A method for processing conical filling holes in ICF target pellets using ultrafast laser

Abstract

This invention discloses a method for processing conical gas-filled holes in ICF target pellets using ultrafast lasers, relating to the field of laser beam processing. It addresses the limitation of traditional machining in target pellet drilling due to the requirements of small hole size and material. The method includes: passing the laser beam from a femtosecond laser through a focusing objective lens to focus on the top of the target pellet; adjusting the average power of the femtosecond laser to 2-4 mW; processing concentric circles with a maximum diameter of 4-20 μm centered on the target pellet apex; after processing one layer, turning off the laser and moving it back to the center, lowering the Z-axis; until the laser focus is located 5-10 μm above the target pellet apex surface or 2 / 3 of the target pellet wall thickness. This invention can process conical gas-filled holes in target pellets of different sizes, ensuring the gas-filled tube is inserted into the required target pellet shell position while significantly improving the accuracy and success rate of subsequent tube-particle assembly, which is of great significance for supporting the advancement of laser inertial confinement fusion experiments.

Description

Technical Field

[0001] The invention relates to the technical field of laser beam processing, and more specifically to the technical field of using femtosecond laser to process the conical gas-filled holes of a target pellet. Background Art

[0002] Inertial confinement fusion (ICF) requires multiple high-energy pulsed lasers to be uniformly irradiated on the target pellet at the same time to induce nuclear fusion. This process requires a large number of target pellets for experiments, and has strict requirements on various parameters of the target pellets. The quality of the laser fusion target pellet is one of the key factors that determine the success of the laser fusion experiment. The target pellet gas filling hole is a necessary microstructure for filling the gas fuel in the physical experiment target. Its processing quality directly affects the quality of the physical experiment tube-ball assembly (gas filling tube and target pellet) and its compliance with the physical design. The processing of the gas filling hole is directly related to the sealing performance of the gas filling tube and the target pellet after they are combined. Therefore, processing the gas filling hole with a size that meets the physical design requirements and a hole shape suitable for the sealing of the tube-ball assembly is of great significance to ensure the success of the laser inertial confinement nuclear fusion experiment.

[0003] For micro-hole processing, the traditional cutting method is limited by the size of the micro-tools on the market, resulting in the processable hole diameter not being small enough to meet the requirements. In addition, contact force will be generated during the processing, which will easily cause micro-cracks in the target pellet, affecting the subsequent use of the target pellet. In addition, the commonly used materials of the target pellet include hard and brittle materials (such as HDC), which can easily cause the collapse of the tool and material. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the requirements of the above-mentioned small hole size and material lead to the limited application of traditional mechanical processing in target pellet drilling. The present invention provides a method for processing conical filling holes in ICF target pellets using ultrafast laser.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical scheme: a method for processing a conical air-filling hole of an ICF target pellet using an ultrafast laser, comprising the following steps:

[0006] Step 1, fix the target pellet and place it under the focusing objective lens in the processing area;

[0007] Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is about 4-7 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet.

[0008] Step 3, keep the Z axis fixed or move the Z axis upward by 2 / 3 of the target pill wall thickness, that is, the focus is now located at the top of the target pill or at a distance of 2 / 3 of the target pill wall thickness above the top of the target pill;

[0009] Step 4, adjusting the average laser power of the femtosecond laser to 2-4 mW;

[0010] Step 5: With the top of the target pellet as the center, use a layer-by-layer rotary cutting process to process concentric circles with a maximum diameter of 4-20 μm;

[0011] Step 6: After processing one layer, turn off the laser, move the laser back to the center of the circle, and lower the Z axis by 10 μm;

[0012] Step 7, repeat steps 5 and 6 until the laser focus is located at the top surface of the target pellet or 5-10 μm above the 2 / 3 position of the target pellet wall thickness. At this time, a conical air-filled hole with a taper of T and an aperture of Ф at 2 / 3 of the target pellet wall thickness is processed.

[0013] In the technical solution of the present application: by improving the beam spot roundness and single-point processing resolution (lateral radius ≤ 0.003μm, depth ≤ 0.005mm), the accuracy and process stability of the ultrafast laser processing method of ICF target pellet conical air-filled holes can be further improved, and the processing of air-filled holes with a diameter of 4-20μm can be completed. For batch production, the size deviation of the target pellet air-filled micropores produced in the same batch is <2μm, the taper deviation is <1°, and the qualified rate is 90%. In the process of the present application, in most cases, the laser processing power used in the processing is less than 10mW, which has certain advantages over the prior art in terms of energy consumption control, processing accuracy, etc., and achieves the purpose of optimizing the use of laser power. Through the control of different parameters, it can adapt to the requirements of different apertures, with strong practicality and low processing cost. The present application establishes a femtosecond laser layered scanning GDP target capsule inflation hole processing process, which can process target capsule conical inflation holes of different sizes. While ensuring that the inflation tube is inserted into the required target capsule shell layer position, it greatly improves the accuracy and success rate of subsequent tube-ball coordination, which has specific application significance for supporting the advancement of laser inertial confinement fusion experiments.

[0014] The process of the present application can be used for processing the inflation holes of GDP target pellets or HDC target pellets.

[0015] The present application provides a method for accurately processing small holes that meet the requirements of physical experiments and ensure that the size and morphology are controllable for air-filled holes with a pore size requirement of less than 20 μm.

[0016] In the technical solution of the present application: GDP stands for glow discharge polymer, and HDC stands for high density carbon.

[0017] In the technical solution of this application, the aperture control method is as follows:

[0018] When the requirement for Ф changes, and the position definition of Ф changes, and it is no longer the aperture at 2 / 3 of the target wall thickness, the aperture control method within the specified depth is given below.

[0019] Since the laser focal position has a great influence on the hole shape and aperture, for the aperture requirements at different specific positions, the laser can be focused on different depth positions of the target capsule shell for processing when the laser power value is fixed, and the micropore diameters of the processing results can be compared to determine the laser focal position on the target capsule that meets the aperture size requirements of the inflation hole, thereby meeting the processing requirements of other aperture conical holes.

[0020] In this application, the processing uses a femtosecond laser to output a laser pulse width of about 100fs. Since the femtosecond laser beam will be widened when passing through a transparent medium during the beam transmission process, the pulse width acting on the material is about 130fs. The central wavelength is 800nm ​​and the bandwidth is 28nm. The output repetition frequency is 1000Hz. Before focusing, a small hole is added to the optical path to select the part with the most uniform intensity distribution of the Gaussian beam cross section as the direct processing light source. A microscope objective (Nikon, LU Plan) is used to focus the femtosecond laser beam and also serves as the microscope lens of the aiming system. The aiming and positioning system adjusts the position of the imaging lens so that the surface of the sample can be clearly imaged on the display when the laser focus is on the sample surface. In this way, the consistency of the relative position between the laser focus and the sample surface can be ensured. The maximum laser pulse energy output by the femtosecond laser is 1.2mJ, and the pulse energy can be adjusted within the range of 0 to 1.2mJ through an energy attenuation unit (composed of a half-wave plate and a polarizer).

[0021] Furthermore, step 1 is specifically to place the target pellet on the double-sided tape on the upper part of the slide after covering the surface of the slide with double-sided tape, and let it stand for 15-20 minutes (to prevent the target pellet from rolling during sample movement or later processing, which may damage the hole shape), and then move the slide with the target pellet fixed to place the target pellet under the focusing objective lens in the processing area.

[0022] Furthermore, the material of the target pellet is GDP.

[0023] Furthermore, the wall thickness of the pellet is 55-70 μm.

[0024] Further, T = 10-20°.

[0025] Further, Φ=4-20μm.

[0026] Furthermore, in step 5, the layer-by-layer peeling process includes drawing concentric circles from the center of the circle to be processed from the inside to the outside through the linkage of the X and Y axes of the translation stage, and the radius increment of adjacent concentric circles is less than the diameter of the laser spot.

[0027] Furthermore, the femtosecond laser outputs a laser pulse width of 100 fs, a central wavelength of 800 nm, a bandwidth of 28 nm, an output repetition frequency of 1000 Hz, and an output average power of 0-40 mW.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. Reduction in the size of machinable small holes and improvement in precision: This processing method can complete the processing of gas-filled holes with a diameter of 4-20μm. In view of the application requirements of high-precision conical gas-filled holes, the precision and process stability of the ultrafast laser processing method of ICF target pellet conical gas-filled holes can be further improved by improving the beam spot roundness and single-point processing resolution (lateral radius ≤ 0.003μm, depth ≤ 0.005mm). For batch production, the size deviation of the gas-filled micropores of the target pellets produced in the same batch is <2μm, the taper deviation is <1°, and the qualified rate is 90%.

[0030] 2. Improvement of laser energy utilization: In most cases, the laser processing power used in processing is less than 10mW. Compared with the existing technology, it has certain advantages in energy consumption control and processing accuracy, and achieves the purpose of optimizing the use of laser power.

[0031] 3. Different processing parameters can be directly used for verification experiments. By controlling different parameters, it can adapt to the requirements of different apertures. It has strong practicality and low processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the morphology and structure of the air-filled pore;

[0033] Figure 2 It is a structural diagram of the requirements for the size parameters of the inflation hole;

[0034] Figure 3 It is a schematic diagram of the laser peeling process path;

[0035] Figure 4 This is a diagram of the conical air-filling hole of the target pellet processed in Example 2;

[0036] Figure 5 This is a rendering of the assembly of the conical inflation hole and the inflation tube of the target pellet processed in Example 2. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] like Figure 1 As shown in the figure, with the gradual increase in the demand for physical experiments, the requirements for the diameter and shape of the current inflation holes are becoming more and more complex. In order to ensure the position of the tube mouth in the inflation hole after the inflation tube is inserted, the processing requirements for conical inflation holes are proposed. Figure 1 As shown in the figure, the entire processing and assembly requirements include the target pellet surface diameter, target pellet inner surface diameter, specific position diameter, diameter taper, inflation tube position, etc. In order to ensure the consistency of physical experimental data, the dimensional deviation of inflation hole processing also has higher requirements: the dimensional deviation of inflation holes in the same batch is within ±2μm. Figure 2 As shown in the figure, for the cone hole processing of the target pellet, two size parameters need to be controlled: the taper T of the small hole and the aperture Φ at a specific position, where Φ is defined as the aperture at 2 / 3 of the target pellet wall thickness. Laser layer-by-layer peeling processing path: Through the linkage of the X and Y axes of the translation table, concentric circles are drawn from the inside to the outside starting from the center of the circle to be processed. The radius increment of adjacent concentric circles needs to be smaller than the diameter of the laser spot. The moving path of the laser spot is as follows: Figure 3 shown.

[0041] Example 2

[0042] like Figures 1 to 5 As shown, this embodiment provides a method for processing a tapered hole with Φ = 15 μm and T = (15 ± 2)°:

[0043] Step 1: After the surface of the glass slide is covered with double-sided tape, the GDP target pellet is placed on the double-sided tape on the upper part of the glass slide, and left to stand for 20 minutes. Then, the glass slide with the target pellet fixed is moved so that the target pellet is placed under the focusing objective lens in the processing area;

[0044] Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is 5 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet.

[0045] Step 3, adjusting the average laser power of the femtosecond laser to 4 mW;

[0046] Step 4: With the top of the target pellet as the center, use a layer-by-layer rotary cutting process to process concentric circles with a maximum diameter of 15 μm;

[0047] Step 5. After processing one layer, turn off the laser, move the laser back to the center of the circle, and lower the Z axis by 10μm;

[0048] Step 6, repeat steps 4 to 5 until the laser focus is 5-10 μm above the 2 / 3 position of the target pellet wall thickness. At this time, the processed small hole taper is T=15, and the aperture at 2 / 3 of the target pellet wall thickness is a conical air-filled hole with a diameter of Ф=15 μm.

[0049] like Figure 4 The figure shows the conical air-filling hole of the target pellet processed in this embodiment. Figure 5 It is a rendering of the assembly of the conical inflation hole of the target pellet and the inflation tube processed in this embodiment.

[0050] Example 3

[0051] like Figures 1 to 3 As shown, this embodiment provides a method for processing a tapered hole with Φ = 10 μm and T = (15 ± 2)°:

[0052] Step 1: After the surface of the glass slide is covered with double-sided tape, the GDP target pellet is placed on the double-sided tape on the upper part of the glass slide, and it is left to stand for 18 minutes. Then, the glass slide with the target pellet fixed is moved so that the target pellet is placed under the focusing objective lens in the processing area;

[0053] Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is 5 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet.

[0054] Step 3, adjusting the average laser power of the femtosecond laser to 2 mW;

[0055] Step 4: With the top of the target pellet as the center, use a layer-by-layer rotary cutting process to process concentric circles with a maximum diameter of 10 μm;

[0056] Step 5. After processing one layer, turn off the laser, move the laser back to the center of the circle, and lower the Z axis by 10μm;

[0057] Step 6, repeat steps 4 to 5 until the laser focus is 5-10 μm above the 2 / 3 position of the target pellet wall thickness. At this time, the processed small hole taper is T=15, and the aperture at 2 / 3 of the target pellet wall thickness is a conical air-filled hole with a diameter of Ф=10 μm.

[0058] The processes of Example 2 and Example 3 are suitable for processing tapered holes with a diameter of 7-20 μm, which can be achieved by adjusting the single drop distance d of the Z axis and the laser power. The value of the single drop distance d of the Z axis will affect the size of Ф. The larger the value of d, the smaller Ф. The absolute values ​​of the two are inversely correlated. The power is only an approximate value, not a definite value. The higher the power, the larger the Ф. During the processing, it needs to be adjusted in real time according to the processing results.

[0059] Example 4

[0060] like Figures 1 to 3 As shown, this embodiment provides a method for processing a tapered hole with Φ = 5 μm and T = (15 ± 2)°:

[0061] Step 1: After the surface of the glass slide is covered with double-sided tape, the GDP target pellet is placed on the double-sided tape on the upper part of the glass slide, and left to stand for 15 minutes. Then, the glass slide with the target pellet fixed is moved so that the target pellet is placed under the focusing objective lens in the processing area;

[0062] Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is 5 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet.

[0063] Step 3, move the Z axis upward by 2 / 3 of the target pill wall thickness, that is, the focus is now located above the top of the target pill by 2 / 3 of the target pill wall thickness;

[0064] Step 4, adjusting the average laser power of the femtosecond laser to 2 mW;

[0065] Step 5: With the top of the target pellet as the center, use a layer-by-layer rotary cutting process to process concentric circles with a maximum diameter of 5 μm;

[0066] Step 6: After processing one layer, turn off the laser, move the laser back to the center of the circle, and lower the Z axis by 10 μm;

[0067] Step 7, repeat steps 5 to 6 until the laser focus is located on the vertex surface of the target pellet. At this time, a conical air-filled hole with a taper of T=15 and a diameter of Φ=5μm at 2 / 3 of the target pellet wall thickness is processed.

[0068] The processing technology of Example 4 is suitable for processing tapered holes with Φ=4-6μm, which can be achieved by adjusting the single drop distance d of the Z axis and the laser power. The value of the single drop distance d of the Z axis will affect the size of Φ. The larger the value of d, the smaller Φ, and the absolute values ​​of the two are inversely correlated. The power is only an approximate value, not a definite value. The higher the power, the larger the Φ. During the processing, it needs to be adjusted in real time depending on the processing results.

[0069] The processing techniques of Examples 2, 3 and 4 are suitable for the case where the wall thickness of the GDP target pellet is about 70 μm.

[0070] The following examples (Examples 5 and 6) also provide a method for processing conical holes in GDP target pellets, where the wall thickness of the GDP target pellets is 60 μm.

[0071] Example 5

[0072] like Figures 1 to 3 As shown, this embodiment provides a method for processing a tapered hole with Φ = 15 μm and T = (10 ± 2)°:

[0073] Step 1: After the surface of the glass slide is covered with double-sided tape, the GDP target pellet is placed on the double-sided tape on the upper part of the glass slide, and left to stand for 20 minutes. Then, the glass slide with the target pellet fixed is moved so that the target pellet is placed under the focusing objective lens in the processing area;

[0074] Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is 5 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet.

[0075] Step 3, adjusting the average laser power of the femtosecond laser to 4 mW;

[0076] Step 4: With the top of the target pellet as the center, use a layer-by-layer rotary cutting process to process concentric circles with a maximum diameter of 15 μm;

[0077] Step 5. After processing one layer, turn off the laser, move the laser back to the center of the circle, and lower the Z axis by 6μm;

[0078] Step 6, repeat steps 4 to 5 until the laser focus is 5-10 μm above the 2 / 3 position of the target pellet wall thickness. At this time, the processed small hole taper is T=10, and the aperture at 2 / 3 of the target pellet wall thickness is a conical air-filled hole with a diameter of Ф=15 μm.

[0079] Example 6

[0080] like Figures 1 to 3 As shown, this embodiment provides a method for processing a tapered hole with Φ = 5 μm and T = (20 ± 2)°:

[0081] Step 1: After the surface of the glass slide is covered with double-sided tape, the GDP target pellet is placed on the double-sided tape on the upper part of the glass slide, and left to stand for 15 minutes. Then, the glass slide with the target pellet fixed is moved so that the target pellet is placed under the focusing objective lens in the processing area;

[0082] Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is 5 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet.

[0083] Step 3, move the Z axis upward by 2 / 3 of the target pill wall thickness, that is, the focus is now located above the top of the target pill by 2 / 3 of the target pill wall thickness;

[0084] Step 4, adjusting the average laser power of the femtosecond laser to 2 mW;

[0085] Step 5: With the top of the target pellet as the center, use a layer-by-layer rotary cutting process to process concentric circles with a maximum diameter of 5 μm;

[0086] Step 6. After processing one layer, turn off the laser, move the laser back to the center of the circle, and lower the Z axis by 15μm;

[0087] Step 7, repeat steps 5 to 6 until the laser focus is located on the vertex surface of the target pellet. At this time, a conical air-filled hole with a taper of T=20 and a diameter of Φ=5μm at 2 / 3 of the target pellet wall thickness is processed.

[0088] The following examples (Examples 7 and 8) also provide a method for processing a tapered hole in a HDC target pellet, wherein the wall thickness of the HDC target pellet is between 25 and 40 μm.

[0089] Example 7

[0090] like Figures 1 to 3 As shown, this embodiment provides a method for processing a tapered hole with Φ = 10 μm and T = (15 ± 2)°:

[0091] Step 1: After the surface of the glass slide is covered with double-sided tape, the HDC target pellet is placed on the double-sided tape on the upper part of the glass slide, and left to stand for 20 minutes. Then, the glass slide with the target pellet fixed is moved so that the target pellet is placed under the focusing objective lens in the processing area;

[0092] Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is 7 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet.

[0093] Step 3, move the Z axis downward by 2 / 3 of the target pill wall thickness, that is, the focus is now located at 2 / 3 of the wall thickness below the top of the target pill;

[0094] Step 4, adjusting the average laser power of the femtosecond laser to 40 mW;

[0095] Step 5: Turn on the laser for 3 seconds and then turn it off to form a small hole;

[0096] Step 6, adjusting the average laser power of the femtosecond laser to 10 mW;

[0097] Step 7: With the small hole in step 5 as the center, use the layer-by-layer rotary cutting process to process a circle with a diameter of 10 μm. At this time, the taper of the small hole is T=15, and the diameter of the hole at 2 / 3 of the target pellet wall thickness is a conical air-filled hole of Ф=10 μm.

[0098] In this embodiment, the power is not a fixed value, and the higher the power, the larger the Φ obtained. During the processing, it needs to be adjusted in real time according to the processing results. Based on the above route, for a tapered hole with Φ = 10-20μm, it can be achieved by adjusting the laser power.

[0099] Example 8

[0100] like Figures 1 to 3 As shown, this embodiment provides a method for processing a tapered hole with Φ = 5 μm and T = (15 ± 2)°:

[0101] Step 1: After the surface of the glass slide is covered with double-sided tape, the HDC target pellet is placed on the double-sided tape on the upper part of the glass slide, and left to stand for 18 minutes. Then, the glass slide with the target pellet fixed is moved so that the target pellet is placed under the focusing objective lens in the processing area;

[0102] Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is 4 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet.

[0103] Step 3, move the Z axis upward by 2 / 3 of the target pill wall thickness, that is, the focus is now located at 2 / 3 of the wall thickness above the top of the target pill;

[0104] Step 4, adjusting the average laser power of the femtosecond laser to 4 mW;

[0105] Step 5: With the top of the target pellet as the center, use a layer-by-layer rotary cutting process to process a circle with a diameter of 5 μm;

[0106] Step 6: Move the Z axis downward by 4 / 3 of the wall thickness, that is, the focus is now located at 2 / 3 of the wall thickness below the top of the target pellet;

[0107] Step 7, turn on the laser for 5 seconds and then turn it off, that is, perform laser single-point processing for 5 seconds. At this time, the processed small hole taper is T=15, and the aperture at 2 / 3 of the target pellet wall thickness is a conical air-filled hole with a diameter of Ф=5μm.

[0108] In this embodiment, the power is not a fixed value, and the higher the power, the larger the Φ obtained. During the processing, it needs to be adjusted in real time according to the processing results. Based on the process of this embodiment, for a tapered hole with Φ=4-10μm, it can be achieved by adjusting the laser power.

Claims

1. A method for processing a conical air-filling hole in an ICF target pellet using an ultrafast laser, characterized in that: The steps include: Step 1, fix the target pellet and place it under the focusing objective lens in the processing area; Step 2: The laser of the femtosecond laser passes through the focusing lens. At this time, the laser spot diameter is 4-7 μm. The longitudinal position of the focusing lens is adjusted by moving the Z axis to focus on the top of the target pellet. Step 3, keep the Z axis fixed or move the Z axis upward by 2 / 3 of the target pill wall thickness, that is, the focus is now located at the top of the target pill or at a distance of 2 / 3 of the target pill wall thickness above the top of the target pill; Step 4, adjusting the average laser power of the femtosecond laser to 2-4 mW; Step 5: With the top of the target pellet as the center, use a layer-by-layer rotary cutting process to process concentric circles with a maximum diameter of 4-20 μm; Step 6: After processing one layer, turn off the laser, move the laser back to the center of the circle, and lower the Z axis by 10 μm; Step 7, repeat steps 5 and 6 until the laser focus is located at the top surface of the target pellet or 5-10 μm above the 2 / 3 position of the target pellet wall thickness. At this time, a conical air-filled hole with a taper of T and an aperture of Ф at 2 / 3 of the target pellet wall thickness is processed.

2. The method of using ultrafast laser to process the conical filling hole of ICF target pellet according to claim 1, characterized in that: Step 1 specifically includes covering the surface of the glass slide with double-sided tape and placing the target pellet on the double-sided tape on the upper part of the glass slide, leaving it to stand for 15-20 minutes, and then moving the glass slide with the target pellet fixed to place the target pellet under the focusing objective lens in the processing area.

3. The method of using ultrafast laser to process the conical filling hole of ICF target pellet according to claim 1, characterized in that: The material of the target pellet is GDP.

4. The method of using ultrafast laser to process the conical filling hole of ICF target pellet according to claim 3, characterized in that: The wall thickness of the pellet is 55-70 μm.

5. The method of using ultrafast laser to process the conical filling hole of ICF target pellet according to claim 1, characterized in that: T＝10-20°。 6. The method of using ultrafast laser to process the conical filling hole of ICF target pellet according to claim 1, characterized in that: Ф=4-20μm.

7. The method of using ultrafast laser to process the conical filling hole of ICF target pellet according to claim 1, characterized in that: In step 5, the layer-by-layer peeling process includes drawing concentric circles from the center of the circle to be processed from the inside to the outside through the linkage of the X and Y axes of the translation stage, and the radius increment of adjacent concentric circles is less than the diameter of the laser spot.

8. The method of using ultrafast laser to process the conical filling hole of ICF target pellet according to claim 1, characterized in that: The femtosecond laser output laser pulse width is 100fs, the central wavelength is 800nm, the bandwidth is 28nm, the output repetition frequency is 1000Hz, and the output average power is 0-40mW.

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