaporation process. For example, if the wavelength of the laser emitted by the laser diode is 808 nm, the antireflection film can be a film system with four layers of alternating stacks of tantalum pentoxide and silicon dioxide; no specific limitation is made here. The center wavelength of the antireflection film can be consistent with the emission center wavelength of the laser diode, achieving a stable antireflection effect within the target operating wavelength band.

[0031] Optionally, the crystal translation component 2 may include a translation stage and a crystal clamping fixture. The crystal clamping fixture can clamp and fix the bonded crystal micro-wafer, restricting its spatial displacement. The crystal clamping fixture can be fixedly connected to the non-light-transmitting side of the bonded crystal micro-wafer and can be fixedly mounted on the moving end of the translation stage. The crystal clamping fixture can be used to fix the bonded crystal micro-wafer inside the laser. For example, the crystal clamping fixture can be a frame structure made of oxygen-free copper, and its overall shape can be U-shaped or rectangular; no specific limitation is made, as long as it can fix the bonded crystal micro-wafer. The translation stage can drive the crystal clamping fixture and the bonded crystal micro-wafer to perform linear translational motion, changing the incident position of the pump light on the bonded crystal micro-wafer. The translation direction of the translation stage can be perpendicular to the light-transmitting direction of the bonded crystal micro-wafer, ensuring that the total light-transmitting length of the bonded crystal micro-wafer is not changed during translation. The aforementioned translation stage can drive the aforementioned bonded crystal microplate to translate. For example, the aforementioned translation stage can be an electric displacement stage that uses a stepper motor to drive a ball screw to move a slider.

[0032] Optionally, the aforementioned translation stage can be at least one of a manual translation stage and an electric translation stage. The manual translation stage allows for translational movement through manual adjustment, making it suitable for applications without electrical control. For example, the manual translation stage may include a slider and a screw. The slider has a threaded hole that matches the screw. The slider and screw are screwed together through the threaded hole. The user can drive the slider to perform linear displacement by rotating the screw. The electric translation stage allows for translational movement through electrical signals, making it suitable for automated control applications. For example, the electric translation stage may be an electric displacement stage that uses a stepper motor to drive a ball screw to move the slider.

[0033] Optionally, the aforementioned medical microchip laser with continuously adjustable pulse width and energy may further include a housing, a built-in optical reference platform, and a multi-channel heat dissipation fin assembly. The housing may be a square structure integrally die-cast from aluminum alloy. The bottom of the housing may be provided with mounting feet. These mounting feet may be cylindrical protrusions providing support for the medical microchip laser. Rubber shock-absorbing pads may be embedded inside the mounting feet. These rubber shock-absorbing pads may be cylindrical rubber blocks, capable of absorbing externally transmitted vibrations and reducing the impact of vibrations on the internal optical components of the medical microchip laser. The built-in optical reference platform may be integrally milled with the bottom surface of the housing. The built-in optical reference platform may be a rectangular flat plate structure, providing a unified mounting reference for the optical components of the medical microchip laser. Both the pump light generating component 1 and the crystal translation component 2 can be fixed to the upper surface of the built-in optical reference platform using locating pins and screws. The locating pins may be cylindrical pins, improving the coaxiality between the pump light generating component 1 and the crystal translation component 2. The aforementioned multi-channel heat dissipation fin assembly can be integrally formed on the outer walls of opposite sides of the aforementioned housing. The multi-channel heat dissipation fin assembly can consist of multiple parallel rectangular fins, increasing the contact area between the housing and the outside air. The root of the multi-channel heat dissipation fin assembly can be thermally connected to the side of the aforementioned built-in optical reference platform. For example, the thermal connection can refer to the root of the multi-channel heat dissipation fin assembly being tightly fitted and pressed against the built-in optical reference platform. The heat generated on the built-in optical reference platform can be transferred to the outside air through the multi-channel heat dissipation fin assembly, achieving passive heat dissipation for the aforementioned medical microchip laser. Limiting blocks can be provided at both ends of the translation stage of the aforementioned crystal translation component 2. The limiting blocks can be rectangular metal blocks, limiting the maximum translation stroke of the translation stage and preventing it from exceeding its working range. The side wall of the aforementioned housing can be provided with an optical path calibration reference hole parallel to the translation direction of the translation stage. The optical path calibration reference hole can be a circular through hole, providing an observation channel for the optical path calibration of the aforementioned medical microchip laser. A quartz glass plate can be embedded in the aforementioned optical path calibration reference hole. This quartz glass plate can be a thin, circular sheet, allowing the calibration laser to pass through while preventing dust from entering the housing. For example, during laser debugging, the calibration beam can pass through the quartz glass plate and the aforementioned optical path calibration reference hole into the housing. The operator can observe the beam's landing point from outside the hole and fine-tune the installation positions of the pump light generating component 1 and the crystal translation component 2 against a standard position, gradually completing the coaxial calibration of the optical path.

[0034] In addressing the technical problems mentioned above by adopting technical solutions, the intended application scenario—for precision ophthalmic surgery (such as laser ablation of vitreous opacities)—often presents the following technical issues: harmful stray light in the laser output and unstable light output at low energy levels leading to poor laser output quality. Considering the following requirements for this application scenario: adaptation to output without harmful second harmonics, stable light output at low energy thresholds, and adaptation to no mechanical vibration interference during translation, we decided to adopt the following solution: A polarization grating structure can be fabricated on the bonding surface of the first wedge-shaped crystal sheet 4 and the second wedge-shaped crystal sheet 5. This polarization grating structure can be a grating formed on the bonding surface of the first wedge-shaped crystal sheet 4 or the second wedge-shaped crystal sheet 5 using micro-nano etching technology. The polarization grating structure can be composed of periodically arranged micro-grooves, the width of each groove being smaller than the fundamental frequency laser wavelength. The fundamental frequency laser can be the native laser generated by direct intracavity oscillation when the gain crystal sheet 3 is pumped. Both the light-transmitting end face of the gain crystal sheet 3 away from the bonding surface and the light-transmitting end face of the second wedge-shaped crystal sheet 5 away from the bonding surface can be coated with a dielectric suppression film. This dielectric suppression film can be deposited onto the crystal end face using vacuum evaporation, and can be layered on two independent light-transmitting end faces. For example, the dielectric suppression film can be a multilayer stack composed of alternating layers of tantalum pentoxide, silicon dioxide, and magnesium fluoride optical media. The aforementioned dielectric suppression film can achieve high transmission of the output laser while reflecting and trapping stray light such as residual pump light. The aforementioned gain crystal 3 can be a neodymium-doped yttrium aluminum garnet crystal. On the side of the gain crystal 3 bonded to the first wedge-shaped crystal 4, a gain region with a gradually changing neodymium ion concentration along the optical axis can be provided, and the neodymium ion concentration in the gain region can increase from the center of the gain crystal 3 towards the bonding surface. The aforementioned neodymium-doped yttrium aluminum garnet crystal can be prepared using a single-crystal pulling process, and the aforementioned gain region can undergo ion doping gradient processing during the crystal raw material growth stage. The high-concentration region of the aforementioned gain region is close to the bonding surface, which allows for a more uniform distribution of heat load within the crystal, reducing refractive index distortion caused by localized overheating. For example, the neodymium ion concentration in the aforementioned gain region can linearly increase from 0.3% in the center of the crystal to 1.2% at the bonding surface. The light-transmitting end face of the aforementioned gain crystal 3 away from the bonding surface can integrate a microlens array matching the pump light spot. The aforementioned microlens array can be composed of multiple microlenses arranged in a regular array. This microlens array can improve the coupling efficiency of the pump light, allowing it to be more uniformly focused into the gain region. Each microlens in the array focuses independently on a single pump spot unit, increasing the interaction area between the pump light and the gain medium, thus reducing reflection and scattering losses. For example, the microlens array can be a 3×3 square arrangement, with each microlens having a focal length of 0.5 mm, without specific limitations. The center of each microlens in the array can be coaxially aligned with the center of the pump light spot. The microlens array can be integrally formed with the three end faces of the gain crystal wafer using a molding process. The non-light-transmitting side of the bonded crystal microwafer can be flexibly connected to an elastic support arm. This elastic support arm can be made from a flexible alloy material and can provide lateral support and restraint to the bonded crystal microwafer.The aforementioned elastic support arm can be a symmetrically distributed cantilever beam structure, integrally formed from elastic materials such as beryllium copper alloy, with its root connected to the crystal clamping fixture. A flexible clamping head can be provided at the free end of the elastic support arm, and the inner surface of the flexible clamping head can be adapted to the contour of the non-light-transmitting side of the bonded crystal micro-film. The flexible clamping head can be an arc-shaped structure located at the free end of the elastic support arm, with its inner surface contour adapted to the non-light-transmitting side of the bonded crystal micro-film. For example, the inner contour of the flexible clamping head can be milled based on the shape of the crystal side. A polyimide buffer layer can be attached to the inner surface of the flexible clamping head, and the polyimide buffer layer can be tightly adhered to the non-light-transmitting side of the bonded crystal micro-film. The polyimide buffer layer can be a thin sheet of polyimide film attached to the inner surface of the flexible clamping head. The aforementioned polyimide buffer layer can be cut into a thin sheet structure, and the aforementioned polyimide buffer layer can be fixed to the inner surface of the aforementioned flexible clamping head by means of adhesive auxiliary material.

[0035] The above-described optional embodiments, as an inventive point of this disclosure, solve the technical problem of "poor laser output quality in precision ophthalmic surgery scenarios." The specific factors leading to poor laser output quality are as follows: nonlinear effects within the laser cavity generate harmful stray light such as second harmonics, which conventional films cannot effectively suppress, easily causing irreversible damage to delicate ocular tissues; uneven thermal distribution in the gain region induces thermal lensing effects, and low pump light coupling efficiency makes it difficult to maintain stable laser oscillation at low energy thresholds. Solving these factors can improve laser output quality. To achieve this effect, this disclosure also provides a medical microchip laser for precision ophthalmic surgery. By using a subwavelength polarization grating structure combined with a multi-band dielectric suppression film, harmful second harmonics and residual pump light output are suppressed; by optimizing the internal thermal distribution of the crystal through a neodymium ion concentration-gradient gain region, combined with an end-face integrated microlens array to improve pump light coupling efficiency, continuous and stable light output at low energy thresholds is achieved. Thus, the laser output quality is improved.

[0036] In addressing the aforementioned technical issues of poor laser output quality, and considering the intended application scenario—precise ophthalmic surgery for patients with high myopia (such as vitreous opacity ablation)—the following technical problems often arise: In such cases, the elongated axial length, thinner retina, and presence of degenerative areas in the eye of highly myopic patients significantly reduce their tolerance to changes in laser polarization and thermal radiation, increasing the risk of burns to healthy areas of the patient's eye and resulting in poor laser safety. To meet the following requirements for this application scenario—constant laser polarization output, zero infrared thermal radiation leakage, and suppression of self-focusing effects—we have decided to adopt the following solution: The aforementioned polarization grating structure can be fabricated on the wedge-shaped bonding surface of the first wedge-shaped crystal sheet 4, and the grating stripes can extend along the translation direction perpendicular to the crystal translation component 2. The grating stripes can refer to periodically arranged microgrooves within the polarization grating structure. The grating stripes can be uniformly arranged laterally along the inclined surfaces of the first wedge-shaped crystal sheet 4 and the second wedge-shaped crystal sheet 5, and the arrangement direction of the grating stripes can be perpendicular to the movement direction of the crystal translation component 2. The grating duty cycle of the aforementioned polarization grating structure can change continuously and linearly along the translation direction of the crystal translation component 2, and the direction of the grating stripes can be parallel to the polarization direction of the laser resonator. The linearly changing duty cycle along the translation direction allows for a continuous change in the average duty cycle of the effective working area of ​​the grating during the translation of the bonded crystal microsheet, thereby achieving non-jumping adjustment of the polarization degree. The grating duty cycle can be gradually varied using segmented etching, and the orientation of the grating stripes can be aligned with the polarization direction of the resonator. For example, the aforementioned polarization grating structure can be a grating etched on the bonding surface of the first wedge-shaped crystal, with a period of 800 nm, a groove depth of 150 nm, and a duty cycle linearly increasing from 0.2 to 0.8 along the translation direction. The fringe direction can be parallel to the polarization direction of the laser resonator. The aforementioned dielectric suppression film can be a film system formed by alternating stacking of three materials: silicon dioxide, tantalum pentoxide, and magnesium fluoride. The three coating materials can be deposited in multiple layers in turn, and the film system can be stacked in layers to form the overall structure of the dielectric suppression film. The light-transmitting end face of the gain crystal 3 away from the bonding surface can be integrated with an infrared cutoff film. The infrared cutoff film can be disposed between the microlens array and the gain crystal 3. The infrared cutoff film can be deposited on the crystal end face first, and then the microlens array can be formed on the outside of the infrared cutoff film. The infrared cutoff film can further block stray light and thermal radiation in the infrared band, preventing them from entering the resonator and interfering with laser oscillation or being output to the treatment end and causing thermal damage to the eye. For example, an infrared cutoff film can be formed by alternating deposition of six layers of germanium and zinc sulfide, deposited on the end face of the gain crystal. This film exhibits a reflectivity >99% for infrared light in the 1100-1700 nm range and a transmittance >98% for light in the 808 nm and 1064 nm ranges. A phase-type self-focusing compensation grating can be fabricated on the light-transmitting end face of the second wedge-shaped crystal 5 away from the bonding surface. This phase-type self-focusing compensation grating can be a binary phase grating fabricated on the light-transmitting end face of the second wedge-shaped crystal away from the bonding surface, possessing phase grooves of varying depths. Furthermore, the grating fringe direction of this binary phase grating can be perpendicular to the fringe direction of the subwavelength polarization grating structure. This phase-type self-focusing compensation grating can compensate for the self-focusing phenomenon caused by the nonlinear Kerr effect during laser propagation in the crystal, improving beam quality at high energy output and reducing laser focus distortion.The reason is that when a high-power laser passes through a crystal, the crystal's refractive index increases with increasing light intensity, causing the beam to converge towards the center (self-focusing). A phase-type self-focusing compensation grating, by introducing divergent phase modulation opposite to the self-focusing effect, counteracts the beam convergence caused by the refractive index change, thus improving beam collimation. For example, the aforementioned phase-type self-focusing compensation grating can be a binary phase grating etched on the light-emitting end face of the second wedge-shaped crystal, with a period of 2 μm, a groove depth of 300 nm, and fringe direction perpendicular to the subwavelength polarization grating. It can be used to compensate for self-focusing effects with peak power below 10 MW / cm². The aforementioned phase-type self-focusing compensation grating can be fabricated on the outer end face of the crystal using a dry etching process.

[0037] The above-described optional embodiments, as an inventive point of this disclosure, solve the technical problem of "poor laser safety." The specific factors leading to poor laser safety are as follows: Highly myopic users have elongated eyeballs, thinner retinas with degenerative areas, significantly reducing their tolerance to changes in laser polarization and thermal radiation; currently used polarization control methods experience polarization jumps during parameter adjustment, causing laser focus shift and easily damaging fragile retinal tissue; a single dielectric film layer is ineffective at blocking infrared thermal radiation, and leaked infrared light is strongly absorbed by the retinal pigment epithelium, causing irreversible thermal damage; high-energy lasers propagate through the crystal, generating a nonlinear Kerr effect, inducing self-focusing, leading to beam distortion and focus diffusion, further reducing laser output accuracy. Solving these factors can improve laser safety. To achieve this effect, this disclosure also provides a laser for users with high myopia. On the one hand, a subwavelength polarization grating structure with a linearly gradually changing duty cycle enables continuous, non-jumping adjustment of the laser polarization, improving the stability of the output laser polarization. An infrared cutoff film further enhances the blocking effect against multi-band stray light and infrared thermal radiation. On the other hand, a phase-type self-focusing compensation grating introduces reverse diverging phase modulation to counteract the self-focusing effect generated by laser propagation in the crystal, improving beam quality and focus stability at high energy output. This enhances the safety of the medical microchip laser.

[0038] In addressing the aforementioned technical problems in the process of adopting technical solutions, the application scenario—laser-assisted posterior capsular capsulotomy for posterior cataracts—often presents the following technical challenges: In this scenario, backscattered light interferes with laser resonance, and the birefringence of different intraocular lenses causes focal shift, resulting in poor laser output stability. Considering the following requirements for this application scenario—adaptability to the absence of backscattered light and compatibility with different intraocular lens materials—we have decided to adopt the following solution: Optionally, a Faraday isolator can be provided at the laser output end of the aforementioned bonded crystal microplate. The Faraday isolator can be fixed at the optical path output position using a metal bracket, and can be arranged on the light output path of the aforementioned bonded crystal microplate. The optical axis of the Faraday isolator can be coaxially arranged with the laser optical axis output from the aforementioned bonded crystal microplate, so that the central optical path of the Faraday isolator and the light output path of the aforementioned bonded crystal microplate are aligned. The Faraday isolator can utilize the Faraday magneto-optical effect to block backscattered and reflected light returning from the eye during surgery, preventing it from entering the laser resonator and causing oscillation instability, mode jumps, or even damage to the gain crystal. A rotatable half-wave plate assembly can be provided between the aforementioned pump light generating component 1 and the aforementioned bonded crystal microplate. The half-wave plate assembly can be sandwiched between the aforementioned pump light generating component 1 and the crystal optical path. The rotation axis of the half-wave plate assembly can be aligned with the optical axis of the pump light. The aforementioned half-wave plate assembly can continuously adjust the polarization direction of the output laser to adapt to the birefringence characteristics of intraocular lenses made of different materials (acrylate, silicone gel, hydrogel), thereby improving the stability of the laser focal position and energy distribution. The half-wave plate assembly may include a waveplate, a waveplate mounting base, a fixing base, ball bearings, a graduated rotary adjustment ring, and locking screws. The waveplate may be a half-wave plate made of quartz. It can be used to adjust the laser polarization direction. The waveplate mounting base may be a cylindrical metal base with a circular through-hole in the center matching the outer diameter of the waveplate. The inner wall of the through-hole has steps to support the edge of the half-wave plate. The waveplate mounting base can serve as the direct support component for the waveplate, rigidly fixing it with optical adhesive or a pressure ring to ensure that the optical axis of the waveplate is coaxial with the rotation axis of the waveplate mounting base. The fixing base may be an integral stepped cylindrical metal structure with an internal hole for mounting ball bearings, and a flange or threaded interface at the bottom for fixing to the laser housing. The outer surface of the aforementioned fixed base may be engraved with an axial indicator line, which aligns with the scale of the aforementioned rotating adjustment ring to read the angle. The fixed base serves as a fixed reference for the aforementioned half-wave plate assembly, providing rigid support for the rotating part. The aforementioned ball bearing enables low-friction rotation of the wave plate mounting base relative to the aforementioned fixed base, reducing rotational resistance and improving the smoothness of angle adjustment. The aforementioned rotating adjustment ring may be an annular metal sleeve, fitted onto the outside of the aforementioned fixed base. Its inner end face is rigidly connected to the end face of the aforementioned wave plate mounting base via a pin, and its outer circumferential surface is engraved with circumferentially evenly distributed angle scale lines (e.g., the total scale range can be 0~360°). The sidewall of the aforementioned rotating adjustment ring may have radial threaded holes for installing the aforementioned locking screws. The aforementioned rotating adjustment ring can serve as a manually adjustable operating component. By rotating the aforementioned rotating adjustment ring, the aforementioned wave plate mounting base and the aforementioned wave plate rotate synchronously. The scale lines align with the indicator line on the aforementioned fixed base, allowing the reading of the rotation angle of the aforementioned wave plate, thus achieving quantitative adjustment of the laser polarization direction.The locking screw can be an internal hexagonal or slotted head screw, and its threaded portion matches the threaded hole on the side wall of the rotary adjusting ring. The locking screw locks the relative position of the rotary adjusting ring and the fixed base after the wave plate is adjusted to the target angle. For example, the assembly relationship of the wave plate, the wave plate mounting base, the fixed base, the ball bearing, the rotary adjusting ring, and the locking screw can be as follows: the wave plate can be fitted and fixed in the central through hole of the wave plate mounting base, and the outer cylindrical surface of the wave plate mounting base can be rotatably engaged with the inner hole of the fixed base through the ball bearing. The wave plate can be snapped into the central opening of the wave plate mounting base, and the ball bearing can fill the gap between the wave plate mounting base and the fixed base. The aforementioned rotating adjusting ring can be sleeved on the outside of the aforementioned fixed base, and the inner end face of the rotating adjusting ring can be fixedly connected to the end face of the aforementioned waveplate mounting base by a pin. The outer circumferential surface of the rotating adjusting ring can be provided with circumferentially evenly distributed angle scale lines, and the outer surface of the aforementioned fixed base can be provided with indicator marks corresponding to the aforementioned angle scale lines. The aforementioned pin can pass through the aforementioned rotating adjusting ring and the aforementioned waveplate mounting base to achieve a fixed connection between the two. The aforementioned locking screw can be radially inserted into the side wall of the aforementioned rotating adjusting ring, and the end of the aforementioned locking screw can abut against the outer surface of the aforementioned fixed base to lock the rotational position. The aforementioned locking screw can be screwed into the threaded hole in the side wall along the radial direction of the aforementioned rotating adjusting ring, and the end of the aforementioned locking screw can restrict the circumferential rotation of the aforementioned rotating adjusting ring by means of compression.

[0039] The above-described optional embodiments, as an inventive point of this disclosure, solve the technical problem of "poor laser output stability." The specific factors leading to poor laser output stability are as follows: During surgery, laser irradiation of the intraocular lens optical surface, posterior capsule, and intraocular tissue generates backscattered light, which, upon returning to the laser resonant cavity, causes oscillation instability, mode jumps, and energy fluctuations; the birefringence characteristics of intraocular lenses made of different materials differ, altering the polarization direction of the incident laser, leading to laser focal point shift and uneven energy distribution. Solving these factors improves laser output stability. To achieve this effect, this disclosure also provides a laser for laser posterior capsulotomy in posterior cataract surgery. By coaxially setting a Faraday isolator at the laser output end, unidirectional laser transmission is achieved using the Faraday magneto-optical effect, blocking backscattered and reflected light returning from the eye; the polarization direction of the output laser is continuously and seamlessly adjusted by a rotatable half-wave plate assembly, offsetting the birefringence effects of intraocular lenses made of different materials, ensuring the stability of the laser focal point position and energy distribution. This improves laser output stability.

[0040] Some embodiments of this disclosure provide a medical microchip laser with continuously adjustable pulse width and energy, which can achieve synchronous adjustment of the pulse energy and pulse width of the output laser, thereby improving the stability of the output beam quality. Specifically, the reason for the poor beam quality stability of most microchip lasers is that currently commonly used microchip lasers cannot synchronously adjust the energy and pulse width through the crystal structure, and can only forcibly change the parameters by adjusting the pump power. However, excessively high pump power will cause a severe thermal lensing effect in the gain medium, leading to resonant cavity mode distortion. Based on this, some embodiments of this disclosure provide a medical microchip laser with continuously adjustable pulse width and energy. The medical microchip laser includes a pump light generating component, a bonding crystal microchip, and a crystal translation component. The pump light generating component is mounted in front of the bonding crystal microchip. The bonding crystal microchip is fixedly mounted on the crystal translation component. The bonding crystal microchip is an integral bonding structure and includes a gain crystal chip, a first wedge crystal chip, and a second wedge crystal chip bonded sequentially. The first wedge crystal chip and the second wedge crystal chip have the same structure but different materials. Both the first wedge crystal chip and the second wedge crystal chip are prism structures with wedge-shaped bevels. The gain crystal chip has a cuboid structure, and one planar end face of the gain crystal chip is bonded and fixed to the planar end face of the first wedge crystal chip, and the wedge-shaped bevel of the first wedge crystal chip is bonded and fixed to the wedge-shaped bevel of the second wedge crystal chip. By using a crystal translation component positioned perpendicular to the light transmission direction, the bonded crystal microplate is translated to continuously change the light transmission thickness of the saturable absorber. Without adjusting the pump power or changing the cavity length, the pulse energy and pulse width of the output laser are simultaneously controlled, reducing the risk of thermal lensing effects in the gain medium and resonant cavity mode distortion. This improves the stability of the output beam quality.

[0041] 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. A medical microchip laser with continuously adjustable pulse width and energy, characterized in that, The medical microchip laser includes a pump light generating component, a bonded crystal microchip, and a crystal translation component, wherein... The pump light generating component is installed at the front position of the bonded crystal microplate; The bonded crystal microplate is fixedly mounted on the crystal translation assembly; The bonded crystal microplate is an integral bonded structure, and includes a gain crystal plate, a first wedge crystal plate and a second wedge crystal plate bonded sequentially. The first wedge-shaped crystal sheet and the second wedge-shaped crystal sheet are crystal sheets with the same structure but different materials; Both the first wedge-shaped crystal sheet and the second wedge-shaped crystal sheet are prism structures with wedge-shaped bevels; The gain crystal is a cuboid structure, and one planar end face of the gain crystal is bonded and fixed to the planar end face of the first wedge crystal. The wedge-shaped slope of the first wedge crystal is bonded and fixed to the wedge-shaped slope of the second wedge crystal.

2. The medical microchip laser with continuously adjustable pulse width and energy according to claim 1, characterized in that, The first wedge-shaped crystal sheet and the second wedge-shaped crystal sheet are bonded together to form a cuboid structure.

3. The medical microchip laser with continuously adjustable pulse width and energy according to claim 1, characterized in that, The light-transmitting end face of the gain crystal wafer away from the bonding surface is coated with a first dielectric film; the light-transmitting end face of the second wedge-shaped crystal wafer away from the bonding surface is coated with a second dielectric film.

4. The medical microchip laser with continuously adjustable pulse width and energy according to claim 1, characterized in that, The pump light generating assembly includes a laser diode, an optical fiber coupler, and a focusing lens group; The laser diode is mounted at the input end of the fiber optic coupler; The output end of the fiber optic coupler and the input end of the focusing lens group are coaxially arranged along the same optical axis, and the output optical axis of the focusing lens group is perpendicular to the light-transmitting end face of the bonded crystal microplate.

5. The medical microchip laser with continuously adjustable pulse width and energy according to claim 4, characterized in that, The input lens surface of the focusing lens group is coated with an anti-reflection film corresponding to the wavelength of the laser emitted by the laser diode.

6. The medical microchip laser with continuously adjustable pulse width and energy according to claim 1, characterized in that, The crystal translation assembly includes a translation stage and a crystal clamping fixture; The crystal clamping fixture is fixedly connected to the non-light-transmitting side of the bonded crystal micro-wafer, and the crystal clamping fixture is fixedly installed on the moving end of the translation stage; The translation direction of the translation stage is perpendicular to the light transmission direction of the bonded crystal microplate.

7. The medical microchip laser with continuously adjustable pulse width and energy according to claim 6, characterized in that, The translation stage is at least one of a manual translation stage and an electric translation stage.

8. The medical microchip laser with continuously adjustable pulse width and energy according to claim 6, characterized in that, The medical microchip laser also includes a housing, a built-in optical reference platform, and a multi-channel heat dissipation fin assembly; The outer shell is integrally die-cast from aluminum alloy and has mounting feet at the bottom; The mounting feet are internally fitted with rubber shock-absorbing pads; The built-in optical reference platform and the bottom surface of the outer shell are integrally milled together; Both the pump light generating component and the crystal translation component are fixed to the upper surface of the built-in optical reference platform; The multi-channel heat dissipation fins are integrally formed on the outer walls of opposite sides of the housing; The root of the multi-channel heat dissipation fin assembly is thermally connected to the side of the built-in optical reference platform; The translation stage of the crystal translation assembly is provided with limiting blocks at both ends. The side wall of the outer shell is provided with an optical path calibration reference hole parallel to the translation direction of the translation stage. A quartz glass plate is embedded in the optical path calibration reference hole.

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