Gas-solid mixing multi-through-cavity system, compression device and method

Abstract

The invention provides a gas-solid mixing multi-pass cavity system, a compression device and a compression method. According to the gas-solid mixing multi-pass cavity system, the compression device and the method, a traditional gas multi-pass cavity and a solid multi-pass cavity are combined, the gas-solid mixing multi-pass cavity system has the advantages of high nonlinearity of the solid multi-pass cavity and high ionization threshold and stability of gas at the same time, the length of the gas-solid mixing multi-pass cavity can be conveniently and rapidly adjusted, and the compression efficiency is improved. The proper length of the vacuum tube, the thickness of the fused quartz plate and the gas type are selected according to requirements, and the device can be suitable for spectrum broadening and compression of high-power and high-repetition-frequency femtosecond laser and has universality.

Description

Technical Field

[0001] This invention belongs to the field of pulsed laser technology, specifically relating to a gas-solid hybrid multi-cavity system, a compression device, and a method. Background Technology

[0002] High-power ultrashort pulse lasers are driving the forefront of science and technology with unprecedented precision and intensity. In basic research, they are the only tools for exploring attosecond-scale ultrafast electron dynamics, used to drive electron acceleration in laser wakefields, and for building desktop particle accelerators. In industry, their extremely high peak power enables "cold processing," allowing for precise three-dimensional internal carving of transparent materials, revolutionizing smartphone glass screen cutting and semiconductor chip manufacturing. In the medical field, femtosecond laser surgery, with its extremely high precision and virtually no thermal damage, has become the gold standard for delicate ophthalmic surgeries such as myopia correction. These applications fully demonstrate the enormous potential of high-power ultrashort pulses as powerful tools in revealing the microscopic mysteries of matter and reshaping advanced manufacturing. Ytterbium-doped (Yb) and Ti:Sa lasers are the two core lasers in the field of ultrafast lasers.

[0003] Ti:sapphire femtosecond lasers, as the traditional mainstay, can directly generate femtosecond pulses due to their extremely wide gain bandwidth. However, their reliance on green light pump sources leads to system complexity, low efficiency, and difficult thermal management, limiting further increases in average power. In contrast, ytterbium-doped femtosecond lasers, benefiting from direct diode pumping, have significant advantages such as high efficiency, compact structure, and average power easily reaching the kilowatt level. However, their inherently narrow gain bandwidth means that the pulse width of direct output is typically in the hundreds of femtoseconds, making it difficult to meet the stringent requirements of many cutting-edge applications for extremely high peak power and ultrafast time resolution. This has spurred the development of post-compression technology, which involves nonlinearly broadening and compressing the ultrashort pulses at the end of the laser amplification chain, overcoming the bandwidth limitations of the Yb crystal gain medium itself, and achieving narrower pulse output.

[0004] Existing multi-pass cavity technologies mainly fall into two categories: gas-based and solid-state solutions. Gas-based multi-pass cavities use inert gases as the nonlinear medium. Their greatest advantage lies in their near-thermal-effect-free characteristics and extremely high damage threshold, enabling them to perfectly handle kilowatt-level high average power. Furthermore, the nonlinear intensity can be continuously adjusted via gas pressure. However, for high-repetition-rate lasers with energies below 0.4 mJ, their nonlinearity is relatively weak, typically requiring more passes and a gas control system. Solid-state multi-pass cavity technology uses thin-film solid media. Its strong nonlinear effect allows for extremely strong spectral broadening within a very small number of passes, resulting in a more compact, stable system with good vacuum compatibility. However, the thermal accumulation and thermal lensing effect of solid materials become the main bottlenecks for increasing average power, and there is an inherent risk of optical damage, making it unable to withstand high average power. Currently, gas-based solutions are driving ultrafast lasers towards the high-power frontier, while solid-state solutions provide an extremely compact and efficient solution for systems below the hundred-watt level. For the output of ytterbium-doped lasers with high average power and low single-pulse energy, gas multi-pass cavities cannot provide high nonlinear accumulation, while solid multi-pass cavities face problems such as excessive heat accumulation, thermal lensing, and air ionization, making stable operation difficult.

[0005] Therefore, there is an urgent need to develop a high-power, adjustable cavity length, and nonlinearly controllable gas-solid hybrid multi-cavity system, compression device, and method for high-power ultrashort pulse laser equipment. Summary of the Invention

[0006] The purpose of this invention is to overcome the deficiencies in the prior art and provide a high-power, adjustable-length, nonlinearly controllable gas-solid mixing multi-cavity system, compression device, and method.

[0007] Before describing the content of this invention, the following terms are defined as follows:

[0008] The term "MPC" refers to a multi-pass cell, which is an optical cavity that confines a beam of light so that it can pass through multiple times. Its basic structure is a passive resonant cavity composed of two concave mirrors.

[0009] The term "compression" refers to the operation of shortening the duration of a laser pulse in ultrafast pulsed lasers.

[0010] Furthermore, in the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0011] The terms "first" and "second" are used 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 as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0012] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0013] To achieve the above objectives, a first aspect of the present invention provides a gas-solid hybrid multi-cavity system for a high-power ultrashort pulse laser device, the gas-solid hybrid multi-cavity system comprising:

[0014] Import mirror, left concave mirror, connecting tube, nonlinear medium, right concave mirror, and export mirror;

[0015] The inlet mirror is used to reflect the laser into the gas-solid mixing multi-pass cavity, the outlet mirror is used to reflect the laser out of the gas-solid mixing multi-pass cavity, and the nonlinear medium is used to provide a nonlinear effect to broaden the spectrum. The left concave mirror and the right concave mirror constitute a multi-pass cavity structure with adjustable cavity length.

[0016] Preferably, in the gas-solid mixing multi-cavity system according to the first aspect of the present invention, the cavity length adjustment of the multi-cavity structure is manual and / or automatic.

[0017] More preferably, the manual adjustment is performed using a manual displacement stage;

[0018] More preferably, the automatic adjustment is performed by an electric displacement stage; the electric displacement stage is a linear motor displacement stage and / or a stepper motor displacement stage.

[0019] Preferably, in the gas-solid hybrid multi-cavity system according to the first aspect of the present invention, the nonlinear medium comprises: a nonlinear medium sheet and an ambient gas, wherein the ambient gas may be replaced by a vacuum;

[0020] More preferably, the nonlinear dielectric sheet is selected from one or more of the following: fused silica sheet, sapphire sheet;

[0021] More preferably, the ambient gas is an inert gas and / or air;

[0022] More preferably, the inert gas is argon and / or krypton.

[0023] Preferably, in the gas-solid mixing multi-cavity system according to the first aspect of the present invention, the nonlinear dielectric sheet is divided into left and right parts;

[0024] More preferably, in the gas-solid mixing multi-cavity system, the left nonlinear dielectric sheet and the right nonlinear dielectric sheet form a closed environment through a connecting pipe, and the closed environment is filled with the ambient gas.

[0025] A second aspect of the present invention provides a nonlinear pulse compression device, the nonlinear pulse compression device comprising, sequentially arranged along the laser propagation direction:

[0026] Laser;

[0027] Pattern matching agency;

[0028] According to the first aspect of the present invention, a gas-solid mixing multi-cavity system; and

[0029] Dispersion compensation mechanism.

[0030] Preferably, in the nonlinear pulse compression device according to the second aspect of the present invention, wherein;

[0031] The output wavelength of the laser is 700-1200nm, preferably 800nm-1080nm, more preferably 1000-1064nm, and most preferably 1030nm;

[0032] The output pulse energy range of the laser is 0-1mJ, preferably 0-0.8mJ, more preferably 0-0.6mJ, and most preferably 0-0.4mJ.

[0033] Preferably, in the nonlinear pulse compression device according to the second aspect of the present invention, wherein;

[0034] The pattern matching mechanism includes a three-lens group or a concave-convex mirror group structure; and / or

[0035] The laser and the pattern matching mechanism are positioned on the same horizontal axis.

[0036] Preferably, in the nonlinear pulse compression device according to the second aspect of the present invention, the dispersion compensation mechanism includes one or more components selected from the following: chirped mirrors, gratings, and prism pairs.

[0037] A third aspect of the present invention provides a method for spectral broadening, the method comprising using a gas-solid hybrid multi-cavity system according to a first aspect of the present invention, such as a laser beam that travels back and forth multiple times within the gas-solid hybrid multi-cavity system to achieve spectral broadening.

[0038] A fourth aspect of the present invention provides a method for compressing pulsed laser light, the method comprising using:

[0039] According to the first aspect of the present invention, a gas-solid mixing multi-cavity system; and / or

[0040] The nonlinear pulse compression device according to the second aspect of the present invention;

[0041] Preferably, when using the nonlinear pulse compression device according to the second aspect of the present invention, the method includes: generating an incident laser from the laser, passing it through a mode matching mechanism to adjust the spot and propagation mode of the incident laser to match the eigenmode of the gas-solid hybrid multi-cavity system, then entering the gas-solid hybrid multi-cavity system through the guide mirror, returning multiple times within the gas-solid hybrid multi-cavity system, and finally exporting it through the exit mirror, followed by dispersion compensation through the dispersion compensation mechanism to achieve pulse laser compression.

[0042] In summary, the concept of this invention is to address the shortcomings of existing technologies by adding an adjustable-length vacuum pipe in the middle of a traditional solid multi-cavity system, thereby completing the gas-solid mixing multi-cavity system, compression device, and method of this invention.

[0043] According to a preferred embodiment of the present invention, a high-power, cavity-length adjustable, nonlinearly controllable gas-solid hybrid multi-cavity nonlinear pulse compression device is provided, comprising a high-power laser, a mode matching mechanism, a cavity-length adjustable gas and solid hybrid multi-cavity system, and a dispersion compensation mechanism arranged sequentially according to the laser propagation direction;

[0044] According to the aforementioned preferred embodiment, the high-power laser is used to generate a 1-micron femtosecond laser with a typical wavelength of 1030 nm and a typical energy of 0.2 mJ. The generated laser passes sequentially through a mode matching mechanism, a cavity-length adjustable gas-solid hybrid multi-cavity system, and a dispersion compensation mechanism.

[0045] According to the aforementioned preferred embodiment, the mode matching mechanism is used to make the spot and mode evolution of the incident laser consistent with the eigenmode in the gas-solid mixed multi-pass cavity, so that it maintains the same spot size every time it passes through the nonlinear medium to obtain the same nonlinear effect growth. A typical mode matching mechanism has three lens groups and two concave-convex mirror groups.

[0046] According to the aforementioned preferred embodiment, the high-power laser and the mode matching mechanism are arranged on the same horizontal optical path;

[0047] According to the aforementioned preferred embodiment, the gas-solid hybrid multi-cavity system is used to achieve spectral broadening of the laser after multiple round trips within it, and consists of an inlet mirror, a left concave mirror, a connecting tube, a nonlinear medium, a right concave mirror, and an outlet mirror; wherein:

[0048] Guide mirror: Used to reflect laser light into a gas-solid mixing multi-channel cavity;

[0049] Export mirror: Used to reflect laser light out of a gas-solid mixing multi-channel cavity;

[0050] Nonlinear media: fused silica sheets with inert gases, typically argon (Ar) and krypton (Kr), are used to provide nonlinear effects and broaden the spectrum;

[0051] The left and right concave mirrors form a multi-cavity structure, which is fixed using a manual displacement stage, allowing the length of the multi-cavity to be changed.

[0052] The left fused silica sheet, the connecting tube, and the right fused silica form a sealed environment, which is filled with inert gas or air.

[0053] The connecting pipe has a gas port on each side for vacuuming and filling with inert gas, and a 4mm internal thread at the bottom for fixing the device.

[0054] According to the aforementioned preferred embodiment, in one possible implementation, the connecting pipe can be corrugated and its length can be adjusted, typically 140mm, for connecting the left and right pieces of fused silica.

[0055] The connecting pipe is made of stainless steel, and the flange is made of oxygen-free copper.

[0056] The first concave mirror has a radius of curvature of R, with a typical value of 300 mm, and a reflectivity of more than 99.9% in the 950 nm-1150 nm wavelength band.

[0057] The first concave mirror has a radius of curvature of R, with a typical value of 300 mm, and a reflectivity of more than 99.9% in the 950 nm-1150 nm wavelength band.

[0058] The inlet mirror has a reflectivity of greater than 99.9% in the 950nm-1150nm wavelength band;

[0059] The outgoing mirror has a reflectivity of greater than 99.9% in the 950nm-1150nm wavelength band;

[0060] The nonlinear medium is fused silica and an inert gas or air;

[0061] The fused silica sheet typically has a diameter of 50.8 mm and a thickness of 1 mm, and has a transmittance of more than 99.9% in the 950 nm-1150 nm wavelength band.

[0062] The center of the connecting pipe is placed in the middle of the multi-pass cavity formed by the left concave mirror and the right concave mirror;

[0063] The left and right fused silica sheets are symmetrically fixed to both sides of the connecting pipe by flanges. The sealing strip can be a rubber ring or an indium ring, the latter being more conducive to heat dissipation.

[0064] The left concave mirror and the left concave mirror are placed on the same horizontal axis;

[0065] The left and right flanges are symmetrically equipped with water-cooled copper pipes for cooling the molten quartz sheets.

[0066] The dispersion compensation mechanism is used to compensate for dispersion in the aligned focusing spot and compress the pulse width. Typical dispersion compensation devices include, but are not limited to, chirped mirrors, gratings, and prism pairs.

[0067] According to another preferred embodiment of the present invention, a compression method for a high-power, adjustable-cavity-length, nonlinearly controllable gas-solid hybrid multi-cavity nonlinear pulse compression system is provided, comprising the following steps;

[0068] The high-power laser, mode matching mechanism, gas-solid multi-cavity system, and dispersion compensation mechanism are arranged sequentially according to the laser propagation direction.

[0069] A high-power laser generates laser light, which passes through a mode matching mechanism to ensure that the incident laser's spot and propagation mode are consistent with the eigenmodes within the multi-pass cavity. This ensures that the laser maintains the same spot mode each time it passes through the nonlinear medium, thereby accumulating similar nonlinear phase shifts. After passing through a gas-solid hybrid multi-pass cavity system, the laser enters the multi-pass cavity through an inlet mirror next to the cavity. After multiple round trips within the cavity, the laser is exited by an outlet mirror next to the cavity. Dispersion compensation is then performed by a dispersion compensation mechanism to achieve pulse compression.

[0070] According to another preferred embodiment of the present invention, a high-power, cavity-length-adjustable, nonlinearly controllable gas-solid hybrid multi-cavity nonlinear pulse compression device is provided, comprising a high-power laser, a mode matching mechanism (1-2), a gas-solid hybrid multi-cavity system, and a dispersion compensation mechanism (11) arranged sequentially along the laser propagation direction.

[0071] According to another preferred embodiment described above, the high-power laser is used to generate laser light, which enters the gas-solid hybrid multi-cavity system sequentially through the mode matching mechanism (1-2) and travels back and forth multiple times within it to achieve spectral broadening; the inlet mirror 3 and outlet mirror 4 guide the laser light into and out of the system, and the dispersion compensation mechanism (11) is used to compensate for dispersion and compress the pulse width; the gas-solid hybrid multi-cavity system is filled with inert gas, and its cavity length is adjustable, as are the gas type, gas pressure, fused silica sheet thickness, and fused silica sheet spacing.

[0072] More preferably, according to another preferred embodiment described above, the high-power laser is a laser with an output wavelength of 1030nm, an output pulse energy range of 0-0.4mJ, and a high repetition frequency.

[0073] More preferably, according to another preferred embodiment described above, the spot size and divergence angle of the incident laser are matched with the intrinsic mode in the multi-pass cavity, and the mode matching mechanism includes a three-lens group or a concave-convex mirror group structure; the high-power laser (1) and the mode matching mechanism (2) are arranged on the same horizontal axis.

[0074] More preferably, according to another preferred embodiment described above, the gas-solid mixing multi-cavity system includes a left concave mirror (5), a right concave mirror (6), and a connecting tube (10) connecting the two; the left concave mirror (5) and the right concave mirror (6); an inlet mirror (3) and an outlet mirror (4) are respectively provided in front of the reflecting surfaces of the left concave mirror (5) and the right concave mirror (6); the laser enters the multi-cavity through the inlet mirror (3) and travels back and forth multiple times between the fused silica sheet (8-9) and the connecting tube (10) to achieve nonlinear spectral broadening, and is then output through the outlet mirror (4).

[0075] More preferably, according to another preferred embodiment described above, it has a transmittance of 99.9% in the 950nm to 1150nm range, a typical size of 50.8mm in diameter, a typical thickness of 1mm, and is connected to the connecting tube using a sealing ring, typically made of rubber and indium.

[0076] More preferably, according to yet another preferred embodiment described above, the connecting pipe includes a water-cooled copper pipe and a sealing ring, the length of which is adjustable, typically 140 mm.

[0077] More preferably, according to another preferred embodiment described above, the connecting pipe is made of stainless steel, the flange is vacuum welded, an M4 screw hole is provided at the bottom for fixing, and two air ports are symmetrically provided on the left and right for vacuuming and filling with inert gas, wherein the inert gas is argon.

[0078] More preferably, according to yet another preferred embodiment described above, the dispersion compensation mechanism includes one or more combinations of chirped mirrors, gratings, or prism pairs.

[0079] According to yet another preferred embodiment of the present invention, a pulse compression method using the aforementioned apparatus of yet another preferred embodiment is provided. The pulse compression method includes the following steps: generating a laser pulse from a high-power laser; performing mode matching on the laser pulse via a mode matching mechanism (1-2) so that its spot and divergence angle are consistent with the eigenmode of the multi-pass cavity; introducing the matched laser into a gas-solid hybrid multi-pass cavity system through an inlet mirror (3), accumulating nonlinear phase shift and achieving spectral broadening by repeatedly passing through the cavity; exporting the broadened laser through an outlet mirror (4), and performing dispersion compensation and pulse width compression on the focused laser using a dispersion compensation mechanism (11).

[0080] More preferably, according to yet another preferred embodiment described above, the device is capable of generating ultrashort femtosecond laser pulses with high peak power, and is suitable for time-resolved scientific research, materials processing, medical applications, laser particle acceleration, nonlinear attosecond science, high-order harmonic generation, laser welding, high-precision medical surgery, mid-infrared laser generation, and vibrational spectroscopy.

[0081] The high-power, cavity-length-adjustable, and nonlinearly controllable gas-solid hybrid multi-cavity nonlinear pulse compression system described in the foregoing series of preferred embodiments of the present invention can generate high peak power ultrashort femtosecond laser pulses. Ultrashort femtosecond laser pulses are widely used in science and technology, such as ultrafast science, materials processing, and medical applications. The high-power, cavity-length-adjustable gas-solid hybrid multi-cavity nonlinear pulse compression system can improve peak power and obtain high average power short pulse width lasers, which can advance applications in fields such as laser particle acceleration, nonlinear optics, and high-order harmonic generation. Femtosecond laser sources with repetition rates in the MHz range and energies in the hundreds of microjoules have important application value in fields such as laser welding, high-precision medical surgery, mid-infrared laser generation, and vibrational spectroscopy.

[0082] The gas-solid hybrid multi-cavity system, compression device, and method of the present invention comprises a high-power laser, a mode matching mechanism, a gas-solid hybrid multi-cavity system, and a dispersion compensation mechanism arranged sequentially according to the laser propagation direction. The high-power laser generates a high-repetition-rate laser beam, which passes sequentially through the mode matching mechanism, the adjustable-cavity gas-solid hybrid multi-cavity system, and the dispersion compensation mechanism. The gas-solid hybrid multi-cavity system allows the laser to achieve spectral broadening through multiple round trips within it. The dispersion compensation mechanism compensates for dispersion and compresses the pulse width. This invention combines traditional gas multi-cavity and solid multi-cavity systems, possessing the advantages of high nonlinearity in solid multi-cavity systems and high ionization threshold and stability in gas multi-cavity systems. The gas-solid hybrid multi-cavity system allows for convenient and quick adjustment of the cavity length, enabling selection of appropriate vacuum tube length, fused silica sheet thickness, and gas type according to requirements. This device is applicable to the spectral broadening and compression of high-power, high-repetition-rate femtosecond lasers and has broad applicability.

[0083] The gas-solid mixing multi-channel system, compression device, and method of the present invention, through the preferred use of a unique structure of a high-power, adjustable-cavity-length, and nonlinearly controllable gas-solid mixing multi-channel system, allows for convenient and quick adjustment of the multi-channel length and control of the required nonlinear accumulation. It is applicable to multiple high-power gas-solid mixing multi-channel nonlinear pulse compression schemes, significantly reducing experimental costs and possessing universality. The gas-solid mixing multi-channel system, compression device, and method of the present invention are applicable to high-power, high-repetition-frequency mixing multi-channel nonlinear pulse compression schemes. According to a preferred embodiment of the present invention, the unique structure of the water-cooled, adjustable-cavity gas-solid mixing multi-channel system allows for convenient and quick adjustment of the vacuum pipe length. Adjusting the pipe length changes the spacing of the solid nonlinear medium, making it applicable to multiple high-power, multi-channel nonlinear pulse compression schemes with different cavity types.

[0084] Compared with the prior art, the gas-solid mixing multi-cavity system, compression device, and method of the present invention have the following beneficial effects, including but not limited to:

[0085] 1) The gas-solid mixing multi-cavity system, compression device and method of the present invention utilizes a unique structure of high power, adjustable cavity length and nonlinear controllable gas-solid mixing multi-cavity, which allows for convenient and quick adjustment of the cavity length and increases or decreases nonlinear accumulation as needed. This device is applicable to various high-power, high-repetition-frequency gas-solid mixing multi-cavity nonlinear pulse compression schemes, which not only saves experimental costs and space, but also has universality.

[0086] 2) The gas-solid hybrid multi-cavity system, compression device, and method according to the present invention can generate ultrashort femtosecond laser pulses with high peak power. These pulses have wide applications in various scientific and technological fields, including time-resolved fundamental scientific research, materials processing, and medical applications. Through optimized design of the system, the peak power of the laser pulse can be effectively increased, and a high average power output can be obtained, thereby promoting further development in related cutting-edge fields such as laser particle acceleration and nonlinear attosecond science. Furthermore, femtosecond laser sources with repetition frequencies on the order of MHz and energy levels in the hundreds of microjoules also demonstrate significant practical value in applications such as laser welding, high-precision medical surgery, mid-infrared laser generation, and vibrational spectroscopy. Attached Figure Description

[0087] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0088] Figure 1 This is a schematic diagram of the structure of the gas-solid mixing multi-cavity system and its compression device as exemplified in Embodiment 1 of the present invention.

[0089] Figure 2 This is a schematic diagram of the connecting pipe structure of the gas-solid mixing multi-cavity system and its compression device, as exemplified in Embodiment 1 of the present invention.

[0090] Figure 3 This is a front view of the connecting pipe structure of the gas-solid mixing multi-cavity system and its compression device, as exemplified in Embodiment 1 of the present invention.

[0091] Figure 4 This is a top view of the connecting pipe structure of the gas-solid mixing multi-cavity system and its compression device, as exemplified in Embodiment 1 of the present invention.

[0092] Figure 5 This is a side view of the connecting pipe structure of the gas-solid mixing multi-cavity system and its compression device, as exemplified in Embodiment 1 of the present invention.

[0093] Explanation of reference numerals in the attached figures:

[0094] 1. Pattern matching concave mirror; 2. Pattern matching convex mirror; 3. Inlet mirror; 4. Outlet mirror; 5. Left concave mirror, forming a multi-channel cavity; 6. Right concave mirror, forming a multi-channel cavity; 7. Collimating concave mirror; 8. Left fused silica plate; 9. Right fused silica plate; 10. Connecting tube; 11. Dispersion compensation mechanism. Detailed Implementation

[0095] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should be understood that these embodiments are only used for more detailed and specific description, and should not be construed as limiting the present invention in any way.

[0096] This section provides a general description of the materials and testing methods used in the experiments of this invention. While many of the materials and methods of operation used to achieve the objectives of this invention are well known in the art, the invention is still described in as much detail as possible herein. It will be apparent to those skilled in the art that, unless otherwise stated in the context, the materials and methods of operation used in this invention are well known in the art.

[0097] Example 1

[0098] This embodiment is an exemplary description of the gas-solid mixing multi-cavity system, compression device, and method of the present invention.

[0099] like Figure 1 As shown, the compression device in this embodiment, which includes the gas-solid hybrid multi-cavity system of the present invention, is a high-power, adjustable-cavity-length, nonlinearly controllable gas-solid hybrid multi-cavity nonlinear pulse compression system, comprising:

[0100] 1) A 1030nm high-power laser for outputting pulsed lasers with an output energy range of 0-0.2mJ;

[0101] 2) Mode matching mechanisms 1 and 2 ensure that the incident laser spot and divergence angle are consistent with the intrinsic modes in the gas-solid hybrid multi-pass cavity with adjustable cavity length, thus avoiding large differences between the two modes, which could affect the nonlinear spectral broadening effect or even cause damage to the concave mirror. Typical mode matching mechanisms include a three-lens group and a concave-convex mirror group. Furthermore, in this embodiment, the mode matching mechanisms 1 and 2 and the high-power amplifier are arranged on the same horizontal axis.

[0102] 3) The gas-solid hybrid multi-cavity system exemplified in this embodiment is used to achieve spectral broadening of laser after multiple round trips inside it. It consists of an inlet mirror 3, an outlet mirror 4, a left concave mirror 5 and a right concave mirror 6, a vacuum connecting tube 10, and fused silica sheets 8 and 9.

[0103] Guiding mirror: with a reflectivity greater than 99.9% in the 950nm-1150nm wavelength band, used to reflect laser light into a gas-solid hybrid multi-channel cavity;

[0104] Connecting pipe: Used to seal the left and right fused quartz plates to form a closed environment, allowing inert gas to fill it. The gas pressure and length are adjustable, and heat is dissipated by an external copper pipe water-cooled heat dissipation ring.

[0105] Outgoing mirror: with a reflectivity greater than 99.9% in the 950nm-1150nm wavelength band, used to reflect laser light out of a gas-solid hybrid multi-channel cavity;

[0106] The right concave mirror and the left concave mirror form a multi-channel cavity;

[0107] The radii of curvature of the left and right concave mirrors 5 and 6 are R, with a typical value of 300 mm. The reflectivity of R in the 950 nm-1150 nm wavelength band is greater than 99.9%.

[0108] 4) The dispersion compensation mechanism 11 is used to compensate for dispersion of the focused light spot and compress the pulse width. Typical dispersion compensation devices include chirped mirrors, gratings and prism pairs.

[0109] like Figure 2 The diagram shows a simplified schematic of the connecting pipe. The left and right sides are copper cover plate flanges, with the water-cooled copper pipe heat dissipation ring tightly attached to the outside of the cover plate. The middle is the vacuum connecting pipe, and the connection between the flange and the cover plate is sealed with a rubber ring or indium ring using a fused silica sheet.

[0110] like Figure 3 The diagram shows a front view of the connecting pipe structure of the compression device including the gas-solid mixing multi-cavity system of this invention in this embodiment. The connecting pipe consists of left and right water-cooled copper pipes for heat dissipation, a sealing ring, a fused silica sheet, a vacuum tube, and an extraction port. It is symmetrical on the left and right, and the length of the connecting pipe can be selected according to the requirements. The length of the multi-cavity can be adjusted conveniently and quickly. An M4 threaded hole is provided at the bottom of the pipe for solid equipment. This device can be applied to multiple high-power gas-solid mixing multi-cavity nonlinear pulse compression schemes, saving experimental costs and having universality.

[0111] like Figure 4 The figure shown is a top view of the vacuum chamber structure of the compression device including the gas-solid mixing multi-cavity system of the present invention in this embodiment. The connecting pipe is made of stainless steel and vacuum welded to ensure that it can operate in a gas environment of 0 Bar to 2 Bar.

[0112] like Figure 5 The image shown is a side view of the vacuum chamber structure of the compression device containing the gas-solid mixing multi-cavity system of the present invention in this embodiment. The outer flange is provided with M4 screw holes for pressing and fixing the fused silica sheet. The center is translucent, and the outer surface is tightly attached to the water-cooled copper tube heat dissipation ring.

[0113] Furthermore, the principle of the compression method exemplified in this embodiment is also as follows. Figure 1 The schematic diagram is shown. In the compression method of this embodiment, under the condition of achieving nonlinear pulse compression, compared with traditional gas or solid multi-cavity systems, the cavity length of the multi-cavity can be adjusted more conveniently and quickly, and the amount of nonlinear accumulation can be adjusted. This device can be applied to multiple high-power gas-solid hybrid multi-cavity nonlinear pulse compression schemes, saving experimental costs and having universality. Figure 1In this system, a high-power femtosecond pulsed laser is introduced into the system through mode-matching concave mirror 1 and mode-matching convex mirror 2. The incident laser spot is matched to the eigenmode within the multi-pass cavity and introduced into the gas-solid hybrid multi-pass cavity by guide mirror 3. The laser oscillates back and forth in the resonant cavity formed by the two concave mirrors, passing through a vacuum tube multiple times during this process. The laser is then exited by exit mirror 4. The vacuum tube 10 is sealed on both sides with two fused silica sheets 8 and 9 using oxygen-free copper flanges. The sealing ring material can be rubber or indium rings, depending on the situation. The outside of the flange is tightly fitted with a copper tube water-cooling heat sink. The inside of the vacuum tube can be a vacuum, air, or inert gas. The nonlinear medium is provided by the fused silica sheets and the inert gas. Finally, the dispersion is compensated by the dispersion compensation mechanism 11, thereby realizing nonlinear pulse compression of the multi-pass cavity.

[0114] While the effects of some embodiments have been shown above, those skilled in the art should understand that, based on the concept of the present invention, other embodiments not specifically shown or other technical solutions of the present invention not shown in the embodiments can also achieve the same technical effects as those claimed in the summary section:

[0115] 1) The gas-solid mixing multi-cavity system, compression device and method of the present invention utilizes a unique structure of high power, adjustable cavity length and nonlinear controllable gas-solid mixing multi-cavity, which allows for convenient and quick adjustment of the cavity length and increases or decreases nonlinear accumulation as needed. This device is applicable to various high-power, high-repetition-frequency gas-solid mixing multi-cavity nonlinear pulse compression schemes, which not only saves experimental costs and space, but also has universality.

[0116] 2) The gas-solid hybrid multi-cavity system, compression device, and method according to the present invention can generate ultrashort femtosecond laser pulses with high peak power. These pulses have wide applications in various scientific and technological fields, including time-resolved fundamental scientific research, materials processing, and medical applications. Through optimized design of the system, the peak power of the laser pulse can be effectively increased, and a high average power output can be obtained, thereby promoting further development in related cutting-edge fields such as laser particle acceleration and nonlinear attosecond science. Furthermore, femtosecond laser sources with repetition frequencies on the order of MHz and energy levels in the hundreds of microjoules also demonstrate significant practical value in applications such as laser welding, high-precision medical surgery, mid-infrared laser generation, and vibrational spectroscopy.

[0117] Although the invention has been described to a certain extent, it is obvious that appropriate changes can be made to various conditions without departing from the spirit and scope of the invention. Those skilled in the art should understand that the invention is not limited to the described embodiments, but falls within the scope of the claims, including equivalent substitutions for each element.

Claims

1. A gas-solid hybrid multi-cavity system for high-power ultrashort pulse laser equipment, characterized in that, The gas-solid mixing multi-cavity system includes: Import mirror, left concave mirror, connecting tube, nonlinear medium, right concave mirror, and export mirror; The inlet mirror is used to reflect the laser into the gas-solid mixing multi-pass cavity, the outlet mirror is used to reflect the laser out of the gas-solid mixing multi-pass cavity, and the nonlinear medium is used to provide a nonlinear effect to broaden the spectrum. The left concave mirror and the right concave mirror constitute a multi-pass cavity structure with adjustable cavity length.

2. The gas-solid mixing multi-cavity system according to claim 1, characterized in that, The cavity length adjustment of the multi-cavity structure can be manual or automatic. Preferably, the manual adjustment is performed using a manual displacement table; Preferably, the automatic adjustment is performed by an electric displacement stage; the electric displacement stage is a linear motor displacement stage and / or a stepper motor displacement stage.

3. The gas-solid mixing multi-cavity system according to claim 1 or 2, characterized in that, The nonlinear medium includes: a nonlinear medium sheet and an ambient gas, wherein the ambient gas can be replaced by a vacuum. Preferably, the nonlinear dielectric sheet is selected from one or more of the following: fused silica sheet, sapphire sheet; Preferably, the ambient gas is an inert gas and / or air; More preferably, the inert gas is argon and / or krypton.

4. The gas-solid mixing multi-cavity system according to any one of claims 1 to 3, characterized in that, The nonlinear dielectric sheet is divided into left and right parts; Preferably, in the gas-solid mixing multi-cavity system, the left nonlinear dielectric sheet and the right nonlinear dielectric sheet form a sealed environment through a connecting pipe, and the sealed environment is filled with the ambient gas.

5. A nonlinear pulse compression device, characterized in that, The nonlinear pulse compression device comprises the following components arranged sequentially along the laser propagation direction: Laser; Pattern matching agency; The gas-solid mixing multi-cavity system according to any one of claims 1 to 4; and Dispersion compensation mechanism.

6. The nonlinear pulse compression device according to claim 5, characterized in that; The output wavelength of the laser is 700-1200nm, preferably 800nm-1080nm, more preferably 1000-1064nm, and most preferably 1030nm; The output pulse energy range of the laser is 0-1mJ, preferably 0-0.8mJ, more preferably 0-0.6mJ, and most preferably 0-0.4mJ.

7. The nonlinear pulse compression device according to claim 5 or 6, characterized in that... ； The pattern matching mechanism includes a three-lens group or a concave-convex mirror group structure; and / or The laser and the pattern matching mechanism are positioned on the same horizontal axis.

8. The nonlinear pulse compression device according to any one of claims 5 to 7, characterized in that, The dispersion compensation mechanism includes one or more components selected from the following: chirped mirrors, gratings, and prism pairs.

9. A method for spectral broadening, characterized in that, The method includes using a gas-solid hybrid multi-cavity system according to any one of claims 1 to 4, such that the emitted laser achieves spectral broadening after multiple round trips within the gas-solid hybrid multi-cavity system.

10. A method for compressing pulsed laser light, characterized in that, The method includes using: The gas-solid mixing multi-cavity system according to any one of claims 1 to 4; and / or The nonlinear pulse compression device according to any one of claims 5 to 7; Preferably, when using the nonlinear pulse compression device according to any one of claims 5 to 7, the method includes: generating an incident laser from the laser, passing it through a mode matching mechanism to adjust the spot and propagation mode of the incident laser to match the eigenmode of the gas-solid hybrid multi-cavity system, then entering the gas-solid hybrid multi-cavity system through the guide mirror, returning multiple times within the gas-solid hybrid multi-cavity system, and finally exporting it through the exit mirror. Dispersion compensation is then performed by the dispersion compensation mechanism to achieve pulse laser compression.

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