An ultrafast laser generation device

Abstract

The application discloses a kind of ultrafast laser generation device.The device includes Yb-doped femtosecond laser light source, first focusing lens, first optical window, first energy transfer device, first level hollow capillary fiber, second optical window, concave mirror, half-wave plate, wire grid polarizer, second focusing lens, third optical window, first gas chamber, second level hollow anti-resonant fiber, second gas chamber, fourth optical window, 90° off-axis parabolic mirror, frequency-resolved optical gating pulse measurement device.By changing the inert gas type and air pressure in the first level hollow capillary fiber, the incident pulse spectrum is broadened using self-phase modulation effect;Then, the second level hollow anti-resonant fiber is filled with inert gas to generate air pressure gradient, and finally realizes flexible transmission of sub-20 fs ultrafast laser using soliton self-compression effect.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrafast lasers, and mainly to a device for generating ultrafast lasers. Background Art

[0002] In today's era of rapid advancements in science and technology, ultrafast laser technology has become an indispensable tool in numerous fields, including physics, chemistry, biology, materials science, and medicine. Currently, ultrafast lasers are primarily generated through mode-locking techniques. However, the resulting femtosecond laser peak power is low, failing to meet the demands of various practical applications. Chirped pulse amplification can produce ultrashort pulses in the millijoule range by stretching, amplifying, and then compressing the pulse in the temporal domain. However, due to the unavoidable gain bandwidth limitations and dispersion mismatch of the gain fiber, the pulse width is typically greater than 200 fs. On January 14, 2015, patent application CN104283097A combined chirped pulse amplification and split pulse amplification techniques, achieving pulse widths in the sub-hundred-femtosecond range. Nonlinear amplification, on the other hand, utilizes nonlinear effects such as self-phase modulation to amplify the pulse energy while broadening the spectrum, effectively producing sub-hundred-femtosecond microjoule pulses in the 100-watt range. On February 13, 2024, the patent application with publication number CN117559204A enabled the generation, amplification, gain management, nonlinear evolution and compression of pulses to be completed in the optical fiber. The final output laser pulse width was about 50fs, and the peak power of the laser could reach the megawatt level. However, it was still impossible to achieve ultrafast laser output with a pulse width of sub-twenty femtoseconds.

[0003] At the same time, how to perfectly transmit laser light is also an important research topic. Flexible laser transmission, which eliminates the limitations of spatial optical paths, enables more flexible and convenient laser transmission, and is in high demand in fields such as precision machining and laser medical treatment.

[0004] Nowadays, a new type of microstructured optical fiber - antiresonant hollow-core optical fiber uses the coherent reflection of light back and forth between the tubular glass films inside the optical fiber to confine the light near the air core and transmit it along the axis. Compared with traditional optical fibers and other microstructured optical fibers, it has the advantages of large mode field area, high damage threshold, low nonlinearity, adjustable dispersion, and free control of the type and composition of the core gas. It is very suitable as a carrier for ultrafast laser transmission. Its unique properties provide new possibilities for the transmission of ultrafast lasers.

[0005] The present invention is based on nonlinear pulse compression technology and two-stage hollow-core optical fiber to generate and transmit ultrafast lasers. It aims to solve the defects of traditional pulse compression technology, such as the compressed pulse width is not narrow enough and the device is complex. It ensures the output of ultrafast laser with ultrashort pulse width while taking into account high stability and compactness, and has broad application prospects. Summary of the Invention

[0006] The present invention provides an ultrafast laser generation device that generates and transmits ultrafast laser light with a high repetition rate, high energy, and high peak power and a sub-twenty femtosecond pulse width. This device overcomes the defects of the prior art, such as the complexity of the device and the insufficiently narrow pulse width compression, and has the advantages of high stability, compactness, and flexible transmission. Furthermore, the device does not require the use of a chirped mirror to compensate for dispersion.

[0007] The technical solution of the present invention is: an ultrafast laser generating device, which comprises, in sequence, an ytterbium-doped femtosecond laser light source, a first focusing lens, a pulse spectrum broadening unit, a concave reflector, a half-wave plate, a wire grid polarizer, a second focusing lens, a dispersion compensation and pulse transmission unit, a 90° off-axis parabolic reflector, and a frequency-resolving optical switch pulse measurement device;

[0008] The pulse spectrum broadening unit is used to achieve spectrum broadening, and includes a first-stage energy transmission device sealed by a first optical window and a second optical window, and a first-stage hollow-core capillary optical fiber placed in the first-stage energy transmission device;

[0009] The dispersion compensation and pulse transmission unit is used to achieve compressed pulse width and transmitted pulse energy, including a first air chamber and a second air chamber connected to the third optical window and the fourth optical window on the front side, respectively, and having sub-micrometer through holes on the back side, and a second-stage hollow-core anti-resonant optical fiber with both ends passing through the through holes and fixed to the first air chamber and the second air chamber.

[0010] Its working process is as follows: the initial laser pulse emitted by the ytterbium-doped femtosecond laser light source is focused and coupled into the first-stage hollow-core capillary fiber placed in the first-stage energy transmission device through the first focusing lens and the first optical window, and is output through the second optical window to achieve spectrum broadening; the broadened laser pulse is collimated by a concave reflector and the optical path is changed, the energy is adjusted by a half-wave plate and a wire grid polarizer, and then it is focused and coupled into the second-stage hollow-core anti-resonance fiber placed in the first and second air chambers through the second focusing lens and the third optical window. In the second-stage hollow-core anti-resonance fiber, the first air chamber at the incident end is evacuated and the second air chamber at the output end is filled with inert gas to form a pressure gradient. Due to the soliton self-compression effect, ultrafast laser flexible transmission of sub-20fs order is achieved, and it is output through the fourth optical window, and then collimated by a 90° off-axis parabolic reflector and the optical path is turned to enter the frequency-resolving optical switch pulse measurement device to measure the pulse width.

[0011] The first-stage energy transmission device includes: a sealing glass plate, a first gas control valve, an optical fiber fixing seat, and a cylindrical cavity. The sealing glass plate is arranged outside the cylindrical cavity and is used to observe the end face position of the first-stage hollow capillary optical fiber to facilitate coupling adjustment; the first gas control valve is arranged outside the cylindrical cavity and is connected to the gas bottle and the vacuum pump through an air pipe; the optical fiber fixing seat is fixed in the cylindrical cavity, and the material is a metal with good thermal conductivity and is provided with a V-shaped groove; the cylindrical cavity is placed on two two-dimensional translation stages; the first-stage hollow capillary is fixed in the V-shaped groove in the optical fiber fixing seat, and the optical fiber fixing seat is fixed in the cylindrical cavity. The sealing glass plate, the first optical window, the second optical window and the first gas control valve form a sealed space, and inert gas is filled through the first gas control valve to achieve initial laser pulse spectrum broadening.

[0012] The initial laser pulse emitted by the Yb-doped femtosecond laser source is focused and coupled by the first focusing lens, and the coupled beam focal spot is 1 / e 2 The diameter of the first-stage hollow capillary fiber is 0.5 to 0.8 times the inner diameter of the first-stage hollow capillary fiber; the broadened laser pulse is focused and coupled by the second focusing lens, and the coupled beam focal spot is 1 / e 2 The diameter at the point is 0.5 to 0.8 times the inner diameter of the second-stage hollow-core antiresonant fiber;

[0013] Preferably, the first focusing lens couples the beam focal spot 1 / e 2 The diameter of the first-stage hollow-core capillary fiber is 0.64 times the inner diameter of the first-stage hollow-core capillary fiber; the second focusing lens couples the beam focal spot 1 / e 2 The diameter at is 0.64 times the inner diameter of the second-stage hollow-core antiresonant fiber.

[0014] The first gas control valve is used for charging and discharging inert gas and regulating and controlling the gas pressure. The inert gas is helium, neon, argon, krypton, or xenon monatomic gas.

[0015] The first gas chamber and the second gas chamber are respectively equipped with a second gas control valve and a third gas control valve. The second gas control valve is used for vacuuming, and the third gas control valve is used for filling and discharging inert gas and regulating and controlling the air pressure. The inert gas is helium, neon, argon, krypton, or xenon monatomic gas.

[0016] The first-stage energy transmission device and the second air chamber are filled with inert gases; the inert gases include helium, neon, argon, krypton, and xenon monatomic gases; the first-stage energy transmission device and the second air chamber are respectively equipped with a first gas control valve and a third gas control valve for filling and discharging the inert gas and regulating and controlling the air pressure; the first air chamber is equipped with a second gas control valve, and the second gas control valve is used for vacuuming.

[0017] The concave reflector and the 90° off-axis parabolic reflector collimate the pulses emitted from the first-stage hollow-core capillary and the second-stage hollow-core antiresonant optical fiber and simultaneously deflect the optical path. Compared with a lens, the light beam passing through the concave reflector and the 90° off-axis parabolic reflector will not introduce dispersion and absorption loss, and will not produce spherical aberration or chromatic aberration.

[0018] The first-stage energy transmission device can transmit 400μJ, 29W high-repetition-rate, high-energy ultrafast laser, and at the same time has the functions of fixing optical fibers, sealing, heat dissipation, and regulating gas types and pressures. It also has the characteristics of simple structure, uniform heat dissipation, and strong practicality.

[0019] The first-stage hollow-core capillary optical fiber is no longer than 1 meter.

[0020] The second-stage hollow-core anti-resonant optical fiber is no longer than 2.5 meters.

[0021] The ytterbium-doped femtosecond laser light source is a laser light source with a central wavelength of 1030 nm, and has an adjustable pulse energy of 0 μJ to 400 μJ and a repetition rate of 0 kHz to 72.4 kHz.

[0022] Beneficial technical effects of the present invention:

[0023] The present invention proposes an ultrafast laser generation device that can output femtosecond laser pulses with adjustable energy, good coherence, and stable output power; by adjusting the incident pulse energy, gas type, and gas pressure, high-energy, high-repetition-rate, sub-20fs-level ultrafast laser pulse generation and transmission can be achieved; the present invention uses spectral broadening and pulse compression to achieve the generation and transmission of broadband femtosecond laser light sources; the first-stage energy transmission device of the present invention has uniform heat dissipation, good stability and airtightness, and low processing difficulty, and can accurately control gas pressure and withstand femtosecond laser transmission with higher power and energy; the present invention takes into account both scientific research and exploration and practical application needs, the experimental device is scientific and reasonable, cost-controllable, and easy to maintain, and the device has the advantage of flexible transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the experimental optical path of an ultrafast laser generating device in an embodiment of the present invention.

[0025] Figure 2 This is a schematic structural diagram of the first-stage energy transmission device of an ultrafast laser generating device in an embodiment of the present invention.

[0026] Figure 3 The frequency domain and time domain measurement diagrams of high energy, high repetition rate sub-20fs pulses transmitted in an embodiment of the present invention are shown in FIG. Figure 3 (a) is the measured FROG trace; Figure 3 (b) is the FROG trace image restored by the algorithm; Figure 3 (c) is the pulse time domain and phase distribution diagram restored by the algorithm; Figure 3 (d) is the measured and recovered pulse frequency domain and phase distribution diagram.

[0027] Reference numerals:

[0028] Ytterbium-doped femtosecond laser light source-1; first focusing lens-2; first optical window-3; first-stage energy transmission device-4; first-stage hollow-core capillary fiber-5; second optical window-6; concave reflector-7; first reflector-8; half-wave plate-9; wire-grid polarizer-10; second reflector-11; third reflector-12; second focusing lens-13; third optical window-14; first gas chamber-15; second gas control valve-151; second-stage hollow-core antiresonant fiber-16; second gas chamber-17; third gas control valve-171; fourth optical window-18; 90° off-axis parabolic reflector-19; fourth reflector-20; frequency-resolved optical switch pulse measurement device-21.

[0029] Sealing glass plate-41; first gas control valve-42; optical fiber fixing seat-43; cylindrical cavity-44. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the following examples and drawings, but the scope of protection of the present invention should not be limited thereto.

[0031] Figure 1 A device for generating an ultrafast laser includes, in sequence: 1. an ytterbium-doped femtosecond laser light source; 2. a first focusing lens; 3. a first optical window; 4. a first-stage energy transmission device; 5. a first-stage hollow-core capillary fiber; 6. a second optical window; 7. a concave reflector; 8. a first reflector; 9. a half-wave plate; 10. a wire-grid polarizer; 11. a second reflector; 12. a third reflector; 13. a second focusing lens; 14. a third optical window; 15. a first gas chamber; 151. a second gas control valve; 16. a second-stage hollow-core antiresonant fiber; 17. a second gas chamber; 171. a third gas control valve; 18. a fourth optical window; 19. a 90° off-axis parabolic reflector; 20. a fourth reflector; 21. a frequency-resolved optical switch pulse measurement device.

[0032] The ytterbium-doped femtosecond laser light source 1 generates an initial laser pulse, and the laser light source parameters are: 1030nm central wavelength, about 190fs pulse width, and 1kHz repetition frequency.

[0033] The half-wave plate 9 and the wire-grid polarizer 10 form a pulse energy and polarization adjustment unit. The half-wave plate can change the polarization of light, and the wire-grid polarizer transmits specific linearly polarized light by fixing the polarization direction. The combination of the two can achieve continuous adjustment of pulse energy.

[0034] The focal lengths of the first and second focusing lenses depend on the size of the focal spot after the laser pulse is focused and the inner diameter of the hollow core waveguide. 2 When the diameter at is about 0.64 times the inner diameter of the hollow-core capillary fiber, the theoretical coupling efficiency of the fundamental mode is about 0.98.

[0035] The first-stage energy transmission device 4 is supported and fixed by two two-dimensional translation stages, while the first and second air chambers 15 and 17 are supported and fixed by two three-dimensional translation stages, ensuring that the laser pulse passes through the first-stage energy transmission device and the first and second air chambers along its axis. The first-stage hollow-core capillary fiber is integrally fixed to a fiber holder within the first-stage energy transmission device 4. The ends of the second-stage hollow-core antiresonant fiber are fixed within V-grooves in the first and second air chambers, ensuring that the axis of the first-stage hollow-core capillary fiber coincides with the axis of the first-stage energy transmission device, and the axis of the second-stage hollow-core antiresonant fiber coincides with the axes of the first and second air chambers. The first-stage energy transmission device 4 is sealed at the front and back by the first optical window 3 and the second optical window 6. A first gas control valve 42 controls the inert gas flow and pressure, ensuring good airtightness when connecting the optical windows. The first and second air chambers 15 and 17 are rectangular cavities, connected to the third and fourth optical windows 14 and 18 on the front, respectively, and feature sub-millimeter through-holes on the back. The second hollow-core antiresonant fiber is inserted through the through-holes at both ends and secured there, sealed with UV glue. The first air chamber is equipped with a second gas control valve 151 for vacuuming, while the second air chamber is equipped with a third gas control valve 171 for injecting and discharging inert gas and controlling gas pressure. Ensure good airtightness when connecting the optical windows and sealing with UV glue. The first optical window 3, the first-stage energy transmission device 4, the first-stage hollow-core capillary fiber 5, and the second optical window 6 form a pulse spectrum broadening unit. The third optical window 14, the first air chamber 15, the second hollow-core antiresonant fiber 16, the second air chamber 17, and the fourth optical window 18 form a dispersion compensation and pulse transmission unit.

[0036] The first optical window, the second optical window, the third optical window and the fourth optical window are made of fused quartz.

[0037] The specific embodiment of the present invention is as follows: an ytterbium-doped femtosecond laser light source 1 outputs an initial laser pulse with a central wavelength of 1030nm, a pulse width of about 190fs, and a repetition frequency of 1kHz, which passes through the first focusing lens 2 to reach the first optical window 3 and the first-stage energy transmission device 4, and is coupled into the first-stage hollow-core capillary fiber 5. The first focusing lens 2 is used to focus the laser pulse, and the selection of its focal length is determined by the numerical relationship between the inner diameter of the first-stage hollow-core capillary fiber 5 and the size of the light spot at the focus. Specifically, a CCD camera is used to detect the size of the light spot at the focus, and by selecting lenses with different focal lengths, the focal spot 1 / e 2 The diameter of the first-stage hollow-core capillary fiber 5 is close to or equal to 0.64 of the inner diameter of the first-stage hollow-core capillary fiber 5, at which point the lens focal length is optimal. In this embodiment, the focal length of the first focusing lens 2 is 501.8 mm. By repeatedly adjusting the two forward and backward two-dimensional translation stages, the spatial position of the pulse spectrum stretching unit changes, and its axis coincides with the axis of the initial laser pulse. As a result, the laser pulse, after being focused by the first focusing lens 2, is efficiently coupled into the first-stage hollow-core capillary fiber 5, which has a length of 80 cm and a core diameter of 250 μm. This ensures that the output pulse energy is maximized and the spot mode is the fundamental mode. The laser pulse output from the pulse spectrum stretching unit is collimated by a concave reflector 7 with a focal length of 500 mm. After being deflected by the first reflector 8, it passes through the energy and polarization adjustment unit to achieve continuous pulse energy adjustment. The optical path is further deflected by the second and third reflectors 11 and 12 before being focused by the second focusing lens 13 with a focal length of 60 mm. The focal length is selected similarly to that of the first focusing lens 2. The three-dimensional translation stage at the incident end is then adjusted to efficiently couple the laser pulse into the second-stage hollow-core antiresonant fiber 16, which has a vacuum end and an inert gas-filled end. The output pulse energy is maximized, and the spot mode is the fundamental mode. The laser pulse is compressed in the second-stage hollow-core antiresonant fiber 16 using the negative dispersion of the hollow-core waveguide and the nonlinear effect of the inert gas. The chirp of the laser pulse output by the pulse spectrum broadening unit is calculated, and the appropriate length of the second-stage hollow-core antiresonant fiber 16 is selected to optimize dispersion compensation and achieve sub-20 fs laser pulse output. By adjusting the half-wave plate to change the laser pulse energy incident on the second focusing lens and the gas type and pressure within the second gas chamber, high-energy, high-repetition-rate, sub-20 fs ultrafast laser pulse generation and transmission can be achieved. The pulse at the output end of the second-stage hollow-core antiresonant fiber 16 is collimated by a 90° off-axis parabolic reflector 19, then deflected by a fourth reflector 20 to enter a frequency-resolving optical switch pulse measurement device 21 for pulse measurement.

[0038] Figure 2 , a structure of a first-stage energy transmission device based on an ultrafast laser generating device, including: a sealing glass plate 41, a first gas control valve 42, an optical fiber fixing seat 43, and a cylindrical cavity 44.

[0039] The sealing glass plate 41 and the cylindrical cavity 44 are tightly connected with screws, which can be used to observe the position of the optical fiber end face and facilitate coupling adjustment. When connecting, the screws need to be tightened to ensure good airtightness and avoid slipping.

[0040] Among them, the first gas control valve 42 is connected to the gas bottle and the vacuum pump through the air pipe, and is used to control the gas in the first-stage energy transmission device 4. Good airtightness must also be ensured during the connection.

[0041] The cylindrical cavity 44 is cylindrical so as to be easily clamped and fixed by the two-dimensional translation stage.

[0042] The optical fiber holder 43 is placed and secured within the cylindrical cavity 44 via a slot. It is made of a metal with good thermal conductivity and is provided with a V-groove. In this embodiment, copper is the preferred material. Copper tape is used to cover one or more segments of the hollow-core capillary fiber to effectively secure the fiber. Copper has excellent thermal conductivity. The close contact between the hollow-core capillary fiber, the optical fiber holder, and the copper tape allows for rapid dissipation of heat generated by high-energy, high-repetition-rate ultrafast laser light transmitted through the hollow-core capillary, preventing the fiber from burning. Due to the secure connection between the hollow-core capillary fiber, the optical fiber holder, and the cylindrical cavity, the primary energy transfer device ensures the stability of laser pulse transmission when the spatial position of the hollow-core capillary fiber is adjusted using a translation stage. The specific operation is as follows: First, the hollow-core capillary fiber is placed on the optical fiber holder, and copper tape is used to secure the fiber. The optical fiber holder is then inserted through one end of the cylindrical cavity until it reaches the slot. Finally, the cylindrical cavity is securely secured to the two two-dimensional translation stages at the head and tail. Through the sealing glass plate, the translation stage is adjusted to position the hollow-core capillary fiber port at the focal point. Finally, the sealing glass plate, the first gas control valve, the gas bottle, and the vacuum pump are connected. The first and second optical windows are used to seal the ends of the cylindrical cavity, ensuring airtightness and enabling precise control of the gas type and pressure within the cavity. In this embodiment, the first-stage energy transmission device can transmit 400 μJ, 29 W of high-repetition-rate, high-energy ultrafast laser light. This is only one example and should not limit the scope of protection of the present invention.

[0043] Figure 3, frequency domain and time domain measurement diagrams of the high-energy, high-repetition-rate, sub-20fs ultrafast laser pulses generated. By adjusting the laser pulse energy output by the pulse spectrum broadening unit, the gas type and pressure in the second gas chamber, high-energy, high-repetition-rate, sub-20fs ultrafast laser pulse generation and transmission can be achieved. Among them, in this embodiment, in the first-stage energy transmission device, the optimal settings for initial laser pulse spectrum broadening are: the inert gas is argon; the optimal setting value of the gas pressure is 1200mbar; and the optimal setting of the drive pulse energy is 400μJ. The optimal settings of the gas type and gas pressure in the first-stage energy transmission device need to be determined according to the length of the second-stage antiresonant hollow-core fiber. In the second gas chamber of this embodiment, the optimal settings for generating and transmitting sub-20fs ultrafast lasers are: the inert gas is neon; the gas pressure range is 3200mbar to 3900mbar; and the driving pulse energy range matched by the gas pressure is 11μJ to 13μJ. Typically, in this embodiment, the optimal settings for generating and transmitting an ultrafast laser with a pulse width of 17.3 fs are: neon as the inert gas, a pressure of 3260 mbar, and a drive pulse energy of 12.48 μJ to match the pressure. Specific parameters such as the gas type, pressure, and drive pulse energy used in the second chamber should be determined based on actual conditions.

Claims

1. An ultrafast laser generating device, characterized in that: Including in order: Ytterbium-doped femtosecond laser light source (1), a first focusing lens (2), a pulse spectrum broadening unit, a concave reflector (7), a half-wave plate (9), a wire grid polarizer (10), a second focusing lens (13), a dispersion compensation and pulse transmission unit, a 90° off-axis parabolic reflector (19), and a frequency-resolved optical switch pulse measurement device (21); The pulse spectrum broadening unit is used to achieve spectrum broadening, and comprises a first-stage energy transmission device (4) sealed by a first optical window (3) and a second optical window (6), and a first-stage hollow-core capillary optical fiber (5) placed in the first-stage energy transmission device; The dispersion compensation and pulse transmission unit is used to achieve compression of pulse width and transmission of pulse energy, and comprises a first air chamber (15) and a second air chamber (17) respectively connected to a third optical window (14) and a fourth optical window (18) on the front side, and having a sub-millimeter through hole on the back side, and a second-stage hollow-core anti-resonance optical fiber (16) with both ends passing through the through holes and fixed to the first air chamber and the second air chamber; The initial laser pulse emitted by the ytterbium-doped femtosecond laser light source is focused and coupled into a first-stage hollow-core capillary fiber placed in a first-stage energy transmission device through a first focusing lens and a first optical window, and is output through a second optical window to achieve spectrum broadening; the broadened laser pulse is collimated by a concave reflector and then the optical path is changed, the energy is adjusted by a half-wave plate and a wire grid polarizer, and then it is focused and coupled into a second-stage hollow-core anti-resonance fiber placed in a first air chamber and a second air chamber through a second focusing lens and a third optical window. In the second-stage hollow-core anti-resonance fiber, the first air chamber at the incident end is evacuated and the second air chamber at the output end is filled with an inert gas to form a pressure gradient. Due to the soliton self-compression effect, flexible transmission of ultrafast laser of sub-20 fs order is achieved, and the laser is output through a fourth optical window, and then collimated by a 90° off-axis parabolic reflector and the optical path is deflected to enter a frequency-resolving optical switch pulse measurement device to measure the pulse width.

2. The ultrafast laser generating device according to claim 1, characterized in that: The first-stage energy transmission device comprises: a sealing glass plate (41), a first gas control valve (42), an optical fiber fixing seat (43), and a cylindrical cavity (44); The sealing glass plate (41) is arranged outside the cylindrical cavity; The first gas control valve (42) is arranged outside the cylindrical cavity and is connected to the gas bottle and the vacuum pump through the air pipe; The optical fiber fixing seat (43) is fixed in the cylindrical cavity (44); the optical fiber fixing seat (43) is made of metal with good electrical conductivity and is provided with a V-shaped groove; The cylindrical cavity (44) is placed on two two-dimensional translation stages; The first-stage hollow-core capillary optical fiber (5) is fixed in a V-groove in an optical fiber fixing seat (43), and the optical fiber fixing seat (43) is fixed in a cylindrical cavity (44). A sealed space is formed by a sealing glass plate (41), a first optical window (3), a second optical window (6), and a first gas control valve (42). Inert gas is introduced through the first gas control valve to achieve initial laser pulse spectrum broadening.

3. An ultrafast laser generating device according to claim 1 or 2, characterized in that: The initial laser pulse emitted by the ytterbium-doped femtosecond laser light source (1) is focused and coupled by the first focusing lens (2), and the coupled beam focal spot 1 / e 2 The diameter of the first-stage hollow-core capillary optical fiber (5) is 0.5 to 0.8 times the inner diameter; the broadened laser pulse is focused and coupled by the second focusing lens (13), and the coupled beam focal spot is 1 / e 2 The diameter at the location is 0.5 to 0.8 times the inner diameter of the second-stage hollow-core anti-resonance optical fiber (16).

4. The ultrafast laser generating device according to claim 3, wherein: The first focusing lens (2) couples the light beam focal spot 1 / e 2 The diameter at the first stage hollow core capillary optical fiber (5) is 0.64 times the inner diameter; the second focusing lens (13) couples the light beam focal spot 1 / e 2 The diameter at the location is 0.64 times the inner diameter of the second-stage hollow-core anti-resonance optical fiber (16).

5. The ultrafast laser generating device according to claim 2, wherein: The first gas control valve is used for charging and discharging inert gas and regulating and controlling the gas pressure. The inert gas is helium, neon, argon, krypton, or xenon monatomic gas.

6. The ultrafast laser generating device according to claim 1, wherein: The first gas chamber (15) and the second gas chamber (17) are respectively equipped with a second gas control valve (151) and a third gas control valve (171). The second gas control valve (151) is used for vacuuming, and the third gas control valve (171) is used for charging and discharging inert gas and regulating and controlling the gas pressure. The inert gas is helium, neon, argon, krypton, or xenon monatomic gas.

7. The ultrafast laser generating device according to claim 1, wherein: The length of the first-stage hollow-core capillary optical fiber (5) is no more than 1 meter.

8. The ultrafast laser generating device according to claim 1, wherein: The length of the second-stage hollow-core anti-resonance optical fiber (16) is no more than 2.5 meters.

9. The ultrafast laser generating device according to claim 1, wherein: The ytterbium-doped femtosecond laser light source (1) is a laser light source with a central wavelength of 1030 nm, an adjustable pulse energy of 0 μJ to 400 μJ, and a repetition rate of 0 kHz to 72.4 kHz.

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