Laser ablation system and method of operation

Abstract

The application relates to a laser ablation system and a working method. The laser beam and the indicating light are combined through a beam alignment module, the laser beam is ensured to stably enter a plaque target position, and the ablation reliability is improved; the laser energy is monitored in real time through an energy monitoring module, the outgoing energy is adjusted, the outgoing energy is ensured to be stably in a required ablation range, the laser parameters of a laser emission module need not to be adjusted, the ablation complexity is reduced, the plaque ablation effect is ensured, the damage risk of a laser catheter is reduced; the laser pulse is time-domainally widened through a pulse widening module, the peak power of the laser beam is reduced, the laser energy more gently acts on the plaque, and the damage to the laser catheter is reduced; the light spot energy distribution is more uniform through a homogenization coupling module, and the damage to the laser catheter is reduced; laser energy is delivered to a plaque target position in a blood vessel through a laser catheter, precise ablation treatment of the plaque in the blood vessel is realized, and the stability and reliability of the laser ablation are improved.

Description

Technical Field

[0001] This application relates to the field of medical technology, and in particular to laser ablation systems and their operating methods. Background Technology

[0002] Laser ablation technology refers to the use of ultraviolet laser to irradiate hardened plaques in blood vessels. Nanosecond-width ultraviolet laser is coupled to a laser catheter and delivered to the lesion tissue, which can precisely ablate organized thrombi, connective tissue and calcifications in the lesion tissue.

[0003] 355nm ultraviolet solid-state laser ablation systems are widely used due to their advantages of efficient ablation of calcified lesions, low thermal effect, and low risk of vascular perforation. However, due to its inherent characteristics of beam quality close to that of a fundamental Gaussian beam and pulse width on the order of nanoseconds, it is extremely easy to focus into a micron-sized high-energy-density spot. When coupled with the bundled optical fiber of the laser conduit, the energy is highly concentrated, which can easily cause local overheating, ablation, or even breakage of the fiber coupling end face, affecting the ablation reliability of the laser ablation system. Summary of the Invention

[0004] Therefore, it is necessary to provide a laser ablation system and its working method to address the problem of poor ablation reliability in existing laser ablation systems.

[0005] A laser ablation system, the laser ablation system comprising:

[0006] Laser emitting module;

[0007] A beam alignment module is used to adjust the transmission path of the laser beam emitted by the laser emitting module so that the laser beam is aligned with the indicator beam emitted by the beam alignment module.

[0008] An energy monitoring module is installed in the output optical path of the beam alignment module to monitor the energy of the laser beam and adjust the laser beam energy in the output optical path.

[0009] A pulse broadening module is disposed in the output optical path of the energy monitoring module and is used to broaden the laser beam pulse.

[0010] A homogenization coupling module is disposed in the output optical path of the pulse broadening module, and is used to homogenize the energy of the laser beam and focus and couple the homogenized beam.

[0011] Laser catheters are used to deliver coupled light beams to the target site of plaque within blood vessels.

[0012] In some embodiments, the beam alignment module includes an indicator laser and at least one optical adjustment frame, the optical adjustment frame being provided with a first reflective element, the incident optical path of the first reflective element being located on the transmission path of the laser beam, and the outgoing optical path of the first reflective element being located on the outgoing optical path of the indicator laser.

[0013] The optical adjustment frame is used to adjust the reflection angle of the first reflective element so that the laser beam is reflected by the first reflective element, and the reflected laser beam combines with the indicator light beam.

[0014] In some embodiments, the energy monitoring module includes a first rotating optical element, a first beam splitter, and an energy meter. The laser beam passes through the first rotating optical element and enters the first beam splitter. The first beam splitter is used to split the laser beam into a first transmitted beam and a first reflected beam. The first transmitted beam is transmitted to the outgoing optical path by the first beam splitter, and the first reflected beam is reflected to the energy meter by the first beam splitter.

[0015] The first rotating optical element is used to adjust the polarization direction of the laser beam in order to adjust the beam splitting ratio of the first transmitted beam and the first reflected beam.

[0016] In some embodiments, the first beam-splitting element includes a beam sampling mirror or a polarizing beam splitter prism.

[0017] In some embodiments, the pulse broadening module includes a second beam splitter, at least two second reflectors, and a first polarizing optical element. The second beam splitter is used to split the laser beam into a first polarized beam and a second polarized beam. The first polarized beam is reflected by the second beam splitter, and the second polarized beam is transmitted by the second beam splitter.

[0018] One of the first polarized beam and the second polarized beam is reflected by at least two of the second reflective elements to the first polarizing optical element, and at least a portion of the polarized beam passing through the first polarizing optical element is combined with the other of the two beams.

[0019] In some embodiments, the first polarizing optical element includes a half-wave plate, a quarter-wave plate, or a Faraday rotator;

[0020] The second polarized beam is reflected by the three second reflective elements to the first polarizing optical element, passes through the first polarizing optical element and enters the second beam splitter, and is split into a third polarized beam and a fourth polarized beam by the second beam splitter; the third polarized beam is transmitted by the second beam splitter and merges with the first polarized beam; the fourth polarized beam is reflected by the second beam splitter and passes through the three second reflective elements, the first polarizing optical element and the second beam splitter to cycle through the next optical path.

[0021] In some embodiments, the first polarizing optical element includes a polarizing beam splitter;

[0022] The first polarized beam is reflected by the two second reflective elements to the first polarizing optical element, and after being reflected by the first polarizing optical element, it is combined with the second polarized beam.

[0023] In some embodiments, the pulse broadening module further includes a second rotating optical element, through which the laser beam enters the second beam splitting element. The second rotating optical element is used to adjust the polarization direction of the laser beam to adjust the splitting ratio of the first polarized beam and the second polarized beam.

[0024] In some embodiments, the homogenization coupling module includes a beam homogenization element and a first coupling lens. The beam homogenization element is used to homogenize the energy of the laser beam, and the first coupling lens is used to focus the homogenized beam and couple it to the laser guide tube.

[0025] Alternatively, the homogenization coupling module includes an anticoherence component and a homogenization component arranged sequentially along the transmission path. The homogenization component is used to homogenize the energy of the laser beam and focus the homogenized beam before coupling it to the laser guide tube. The anticoherence component includes a scattering sheet, a focusing lens, and a first optical fiber arranged sequentially along the transmission path. The homogenization component includes a collimating lens, a microlens array, and a second coupling lens. The laser beam emitted from the first optical fiber is collimated by the collimating lens and then passes sequentially through the microlens array and the second coupling lens.

[0026] A method for operating a laser ablation system, based on the laser ablation system described above, the method comprising:

[0027] The laser emitting module emits a beam of light;

[0028] The beam alignment module adjusts the transmission path of the laser beam so that the laser beam is combined with the indicator beam emitted by the beam alignment module;

[0029] The energy monitoring module monitors the energy of the laser beam and adjusts the energy of the laser beam in the output optical path;

[0030] The pulse broadening module broadens the laser beam pulse;

[0031] The homogenization coupling module homogenizes the energy of the laser beam and then focuses and couples the homogenized beam.

[0032] The laser catheter delivers the coupled light beam to the target site of the plaque within the blood vessel.

[0033] The aforementioned laser ablation system and its working method utilize a laser emission module to emit a laser beam, providing laser output for plaque ablation. A beam alignment module ensures the laser beam aligns with an indicator beam, guaranteeing accurate target entry and improving ablation reliability. An energy monitoring module monitors laser energy in real-time and adjusts the emitted beam's energy to maintain stability within the desired ablation range, eliminating the need to adjust laser parameters of the emission module, reducing ablation complexity while ensuring effective plaque ablation and minimizing the risk of damage to the laser catheter. A pulse broadening module temporally broadens the laser pulse, reducing peak power and allowing for gentler application of laser energy to the plaque, minimizing damage to the laser catheter. A homogenization coupling module ensures more uniform energy distribution, avoiding localized high-energy hotspots and further reducing laser catheter damage. Finally, the laser catheter delivers laser energy to the target plaque site within the blood vessel, achieving precise ablation treatment and enhancing the stability and reliability of laser ablation. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments or exemplary embodiments of this application, the drawings used in the description of the embodiments or exemplary embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A simplified diagram of a laser ablation system provided in an embodiment of this application.

[0036] Figure 2 for Figure 1 The diagram shows a beam alignment module in a laser ablation system.

[0037] Figure 3 for Figure 1 The diagram shows the energy detection module in the laser ablation system.

[0038] Figure 4 A schematic diagram of the energy detection module in a laser ablation system provided in another embodiment.

[0039] Figure 5 for Figure 1 The diagram shows a pulse broadening module in a laser ablation system.

[0040] Figure 6 The pulse waveform of the incident beam emitted by the laser emitting module.

[0041] Figure 7 The waveform of the sub-pulse laser beam emitted from the second beam splitter and combined with the first polarized beam.

[0042] Figure 8 for Figure 7 The pulse waveform of the output laser beam after multiple sub-pulses are combined is shown.

[0043] Figure 9 A schematic diagram of a pulse broadening module in a laser ablation system provided in another embodiment.

[0044] Figure 10 This represents the waveform of the sub-pulse laser beam emitted along the output optical path.

[0045] Figure 11 for Figure 10 The pulse waveform of the output laser beam after multiple sub-pulses are combined is shown.

[0046] Figure 12 for Figure 1 The diagram shows a homogenization coupling module in a laser ablation system.

[0047] Figure 13 A schematic diagram of a homogenization coupling module in a laser ablation system provided in another embodiment.

[0048] Figure 14 for Figure 1 The diagram shows a laser conduit in a laser ablation system.

[0049] Figure 15 A schematic diagram of a laser conduit in a laser ablation system provided for another embodiment.

[0050] Figure 16 A flowchart illustrating the working method of a laser ablation system provided in an embodiment of this application.

[0051] Reference numerals: 100, Laser emission module; 200, Beam alignment module; 210, Indicator laser; 220, First reflective element; 300, Energy monitoring module; 310, First rotating optical element; 320, First beam splitter; 330, Energy meter; 400, Pulse broadening module; 410, Second rotating optical element; 420, Second beam splitter; 430, Second reflective element; 440, First polarization optical element; 500, Homogenization coupling module; 510, Light... 520. Beam homogenizing element; 530. First coupling lens; 531. Decoherence component; 532. Scattering sheet; 533. Focusing lens; 534. First optical fiber; 540. Homogenizing component; 541. Collimating lens; 542. Microlens array; 543. Second coupling lens; 600. Laser guide tube; 610. Sleeve; 620. Bundling fiber; 621. Second optical fiber; I1. First polarized beam; I2. Second polarized beam; I3. Third polarized beam; I4. Fourth polarized beam. Detailed Implementation

[0052] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0053] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0054] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0056] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0057] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0058] Ultraviolet laser ablation can precisely ablate organized thrombi, connective tissue, and calcifications in diseased tissue. It works by coupling nanosecond-level pulse width ultraviolet laser to a laser catheter and delivering it to the lesion. The laser catheter uses a bundled design of multiple small-core optical fibers to reduce the bending radius, and the input end is treated with a special process to ensure efficient laser coupling without damaging the end face.

[0059] Currently, there are two main ultraviolet laser ablation methods. One is the 308nm excimer laser system, which has limited ablation effect on calcified lesions and, due to its relatively large pulse width (125ns-200ns), carries risks of low peak power, significant thermal effects, and vascular perforation. The other is the 355nm ultraviolet solid-state laser ablation system. This system has a smaller laser size, lower cost, and a pulse width of only 5ns. At the same energy, its peak power is 25-40 times that of the 308nm excimer laser system, enabling efficient ablation of calcified lesions with less thermal effect and lower risk of vascular perforation, making it more suitable for treating complex lesions.

[0060] The inventors of this application have discovered that the existing 355nm ultraviolet solid-state laser intravascular plaque ablation technology still has the following shortcomings: its inherent characteristics of beam quality close to the fundamental mode Gaussian beam and pulse width on the order of nanoseconds make it extremely easy to focus and form a micron-sized high energy density spot. When coupled with the bundled fiber of the laser conduit, the energy is highly concentrated, which can easily cause local overheating, ablation or even breakage of the coupling end face of the bundled fiber, thereby affecting the reliability and stability of the laser ablation system.

[0061] Based on this, one embodiment of this application provides a laser ablation system that can improve the above-mentioned phenomena. The laser ablation system provided by one embodiment of this application will now be described in detail with reference to the accompanying drawings.

[0062] See Figure 1 An embodiment of this application provides a laser ablation system including a laser emitting module 100, a beam alignment module 200, an energy monitoring module 300, a pulse broadening module 400, a homogenization coupling module 500, and a laser conduit 600. The laser emitting module 100 is used to emit a laser beam. The beam alignment module 200 is used to adjust the transmission path of the laser beam emitted by the laser emitting module 100 so that the laser beam is combined with the indicator beam emitted by the beam alignment module 200. The energy monitoring module 300 is disposed on the output optical path of the beam alignment module 200 and is used to monitor the energy of the laser beam and adjust the energy of the laser beam on the output optical path. The pulse broadening module 400 is disposed on the output optical path of the energy monitoring module 300 and is used to perform pulse broadening on the laser beam. The homogenization coupling module 500 is disposed on the output optical path of the pulse broadening module 400 and is used to homogenize the energy of the laser beam and focus and couple the homogenized beam. The laser conduit 600 is used to deliver the coupled beam to the target site of the plaque in the blood vessel.

[0063] Specifically, the laser emission module 100 emits a laser beam to provide laser output for the ablation of intravascular plaques; the beam alignment module 200 ensures that the laser beam is aligned with the indicator beam, ensuring that the laser beam accurately enters the target site and improving the reliability of ablation; the energy monitoring module 300 monitors the laser energy in real time and adjusts the energy of the emitted beam to ensure that the energy of the emitted beam is stable within the required ablation range, eliminating the need to adjust the laser parameters of the laser emission module 100, reducing the complexity of ablation while ensuring the plaque ablation effect and reducing the risk of damage to the laser catheter 600; the pulse broadening module 400 broadens the laser pulse in the time domain, reducing the peak power of the laser beam, allowing the laser energy to act on the plaque more gently and reducing damage to the laser catheter 600; the homogenization coupling module 500 makes the energy distribution of the spot more uniform, avoiding local high-energy hot spots and reducing damage to the laser catheter 600; together with the laser catheter 600, the laser energy is delivered to the target site of the intravascular plaque, realizing precise ablation treatment of intravascular plaques and improving the stability and reliability of laser ablation.

[0064] In some embodiments, the laser ablation system is used to ablate plaques within peripheral blood vessels. In other embodiments, the laser ablation system is used to ablate plaques within coronary arteries. When ablating plaques within coronary arteries, the laser beam can be broadened without utilizing a pulse width broadening module, retaining the advantages of ultra-short pulse width lasers and adapting to the requirements of precise ablation and low thermal damage of plaques within coronary arteries.

[0065] In some embodiments, the laser emitting module 100 may be a third- or fourth-harmonic Nd:YAG laser, which outputs ultraviolet laser light with a wavelength of 355 nm or 266 nm, a pulse width of 3 ns-12 ns, and can output linearly polarized light with a beam quality factor M. 2 Greater than 5.

[0066] like Figure 2 As shown, in some embodiments, the beam alignment module 200 includes an indicator laser 210 and at least one optical adjustment frame (not shown). A first reflective element 220 is disposed on the optical adjustment frame. The incident light path of the first reflective element 220 is located on the transmission path of the laser beam, and the outgoing light path of the first reflective element 220 is located on the outgoing light path of the indicator laser 210. The optical adjustment frame is used to adjust the reflection angle of the first reflective element 220, so that the laser beam is reflected by the first reflective element 220. The reflected laser beam is then combined with the indicator light emitted by the indicator laser 210, meaning the laser beam and the indicator light are output coaxially. Thus, when the laser beam emitted by the laser emission module 100 is incident on the first reflective element 220, it is reflected by the first reflective element 220 to change its transmission direction, thereby combining with the indicator light and ensuring that the laser beam accurately enters the target area, improving ablation reliability.

[0067] In some embodiments, the number of optical adjustment frames is one, and the number of first reflective elements 220 is also one. For example, the laser emitting module 100 can be disposed above the first reflective element 220, and the indicator laser 210 can be disposed to the left of the first reflective element 220. After the laser beam emitted by the laser emitting module 100 is transmitted downward to the first reflective element 220, the transmission direction of the laser beam changes, so that it combines with the indicator light beam transmitted in the horizontal direction.

[0068] In other embodiments, the number of optical adjustment frames is at least two, and correspondingly, the number of first reflective elements 220 is at least two. These at least two first reflective elements 220 are arranged vertically, one of which is disposed in the output optical path of the laser emitting module 100, and the other is disposed in the output optical path of the indicator light. For example, in... Figure 2 In the illustrated embodiment, two optical adjustment frames are provided, each with one first reflective element 220, meaning there are two first reflective elements 220. These two first reflective elements 220 are designated as First Reflective Element No. 1 and First Reflective Element No. 2. First Reflective Element No. 1 is located in the output optical path of the laser emitting module 100, while First Reflective Element No. 2 is located in the output optical path of the indicator laser 210, i.e., the output optical path of the indicator light. Thus, by adjusting the reflection angle of the corresponding first reflective elements 220 using the two optical adjustment frames, the laser beam is reflected sequentially by First Reflective Element No. 1 and First Reflective Element No. 2, and the reflected laser beam is then combined with the indicator light.

[0069] In some embodiments, the first reflecting element 220 can be a reflector. Two reflectors are respectively mounted on two optical adjustment frames, which have two-dimensional angle adjustment functions, enabling pitch and yaw adjustments. For example, the optical adjustment frame is equipped with a pitch screw and a yaw screw. By adjusting the pitch screw of one optical adjustment frame, the angle of the corresponding reflector is adjusted, causing the laser beam to hit the center position of the other reflector. By adjusting the pitch screw of the other optical adjustment frame, the laser beam reflected by the other reflector is aligned with the indicator light. For example, in the embodiment shown in the figures, the upper reflector changes the transmission direction of the horizontally emitted laser beam, causing the laser beam to hit the lower reflector downwards. The lower reflector then changes the transmission direction of the laser beam again, causing it to combine with the horizontally transmitted indicator light.

[0070] In some embodiments, the indicator light can be a red indicator light, which offers high visibility and facilitates real-time aiming during the procedure, ensuring that the output laser beam is aligned with the target plaque within the blood vessel, thereby improving treatment accuracy and the reliability of the laser ablation system. In some embodiments, the reflective surface of the reflector is coated with a 45-degree high-reflectivity film. In some embodiments, the reflectivity of the 45-degree high-reflectivity film in the red indicator beam band should not exceed 40% to ensure that a significant amount of indicator light passes through the reflector.

[0071] like Figure 3 As shown, in some embodiments, the energy monitoring module 300 includes a first rotating optical element 310, a first beam splitter 320, and an energy meter 330. The laser beam enters the first beam splitter 320 after passing through the first rotating optical element 310. The first beam splitter 320 is used to split the laser beam into a first transmitted beam I5 and a first reflected beam I6. The first transmitted beam I5 is transmitted to the output optical path by the first beam splitter 320, and the first reflected beam I6 is reflected to the energy meter 330 by the first beam splitter 320. The first rotating optical element 310 is used to adjust the polarization direction of the laser beam to adjust the beam splitting ratio of the first transmitted beam I5 and the first reflected beam I6.

[0072] A first beam splitter 320 divides the laser beam into a first transmitted beam I5 and a first reflected beam I6. The first transmitted beam I5 continues to propagate along the output optical path, while the first reflected beam I6 is incident on an energy meter 330 for energy monitoring. This allows for accurate detection of laser energy without affecting the transmission of the main treatment beam. By adjusting the splitting ratio of the first transmitted beam I5 and the first reflected beam I6 using a first rotating optical element 310, the laser beam energy on the output optical path can be precisely adjusted, stabilizing the output energy within a preset treatment range. This ensures effective plaque ablation while preventing damage to vascular tissue or the laser catheter 600 caused by abnormal output energy, thus improving the safety and reliability of the laser ablation system.

[0073] like Figure 3 As shown, in some embodiments, the first beam splitter 320 can be a beam sampling mirror. The beam sampling mirror samples 1% to 10% of the energy of the incident beam through Fresnel reflection generated by the uncoated optical surface, according to the polarization direction of the incident beam. Typically, the laser beam emitted by the laser emitting module 100 is linearly polarized light, which can be decomposed into P-polarized light and S-polarized light according to the polarization direction.

[0074] For example, when the laser beam is P-polarized and incident on the beam sampling mirror at a 45-degree angle, the beam sampling mirror will produce about 1% reflection, that is, the energy of the first reflected beam I6 is about 1%, and the energy of the first transmitted beam I5 is about 99%.

[0075] When the laser beam is S-polarized and incident at a 45-degree angle, the beam sampling mirror will produce approximately 10% reflection, meaning the energy proportion of the first reflected beam I6 is approximately 10%, and the energy proportion of the first transmitted beam I5 is approximately 90%. By rotating the first rotating optical element 310, the beam splitting ratio in the P-polarized and S-polarized directions can be adjusted. Since the beam sampling mirror has different Fresnel reflectivities for P-polarized and S-polarized light, the energy proportion of the sampled reflected light can be continuously adjusted within the range of 1% to 10%, which means the energy proportion split to the energy meter 330 and the energy proportion split to the output light path can be adjusted. In some embodiments, the first rotating optical element 310 can be a half-wave plate, a quarter-wave plate, or a Faraday rotator.

[0076] like Figure 4 As shown, in some embodiments, the first beam-splitting element 320 can be a polarizing beam-splitting prism. The polarizing beam-splitting prism has polarization selection characteristics, allowing P-polarized light to pass through and reflecting S-polarized light to the energy meter 330. By rotating the first rotating optical element 310, the beam splitting ratio in the P-polarization direction and the S-polarization direction can be adjusted, thereby splitting the laser beam with the desired ratio onto the energy meter 330 and the output optical path, respectively.

[0077] like Figure 5 or Figure 9 As shown, in some embodiments, the pulse broadening module 400 includes a second beam splitter 420, at least two second reflective elements 430, and a first polarizing optical element 440. The second beam splitter 420 is used to split the laser beam into a first polarized beam I1 and a second polarized beam I2. The first polarized beam I1 is reflected by the second beam splitter 420, and the second polarized beam I2 is transmitted by the second beam splitter 420. One of the first polarized beam I1 and the second polarized beam I2 is reflected by the at least two second reflective elements 430 to the first polarizing optical element 440. At least a portion of the polarized beam passing through the first polarizing optical element 440 is combined with the other one of the two beams.

[0078] The second beam splitter 420 splits the incident beam into a reflected first polarized beam I1 and a transmitted second polarized beam I2 according to the polarization state. The two beams follow different optical paths. One of the beams is reflected by multiple second reflective elements 430 to form a reflected optical path to extend the optical path. The reflected beam passes through the first polarizing optical element 440 to form a polarized beam. At least part of the polarized beam can be efficiently combined with the other beam, so that the two pulsed laser beams are staggered in time. The optical path difference between the two pulsed laser beams is used to achieve pulse broadening, reduce the peak power of the pulse, and improve the ablation safety.

[0079] In some embodiments, the number of second reflective elements 430 is not limited, but is at least two. The number and distribution structure of the second reflective elements 430 can be determined according to the specific optical path and delay time. The optical path length can be flexibly changed, thereby precisely controlling the pulse broadening width and adapting to the clinical needs of different power, different pulse widths and different ablation scenarios, making it more applicable.

[0080] like Figure 5 As shown, in some embodiments, the first polarizing optical element 440 includes a half-wave plate, a quarter-wave plate, or a Faraday rotator. The reflected beam passes through the first polarizing optical element 440 to form a polarized beam. The polarization direction of the polarized beam is changed by the first polarizing optical element 440, ensuring that the polarized beam can be efficiently combined with the beam on the outgoing optical path when it re-enters the second beam splitter element 420.

[0081] In this embodiment, three second reflecting elements 430 are provided, each with an incident angle of 45 degrees. The first polarized beam I1 is reflected to the outgoing optical path. The second polarized beam I2 is reflected by the three second reflecting elements 430 to form a reflected beam. The reflected beam passes through the first polarizing optical element 440 to form a polarized beam. The polarized beam enters the second beam splitter 420 and is split into a third polarized beam I3 and a fourth polarized beam I4. The third polarized beam I3 is transmitted through the second beam splitter 420 and merges with the first polarized beam I1. The fourth polarized beam I4 is reflected by the second beam splitter 420 and cycles through at least two second reflecting elements 430, the first polarizing optical element 440, and the second beam splitter 420 to the next optical path.

[0082] As mentioned above, the incident beam is linearly polarized light, which can be decomposed into P-polarized light and S-polarized light according to its polarization direction. The second beam splitter 420 separates the S-polarized light and P-polarized light in the incident beam to form a first polarized beam I1 and a second polarized beam I2. In some embodiments, taking a polarizing beam splitter prism as an example, the S-polarized light passing through the polarizing beam splitter prism is reflected to form the first polarized beam I1, and the P-polarized light passing through the polarizing beam splitter prism is transmitted to form the second polarized beam I2. In other embodiments, the P-polarized light in the incident beam may also be reflected to form the first polarized beam I1, and the S-polarized light may be transmitted to form the second polarized beam I2.

[0083] In the appendix Figure 5In the illustrated embodiment, the second polarized beam I2 is reflected by the first second reflecting element 430 and then deflected by 90 degrees to form the first intermediate beam. The first intermediate beam is reflected by the second second reflecting element 430 and then deflected by 90 degrees to form the second intermediate beam. The second intermediate beam is reflected by the third second reflecting element 430 and then deflected by 90 degrees to form the reflected beam. When the reflected beam passes through the first polarizing optical element 440, its polarization direction changes, forming a polarized beam. The total optical path of the second polarized beam I2, the first intermediate beam, the second intermediate beam, the reflected beam, and the polarized beam is L1. The resulting delay time... t = L1 / c, where c is the speed of light, thus achieving pulse broadening, reducing peak pulse power, and improving ablation safety. In some embodiments, the second reflective element can be a mirror.

[0084] Taking the second beam-splitting element 420 as a polarizing beam splitter, the first polarized beam I1 as S-polarized light, the second polarized beam I2 as P-polarized light, and the first polarizing optical element 440 as a half-wave plate as an example, the incident beam illuminates the front of the second beam-splitting element 420, i.e., the polarizing beam splitter. The first polarized beam I1, i.e., S-polarized light, is reflected by the polarizing beam splitter, and the second polarized beam I2, i.e., P-polarized light, is transmitted by the second beam-splitting element 420 (polarizing beam splitter). The second polarized beam I2 is reflected by multiple second reflecting elements 430 in sequence to form a reflected beam. The reflected beam is incident on the first polarizing optical element 440 (half-wave plate) to form a polarized beam. The polarization direction of the laser beam has changed, and in addition to P-polarized light, S-polarized light will also be obtained. At this time, the polarized beam is incident on the back of the polarizing beam splitter again and coincides with the beam direction of the first polarized beam I1, so that the polarized beam illuminates the back of the second beam splitter 420 (polarizing beam splitter). After passing through the second beam splitter 420 (polarizing beam splitter), the third polarized beam I3 (P-polarized light) is transmitted and combines with the first polarized beam I1 (S-polarized light) to form the outgoing beam. The fourth polarized beam I4 (S-polarized light) is reflected by the second beam splitter 420 (polarizing beam splitter) and enters the next cycle of the optical path. The optical path is that the laser beam passes through multiple second reflecting elements 430, the first polarizing optical element 440 and the second beam splitter 420 in sequence.

[0085] Following this pattern, after n cycles, all sub-pulse laser beams will be combined with the first polarized beam I1 to form the final output beam. Since the sub-pulse laser beam increases its optical path with each cycle, and the P-polarized light in each cycle is delayed and superimposed, the pulse width of the combined output laser beam, i.e., the output beam, is broadened.

[0086] Please see Figures 6 to 8 This demonstrates the process of laser pulse width broadening. Figure 6The pulse waveform representing the incident beam emitted by the laser emitting module 100 is also the pulse waveform of the unstretched laser beam. Figure 7 This represents the waveform of each P-polarized photon sub-pulse laser beam emitted from the second beam-splitter 420 and combined with the first polarized beam I1. Viewed from left to right, these are the waveforms of the first, second, third, and so on. The first sub-pulse laser beam waveform is the waveform of the third polarized beam I3, and the second sub-pulse laser beam waveform is the waveform of the P-polarized light transmitted through the second beam-splitter 420 again after the fourth polarized beam I4 has undergone one optical path cycle. The delay time between two adjacent sub-pulse laser beam waveforms is... Similarly, the waveform of the third sub-pulse laser beam is the waveform of the P-polarized light transmitted through the second beam splitter 420 after the third optical path cycle, and the waveform of the fourth sub-pulse laser beam is the waveform of the P-polarized light transmitted through the second beam splitter 420 after the fourth cycle. This cycle repeats until all sub-pulse lasers are combined with the first polarized beam I1.

[0087] Figure 8 The diagram shows the pulse waveform of the output laser beam after beam combining. It can be seen that by changing the optical path length L1, the delay time between the two sub-pulse laser beams can be changed. t, thereby changing the pulse width of the output laser beam and obtaining laser beam pulse widths with different widths.

[0088] In some embodiments, the first polarizing optical element 440 is a half-wave plate, which can change the polarization direction of linearly polarized light. By rotating the first polarizing optical element 440, the beam splitting ratio of the third polarized beam I3 and the fourth polarized beam I4 can be adjusted, thereby adjusting the beam splitting ratio of P-polarized light and S-polarized light incident on the second beam splitting element 420.

[0089] In some embodiments, the first polarizing optical element 440 is a Faraday rotator, and the polarization direction of linearly polarized light can be changed by selecting different types of Faraday rotators.

[0090] In some embodiments, the first polarizing optical element 440 is a quarter-wave plate. When the reflected light beam is incident on the quarter-wave plate, the outgoing light will become circularly polarized light or elliptically polarized light, thus generating laser light with P-polarization and S-polarization directions, i.e., P-polarized light and S-polarized light. If it is circularly polarized light, the splitting ratio of the P-polarization direction and the S-polarization direction is the same; if it is elliptically polarized light, the splitting ratio of the P-polarization direction and the S-polarization direction is different, and the splitting ratio of the laser beam in the P-polarization direction and the S-polarization direction can be adjusted according to actual needs.

[0091] like Figure 5As shown, in one embodiment, the pulse broadening module 400 further includes a second rotating optical element 410. After the incident beam passes through the second rotating optical element 410, it enters the second beam splitting element 420. The second rotating optical element 410 is used to adjust the polarization direction of the laser beam to adjust the beam splitting ratio of the first polarized beam I1 and the second polarized beam I2.

[0092] By adjusting the angle of the second rotating optical element 410, the splitting ratio of the first polarized beam I1 and the second polarized beam I2 can be controlled. Combined with the first polarizing optical element 440, the splitting ratio of P-polarized and S-polarized light in the reflected beam and subsequent reflected beams corresponding to each optical path cycle can be further controlled. Through the cooperation of the second rotating optical element 410 and the first polarizing optical element 440, the leading and trailing edges of the pulse waveform of the combined output laser beam can be adjusted, thereby adjusting the entire pulse waveform and making the broadened waveform controllable. In some embodiments, to avoid affecting ablation efficiency, the delay time between the two sub-pulse laser beams is less than the relaxation time during plaque ablation.

[0093] like Figure 9 As shown, in some embodiments, the first polarizing optical element 440 and the second beam-splitting element 420 are both polarizing beam splitters. The incident beam passes through the second beam splitter 420, where the P-polarized light is transmitted to form a second polarized beam I2, which is then output along the outgoing optical path. The S-polarized light is reflected to form a first polarized beam I1. The first polarized beam I1 (S-polarized light) is reflected by two second reflecting elements 430 to the first polarizing optical element 440 (polarizing beam splitter), and the S-polarized light is reflected by the first polarizing optical element 440 (polarizing beam splitter), thus combining with the second polarized beam I2 for output.

[0094] like Figure 6 , Figure 10 and Figure 11 As shown, the two sub-pulse laser beams, namely the first polarized beam I1 and the second polarized beam I2, travel different optical paths, resulting in an optical path difference L2. The delay time generated by the two sub-pulse laser beams... t = L2 / c. Laser pulse broadening is achieved through the optical path difference between the two sub-pulse laser beams, reducing peak pulse power and ablation risk. The delay time between the two sub-pulses can be changed by altering the optical path difference L2. t, thereby changing the pulse width of the output laser beam and obtaining laser pulse widths with different widths.

[0095] like Figure 12As shown, in some embodiments, the homogenization coupling module 500 includes a beam homogenization element 510 and a first coupling lens 520. The beam homogenization element 510 is used to homogenize the energy of the laser beam, and the first coupling lens 520 is used to focus the homogenized beam and couple it to the laser conduit 600. By homogenizing the laser beam energy through the beam homogenization element 510, the energy distribution of the light spot is made uniform, avoiding the generation of local high-energy hot spots during ablation and improving the reliability of ablation. The first coupling lens 520 focuses the homogenized beam and efficiently couples it to the laser conduit 600, improving the laser energy transmission efficiency, ensuring that the ablation energy effectively reaches the target site of the plaque in the blood vessel, and improving the stability and reliability of the laser ablation system.

[0096] In some embodiments, the beam homogenizing element 510 may be a diffractive optical element (DOE). The laser beam is first homogenized by the diffractive optical element and then focused by the first coupling lens 520 to form a flat-top beam on the focal plane of the first coupling lens 520. The near-end incident surface of the laser guide tube 600 is placed at the focal plane of the first coupling lens 520 to improve the coupling efficiency of the laser guide tube 600.

[0097] In some embodiments, the diffractive optical element is selected as a diffuser-type diffractive optical element. The diffractive optical element includes two diffractive surfaces: the first diffractive surface reduces the coherence of the incident beam, and the second diffractive surface shapes the optical profile. The diffractive optical element is designed using a binary optical design, and the diffraction efficiency η of the binary optical element is calculated using the following formula:

[0098] ;

[0099] L=2 N (N is a positive integer) represents the number of steps in the diffraction grating. When L≥8 (N≥3), the diffraction efficiency η≥94.96%. In some embodiments, diffraction optical elements of better diffuser types, such as 8th or 16th steps, are selected.

[0100] When the laser beam quality factor M 2 When the beam quality factor approaches 1, due to the zero-order effect of the diffractive optical element, a strong point will form at the center of the homogenized beam spot, which could easily damage the second optical fiber at the center of the laser guide tube 600. To avoid the strong point at the center, the beam quality factor M of the laser beam emitted by the laser emitting module 100 is... 2 It should be greater than 5. In some embodiments, the beam quality factor M 2 Greater than 10.

[0101] The spot diameter D of the flat-top beam at the focal plane of the first coupling lens 520 is determined by the focal length f of the first coupling lens 520 and the diffraction angle θ (full angle) of the diffraction optical element, and its calculation formula is as follows:

[0102] ;

[0103] The spot diameter D of the flat-top beam of the first coupling lens 520 focal plane should be slightly larger than the diameter of the near-end bundled fiber 620 of the laser guide 600, to ensure that the laser irradiates each of the second fibers 621 on the bundled fiber 620.

[0104] like Figure 13 As shown, in some embodiments, the homogenization coupling module 500 includes an anticoherence component 530 and a homogenization component 540 arranged sequentially along the transmission path. The laser beam first passes through the anticoherence component 530 and then through the homogenization component 540. The anticoherence component 530 is used to reduce the spatial correlation of the laser beam, and the homogenization component 540 is used to homogenize the energy of the laser beam to obtain a uniform focused spot, and then focuses and couples the homogenized focused spot to the laser guide tube 600.

[0105] like Figure 13 As shown, in some embodiments, the decoherence component 530 includes a scattering sheet 531, a focusing lens 532, and a first optical fiber 533 arranged sequentially along the transmission path. The scattering sheet 531 can increase the focused spot of the focusing lens 532, thereby reducing the laser energy density at the end face of the first optical fiber 533, increasing the laser energy coupled into the first optical fiber 533, and simultaneously reducing the spatial coherence of the laser beam to a certain extent. The scattering sheet 531 can be a frosted scattering sheet or a holographic diffuser. After the laser is transmitted through the first optical fiber 533, the spatial coherence of the emitted laser beam is further reduced. In some embodiments, the first optical fiber 533 is a large-core fiber with a core diameter greater than 600 μm.

[0106] like Figure 13 As shown, in some embodiments, the homogenization component 540 includes a collimating lens 541, a microlens array 542, and a second coupling lens 543. The laser beam emitted from the first optical fiber 533 is collimated by the collimating lens 541 and then passes sequentially through the microlens array 542 and the second coupling lens 543. In some embodiments, the microlens array 542 includes two microlenses. The laser beam emitted from the first optical fiber 533 is collimated by the collimating lens 541, then passes sequentially through the two microlenses, and then through the second coupling lens 543 to obtain a homogenized focused spot, which is then coupled into the bundled optical fiber 620 of the laser guide tube 600.

[0107] The laser beam emitted from the decoherence component 530 has deteriorated spatial coherence and beam quality factor. When it passes through the homogenization component 540, the microlens will not focus the laser beam into a very small spot. It will not cause damage to the optical surface or generate air ionization.

[0108] like Figure 14As shown, in some embodiments, the laser conduit 600 includes a sleeve 610 and a bundled optical fiber 620, the bundled optical fiber 620 being disposed within the sleeve 610 and including multiple second optical fibers 621. In some embodiments, the multiple second optical fibers 621 are connected together by bundling.

[0109] like Figure 15 As shown, in some other embodiments, the sleeve 610 is connected to the bundled optical fiber 620 by thermoforming. When the sleeve 610 is heated and compressed, it shrinks inward, simultaneously compressing the second optical fiber 621 inserted inside the sleeve 610. After being compressed by the sleeve 610, the proximal end of the second optical fiber 621 can change its cross-sectional shape from circular to hexagonal, forming a honeycomb structure. This allows the sleeve 610 to be fused with the outermost second optical fiber 621 of the bundled optical fiber 620, and adjacent second optical fibers 621 in the bundled optical fiber 620 are also fused together.

[0110] In some embodiments, the near end of each second optical fiber 621 includes a fiber core and a cladding covering the fiber core; the far end and middle portion of the second optical fiber 621 include a fiber core, a cladding covering the fiber core, and a coating layer covering the cladding.

[0111] In some embodiments, the second optical fiber 621 may be a silica optical fiber. To ensure the permeability of the laser guide 600, the core diameter of a single silica optical fiber does not exceed 150 μm. In some embodiments, the core diameter of the silica optical fiber is 50 μm, and the cladding and coating are as thin as possible to ensure that the bending radius of the laser guide 600 is as small as possible.

[0112] Furthermore, one embodiment of this application also provides a method for operating a laser ablation system. Based on the above-described laser ablation system, the method for operating the laser ablation system includes:

[0113] In step S100, the laser emitting module 100 emits a beam.

[0114] The laser emitting module 100 can be a third- or fourth-harmonic Nd:YAG laser, which outputs ultraviolet laser light with a wavelength of 355nm or 266nm, a pulse width of 3ns-12ns, and can output linearly polarized light with a beam quality factor M. 2 Greater than 5.

[0115] In step S200, the beam alignment module 200 adjusts the transmission path of the laser beam so that the laser beam is combined with the indicator beam emitted by the beam alignment module 200.

[0116] In some embodiments, the beam alignment module 200 includes an indicator laser 210 and two optical adjustment frames. The optical adjustment frames are provided with first reflective elements 220, one of which is located in the output light path of the laser emitting module 100, and the other is located in the output light path of the indicator light. The optical adjustment frames are used to adjust the reflection angle of the first reflective elements 220 so that the laser beam is reflected by the two first reflective elements 220 in sequence. The reflected laser beam is output coaxially with the indicator light, ensuring that the output beam is aligned with the target site of the plaque in the blood vessel, thereby improving the treatment accuracy and the reliability of laser ablation.

[0117] In step S300, the energy monitoring module 300 monitors the energy of the laser beam and adjusts the energy of the laser beam on the output optical path.

[0118] In some embodiments, the energy monitoring module 300 includes a first rotating optical element 310, a first beam splitter 320, and an energy meter 330. The laser beam enters the first beam splitter 320 after passing through the first rotating optical element 310. The first beam splitter 320 is used to split the laser beam into a first transmitted beam I5 and a first reflected beam I6. The first transmitted beam I5 is transmitted to the output optical path by the first beam splitter 320, and the first reflected beam I6 is reflected to the energy meter 330 by the first beam splitter 320. The first rotating optical element 310 is used to adjust the polarization direction of the laser beam to adjust the splitting ratio of the first transmitted beam I5 and the first reflected beam I6.

[0119] A first beam splitter 320 divides the laser beam into a first transmitted beam I5 and a first reflected beam I6. The first transmitted beam I5 continues to propagate along the main optical path, while the first reflected beam I6 is incident on an energy meter 330 for energy monitoring. This allows for accurate detection of laser energy without affecting the transmission of the main treatment beam. By adjusting the splitting ratio of the first transmitted beam I5 and the first reflected beam I6 using a first rotating optical element 310, the laser beam energy on the output optical path can be precisely adjusted, stabilizing the output laser beam energy within a preset treatment range. This ensures effective plaque ablation while preventing damage to vascular tissue or the laser catheter 600 caused by abnormal output laser beam energy, thus improving the safety and reliability of laser ablation.

[0120] In step S400, the pulse broadening module 400 broadens the laser beam.

[0121] The laser pulse is stretched in the time domain by the pulse stretching module, which reduces the peak power of the laser beam and allows the laser energy to act on the patch more gently, reducing damage to the laser guide tube 600.

[0122] In step S500, the homogenization coupling module 500 homogenizes the energy of the laser beam and then focuses and couples the homogenized beam.

[0123] In some embodiments, the homogenization coupling module 500 includes a beam homogenization element 510 and a first coupling lens 520. The beam homogenization element 510 is used to homogenize the energy of the laser beam, and the first coupling lens 520 is used to focus the homogenized beam and couple it to the laser conduit 600. The beam homogenization element 510 homogenizes the laser beam energy, making the energy distribution of the spot uniform, avoiding the generation of local high-energy hot spots during ablation, and improving the reliability of ablation. The first coupling lens 520 focuses the homogenized beam and efficiently couples it to the laser conduit 600, improving the laser energy transmission efficiency, ensuring that the ablation energy effectively reaches the target site of the plaque in the blood vessel, and improving the stability and reliability of laser ablation.

[0124] In step S600, the laser catheter 600 delivers the coupled light beam to the target site of the plaque in the blood vessel, thereby achieving precise ablation treatment of the plaque in the blood vessel.

[0125] Thus, the laser emission module 100 emits a laser beam to provide laser output for plaque ablation; the beam alignment module 200 ensures that the laser beam and the indicator beam are aligned, ensuring that the laser beam stably enters the plaque target area and improving ablation reliability; the energy monitoring module 300 monitors the laser energy in real time and adjusts the energy of the emitted beam to ensure that the emitted beam energy is stable within the required ablation range, eliminating the need to adjust the laser parameters of the laser emission module 100, reducing ablation complexity while ensuring plaque ablation effect and reducing the risk of damage to the laser conduit 600; the pulse broadening module 400 broadens the laser pulse in the time domain, reducing the peak power of the laser beam, allowing the laser energy to act on the plaque more gently and reducing damage to the laser conduit 600; the homogenization coupling module 500 makes the energy distribution of the spot more uniform, avoiding local high-energy hot spots and reducing damage to the laser conduit 600; together with the laser conduit 600, the laser energy is delivered to the plaque target area in the blood vessel, realizing precise ablation treatment of intravascular plaques and improving the stability and reliability of laser ablation.

[0126] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A laser ablation system, characterized in that, The laser ablation system includes: Laser emitting module (100); A beam alignment module (200) is used to adjust the transmission path of the laser beam emitted by the laser emitting module (100) so that the laser beam is aligned with the indicator beam emitted by the beam alignment module (200). An energy monitoring module (300) is disposed on the output optical path of the beam alignment module (200) for monitoring the energy of the laser beam and adjusting the laser beam energy on the output optical path; A pulse broadening module (400) is disposed in the output optical path of the energy monitoring module (300) and is used to broaden the laser beam pulse; A homogenization coupling module (500) is disposed in the output optical path of the pulse broadening module (400) for homogenizing the energy of the laser beam and focusing and coupling the homogenized beam. Laser catheter (600) is used to deliver a coupled light beam to the target site of plaque in blood vessels.

2. The laser ablation system according to claim 1, characterized in that, The beam alignment module (200) includes an indicator laser (210) and at least one optical adjustment frame. The optical adjustment frame is provided with a first reflective element (220). The incident optical path of the first reflective element (220) is located on the transmission path of the laser beam, and the outgoing optical path of the first reflective element (220) is located on the outgoing optical path of the indicator laser (210). The optical adjustment frame is used to adjust the reflection angle of the first reflective element (220) so that the laser beam is reflected by the first reflective element (220), and the reflected laser beam is combined with the indicator light beam.

3. The laser ablation system according to claim 1, characterized in that, The energy monitoring module (300) includes a first rotating optical element (310), a first beam splitter (320), and an energy meter (330). The laser beam passes through the first rotating optical element (310) and enters the first beam splitter (320). The first beam splitter (320) is used to split the laser beam into a first transmitted beam (I5) and a first reflected beam (I6). The first transmitted beam (I5) is transmitted to the output optical path by the first beam splitter (320), and the first reflected beam (I6) is reflected to the energy meter (330) by the first beam splitter (320). The first rotating optical element (310) is used to adjust the polarization direction of the laser beam to adjust the beam splitting ratio of the first transmitted beam (I5) and the first reflected beam (I6).

4. The laser ablation system according to claim 3, characterized in that, The first beam splitting element (320) includes a beam sampling mirror or a polarizing beam splitter prism.

5. The laser ablation system according to claim 1, characterized in that, The pulse broadening module (400) includes a second beam splitter (420), at least two second reflective elements (430), and a first polarizing optical element (440). The second beam splitter (420) is used to split the laser beam into a first polarized beam (I1) and a second polarized beam (I2). The first polarized beam (I1) is reflected by the second beam splitter (420), and the second polarized beam (I2) is transmitted by the second beam splitter (420). One of the first polarized beam (I1) and the second polarized beam (I2) is reflected by at least two of the second reflective elements (430) to the first polarizing optical element (440), and at least a portion of the polarized beam passing through the first polarizing optical element (440) is combined with the other of the two.

6. The laser ablation system according to claim 5, characterized in that, The first polarizing optical element (440) includes a half-wave plate, a quarter-wave plate, or a Faraday rotator; The second polarized beam (I2) is reflected by the three second reflective elements (430) to the first polarizing optical element (440), enters the second beam splitter (420) through the first polarizing optical element (440), and is split into a third polarized beam (I3) and a fourth polarized beam (I4) by the second beam splitter (420); the third polarized beam (I3) is transmitted by the second beam splitter (420) and merges with the first polarized beam (I1); the fourth polarized beam (I4) is reflected by the second beam splitter (420) and passes through the three second reflective elements (430), the first polarizing optical element (440) and the second beam splitter (420) to cycle through the next optical path.

7. The laser ablation system according to claim 5, characterized in that, The first polarizing optical element (440) includes a polarizing beam splitter; The first polarized beam (I1) is reflected by the two second reflective elements (430) to the first polarizing optical element (440), and after being reflected by the first polarizing optical element (440), it is combined with the second polarized beam (I2).

8. The laser ablation system according to claim 5, characterized in that, The pulse broadening module (400) further includes a second rotating optical element (410). After passing through the second rotating optical element (410), the laser beam enters the second beam splitting element (420). The second rotating optical element (410) is used to adjust the polarization direction of the laser beam to adjust the beam splitting ratio of the first polarized beam (I1) and the second polarized beam (I2).

9. The laser ablation system according to claim 1, characterized in that, The homogenization coupling module (500) includes a beam homogenization element (510) and a first coupling lens (520). The beam homogenization element (510) is used to homogenize the energy of the laser beam, and the first coupling lens (520) is used to focus the homogenized beam and couple it to the laser guide tube (600). Alternatively, the homogenization coupling module (500) includes an anticoherence component (530) and a homogenization component (540) arranged sequentially along the transmission path. The homogenization component (540) is used to homogenize the energy of the laser beam and focus the homogenized beam before coupling it to the laser guide tube (600). The anticoherence component (530) includes a scattering sheet (531), a focusing lens (532), and a first optical fiber (533) arranged sequentially along the transmission path. The homogenization component (540) includes a collimating lens (541), a microlens array (542), and a second coupling lens (543). The laser beam emitted from the first optical fiber (533) is collimated by the collimating lens (541) and then passes sequentially through the microlens array (542) and the second coupling lens (543).

10. A method for operating a laser ablation system, characterized in that, Based on the laser ablation system according to any one of claims 1 to 9, the method comprises: The laser emitting module (100) emits a beam; The beam alignment module (200) adjusts the transmission path of the laser beam so that the laser beam is aligned with the indicator beam emitted by the beam alignment module (200); The energy monitoring module (300) monitors the energy of the laser beam and adjusts the energy of the laser beam in the output optical path; The pulse broadening module (400) broadens the laser beam pulse; The homogenization coupling module (500) homogenizes the energy of the laser beam and focuses and couples the homogenized beam. The laser conduit (600) delivers the coupled beam of light to the target site of the plaque within the blood vessel.

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