Pulse laser amplification module and pulse laser

Abstract

The invention discloses a pulse laser amplification module, which is used for amplifying a pulse laser beam and comprises a rod-like crystal optical fiber, and the periphery of the rod-like crystal optical fiber is coated with a gold film; an input coupling lens is arranged at one end of the rod-shaped crystal optical fiber, one end of the input coupling lens is used for inputting a pulse laser beam and pump light, and the pulse laser beam and the pump light can penetrate through the center of the end face of one end of the rod-shaped crystal optical fiber and are focused into the rod-shaped crystal optical fiber; an output collimating lens is arranged at the other end of the rodlike crystal fiber and is used for converting the pulse laser beam output from the rodlike crystal fiber into a collimated light beam; pump light enters the rod-like crystal fiber through the center of the end face of the rod-like crystal fiber to be transmitted, generates total reflection on the inner surface of the rod-like crystal fiber and is converged on the center line of the rod-like crystal fiber, so that the light intensity of the pump light in the rod-like crystal fiber is the maximum, and the maximum gain particle inversion number is obtained. And thus, wide-spectrum self-waveguide amplification of the pulse laser beam is realized.

Description

Technical Field

[0001] The invention relates to the technical field of laser amplification, and in particular to a pulse laser amplification module and a pulse laser. Background Art

[0002] High-energy femtosecond lasers have important applications in the fields of strong field physics research, atomic and molecular dynamics research, and spectral detection, and are of great scientific research value. In recent years, with the study of the mechanism of action between lasers and materials, high-energy ultrafast lasers have the characteristics of non-contact, cold processing, and high precision; their applications in additive manufacturing, subtractive manufacturing, and other fields have gradually expanded, and have become a new type of processing tool.

[0003] At present, the generation of high-energy femtosecond lasers mainly adopts chirped pulse amplification technology, separated pulse amplification technology and regeneration amplification technology. Chirped pulse amplification technology first widens the picosecond or femtosecond seed pulse to the nanosecond level through a dispersion device before amplification, and then compresses the pulse to hundreds of femtoseconds through a dispersion compensation device. Separated pulse amplification technology is to first separate the seed pulse into multiple sub-pulse strings, then enter the amplifier for amplification, and then synthesize it into a single pulse with higher energy. The use of chirped pulse amplification technology and separated pulse amplification technology can effectively avoid the light wave splitting effect and pulse amplification inhibition effect caused by high peak energy during the pulse amplification process. Regeneration amplification technology achieves a significant increase in pulse energy by multiple cycles of pulse amplification in the regeneration cavity.

[0004] The above three pulse amplification technologies are inevitably affected by the gain narrowing effect of the gain medium during the process of laser pulse energy amplification, which leads to the limitation of the frequency domain width of the output spectrum, further limiting the pulse compression and pulse energy enhancement. In addition, for regenerative amplification technology, during the pulse cycle amplification process, as the number of intracavity pulse amplification increases, high pulse energy poses a serious risk of damage to devices such as Pockels cells and amplifying crystals.

[0005] Therefore, it is necessary to make improvements based on the above-mentioned technical problems to solve the technical problem in the prior art that, during the laser pulse energy amplification process, the gain medium gain narrowing effect is inevitably affected, so as to obtain pulses with high energy, narrow pulse width, wide spectrum and high beam quality. Summary of the invention

[0006] The present invention aims to provide a pulse laser amplification module and a pulse laser to solve the technical problem in the prior art that, during the laser pulse energy amplification process, the gain medium gain narrowing effect is inevitably affected.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: In a first aspect, the present invention discloses a pulse laser amplification module for amplifying a pulse laser beam, comprising a rod-shaped crystal fiber, wherein the outer periphery of the rod-shaped crystal fiber is coated with a gold film; an input coupling lens is arranged at one end of the rod-shaped crystal fiber, and one end of the input coupling lens is used to input a pulse laser beam and a pump light, and the input coupling lens can make the pulse laser beam and the pump light pass through the end face center of one end of the rod-shaped crystal fiber and focus inside the rod-shaped crystal fiber, that is, the focused light spot is incident into the rod-shaped crystal fiber through the end face center of the rod-shaped crystal fiber, and the focus of the focused light beam is inside the fiber; the rod-shaped crystal fiber An output collimating lens is arranged at the other end of the optical fiber, which is used to convert the pulsed laser beam output from the rod-shaped crystal fiber into a collimated beam; the pump light enters the rod-shaped crystal fiber through the center of the end face of the rod-shaped crystal fiber and propagates, and generates total reflection at the inner surface of the rod-shaped crystal fiber, and converges on the center line of the rod-shaped crystal fiber, so that the light intensity of the pump light in the rod-shaped crystal fiber is maximized, so as to obtain the maximum gain particle inversion number, and the beam self-focusing effect of the Kerr effect and thermal lens effect generated by the strong pump light is clamped with the spectrum broadening mode field self-defocusing effect in the laser beam gain amplification process, thereby realizing the wide-spectrum self-waveguide amplification of the pulsed laser beam.

[0008] This scheme will use the strongest pump light intensity and the largest gain particle inversion number at the center of the rod-shaped crystal fiber. During the amplification process, the pulsed laser beam will produce a thermal lens effect related to the pump light intensity and a Kerr effect related to gain amplification, which will cause the beam to self-focus during energy amplification. At the same time, through the energy boost of the laser pulse during the gain amplification process, nonlinear amplification is generated, and self-phase modulation spectrum broadening is achieved. Since the spectrum broadening of the pulsed laser beam will introduce an increase in the beam mode field and produce a divergence effect, the pulsed laser beam will also self-defocus during the amplification process. During the amplification process, the self-waveguide beam self-balances the mode field, discards the spectral components at the edge of the light spot mode field, suppresses mode field distortion, has the characteristics of mode self-cleaning, and achieves high beam quality output.

[0009] Preferably, under the condition that the doping concentration of the rod-shaped crystal fiber remains unchanged, the amplified light beam can be regulated from the waveguide aperture by adjusting the pump spot size and the amplified light beam diameter.

[0010] By adjusting the larger signal beam diameter and pump beam diameter, large-aperture beam self-waveguide amplification can be achieved. While reducing the beam energy density, the pulse compression and pulse energy of the pulsed laser beam can be further improved, avoiding the damage of high-energy pulses to the rod-shaped crystal fiber, and being more conducive to obtaining pulses with high energy, narrow pulse width, wide spectrum, and high beam quality, which has the advantage of producing high-energy laser pulse amplification.

[0011] Specifically, as a preferred embodiment, the ratio of the diameter of the pump spot to the diameter of the amplified light beam is 3:2, and the diameter of the amplified light beam from the waveguide is 2 / 3 to 1 of the diameter of the pump spot.

[0012] Preferably, the end faces at both ends of the rod-shaped crystal fiber and the outer surfaces of the input coupling lens and the output collimating lens are respectively coated with anti-reflection films, and the wavelength of the anti-reflection films matches the wavelength of the input light to increase the transmittance.

[0013] Preferably, the rod-shaped crystal optical fiber is embedded in a copper block heat sink by welding. The gold film coated on the cylindrical surface of the rod-shaped crystal fiber not only has the function of reflecting signal light and pump light, but also can be used as a heat transfer medium between the rod-shaped crystal fiber and the copper heat sink. The gold film has good thermal conductivity, so that the rod-shaped crystal fiber can be well cooled, which can prevent the gain medium from being damaged due to overheating, allowing higher laser output power, thereby improving the laser output power; it can also avoid uneven heating of the gain medium, help maintain the pulse shape and time characteristics, and thus improve the beam quality; it can reduce the changes in laser parameters or physical size changes of optical components caused by temperature fluctuations, thereby affecting the focusing and directivity of the beam. Good heat dissipation can reduce this thermal drift and improve the stability of the entire laser system; it avoids damage to optical components such as lenses and reflectors, reduces thermal stress and thermal damage, reduces the failure rate, thereby extending the service life of the laser and its components, and improving the reliability of the system; it avoids the change in the refractive index of the gain medium that may be caused by high temperature, which in turn leads to the degradation of the laser mode, and helps maintain the stability of the mode; it reduces the loss of pump light and laser signal light due to thermal effects and improves the laser conversion efficiency.

[0014] Preferably, the pulse laser amplification module is a single-channel amplification module, and the input pulse laser beam and pump light can be amplified once in the pulse laser amplification module.

[0015] Preferably, the pulse laser amplification module is a multi-channel amplification module for amplifying the pulse laser multiple times.

[0016] As one of the implementation methods of the multi-channel amplification module, the pulse laser amplification module also includes a first half-wave plate, one side of the first half-wave plate is used to set a pulse seed source, the other side of the first half-wave plate is provided with a first polarization beam splitter, the side of the first polarization beam splitter away from the first half-wave plate is provided with an input coupling lens, a rod-shaped crystal fiber and an output collimating lens in sequence, and the side of the output collimating lens away from the rod-shaped crystal fiber is provided with a first Faraday rotator and a first end face zero-degree reflector in sequence; thereby, a two-channel pulse laser amplification module is formed, which can realize secondary amplification of pulsed laser.

[0017] The amplification principle of the two-channel pulse laser amplification module is: after the first half-wave plate receives the pulse laser output by the pulse seed source and changes the polarization direction of the pulse laser, the pulse laser is transmitted to the first polarization beam splitter, and after the beam splitting effect of the first polarization beam splitter, the pulse laser is further transmitted to the input coupling lens, and the pulse laser is amplified for the first time through the rod-shaped crystal fiber in sequence, and then transmitted to the output collimating lens and the first Faraday rotator in sequence, and then transmitted to the first end face zero-degree reflector for reflection; The pulsed laser after the first amplification is reflected by the first end face zero-degree reflector, returns to the first Faraday rotator, and passes through the output collimating lens, rod-shaped crystal fiber, input coupling lens, first polarization beam splitter in sequence, and then undergoes the beam splitting effect of the first polarization beam splitter to output the pulsed laser after the second amplification.

[0018] Specifically, a half-wave plate changes the polarization state of polarized light by introducing phase delay. When linearly polarized light passes through a half-wave plate, its polarization direction rotates according to the optical axis direction of the wave plate.

[0019] As one implementation of the multi-channel amplification module, the pulse laser amplification module further includes a first half-wave plate, one side of the first half-wave plate is used to set a pulse seed source, the other side of the first half-wave plate is provided with a first polarization beam splitter, and the side of the first polarization beam splitter away from the first half-wave plate is sequentially provided with a second Faraday rotator and a second half-wave plate, A second polarization beam splitter is disposed on a side of the second half-wave plate away from the second Faraday rotator, an input coupling lens, a rod-shaped crystal fiber and an output collimating lens are sequentially disposed on one side of a first output end of the second polarization beam splitter, and a first Faraday rotator and a first end face zero-degree reflector are sequentially disposed on a side of the output collimating lens away from the rod-shaped crystal fiber; A second end face zero-degree reflector is provided at one side of the second output end of the second polarization beam splitter, for reflecting the light split by the second polarization beam splitter; Thus, a four-channel pulse laser amplification module is formed, which can realize four-fold amplification of the pulse laser.

[0020] The amplification principle of the four-channel pulse laser amplification module is: after the first half-wave plate receives the pulse laser output by the pulse seed source and changes the polarization direction of the pulse laser, the pulse laser is transmitted to the first polarization beam splitter, and after the beam splitting effect of the first polarization beam splitter, the pulse laser is continuously transmitted, and sequentially passes through the second Faraday rotator, the second half-wave plate and the second polarization beam splitter, and after the beam splitting effect of the second polarization beam splitter, the pulse laser is continuously transmitted to the input coupling lens, and sequentially passes through the rod-shaped crystal fiber to perform the first amplification on the pulse laser, and then sequentially transmits it to the output collimating lens and the first Faraday rotator, and then transmits it to the first end face zero-degree reflector for reflection; The pulse laser after the first amplification is reflected by the first end face zero-degree reflector, returns to the first Faraday rotator, and passes through the output collimating lens, the rod-shaped crystal fiber, and the input coupling lens in sequence to output the pulse laser after the second amplification; When the pulse laser after the second amplification is transmitted to the second polarization beam splitter, it is transmitted to the second end face zero-degree reflector for reflection. After the reflection, the pulse laser after the second amplification is transmitted to the input coupling lens again, and is amplified for the third time through the rod-shaped crystal fiber in sequence, and then transmitted to the output collimating lens and the first Faraday rotator in sequence, and then transmitted to the first end face zero-degree reflector for reflection; The pulse laser after the third amplification is reflected by the first end face zero-degree reflector, returns to the first Faraday rotator, and passes through the output collimating lens, the rod-shaped crystal fiber, and the input coupling lens in sequence to undergo the fourth amplification of the pulse laser; Then adjust the second Faraday rotator and the second half-wave plate, and then adjust the polarization state of the pulsed laser amplified for the fourth time, so that the pulsed laser amplified for the fourth time passes through the second polarization beam splitter, and is transmitted to the first polarization beam splitter through the second half-wave plate and the second Faraday rotator in sequence, and then passes through the beam splitting effect of the first polarization beam splitter to output the pulsed laser amplified four times.

[0021] In a second aspect, the present invention further discloses a pulse laser, comprising any one of the pulse laser amplification modules described above.

[0022] In summary, the present invention has the following beneficial effects: 1. In the pulse laser amplification module and pulse laser of the present invention, the signal light beam realizes self-waveguide amplification in the rod-shaped crystal, which has the advantage of self-cleaning of the spot mode and can realize high beam quality laser amplification. Specifically, the signal light beam is self-waveguided in the rod-shaped crystal fiber; in the laser pulse amplification process, the signal light beam realizes the dynamic balance of the light beam mode field through the self-focusing process of the Kerr effect and the thermal lens effect and the self-defocusing process of the nonlinear amplification spectrum broadening spot mode field, and forms a light beam self-waveguide in the rod-shaped crystal. During the amplification process, the self-waveguide light beam achieves self-balancing of the mode field, discards the spectral components at the edge of the spot mode field, suppresses the mode field distortion, has the characteristics of mode self-cleaning, and realizes high beam quality output. This technology provides a brand-new solution for achieving the generation of high beam quality, high energy, high power, narrow pulse width ultrashort pulse lasers.

[0023] 2. In the pulse laser amplification module and pulse laser of the present invention, the amplification module is based on a rod-shaped crystal structure, which can improve the gain amplification pump conversion efficiency, produce high pump conversion efficiency, and achieve high-power laser generation. Specifically embodied in: a rod-shaped crystal structure based on a gold-plated film on the side of a small core diameter and the use of end-face pumping. The pump light enters from the end face of the rod-shaped crystal fiber, produces total reflection on the cylindrical surface, and converges the transmission to the center of the rod-shaped crystal fiber. This process enables the center of the rod-shaped crystal fiber to produce the strongest pump light intensity and the largest gain particle inversion number, which is beneficial to the efficient absorption of pump energy by the signal beam, while making the thermal lens self-focusing effect more likely to occur, which is more conducive to the formation of a beam amplification self-waveguide.

[0024] 3. In the pulse laser amplification module and pulse laser of the present invention, the self-waveguide amplification process realizes nonlinear amplification spectrum broadening, thereby suppressing the gain narrowing effect, realizing wide-spectrum laser amplification, and having the advantages of outputting high peak energy and narrow pulse laser. Specifically, the signal light beam is self-waveguided amplified in the rod-shaped crystal fiber, and the nonlinear self-phase modulation effect is generated by amplifying the pulse, thereby realizing pulse spectrum broadening, effectively overcoming the gain narrowing effect of the rod-shaped crystal fiber, and ensuring pulse broadband spectrum amplification; at the same time, the spectrum broadening and mode field divergence of the amplification process can be balanced with the Kerr effect and thermal lens self-focusing to form an amplified light beam self-waveguide. Therefore, the self-waveguide spectrum broadening and amplification of the pulse is conducive to pulse width compression, and can achieve sub-hundred femtosecond, high peak energy laser generation.

[0025] 4. In the pulse laser amplification module and pulse laser of the present invention, the pump spot and mode field aperture can be flexibly adjusted during the self-waveguide amplification process, so it has the advantage of achieving high-power and high-energy amplification and can reduce the risk of damage to the device. Specifically, the signal light beam is self-waveguided amplified in the rod-shaped crystal fiber, and the self-waveguide aperture can be flexibly adjusted by the signal beam diameter, the pump beam diameter and the gain medium doping concentration. Large-aperture light beam self-waveguide amplification can be achieved by adjusting the larger signal beam diameter and pump beam diameter, which reduces the beam energy density while avoiding the damage of the rod-shaped crystal fiber by high-energy pulses, and has the advantage of producing high-energy laser pulse amplification.

[0026] 5. The pulse laser amplification module and pulse laser of the present invention can utilize the beam self-waveguide amplification with dynamic balance of the spot mode field to suppress the degradation of the spot mode, and the beam has a self-cleaning effect during the amplification process. At the same time, the spectrum broadening of the beam during the high-energy nonlinear amplification process of the self-waveguide is utilized to effectively suppress the gain narrowing effect of the rod-shaped crystal fiber, which is conducive to compressing the pulse width to sub-hundred femtoseconds and achieving extremely high peak energy output. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the purpose, technical solution and advantages of the invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings, in which: Figure 1 This is a schematic diagram of the self-waveguide amplification of the pulsed laser beam generated by the rod-shaped crystal optical fiber of the present invention.

[0028] Figure 2 Schematic diagram of a pulse laser device using a single-channel amplification module in Embodiment 1 of the present invention.

[0029] Figure 3 Schematic diagram of a pulse laser device using a two-channel amplification module in Embodiment 2 of the present invention.

[0030] Figure 4 Schematic diagram of a pulse laser device using a four-channel amplification module in Embodiment 3 of the present invention.

[0031] Figure 5 The diagram is a schematic diagram of a pulse laser spectrum emitted by a pulse seed source when the rod-shaped crystal optical fiber of the present invention generates a pulse laser beam from a waveguide for amplification.

[0032] Figure 6 It is a schematic diagram of the self-phase modulation broadening spectrum when the pulsed laser beam generated by the rod-shaped crystal optical fiber of the present invention is amplified by the waveguide.

[0033] Figure 7 It is a schematic diagram of the amplified laser spectrum when the pulsed laser beam generated by the rod-shaped crystal optical fiber of the present invention is amplified by the waveguide.

[0034] Explanation of the reference numerals: 100, pulse seed source; 101, pulse laser beam; 200, pump coupling module; 201, pump source; 202, pump collimating lens; 203, dichroic mirror; 204, pump light; 300, pulse laser amplification module; 301, input coupling lens; 302, rod-shaped crystal fiber; 303, output collimating lens; 304, first half-wave plate; 305, first polarization beam splitter; 306, first Faraday rotator; 307, first end face zero degree mirror; 308, second Faraday rotator; 309, second half-wave plate; 310, second polarization beam splitter; 311, second end face zero degree mirror; 312, gold film; 400, pulse compression module; 401, mirror; 402, right-angle mirror; 403, first diffraction grating; 404, second diffraction grating; 405, downward-pressed roof mirror. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0036] It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invention product is usually placed when used, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical", etc. do not mean that the components are absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium, and internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The present invention can be applied to the technical field of laser amplification, specifically to the field of high-energy ultrashort pulse laser amplification and strong-field nonlinear optics, and solves the technical problem in the prior art that, during the laser pulse energy amplification process, the gain medium gain narrowing effect is inevitably affected.

[0038] The present invention forms a dynamic balance between the self-focusing process of the Kerr effect and the thermal lens effect and the self-defocusing process of the light spot mode field; utilizes the dynamically balanced light beam self-waveguide effect, the light spot mode self-cleaning phenomenon, and the self-phase modulation spectrum broadening effect to generate high-energy, narrow pulse width, wide spectrum, and high beam quality laser pulses.

[0039] See also Figure 1 Based on the technical problems solved above, the present invention discloses a pulse laser amplification module 300 for amplifying a pulse laser beam 101, comprising a rod-shaped crystal fiber 302, the outer periphery of which is coated with a gold film 312; an input coupling lens 301 is provided at one end of the rod-shaped crystal fiber 302, and one end of the input coupling lens 301 is used to input the pulse laser beam 101 and the pump light 204, and the input coupling lens 301 can make the pulse laser beam 101 and the pump light 204 pass through the end face center of one end of the rod-shaped crystal fiber 302, and focus inside the rod-shaped crystal fiber 302, that is, the focused light spot is formed by the rod-shaped crystal fiber 302. The center of the end face of the rod-shaped crystal fiber 302 is incident into the rod-shaped crystal fiber 302, and the focus of the focused light beam is inside the fiber; the other end of the rod-shaped crystal fiber 302 is provided with an output collimating lens 303, which is used to convert the pulsed laser beam 101 output from the rod-shaped crystal fiber 302 into a collimated light beam; the pump light 204 enters the rod-shaped crystal fiber 302 through the center of the end face of the rod-shaped crystal fiber 302 and propagates, and generates total reflection on the inner surface of the rod-shaped crystal fiber 302, and converges on the center line of the rod-shaped crystal fiber 302, so that the light intensity of the pump light 204 in the rod-shaped crystal fiber 302 is maximized, so as to obtain the maximum gain particle inversion number, thereby realizing wide-spectrum self-waveguide amplification of the pulsed laser beam 101.

[0040] See also Figure 1 , Figures 5 to 7, respectively show the schematic diagram of the pulsed laser spectrum emitted by the pulse seed source when the rod-shaped crystal fiber generates a pulsed laser beam from the waveguide amplification, the schematic diagram of the self-phase modulation broadening spectrum, and the schematic diagram of the amplified laser spectrum. As can be seen from the figure, this scheme uses the strongest pump light intensity and the largest gain particle inversion number at the center of the rod-shaped crystal fiber. During the amplification process, the pulsed laser beam will produce a thermal lens effect related to the pump light intensity and a Kerr effect related to the gain amplification, which will cause the beam to self-focus during energy amplification. At the same time, through the energy increase of the laser pulse during the gain amplification process, nonlinear amplification is generated to achieve self-phase modulation spectrum broadening. Since the spectrum broadening of the pulsed laser beam will introduce an increase in the beam mode field and produce a divergence effect, the pulsed laser beam will also self-defocus during the amplification process. During the amplification process, the self-waveguide beam abandons the spectral components at the edge of the light spot mode field through mode field self-balancing, suppresses mode field distortion, has the characteristics of mode self-cleaning, and achieves high beam quality output.

[0041] Then, this scheme can achieve a dynamic balance between the self-focusing process of the Kerr effect and the thermal lens effect and the self-defocusing process of the light spot mode field. Based on the amplification of the pulsed laser beam in the rod-shaped crystal fiber, the self-focusing and self-defocusing phenomena of the beam related to the pump light intensity, laser gain amplification and nonlinear amplification are utilized, the self-waveguide process induced by the dynamic balance of the light spot mode field, the wide spectrum characteristics of self-phase modulation, the mode self-cleaning advantages of the self-waveguide process, and the amplification characteristics of the gain medium are combined to achieve wide-spectrum self-waveguide amplification with dynamic balance of the beam.

[0042] This scheme can utilize the self-defocusing effect of the pulsed laser beam spectrum broadening mode field and the self-focusing effect of the Kerr effect and the thermal lens effect to clamp each other during the gain amplification process, forming a self-waveguide with dynamic balance of the beam mode field, thereby suppressing the degradation of the spot mode and making the beam have a self-cleaning effect during the amplification process.

[0043] This scheme can avoid the gain narrowing effect of the gain medium, has the wide spectrum characteristics of self-phase modulation, and combines the mode self-cleaning advantages of the self-waveguide process and the amplification characteristics of the gain medium to widen the frequency domain width of the output spectrum, and can further improve the pulse compression and pulse energy of the pulsed laser beam, ultimately forming a hundred-femtosecond pulse laser with a wide spectral range of 800~1100nm, mode self-cleaning, and tens of millijoules of high energy gain output, which becomes a way to obtain high-energy, narrow pulse width, wide spectrum, and high beam quality pulses.

[0044] Specifically, the pulse laser beam is output through a pulse seed source device, and the pump light is output through a pump source device.

[0045] Specifically, the input coupling lens of the present solution can focus the input pulsed laser beam to the center of the rod-shaped crystal fiber through the input coupling lens, so that the light beam can be more effectively converted and amplified in the gain medium inside the optical fiber. In addition, the input coupling lens also helps to match the mode of the pulsed laser beam with the mode field distribution of the optical fiber, ensuring that the laser energy can be effectively coupled into the optical fiber and reducing the loss caused by mode mismatch.

[0046] Preferably, when the rod-shaped crystal fiber is used as the gain medium, the doping concentration of the rod-shaped crystal fiber is 0.5% to 10%.

[0047] Under the condition that the doping concentration of the rod-shaped crystal fiber remains unchanged, the self-waveguide aperture of the amplified beam can be regulated by adjusting the pump spot size and the amplified beam diameter. Large-caliber beam self-waveguide amplification can be achieved by adjusting the larger signal beam diameter and the pump beam diameter. While reducing the beam energy density, the pulse compression and pulse energy of the pulsed laser beam can be further improved, avoiding the damage of the high-energy pulse to the rod-shaped crystal fiber, and being more conducive to obtaining high-energy, narrow pulse width, wide spectrum, and high beam quality pulses, with the advantage of generating high-energy laser pulse amplification. Specifically, the ratio of the pump spot diameter to the amplified beam diameter is 3:2, the amplified beam self-waveguide aperture size is between 2 / 3 and 1 of the pump spot diameter size, and the amplified beam self-waveguide aperture size can be regulated. In addition, the self-waveguide aperture can also be regulated by selecting different gain medium doping concentrations. In specific application implementations, when a rod-shaped crystal fiber is used as a gain medium, the doping concentration of the rod-shaped crystal fiber can be selected to be 0.5% to 10%.

[0048] In a specific implementation, the rod-shaped crystal fiber uses a yttrium aluminum garnet (YAG) laser crystal doped with rare earth elements; or, the rod-shaped crystal fiber uses a yttrium aluminum garnet (YAG) laser crystal doped with ytterbium (Yb) particles.

[0049] As one of the application sizes of the rod-shaped crystal fiber, its length is 30 mm and its diameter is 2 mm.

[0050] Preferably, the end faces at both ends of the rod-shaped crystal optical fiber are respectively coated with anti-reflection films, and the wavelength of the anti-reflection films matches the wavelength of the input light to increase the transmittance.

[0051] Preferably, outer surfaces of the input coupling lens and the output collimating lens are respectively coated with anti-reflection films to increase transmittance.

[0052] In specific implementation, the pulse seed source 100 uses a broadband ultrashort pulse laser, which can emit a broadband ultrashort pulse seed source with a certain spectral width, and an output repetition rate of a picosecond or femtosecond ultrafast laser with a low repetition rate to an ultra-high repetition rate (Hz to terahertz THz). When the signal light emitted by the broadband ultrashort pulse seed source is amplified in a rod-shaped crystal fiber, the polarization state is arbitrary and unlimited, and can be horizontal polarization, vertical polarization, or circular polarization, etc.

[0053] In specific implementation, the pulse seed source 100 can generate pulsed laser seed signal light, with an emission center wavelength of 800 nm, 1030 nm, 1064 nm and 1560 nm, etc., a spectral width greater than 10 nm, and can be an ultrafast seed source with adjustable repetition rate from 1 Hz to MHz or a high repetition rate of GHz or THz, with a pulse width of several picoseconds or hundreds of femtoseconds.

[0054] Preferably, the rod-shaped crystal optical fiber is embedded in a copper block heat sink by welding. The gold film coated on the cylindrical surface of the rod-shaped crystal fiber can reflect the signal light and pump light, and can also be used as a heat transfer medium between the rod-shaped crystal fiber and the copper heat sink. The gold film has good thermal conductivity, so that the rod-shaped crystal fiber can be well cooled, which can prevent the gain medium from being damaged due to overheating, allowing higher laser output power, thereby improving the laser output power; it can also avoid uneven heating of the gain medium, help maintain the pulse shape and time characteristics, and thus improve the beam quality; it can reduce the changes in laser parameters or physical size changes of optical components caused by temperature fluctuations, thereby affecting the focusing and directivity of the beam. Good heat dissipation can reduce this thermal drift and improve the stability of the entire laser system; it can avoid damage to optical components such as lenses and reflectors, reduce thermal stress and thermal damage, reduce the failure rate, thereby extending the service life of the laser and its components, and improving the reliability of the system; it can avoid the change in the refractive index of the gain medium that may be caused by high temperature, which in turn leads to the degradation of the laser mode, and help maintain the stability of the mode; it can reduce the loss of pump light and laser signal light due to thermal effects and improve the laser conversion efficiency.

[0055] Preferably, the pulse laser amplification module is a single-channel amplification module, and the input pulse laser beam and pump light can be amplified once in the pulse laser amplification module.

[0056] As one of the implementations of a single-channel amplification module, the present invention discloses Embodiment 1.

[0057] Embodiment 1 It should be noted that, in this embodiment, the pulse laser amplification module is suitable for amplifying various seed source laser wavelengths. In this embodiment, only the seed source pulse laser with a wavelength of 1030nm is used as an example for explanation, and it is not limited to use. The pump light in this embodiment uses 969nm.

[0058] See also Figure 1 and Figure 2 The pulse laser amplification module includes a rod-shaped crystal fiber, the outer periphery of which is coated with a gold film; the rod-shaped crystal fiber is cylindrical in shape.

[0059] The rod-shaped crystal fiber 302 is a YAG laser crystal doped with Yb particles, with a length of 30 mm and a diameter of 2 mm, and the end faces are coated with 969 nm and 1030 nm anti-reflection films; it is used to amplify the signal light output by the broadband ultrashort pulse seed source.

[0060] An input coupling lens 301 is provided at one end of the rod-shaped crystal fiber 302. One end of the input coupling lens 301 is used to input the pulse laser beam 101 and the pump light 204. The pulse laser beam 101 and the pump light 204 can be focused by the input coupling lens 301 to the center of the end face of one end of the rod-shaped crystal fiber 302. In this embodiment, the input coupling lens 301 is a fused silica plano-convex lens with a focal length of 400 mm and coated with a 700-1100 nm anti-reflection film, which is used to couple 969 nm pump light into the rod-shaped crystal fiber 302 and simultaneously focus 1030 nm signal light into the rod-shaped crystal fiber 302 for self-waveguide amplification.

[0061] The other end of the rod-shaped crystal fiber 302 is provided with an output collimating lens 303 for converting the pulsed laser beam 101 output from the rod-shaped crystal fiber 302 into a collimated beam; In this embodiment, the output collimating lens 301 may be a fused silica plano-convex lens with a focal length of 400 mm and coated with a 700-1100 nm anti-reflection film; it is used to collimate the 1030 nm amplified self-waveguide light beam output by the Yb / YAG rod-shaped crystal fiber 302 .

[0062] The pump light 204 enters the rod-shaped crystal fiber 302 through the center of the end face of the rod-shaped crystal fiber 302 and propagates therein, and generates total reflection at the inner surface of the rod-shaped crystal fiber 302 and converges on the center line of the rod-shaped crystal fiber 302, so that the light intensity of the pump light 204 in the rod-shaped crystal fiber 302 is maximized, so as to obtain the maximum gain particle inversion number, thereby realizing wide-spectrum self-waveguide amplification of the pulsed laser beam 101.

[0063] The pulse laser amplification module of this embodiment uses the strongest pump light intensity and the largest gain particle inversion number at the center of the rod-shaped crystal fiber. During the amplification process, the pulsed laser beam will produce a thermal lens effect related to the pump light intensity and a Kerr effect related to gain amplification, thereby causing the light beam to self-focus during energy amplification. At the same time, through the energy increase of the laser pulse during the gain amplification process, nonlinear amplification is generated to achieve self-phase modulation spectrum broadening. Since the spectrum broadening of the pulsed laser beam will introduce an increase in the beam mode field and produce a divergence effect, the pulsed laser beam will also experience self-defocusing during the amplification process.

[0064] The pulse laser amplification module of this embodiment can utilize the self-defocusing effect of the pulse laser beam spectrum broadening mode field and the self-focusing effect of the Kerr effect and the thermal lens effect during the gain amplification process to clamp each other, forming a self-waveguide with dynamic balance of the beam mode field, thereby suppressing the degradation of the spot mode and making the beam have a self-cleaning effect during the amplification process.

[0065] This embodiment also discloses a pulse laser including the above-mentioned pulse amplifier, wherein the pulse laser includes a pulse seed source 100, a pump coupling module 200, a pulse laser amplification module 300 and a pulse compression module 400; See also Figure 1 , is a schematic diagram of the self-waveguide amplification process and effect of the pulse laser amplification module. The laser pulse realizes self-cleaning high-energy amplification in a wide spectrum mode, and its main process occurs in the pulse laser amplification module 300.

[0066] The pump coupling module 200 includes a pump source 201, a pump collimating lens 202 and a dichroic mirror 203 which are connected in series in sequence. The pump source 201 is used to emit pump light. The light output end of the pump source 201 is connected to the pump collimating lens 202. After the pump light is collimated by the pump collimating lens 202, the pump light is emitted to the dichroic mirror 203 and is colinear with the pulse laser emitted by the pulse seed source at the reflection end of the dichroic mirror 203.

[0067] The pulse emission end of the pulse seed source 100 is connected to the light input end of the dichroic mirror 203 , and is emitted from the light projection end of the dichroic mirror 203 and is colinear with the pump light.

[0068] Specifically, the pulse seed source 100 adopts a broadband ultrashort pulse seed source.

[0069] Specifically, the pulse seed source 100 of the present embodiment can generate pulsed laser seed signal light, with an emission center wavelength of 800 nm, 1030 nm, 1064 nm and 1560 nm, etc., a spectral width greater than 10 nm, and can be an ultrafast seed source with an adjustable repetition rate from 1 Hz to MHz or a high repetition rate of GHz or THz, with a pulse width of several picoseconds or hundreds of femtoseconds.

[0070] Specifically, the pump source 201 of this embodiment adopts a semiconductor diode pump, whose emission wavelength is 969 nm and output power can be 400 W, and is used to pump the rod-shaped crystal fiber 302 .

[0071] Specifically, the pump collimating lens 202 of this embodiment is a plano-convex lens made of fused quartz, with a focal length of 40 mm and coated with a 969 nm anti-reflection film, and is used to collimate the pump light.

[0072] Specifically, the dichroic mirror 203 of the present embodiment is a 1000nm long-pass dichroic mirror, which has a reflective effect on light incident at a 45-degree angle and less than 1000nm; and has a transmissive effect on light incident at a 45-degree angle and greater than 1000nm; and is used to reflect the 969nm pump light and transmit the 1030nm seed signal light and then transmit them colinearly to the pulse laser amplification module 300.

[0073] The pulse compression module 400 includes a reflector 401, a right-angle reflector 402, a first diffraction grating 403, a second diffraction grating 404 and a downward-pressing roof mirror 405; the pulse compression module 400 is used to compress the amplified laser output by the Yb / YAG rod-shaped crystal fiber 302 and compress the pulse width to a hundred femtosecond level.

[0074] Specifically, the reflector 401 of this embodiment adopts a 1-inch diameter dielectric film reflector, and the reflectivity of the 1000~1100nm 45-degree incident light beam is greater than 99.5%; it is used to deflect the amplified laser output by the Yb / YAG rod-shaped crystal fiber amplifier 302 and introduce it into the pulse compression module 400.

[0075] Specifically, the right-angle reflector 402 of this embodiment adopts a 45-degree dielectric film reflector with a right-angle side length of 10 mm, which is placed at the incident light path end of the pulse compression module 400. Its center height is lower than the incident light beam height, and the height difference is 10 mm; it is used to reflect the compressed pulse of the pulse compression module 400 to export the laser.

[0076] Specifically, the first diffraction grating 403 and the second diffraction grating 404 of this embodiment are 1000 Line transmission gratings or reflection gratings, which are placed in parallel in the pulse compression module 400 and work at the Littow angle to compensate for the dispersion of the amplified pulse and compress the pulse width.

[0077] The Littrow angle refers to the condition where the diffraction angle of the diffraction grating is equal to the incident angle, that is, the angle when the first-order diffracted beam is parallel to the incident beam; in laser systems, the Littrow configuration can be used for pulse compression, where the diffraction grating is used to compensate for the temporal broadening of the laser pulse. The relationship expression of the Littrow angle is: sin( θ L ) = mλ / d ; In the formula, θ L is the Littrow angle, m is the diffraction order (usually taken as 1 for a Littrow configuration), λ is the wavelength of the incident light, d is the grating constant of the diffraction grating, i.e. the distance between adjacent grating lines.

[0078] Specifically, the downward-pressing roof mirror 405 of the present embodiment includes two glued reflecting prisms coated with 700-1100nm dielectric films, which are used to depress the height of the light beam passing through the first diffraction grating 403 and the second diffraction grating 404 in the forward direction, and reverse the transmission direction of the diffracted light beam after passing through the first diffraction grating 403 and the second diffraction grating 404 in the forward direction, and the height to which the light beam is depressed is 10mm.

[0079] The working process of the pulse laser of this embodiment is as follows: the signal light emitted by the pulse seed source is transmitted to the right, and after being colinear with the pump light emitted by the pump coupling module 200 at the dichroic mirror 203, it is transmitted into the pulse laser amplification module 300, and after being amplified by the pulse laser amplification module 300, it is transmitted to the pulse compression module 400 for pulse compression. After the pulse compression module 400 completes the pulse width compression, the transmission height will drop by 10mm and the transmission direction will be reversed, and then it will be transmitted to the right-angle reflector 402, and the pulse laser will be derived through reflection by the reflector 402. At this point, the signal light emitted by the ultrashort pulse seed source has achieved high-energy, narrow pulse width laser generation after the above-mentioned transmission, self-waveguide amplification, and pulse compression process.

[0080] This embodiment can achieve a dynamic balance between the self-focusing process of the Kerr effect and the thermal lens effect and the self-defocusing process of the light spot mode field in the pulse laser amplification module. Based on the amplification of the pulsed laser beam in the rod-shaped crystal fiber, the self-focusing and self-defocusing phenomena of the light beam related to the pump light intensity, laser gain amplification and nonlinear amplification are utilized, the self-waveguide process induced after the dynamic balance of the light spot mode field, the wide spectrum characteristics of the self-phase modulation, the mode self-cleaning advantages of the self-waveguide process, and the amplification characteristics of the gain medium are utilized to achieve a wide spectrum self-waveguide amplification of the light beam with dynamic balance.

[0081] As one of the implementations of the multi-channel amplifier, the present invention discloses Embodiment 2.

[0082] Embodiment 2 Preferably, the pulse laser amplification module is a multi-channel amplification module for amplifying the pulse laser multiple times.

[0083] See also Figure 3 As one implementation of a multi-channel amplification module, the pulse laser amplification module 300 is a two-channel pulse laser amplification module 300, which can realize secondary amplification of pulse laser. Figure 3 As shown, the two-channel pulse laser amplification module 300 of this embodiment is based on the single-channel amplification module and further includes a first half-wave plate 304, one side of the first half-wave plate 304 is used to set the pulse seed source 100, the other side of the first half-wave plate 304 is provided with a first polarization beam splitter 305, the side of the first polarization beam splitter 305 away from the first half-wave plate 304 is sequentially provided with an input coupling lens 301, a rod-shaped crystal fiber 302 and an output collimating lens 303, and the side of the output collimating lens 303 away from the rod-shaped crystal fiber 302 is sequentially provided with a first Faraday rotator 306 and a first end face zero-degree reflector 307; thus, a two-channel pulse laser amplification module is formed. Among them, the first half-wave plate 304, the polarization beam splitter, the first Faraday rotator 306 and the first end face zero-degree reflector 307 are optical devices used to change the polarization state and transmission direction of the light beam.

[0084] The amplification principle of the two-channel pulse laser amplification module 300 of this embodiment is: After the first half-wave plate 304 receives the pulse laser output by the pulse seed source 100 and changes the polarization direction of the pulse laser, the pulse laser is transmitted to the first polarization beam splitter 305. After the beam splitting effect of the first polarization beam splitter 305, the pulse laser is further transmitted to the input coupling lens 301, and the pulse laser is amplified for the first time through the rod-shaped crystal fiber 302 in sequence, and then transmitted to the output collimating lens 303 and the first Faraday rotator 306 in sequence, and then transmitted to the first end face zero-degree reflector 307 for reflection; The pulse laser after the first amplification is reflected by the first end face zero-degree reflector 307, returns to the first Faraday rotator 306, and passes through the output collimating lens 303, the rod-shaped crystal fiber 302, the input coupling lens 301, the first polarization beam splitter 305 in sequence, and then undergoes the beam splitting effect of the first polarization beam splitter 305 to output the pulse laser after the second amplification.

[0085] Specifically, a half-wave plate changes the polarization state of polarized light by introducing phase delay. When linearly polarized light passes through a half-wave plate, its polarization direction rotates according to the optical axis direction of the wave plate.

[0086] It should be noted that, in this embodiment, the pulse laser amplification module is suitable for amplifying various seed source laser wavelengths. In this embodiment, only the seed source pulse laser with a wavelength of 1030nm is used as an example for explanation, and it is not limited to use. The pump light in this embodiment uses 969nm.

[0087] Specifically, the rod-shaped crystal fiber 302 of this embodiment is a YAG laser crystal doped with Yb particles, with a length of 30 mm and a diameter of 2 mm, and end faces coated with 969 nm and 1030 nm anti-reflection films; it is used to amplify the signal light output by the broadband ultrashort pulse seed source.

[0088] An input coupling lens 301 is provided at one end of the rod-shaped crystal fiber 302. One end of the input coupling lens 301 is used to input the pulse laser beam 101 and the pump light 204. The pulse laser beam 101 and the pump light 204 can be focused by the input coupling lens 301 to the center of the end face of one end of the rod-shaped crystal fiber 302. In this embodiment, the input coupling lens 301 is a fused silica plano-convex lens with a focal length of 400 mm and coated with a 700-1100 nm anti-reflection film, which is used to couple 969 nm pump light into the rod-shaped crystal fiber 302 and simultaneously focus 1030 nm signal light into the rod-shaped crystal fiber 302 for self-waveguide amplification.

[0089] The other end of the rod-shaped crystal fiber 302 is provided with an output collimating lens 303 for converting the pulsed laser beam 101 output from the rod-shaped crystal fiber 302 into a collimated beam; In this embodiment, the output collimating lens 301 may be a fused silica plano-convex lens with a focal length of 400 mm and coated with a 700-1100 nm anti-reflection film; it is used to collimate the 1030 nm amplified self-waveguide light beam output by the Yb / YAG rod-shaped crystal fiber 302 .

[0090] The pump light enters the rod-shaped crystal fiber through the center of the end face of the rod-shaped crystal fiber and propagates in the rod-shaped crystal fiber, generates total reflection at the inner surface of the rod-shaped crystal fiber, and converges on the center line of the rod-shaped crystal fiber, so that the light intensity of the pump light in the rod-shaped crystal fiber is maximized, so as to obtain the maximum gain particle inversion number, thereby realizing wide-spectrum self-waveguide amplification of the pulsed laser beam.

[0091] Specifically, the wavelength of the first half-wave plate of this embodiment is 1030nm, and a 0.5-inch true 0-order air-gap fused quartz 1 / 2 wave plate coated with a 1030nm anti-reflection film is used; it is used to rotate the polarization state of the 1030nm signal light so that the 1030nm signal light is fully transmitted through the first polarization beam splitter 305 in a horizontal polarization state.

[0092] Specifically, the first polarization beam splitter 305 of this embodiment adopts a beam splitter cube with a side length of 10 mm and coated with a polarization beam splitting film, which has the function of fully transmitting horizontally polarized light and fully reflecting vertically polarized light.

[0093] Specifically, the first Faraday rotator 306 of the present embodiment is composed of a strong magnet and an optically active crystal. The first Faraday rotator 306 used has a polarization rotation of 45 degrees in the counterclockwise direction for the forward and reverse light beams, and produces a 90-degree polarization rotation for the same light beam passing through the first Faraday rotator 306 twice.

[0094] Specifically, the first end surface zero-degree reflector 307 of this embodiment is coated with a 1030nm 0-degree high-reflection film and has a size of 1 inch.

[0095] The pulse laser amplification module of this embodiment uses the strongest pump light intensity and the largest gain particle inversion number at the center of the rod-shaped crystal fiber. During the amplification process, the pulsed laser beam will produce a thermal lens effect related to the pump light intensity and a Kerr effect related to gain amplification, thereby causing the light beam to self-focus during energy amplification. At the same time, through the energy increase of the laser pulse during the gain amplification process, nonlinear amplification is generated to achieve self-phase modulation spectrum broadening. Since the spectrum broadening of the pulsed laser beam will introduce an increase in the beam mode field and produce a divergence effect, the pulsed laser beam will also experience self-defocusing during the amplification process.

[0096] The pulse laser amplification module of this embodiment can utilize the self-defocusing effect of the pulse laser beam spectrum broadening mode field and the self-focusing effect of the Kerr effect and the thermal lens effect during the gain amplification process to clamp each other, forming a self-waveguide with dynamic balance of the beam mode field, thereby suppressing the degradation of the spot mode and making the beam have a self-cleaning effect during the amplification process.

[0097] like Figure 3 As shown, this embodiment also discloses a pulse laser including the above-mentioned pulse amplifier, wherein the pulse laser includes a pulse seed source 100, a pump coupling module 200, a pulse laser amplification module 300 and a pulse compression module 400; The pump coupling module 200 includes a pump source 201, a pump collimating lens 202 and a dichroic mirror 203 which are connected in series in sequence, and the dichroic mirror 203 is arranged between the first polarization beam splitter 305 and the input coupling lens 301; The pump source 201 is used to emit pump light. The light output end of the pump source 201 is connected to the pump collimating lens 202. After the pump light is collimated by the pump collimating lens 202, the pump light is emitted to the dichroic mirror 203 and is colinear with the pulsed laser output by the first polarization beam splitter 305 at the reflection end of the dichroic mirror 203.

[0098] The pulse emission end of the pulse seed source 100 is connected to the light input end of the first half-wave plate 304, and is emitted from the light projection end of the first half-wave plate 304 to the first polarization beam splitter 305. Then, the pulse laser is colinear with the pump light through the beam splitting effect of the first polarization beam splitter 305.

[0099] Specifically, the pulse seed source 100 adopts a broadband ultrashort pulse seed source.

[0100] Specifically, the pulse seed source 100 of the present embodiment can generate pulsed laser seed signal light, with an emission center wavelength of 800 nm, 1030 nm, 1064 nm and 1560 nm, etc., a spectral width greater than 10 nm, and can be an ultrafast seed source with an adjustable repetition rate from 1 Hz to MHz or a high repetition rate of GHz or THz, with a pulse width of several picoseconds or hundreds of femtoseconds.

[0101] Specifically, the pump source 201 of this embodiment adopts a semiconductor diode pump, whose emission wavelength is 969 nm and output power can be 400 W, and is used to pump the rod-shaped crystal fiber 302 .

[0102] Specifically, the pump collimating lens 202 of this embodiment is a plano-convex lens made of fused quartz, with a focal length of 40 mm and coated with a 969 nm anti-reflection film, and is used to collimate the pump light.

[0103] Specifically, the dichroic mirror 203 of the present embodiment is a 1000nm long-pass dichroic mirror, which has a reflective effect on light incident at a 45-degree angle and less than 1000nm; and has a transmissive effect on light incident at a 45-degree angle and greater than 1000nm; and is used to reflect the 969nm pump light and transmit the 1030nm seed signal light and then transmit them colinearly to the pulse laser amplification module 300.

[0104] The pulse compression module 400 includes a right-angle reflector 402, a first diffraction grating 403, a second diffraction grating 404 and a downward-pressing roof mirror 405; the pulse compression module 400 is used to compress the amplified laser output by the Yb / YAG rod-shaped crystal fiber 302 and compress the pulse width to a level of hundreds of femtoseconds.

[0105] Specifically, the right-angle reflector 402 of this embodiment adopts a 45-degree dielectric film reflector with a right-angle side length of 10 mm, which is placed at the incident light path end of the pulse compression module 400, and is used to receive the incident light from the first polarization beam splitter 305. Its center height is lower than the incident light beam height, and the height difference is 10 mm; it is used to reflect the compressed pulse of the pulse compression module 400 to export the laser.

[0106] Specifically, the first diffraction grating 403 and the second diffraction grating 404 of this embodiment are 1000 Line transmission gratings or reflection gratings, which are placed in parallel in the pulse compression module 400 and work at the Littow angle to compensate for the dispersion of the amplified pulse and compress the pulse width.

[0107] Specifically, the downward-pressing roof mirror 405 of the present embodiment includes two glued reflecting prisms coated with 700-1100nm dielectric films, which are used to depress the height of the light beam passing through the first diffraction grating 403 and the second diffraction grating 404 in the forward direction, and reverse the transmission direction of the diffracted light beam after passing through the first diffraction grating 403 and the second diffraction grating 404 in the forward direction, and the height to which the light beam is depressed is 10mm.

[0108] The working process of the pulse laser in this embodiment: Figure 3 First, a pulsed laser is generated by a pulse seed source, transmitted through the first half-wave plate 304, and becomes a horizontal polarization state under the polarization rotation of the first half-wave plate 304; then, it is transmitted through the first polarization beam splitter (PBS) 305 and transmitted to the dichroic mirror 203, and after transmitting through the dichroic mirror 203, it is colinearly transmitted with the 969nm pump light, and after being focused by the input coupling lens 301, it enters the Yb / YAG rod-shaped crystal fiber 302 and undergoes wide-spectrum self-waveguide amplification; then, the pulsed laser forms an amplified laser after the first self-waveguide amplification, and continues to be transmitted and collimated by the output collimating lens 303, and then After that, it reaches the first Faraday rotator 306; the polarization direction of the amplified laser transmitted through the first Faraday rotator 306 will be rotated 45 degrees counterclockwise; then it is transmitted to the first end face zero-degree reflector 307 for 0-degree reflection, and the propagation direction is reversed and then it starts to transmit in the opposite direction; then it passes through the first Faraday rotator 306 for the second time, and the polarization direction is rotated 45 degrees counterclockwise again to become a vertical polarization state; and it passes through the output coupling lens 303 again, and enters the Yb / YAG rod-shaped crystal fiber 302 after being focused, and undergoes a second self-waveguide amplification in a vertical polarization state; After the second self-waveguide amplification, the amplified light beam is collimated by the input coupling lens 301, transmitted through the dichroic mirror 203, and then reaches the first polarization beam splitter 305; the amplified light beam in the vertical polarization state is reflected at the first polarization beam splitter 305 and enters the pulse compression module 400. After the pulse width is compressed in the pulse compression module 400, a high-energy, narrow-pulse-width compressed laser output is formed; so far, the above whole process completes the two-pass beam wide-spectrum self-waveguide amplified laser output.

[0109] As one of the implementations of the multi-channel amplifier, the present invention discloses Embodiment 3.

[0110] Embodiment 3 See also Figure 4As one implementation of a multi-channel amplification module, the pulse laser amplification module 300 is a four-channel pulse laser amplification module 300, which can realize four times amplification of the pulse laser. Figure 4 As shown, the four-channel pulse laser amplification module 300 of this embodiment is based on the single-channel amplification module and further includes a first half-wave plate 304, one side of the first half-wave plate 304 is used to set the pulse seed source 100, the other side of the first half-wave plate 304 is provided with a first polarization beam splitter 305, and the side of the first polarization beam splitter 305 away from the first half-wave plate 304 is sequentially provided with a second Faraday rotator 308 and a second half-wave plate 309; A second polarization beam splitter 310 is disposed on a side of the second half-wave plate 309 away from the second Faraday rotator 308, an input coupling lens 301, a rod-shaped crystal fiber 302 and an output collimating lens 303 are sequentially disposed on one side of a first output end of the second polarization beam splitter 310, and a first Faraday rotator 306 and a first end face zero-degree reflector 307 are sequentially disposed on a side of the output collimating lens 303 away from the rod-shaped crystal fiber 302; A second end face zero-degree reflector 311 is provided at one side of the second output end of the second polarization beam splitter 310, for reflecting the light split by the second polarization beam splitter 310; Thus, a four-channel pulse laser amplification module is formed.

[0111] The amplification principle of the four-channel pulse laser amplification module 300 is as follows: after the first half-wave plate 304 receives the pulse laser output by the pulse seed source 100 and changes the polarization direction of the pulse laser, the pulse laser is transmitted to the first polarization beam splitter 305, and after the beam splitting effect of the first polarization beam splitter 305, the pulse laser is continuously transmitted, and sequentially passes through the second Faraday rotator 308, the second half-wave plate 309 and the second polarization beam splitter 310, and after the beam splitting effect of the second polarization beam splitter 310, the pulse laser is continuously transmitted to the input coupling lens 301, and sequentially passes through the rod-shaped crystal fiber 302 to amplify the pulse laser for the first time, and then sequentially transmits to the output collimating lens 303 and the first Faraday rotator 306, and then transmits to the first end face zero-degree reflector 307 for reflection; The pulse laser after the first amplification is reflected by the first end face zero-degree reflector 307, returns to the first Faraday rotator 306, and passes through the output collimating lens 303, the rod-shaped crystal fiber 302, and the input coupling lens 301 in sequence to output the pulse laser after the second amplification; When the pulse laser after the second amplification is transmitted to the second polarization beam splitter 310, it is transmitted to the second end face zero-degree reflector 311 for reflection. After the reflection, the pulse laser after the second amplification is transmitted to the input coupling lens 301 again, and is amplified for the third time by the rod-shaped crystal fiber 302 in sequence, and then transmitted to the output collimating lens 303 and the first Faraday rotator 306 in sequence, and then transmitted to the first end face zero-degree reflector 307 for reflection; The pulse laser after the third amplification is reflected by the first end face zero-degree reflector 307, returns to the first Faraday rotator 306, and passes through the output collimating lens 303, the rod-shaped crystal fiber 302, and the input coupling lens 301 in sequence to undergo the fourth amplification of the pulse laser; Then, the second Faraday rotator 308 and the second half-wave plate 309 are adjusted to further adjust the polarization state of the pulsed laser amplified for the fourth time, so that the pulsed laser amplified for the fourth time passes through the second polarization beam splitter 310, and is sequentially transmitted to the first polarization beam splitter 305 through the second half-wave plate 309 and the second Faraday rotator 308, and then outputs the pulsed laser amplified for the fourth time through the beam splitting effect of the first polarization beam splitter 305. Among them, each half-wave plate, each polarization beam splitter, each Faraday rotator and each end zero-degree reflector 401 are optical devices used to change the polarization state and transmission direction of the light beam.

[0112] It should be noted that, in this embodiment, the pulse laser amplification module is suitable for amplifying various seed source laser wavelengths. In this embodiment, only the seed source pulse laser with a wavelength of 1030nm is used as an example for explanation, and it is not limited to use. The pump light in this embodiment uses 969nm.

[0113] Specifically, the rod-shaped crystal fiber 302 of this embodiment is a YAG laser crystal doped with Yb particles, with a length of 30 mm and a diameter of 2 mm, and end faces coated with 969 nm and 1030 nm anti-reflection films; it is used to amplify the signal light output by the broadband ultrashort pulse seed source.

[0114] An input coupling lens 301 is provided at one end of the rod-shaped crystal fiber 302. One end of the input coupling lens 301 is used to input the pulse laser beam 101 and the pump light 204. The pulse laser beam 101 and the pump light 204 can be focused by the input coupling lens 301 to the center of the end face of one end of the rod-shaped crystal fiber 302. In this embodiment, the input coupling lens 301 is a fused silica plano-convex lens with a focal length of 400 mm and coated with a 700-1100 nm anti-reflection film, which is used to couple 969 nm pump light into the rod-shaped crystal fiber 302 and simultaneously focus 1030 nm signal light into the rod-shaped crystal fiber 302 for self-waveguide amplification.

[0115] The other end of the rod-shaped crystal fiber 302 is provided with an output collimating lens 303 for converting the pulsed laser beam 101 output from the rod-shaped crystal fiber 302 into a collimated beam; In this embodiment, the output collimating lens 301 may be a fused silica plano-convex lens with a focal length of 400 mm and coated with a 700-1100 nm anti-reflection film; it is used to collimate the 1030 nm amplified self-waveguide light beam output by the Yb / YAG rod-shaped crystal fiber 302 .

[0116] The pump light enters the rod-shaped crystal fiber through the center of the end face of the rod-shaped crystal fiber and propagates in the rod-shaped crystal fiber, generates total reflection at the inner surface of the rod-shaped crystal fiber, and converges on the center line of the rod-shaped crystal fiber, so that the light intensity of the pump light in the rod-shaped crystal fiber is maximized, so as to obtain the maximum gain particle inversion number, thereby realizing wide-spectrum self-waveguide amplification of the pulsed laser beam.

[0117] Specifically, the wavelength of the first half-wave plate and the second half-wave plate of this embodiment are both 1030nm, and a 0.5-inch true 0-order air gap fused quartz 1 / 2 wave plate coated with a 1030nm anti-reflection film is used; it is used to rotate the polarization state of the 1030nm signal light so that the 1030nm signal light is fully transmitted through the first polarization beam splitter 305 in a horizontal polarization state.

[0118] Specifically, the first polarization beam splitter 305 and the second polarization beam splitter 310 of this embodiment both use a beam splitter cube with a side length of 10 mm and coated with a polarization beam splitting film, which has the function of fully transmitting horizontal polarized light and fully reflecting vertical polarized light.

[0119] Specifically, the first Faraday rotator 306 and the second Faraday rotator 308 of the present embodiment are both composed of a strong magnet and an optically active crystal. The first Faraday rotator 306 used has a polarization rotation of 45 degrees in the counterclockwise direction for the light beams passing in the forward direction and the reverse direction, and produces a 90-degree polarization rotation for the same light beam passing through the first Faraday rotator 306 twice. Similarly, the second Faraday rotator 308 used has a polarization rotation of 45 degrees in the counterclockwise direction for the light beams passing in the forward direction and the reverse direction, and produces a 90-degree polarization rotation for the same light beam passing through the second Faraday rotator 308 twice.

[0120] Specifically, the first end surface zero-degree reflector 307 of this embodiment is coated with a 1030nm 0-degree high-reflection film and has a size of 1 inch.

[0121] The pulse laser amplification module of this embodiment uses the strongest pump light intensity and the largest gain particle inversion number at the center of the rod-shaped crystal fiber. During the amplification process, the pulsed laser beam will produce a thermal lens effect related to the pump light intensity and a Kerr effect related to gain amplification, thereby causing the light beam to self-focus during energy amplification. At the same time, through the energy increase of the laser pulse during the gain amplification process, nonlinear amplification is generated to achieve self-phase modulation spectrum broadening. Since the spectrum broadening of the pulsed laser beam will introduce an increase in the beam mode field and produce a divergence effect, the pulsed laser beam will also experience self-defocusing during the amplification process.

[0122] The pulse laser amplification module of this embodiment can utilize the self-defocusing effect of the pulse laser beam spectrum broadening mode field and the self-focusing effect of the Kerr effect and the thermal lens effect during the gain amplification process to clamp each other, forming a self-waveguide with dynamic balance of the beam mode field, thereby suppressing the degradation of the spot mode and making the beam have a self-cleaning effect during the amplification process.

[0123] like Figure 4 As shown, this embodiment also discloses a pulse laser including the above-mentioned pulse amplifier, wherein the pulse laser includes a pulse seed source 100, a pump coupling module 200, a pulse laser amplification module 300 and a pulse compression module 400; The pump coupling module 200 includes a pump source 201, a pump collimating lens 202 and a dichroic mirror 203 which are sequentially connected in series, and the dichroic mirror 203 is arranged between the second polarization beam splitter 310 and the input coupling lens 301; The pump source 201 is used to emit pump light. The light output end of the pump source 201 is connected to the pump collimating lens 202. After the pump light is collimated by the pump collimating lens 202, the pump light is emitted to the dichroic mirror 203 and is colinear with the pulsed laser output by the second polarization beam splitter 310 at the reflection end of the dichroic mirror 203.

[0124] The pulse emitting end of the pulse seed source 100 is connected to the light input end of the first half-wave plate 304, and is emitted from the light projection end of the first half-wave plate 304 to the first polarization beam splitter 305. Then, the pulse laser passes through the second Faraday rotator 308 and the second half-wave plate in sequence, and then passes through the beam splitting effect of the second polarization beam splitter 310 to be colinear with the pump light.

[0125] Specifically, the pulse seed source 100 adopts a broadband ultrashort pulse seed source.

[0126] Specifically, the pulse seed source 100 of the present embodiment can generate pulsed laser seed signal light, with an emission center wavelength of 800 nm, 1030 nm, 1064 nm and 1560 nm, etc., a spectral width greater than 10 nm, and can be an ultrafast seed source with an adjustable repetition rate from 1 Hz to MHz or a high repetition rate of GHz or THz, with a pulse width of several picoseconds or hundreds of femtoseconds.

[0127] Specifically, the pump source 201 of this embodiment adopts a semiconductor diode pump, whose emission wavelength is 969 nm and output power can be 400 W, and is used to pump the rod-shaped crystal fiber 302 .

[0128] Specifically, the pump collimating lens 202 of this embodiment is a plano-convex lens made of fused quartz, with a focal length of 40 mm and coated with a 969 nm anti-reflection film, and is used to collimate the pump light.

[0129] Specifically, the dichroic mirror 203 of the present embodiment is a 1000nm long-pass dichroic mirror, which has a reflective effect on light incident at a 45-degree angle and less than 1000nm; and has a transmissive effect on light incident at a 45-degree angle and greater than 1000nm; and is used to reflect the 969nm pump light and transmit the 1030nm seed signal light and then transmit them colinearly to the pulse laser amplification module 300.

[0130] The pulse compression module 400 includes a right-angle reflector 402, a first diffraction grating 403, a second diffraction grating 404 and a downward-pressing roof mirror 405; the pulse compression module 400 is used to compress the amplified laser output by the Yb / YAG rod-shaped crystal fiber 302 and compress the pulse width to a level of hundreds of femtoseconds.

[0131] Specifically, the right-angle reflector 402 of this embodiment adopts a 45-degree dielectric film reflector with a right-angle side length of 10 mm, which is placed at the incident light path end of the pulse compression module 400, and is used to receive the incident light from the first polarization beam splitter 305. Its center height is lower than the incident light beam height, and the height difference is 10 mm; it is used to reflect the compressed pulse of the pulse compression module 400 to export the laser.

[0132] Specifically, the first diffraction grating 403 and the second diffraction grating 404 of this embodiment are 1000 Line transmission gratings or reflection gratings, which are placed in parallel in the pulse compression module 400 and work at the Littow angle to compensate for the dispersion of the amplified pulse and compress the pulse width.

[0133] Specifically, the downward-pressing roof mirror 405 of the present embodiment includes two glued reflecting prisms coated with 700-1100nm dielectric films, which are used to depress the height of the light beam passing through the first diffraction grating 403 and the second diffraction grating 404 in the forward direction, and reverse the transmission direction of the diffracted light beam after passing through the first diffraction grating 403 and the second diffraction grating 404 in the forward direction, and the height to which the light beam is depressed is 10mm.

[0134] The working process of the pulse laser in this embodiment: Figure 4 First, the pulse seed source generates seed signal light, which is transmitted to the right and first passes through the first half-wave plate 304, and becomes a horizontal polarization state under the polarization rotation of the first half-wave plate 304; then it is transmitted through the polarization beam splitter 405, the second Faraday rotator 308 and the second half-wave plate 309 in sequence. When passing through the second Faraday rotator 308, its polarization direction will rotate 45 degrees counterclockwise. After passing through the second half-wave plate 309, the polarization direction is rotated 45 degrees clockwise and becomes a horizontal polarization state again; then it is transmitted through the second polarization beam splitter 310 and the dichroic mirror 203 in sequence, and then co-linearly transmitted with the 969nm pump light; under the focusing of the input coupling lens 301, it enters the Yb / YAG rod-shaped crystal fiber 302 for broadband self-waveguide amplification; After the signal light is amplified by the self-waveguide, it is collimated by the output collimating lens 303, and then enters the first Faraday rotator 306. After being transmitted through the first Faraday rotator 306, the polarization direction of the light beam is rotated 45 degrees counterclockwise, and then it is transmitted to the end face zero-degree reflector 307. After a 0-degree reflection, the propagation direction of the light beam is reversed, and then it is transmitted to the left and passes through the first Faraday rotator 306 again. The polarization direction is rotated 45 degrees counterclockwise again and becomes a vertical polarization state. After passing through the output coupling lens 303 again, the light beam is focused into the Yb / YAG rod-shaped crystal fiber 302, and then a second wide-spectrum self-waveguide amplification is performed in a vertical polarization state. The light beam after the second wide-spectrum self-waveguide amplification continues to be transmitted to the left under the collimation of the input coupling lens 301, and reaches the second polarization beam splitter 310 after being transmitted through the dichroic mirror 203; since the polarization state of the amplified light beam is vertical polarization, a 90-degree reflection will occur at the second polarization beam splitter 310, and then it will be transmitted downward to the end face zero-degree reflection mirror 311; after the 0-degree reflection occurs, it will return along the original path, pass through the second polarization beam splitter 310 and the dichroic mirror 203 in sequence, and then be transmitted to the right in line with the 969nm pump light, and enter the Yb / YAG rod-shaped crystal fiber 302 under the focus of the input coupling lens 301 to produce the third wide-spectrum self-waveguide amplification, and the light beam after the third wide-spectrum self-waveguide amplification continues to be transmitted to the right, and is collimated by the output collimating lens 303 again, and enters the first Faraday rotator 306; After passing through the first Faraday rotator 306, the polarization direction of the light beam rotates 45 degrees counterclockwise again; then it is transmitted to the end face zero-degree reflector 307, and after generating 0-degree reflection again, the propagation direction of the light beam is reversed again; then it is transmitted to the left again through the first Faraday rotator 306, and the polarization direction rotates 45 degrees counterclockwise again to become a horizontal polarization state. After passing through the output coupling lens 303 for the fourth time, the collimated light beam is focused again into the Yb / YAG rod-shaped crystal fiber 302; then it undergoes the fourth wide-spectrum self-waveguide amplification in a horizontal polarization state; The light beam after the fourth broad spectrum self-waveguide amplification is collimated by the input coupling lens 301 again, and transmitted through the dichroic mirror 203 to reach the second polarization beam splitter 310; the amplified light beam in the horizontal polarization state is transmitted through the second polarization beam splitter 310; Then, after passing through the second half-wave plate 309 again, the polarization direction will rotate 45 degrees counterclockwise, and then after transmitting through the second Faraday rotator 308, the polarization direction will rotate 45 degrees counterclockwise again and become a vertical polarization state; after being transmitted to the polarization beam splitter 305, a 90-degree reflection will occur; then, it will enter the pulse compression module 400, where pulse compression is completed to form a high-energy, narrow-pulse-width laser output. So far, the above whole process completes the four-way beam wide-spectrum self-waveguide amplified laser output.

[0135] In summary, the pulse laser amplification module and pulse laser disclosed in the present invention have the following technical effects: 1. In the pulse laser amplification module and pulse laser of the present invention, the signal light beam realizes self-waveguide amplification in the rod-shaped crystal, which has the advantage of self-cleaning of the spot mode and can realize high beam quality laser amplification. Specifically, the signal light beam is self-waveguided in the rod-shaped crystal fiber; in the laser pulse amplification process, the signal light beam realizes the dynamic balance of the light beam mode field through the self-focusing process of the Kerr effect and the thermal lens effect and the self-defocusing process of the nonlinear amplification spectrum broadening spot mode field, and forms a light beam self-waveguide in the rod-shaped crystal. During the amplification process, the self-waveguide light beam achieves self-balancing of the mode field, discards the spectral components at the edge of the spot mode field, suppresses the mode field distortion, has the characteristics of mode self-cleaning, and realizes high beam quality output. This technology provides a brand-new solution for achieving the generation of high beam quality, high energy, high power, narrow pulse width ultrashort pulse lasers.

[0136] 2. In the pulse laser amplification module and pulse laser of the present invention, the amplification module is based on a rod-shaped crystal structure, which can improve the gain amplification pump conversion efficiency, produce high pump conversion efficiency, and achieve high-power laser generation. Specifically embodied in: a rod-shaped crystal structure based on a gold-plated film on the side of a small core diameter and the use of end-face pumping. The pump light enters from the end face of the rod-shaped crystal fiber, produces total reflection on the cylindrical surface, and converges the transmission to the center of the rod-shaped crystal fiber. This process enables the center of the rod-shaped crystal fiber to produce the strongest pump light intensity and the largest gain particle inversion number, which is beneficial to the efficient absorption of pump energy by the signal beam, while making the thermal lens self-focusing effect more likely to occur, which is more conducive to the formation of a beam amplification self-waveguide.

[0137] 3. In the pulse laser amplification module and pulse laser of the present invention, the self-waveguide amplification process realizes nonlinear amplification spectrum broadening, thereby suppressing the gain narrowing effect, realizing wide-spectrum laser amplification, and having the advantages of outputting high peak energy and narrow pulse laser. Specifically, the signal light beam is self-waveguided amplified in the rod-shaped crystal fiber, and the nonlinear self-phase modulation effect is generated by amplifying the pulse, thereby realizing pulse spectrum broadening, effectively overcoming the gain narrowing effect of the rod-shaped crystal fiber, and ensuring pulse broadband spectrum amplification; at the same time, the spectrum broadening and mode field divergence of the amplification process can be balanced with the Kerr effect and thermal lens self-focusing to form an amplified light beam self-waveguide. Therefore, the self-waveguide spectrum broadening and amplification of the pulse is conducive to pulse width compression, and can achieve sub-hundred femtosecond, high peak energy laser generation.

[0138] 4. In the pulse laser amplification module and pulse laser of the present invention, the pump spot and mode field aperture can be flexibly adjusted during the self-waveguide amplification process, so it has the advantage of achieving high-power and high-energy amplification and can reduce the risk of damage to the device. Specifically, the signal light beam is self-waveguided amplified in the rod-shaped crystal fiber, and the self-waveguide aperture can be flexibly adjusted by the signal beam diameter, the pump beam diameter and the gain medium doping concentration. Large-aperture light beam self-waveguide amplification can be achieved by adjusting the larger signal beam diameter and pump beam diameter, which reduces the beam energy density while avoiding the damage of the rod-shaped crystal fiber by high-energy pulses, and has the advantage of producing high-energy laser pulse amplification.

[0139] 5. The pulse laser amplification module and pulse laser of the present invention can utilize the beam self-waveguide amplification with dynamic balance of the spot mode field to suppress the degradation of the spot mode, and the beam has a self-cleaning effect during the amplification process. At the same time, the spectrum broadening of the beam during the high-energy nonlinear amplification process of the self-waveguide is utilized to effectively suppress the gain narrowing effect of the rod-shaped crystal fiber, which is conducive to compressing the pulse width to sub-hundred femtoseconds and achieving extremely high peak energy output.

[0140] It is understood that the present invention is described by some embodiments, and those skilled in the art are aware that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. The embodiments described in the present invention are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all other embodiments obtained by ordinary technicians in the art without creative work based on the embodiments in the present invention belong to the scope of protection of the present invention.

Claims

1. A pulse laser amplification module, used to amplify a pulse laser beam, characterized in that: The invention comprises a rod-shaped crystal fiber, the outer periphery of which is coated with a gold film; an input coupling lens is arranged at one end of the rod-shaped crystal fiber, one end of which is used to input a pulsed laser beam and a pumping light, and the input coupling lens can make the pulsed laser beam and the pumping light pass through the end face center of one end of the rod-shaped crystal fiber and focus inside the rod-shaped crystal fiber; an output collimating lens is arranged at the other end of the rod-shaped crystal fiber, which is used to convert the pulsed laser beam output from the rod-shaped crystal fiber into a collimated beam; the pumping light enters the rod-shaped crystal fiber through the end face center of the rod-shaped crystal fiber and propagates, generates total reflection at the inner surface of the rod-shaped crystal fiber, and converges on the center line of the rod-shaped crystal fiber, so that the light intensity of the pumping light in the rod-shaped crystal fiber is maximized, so as to obtain the maximum gain particle inversion number, thereby realizing the wide-spectrum self-waveguide amplification of the pulsed laser beam.

2. The pulse laser amplification module according to claim 1, characterized in that: Under the condition that the doping concentration of the rod-shaped crystal optical fiber remains unchanged, the aperture of the amplified light beam from the waveguide can be regulated by adjusting the size of the pump light spot and the diameter of the amplified light beam.

3. The pulse laser amplification module according to claim 2, characterized in that: The ratio of the diameter of the pump spot to the diameter of the amplified beam is 3:2, and the diameter of the amplified beam from the waveguide is 2 / 3~1 of the diameter of the pump spot.

4. The pulse laser amplification module according to claim 1, characterized in that: The end faces at both ends of the rod-shaped crystal optical fiber and the outer surfaces of the input coupling lens and the output collimating lens are respectively coated with anti-reflection films, and the wavelength of the anti-reflection films matches the wavelength of the input light.

5. The pulse laser amplification module according to claim 1, characterized in that: The rod-shaped crystal optical fiber is embedded in the copper block heat sink by welding.

6. The pulse laser amplification module according to claim 1, characterized in that: The pulse laser amplification module is a single-channel amplification module, and the input pulse laser beam and pump light can be amplified once in the pulse laser amplification module.

7. The pulse laser amplification module according to claim 1, characterized in that: The pulse laser amplification module is a multi-channel amplification module, which is used to amplify the pulse laser multiple times.

8. The pulse laser amplification module according to claim 1, characterized in that: It also includes a first half-wave plate, one side of the first half-wave plate is used to set a pulse seed source, the other side of the first half-wave plate is provided with a first polarization beam splitter, the side of the first polarization beam splitter away from the first half-wave plate is provided with an input coupling lens, a rod-shaped crystal fiber and an output collimating lens in sequence, and the side of the output collimating lens away from the rod-shaped crystal fiber is provided with a first Faraday rotator and a first end face zero-degree reflector in sequence; thereby, a two-channel pulse laser amplification module is formed, which can realize secondary amplification of pulse laser.

9. The pulse laser amplification module according to claim 1, characterized in that: It also includes a first half-wave plate, one side of the first half-wave plate is used to set a pulse seed source, the other side of the first half-wave plate is provided with a first polarization beam splitter, and the side of the first polarization beam splitter away from the first half-wave plate is sequentially provided with a second Faraday rotator and a second half-wave plate; A second polarization beam splitter is disposed on a side of the second half-wave plate away from the second Faraday rotator, an input coupling lens, a rod-shaped crystal fiber and an output collimating lens are sequentially disposed on one side of a first output end of the second polarization beam splitter, and a first Faraday rotator and a first end face zero-degree reflector are sequentially disposed on a side of the output collimating lens away from the rod-shaped crystal fiber; A second end face zero-degree reflector is provided at one side of the second output end of the second polarization beam splitter, for reflecting the light split by the second polarization beam splitter; Thus, a four-channel pulse laser amplification module is formed, which can realize four-fold amplification of the pulse laser.

10. A pulsed laser, characterized in that The invention comprises a pulse laser amplification module as claimed in any one of claims 1 to 9.

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