Plasma light pulse amplification device and method for generating few-cycle high-power light pulses

Abstract

The application discloses a kind of plasma light pulse amplification device and method, the device includes laser system, vacuum target chamber and plasma target generation device, laser system is used to generate pump light pulse and seed light pulse;Vacuum target chamber is used to provide the vacuum environment of laser and matter interaction;Plasma target generation device is arranged in vacuum target chamber, wherein plasma target generation device is used to provide plasma target;Laser system is configured to make pump light pulse and seed light pulse propagate along plasma target in the same direction, it is also configured to make pump light pulse and seed light pulse in plasma target in spatial position, seed light pulse is located in the front of pump light pulse, using the Raman forward scattering mechanism of pump light pulse in plasma, energy and intensity amplification of seed light pulse are carried out;The time-domain pulse width of amplified seed light pulse is further compressed when it further propagates in plasma target, to generate near-infrared and mid-infrared pulse of superhigh power, near single cycle, high time-domain contrast (i.e. high signal-to-noise ratio).The device and method can stably generate high-power, few-cycle near-infrared and mid-infrared light pulses in a relatively small spatial scale, and the light pulses have tunable center frequency and high time-domain contrast.

Description

Technical Field

[0001] This application relates to the fields of laser plasma physics and nonlinear optics, and in particular to a plasma optical pulse amplification device and a method for generating short-cycle high-power optical pulses. Background Technology

[0002] Since its invention in 1960, the laser has become an indispensable tool, widely used in basic scientific research, industrial manufacturing, biomedicine, and other fields. With the emergence of new laser technologies such as chirped pulse amplification (CPA) and optical parametric chirped pulse amplification (OPCPA), laser power has been pushed to even higher levels. This high-power laser has unique application value in physics research such as inertial confinement fusion, ultrafast science, and particle acceleration. In particular, the near- and mid-infrared bands (1–20 micrometers) are widely used in research such as ultra-high harmonic radiation, high-energy attosecond pulses, ultrafast dynamics imaging, and particle acceleration. The 2018 Nobel Prize in Physics was awarded to Donna Strickland and Gérard Morrow for their contributions to the field of laser amplification technology; in 2023, the Nobel Prize in Physics was again awarded to the field of ultrafast optics for the contributions of Pierre Agostini, Ferenc Krauss, and Anne Lullier to attosecond light pulse experiments. These scientific developments reflect the significance and status of current high-power laser technology and its applications for human development. However, since current mainstream laser modulation technology is based on nonlinear crystal materials, the damage threshold of the solid-state optical materials and optical components (such as gratings) used for amplification is limited, and further increases in laser power have faced challenges for many years. On the other hand, existing optical amplification methods are also limited by the frequency bandwidth and energy gain of the available gain medium, resulting in high-power laser wavelengths mainly concentrated around 0.8 micrometers and 1.06 micrometers. Therefore, there is currently a lack of effective, simple, and universally applicable modulation schemes for amplifying laser pulses in specific near- and mid-infrared bands to extremely high power levels, while also making it difficult to guarantee their ultra-short pulse width characteristics.

[0003] In recent years, high-energy laser manipulation techniques based on plasma have received increasing attention. The maximum energy density that plasma can withstand (~10⁻⁶) 17 W / cm 2 Compared to solid crystals (~10) 13 W / cm 2The intensity of laser pulses in plasma is several orders of magnitude higher than that in traditional optical crystal materials. Therefore, plasma, as an amplification medium, can withstand laser pulses with extremely high power, intensity, and energy, making it more suitable for controlling high-intensity optical pulses. To date, laser pulse amplification schemes in plasma are based on two pulses propagating in opposite directions within the plasma and colliding, triggered by a backscattering mechanism. However, negative effects such as plasma kinetic instability, transverse instability of laser pulse propagation, spatiotemporal jitter of optical pulses, and forward scattering instability have hindered the practical application and promotion of these schemes. For example, to alleviate the filamentation phenomenon that leads to the deterioration of the transverse structure of the laser, low plasma density and long-duration low-intensity pumping are required. This results in low energy transfer efficiency, increased plasma size, and the ability to amplify only seed pulses with wavelengths close to the pump pulse wavelength. Furthermore, the backscattering scheme requires a certain angle between the two pulses to avoid damage to the laser system, which increases the complexity of experimental operations and reduces efficiency. These factors significantly limit the practical applications, value, and scope of plasma optical amplification mechanisms.

[0004] Therefore, there is an urgent need in the field to develop a novel plasma optical pulse amplification device and method that, by causing the pump optical pulse and the seed optical pulse to propagate in the same direction along the plasma target, can significantly and stably generate high-power, short-period near-infrared and mid-infrared optical pulses within a small spatiotemporal scale, and has tunable spectra and high temporal contrast of the optical pulses. Summary of the Invention

[0005] The purpose of this application is to provide a plasma optical pulse amplification device and method, which, by causing the pump optical pulse and the seed optical pulse to propagate in the same direction along the plasma target, can significantly and stably generate high-power, short-period near-infrared and mid-infrared optical pulses within a small spatiotemporal scale, and has a tunable center frequency and high temporal contrast of the optical pulses.

[0006] This application provides a plasma optical pulse amplification device, comprising:

[0007] A laser system for generating pump pulses and seed pulses, the pump pulses having a first pulse width and including a light pulse having a first center frequency, the seed pulses having a second pulse width and including a light pulse having a second center frequency, the first center frequency being higher than the second center frequency, and the first pulse width being greater than the second pulse width.

[0008] A vacuum target chamber, which provides a vacuum environment for the interaction of laser and matter;

[0009] A plasma target generating device is disposed in the vacuum target chamber, wherein the plasma target generating device is used to provide a plasma target;

[0010] The laser system is configured to cause the pump pulse and the seed pulse to propagate in the same or substantially in the same direction along the plasma target. The laser system is also configured such that the pump pulse and the seed pulse are spatially positioned within the plasma target, with the seed pulse located at the leading edge of the pump pulse. Utilizing the Raman forward scattering mechanism of the pump pulse in the plasma, the energy of the pump pulse is transferred to the seed pulse, thereby amplifying the seed pulse. The amplified pulse further propagates within the plasma target, and the time-domain pulse width of the amplified pulse is further compressed, thereby generating ultra-high power, near-single-cycle, high-contrast (i.e., high signal-to-noise ratio) near-infrared and mid-infrared light pulses.

[0011] In another preferred embodiment, the pump light pulse and the seed light pulse are simultaneously injected into the plasma target, or the pump light pulse is injected into the plasma target with a delay of tens of femtoseconds compared to the seed light pulse.

[0012] In another preferred embodiment, the lateral characteristic distribution of the pump light pulse spot is Gaussian or super-Gaussian.

[0013] In another preferred embodiment, the lateral characteristic distribution of the seed pulse spot can be one of the following types: Gaussian, super-Gaussian, Laguerre-Gaussian, Bessel-Gaussian, Hermite-Gaussian, and Airy.

[0014] In another preferred embodiment, the pump light pulse and the seed light pulse are superimposed in the plasma target by beat frequency to generate an electron plasma wave. The pump light pulse has a higher group velocity in the plasma target than the seed light pulse, so during propagation, the seed light pulse is gradually completely surpassed by the pump light pulse.

[0015] In another preferred embodiment, the further propagation of the amplified seed light pulse in the plasma target induces self-phase modulation, and the time-domain pulse width of the amplified seed light pulse is further compressed.

[0016] In another preferred embodiment, the seed light pulse may also include a light pulse having a different frequency than the first center frequency.

[0017] In another preferred embodiment, the pump light pulse and the seed light pulse propagating in the same direction along the plasma target means that the pump light pulse and the seed light pulse propagate in the same direction.

[0018] In another preferred embodiment, the pump light pulse and the seed light pulse propagating substantially in the same direction along the plasma target means that the angle between the propagation directions of the pump light pulse and the seed light pulse is within the range of ±5°.

[0019] In another preferred embodiment, the difference between the first center frequency of the pump light pulse and the second center frequency of the seed light pulse is equal to the plasma characteristic frequency corresponding to the plasma density of the plasma target.

[0020] In another preferred embodiment, the spectral components of the seed light pulse satisfy the difference between the pump light pulse and the plasma density of the plasma target corresponding to the plasma characteristic frequency, which corresponds to the Raman forward scattering phase-matching condition. That is, this application can use a seed light pulse with a very wide spectrum, whose spectrum covers the frequency values ​​required to satisfy the phase-matching condition; rather than a specific monochromatic light (single frequency component) that satisfies the phase-matching condition.

[0021] In another preferred embodiment, the first center frequency is typically the frequency corresponding to a wavelength of 0.8 micrometers and approximately 1 micrometer, i.e., about 3.75 × 10⁻⁶. 14 Hertz and 3.0 × 10 14 Hertz. The second center frequency is typically lower than the first frequency, and the difference between the two is the plasma characteristic frequency corresponding to the plasma density of the plasma target. In principle, the present invention is also applicable to using other values ​​for the first and second center frequencies.

[0022] In another preferred embodiment, the first pulse width is the oscillation period corresponding to 20 to 200 seed light pulse wavelengths, and / or the second pulse width is the oscillation period corresponding to 10 to 60 seed light pulse wavelengths.

[0023] In another preferred embodiment, the second pulse width of the seed light pulse is less than or equal to half the first pulse width of the pump light pulse.

[0024] In another preferred embodiment, the initial peak power of the seed light pulse is 10 times the initial peak power of the corresponding pump light pulse. -5 ~10 -3 Magnitude.

[0025] In another preferred embodiment, the peak power of the pump light pulse is 0.1 terawatt to 10 petawatts, and / or the peak power of the seed light pulse is 10 megawatts to 1 terawatt. Wherein, 1 megawatt = 10 6 Watts, 1 gigawatt = 10 9 watts, 1 terawatt = 10 12 Tiles, 1 petawatt = 10 15 watt.

[0026] More preferably, the peak power of the seed light pulse differs from the peak power of the pump light pulse by 10. -4 Magnitude.

[0027] In another preferred embodiment, the length of the plasma target along the laser propagation direction is 100–1000 micrometers, and the lateral dimension is greater than 100 micrometers; however, the principle of the present invention is not limited by the aforementioned plasma target dimensions.

[0028] In another preferred embodiment, the lateral dimension refers to the width of the plasma target, which is perpendicular to the laser propagation direction and is generally required to be greater than the spot diameter.

[0029] In another preferred embodiment, the electron number density of the plasma target is 10. 18 ~10 21 Each cubic centimeter.

[0030] In another preferred embodiment, the pump light pulse and the seed light pulse are focused on the plasma target with a beam waist radius of 100 micrometers to 1 centimeter.

[0031] In another preferred embodiment, the plasma target generating device includes a gas generating device, an electrode device, and a capillary channel device. Gas is introduced into the capillary channel device through the gas generating device, and then the gas inside the tube is ionized by the high voltage provided by the electrode device, thereby generating a plasma target that is substantially uniform along the axial direction, where the axial direction also refers to the "propagation direction of the laser".

[0032] In another preferred embodiment, the gas composition used to form the plasma target is a mixture of hydrogen, helium, nitrogen, or combinations thereof.

[0033] In another preferred embodiment, the parameters of the generated infrared light pulse are controlled by adjusting the parameters of the plasma target, pump light pulse, or seed light pulse.

[0034] In another preferred embodiment, the plasma optical pulse amplification device further includes a control system for controlling the laser system and the plasma target generating device.

[0035] In another preferred embodiment, the obtained near-infrared and mid-infrared pulses have one or more characteristics selected from the group consisting of:

[0036] (a) The peak intensity of the amplified seed light pulse is 10 times the initial intensity of the seed light pulse. 3 ~10 5 times;

[0037] (b) The pulse width is as short as a single optical cycle at half maximum width at half maximum light intensity;

[0038] (c) The center wavelength is 1 to 2 times the center wavelength of the pump light pulse.

[0039] This application also provides a method for generating ultra-high power, near-single-cycle, high-contrast near-infrared and mid-infrared pulses, comprising the following steps:

[0040] (a) Provide a plasma gas target;

[0041] (b) A pump light pulse and a seed light pulse, the pump light pulse having a first pulse width and including a light pulse having a first center frequency, the seed light pulse having a second pulse width and including a light pulse having a second center frequency, the first center frequency being higher than the second center frequency, and the first pulse width being greater than the second pulse width;

[0042] (c) The pump light pulse and the seed light pulse are made to propagate in the same direction along the plasma target, and the pump light pulse and the seed light pulse are positioned in the plasma target with the seed light pulse at the leading edge of the pump light pulse. Using the Raman forward scattering mechanism of the pump light pulse in the plasma, the energy of the pump light pulse is transferred to the seed light pulse, thereby amplifying the seed light pulse to generate an amplified light pulse. The amplified light pulse propagates further in the plasma target, and the time-domain pulse width of the amplified pulse is further compressed, thereby generating a near-infrared and mid-infrared light pulse with ultra-high power, near-single cycle, and high time-domain contrast.

[0043] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. It should be understood that the accompanying drawings described below are merely some implementation examples of the present invention, and those skilled in the art can obtain other implementation examples based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the structure of the laser pulse amplification device of the present invention;

[0046] Figure 2(a) is a schematic diagram of the pump light pulse and seed light pulse in three stages during the optical amplification process according to the first embodiment of this application;

[0047] Figure 2(b) is an amplified electric field distribution diagram of the seed light pulse according to the first embodiment of this application;

[0048] Figure 2(c) is a spectrum distribution diagram of the initial seed light pulse and pump light pulse, and the enlarged seed light pulse, according to the first embodiment of this application.

[0049] Figure 3(a) shows the spatial distribution of the light field of the pump light pulse and the seed light pulse in the early stage, and the spatial distribution of the electrostatic field corresponding to the generated electron plasma wave in the second embodiment of this application.

[0050] Figure 3(b) shows the spatial distribution of the light field of the pump light pulse and the seed light pulse in the intermediate stage, and the lateral spot distribution of the consumed pump light pulse in the second embodiment of this application.

[0051] Figure 3(c) shows the spatial distribution of the light field of the seed light pulse after it has been amplified and compressed in the later output in the second embodiment of this application.

[0052] The labels in each of the attached figures are as follows:

[0053] 1-Vacuum target chamber

[0054] 2-Laser Device

[0055] 3-Input pump light pulse

[0056] 4-Input seed light pulse

[0057] 5-Capillary Channel Device

[0058] 6-Gas Generating Device

[0059] 7-High Voltage Power Supply

[0060] 8-Plasma Target

[0061] 9-Magnified seed light pulse

[0062] 10 - Consumed pump light pulses

[0063] 11- Amplified and compressed seed light pulse output Detailed Implementation

[0064] Through extensive and in-depth research, the inventors have developed for the first time a plasma optical pulse amplification device and method for generating short-cycle, high-power optical pulses. This method utilizes plasma as a medium to amplify the energy and intensity of an initial low-power laser pulse by 10%. 4This method, exceeding orders of magnitude in intensity, is suitable for generating high-power, near-single-cycle, high-temporal-contrast near-infrared and mid-infrared optical pulses. The device boasts advantages such as high efficiency, compact size, high repetition rate, and high signal-to-noise ratio, providing economical, practical, and reliable ultrashort and ultra-intense near-(mid-)infrared optical pulses. These ultrashort and ultra-intense near-(mid-)infrared optical pulses have potentially wide-ranging applications in basic scientific research, medicine, and industrial applications. Furthermore, the method requires relatively simple and easy-to-implement conditions, is economical and practical, and has the potential to achieve high repetition rate operation. Additionally, the parameters for generating mid-infrared pulses can be conveniently controlled by simply changing the plasma parameters or the incident laser pulse.

[0065] This invention utilizes terawatt-level (1 terawatt = 10 12 W), pulse width is 100 femtoseconds (1 femtosecond = 100 femtoseconds). 15 A high-power pump light pulse (100 femtoseconds) and a low-power seed light pulse with a center wavelength in the range of 1 to 2 times the center wavelength of the pump light, with a pulse width close to 100 femtoseconds, are transmitted in the same direction in the plasma to realize the amplification and compression of the seed light pulse.

[0066] Previously, it was proposed to amplify laser pulses using Raman backscattering or strongly coupled Brillouin backscattering mechanisms. These schemes have been experimentally validated to some extent. However, negative effects such as plasmonic instabilities (Landau damping, particle trapping, wave breaking), transverse instabilities in pulse transmission (filamentation, self-focusing), pulse spatiotemporal jitter, and forward scattering instabilities have begun to emerge, becoming major obstacles to these schemes and leading to low energy conversion efficiency in experiments. For example, to alleviate the filamentation instability that worsens the transverse structure of the laser, low plasma density and low intensity pump pulses with longer durations must be used. However, this results in low energy transfer efficiency; even with larger plasma sizes, only seed pulses with wavelengths close to the pump pulse wavelength can be amplified. Furthermore, in current experiments, backscattering schemes require a certain angle between the two pulses to avoid head-on collisions that could damage the laser system, which increases experimental complexity and reduces efficiency. These factors significantly limit the practical applications and value of the aforementioned two mechanisms (schemes).

[0067] In this invention, the two beams propagate in the same direction, which is easier to achieve in practical experiments and applications. This reduces the difficulty of experimental operation while ensuring high amplification efficiency. The optical amplification mechanism corresponding to the same-direction propagation is the forward scattering process in plasma. This process suppresses the kinetic instability in plasma and ensures the quality of the amplified beam. On the other hand, by combining the effect of the group velocity difference between two beams of different frequencies propagating in plasma, the laser pulse amplification achieved by this invention can complete the corresponding process more fully and efficiently within a smaller time and space scale. This makes the amplified infrared pulse faster, more stable, and more reliable.

[0068] Furthermore, the significant compression of the optical pulse in this invention is achieved by triggering self-phase modulation with an amplified laser pulse. On the one hand, this compression method can achieve a shorter pulse width compression effect compared with other plasma optical amplification schemes. On the other hand, the compression of the laser pulse is carried out after the laser pulse amplification, making the overall optical control process more coherent, thereby reducing the size of the device.

[0069] The pump pulse of this invention can be a commonly used commercial terawatt-level or higher laser, or a seed pulse amplified in the previous stage. The initial low-power seed pulse is a specific frequency pulse generated based on a nonlinear crystal, or a broadband laser containing frequency components that meet the phase-matching condition. Furthermore, this invention can modulate the output near (mid) infrared pulse parameters, including pulse energy, center frequency, and spectral width, by changing the parameters of the pump laser pulse, seed laser pulse, or plasma target. Therefore, it has adjustable wavelength and other pulse parameters, making it more practical and applicable to a wider range of applications.

[0070] In the following description, many technical details are provided to help the reader better understand this application. However, those skilled in the art will understand that the technical solutions claimed in this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0071] the term

[0072] As used herein, the "amplified seed light pulse" output by the apparatus and method of this application refers to the same thing as the "ultra-high power, near-single-cycle, high-contrast near-infrared and mid-infrared light pulse" obtained by the apparatus of this application.

[0073] As used in this article, “initial peak power” refers to the peak power of the laser pulse at the initial moment of incidence.

[0074] It should be noted that in this patent application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this patent application, if it refers to performing an action according to an element, it means performing the action at least according to that element, including two cases: performing the action only according to that element, and performing the action according to that element and other elements. Expressions such as "multiple," "repeatedly," and "various" include two, two times, two kinds, and more than two, more than two times, and more than two kinds.

[0075] In this invention, all directional indicators (such as up, down, left, right, front, back, etc.) are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0076] A plasma optical pulse amplification device

[0077] This application provides a plasma optical pulse amplification device, which is a laser-driven plasma optical pulse amplification and pulse compression device to realize laser pulse amplification and pulse width compression. The plasma optical pulse amplification device includes a laser system, a vacuum target chamber, a plasma target generation device, and a control system; the control system is used to control the laser system and the plasma target generation device.

[0078] The laser system is used to output a pump pulse with a long pulse width, a high frequency, and a high intensity (relative to the seed pulse), and a seed pulse with a short pulse width, a low frequency, and a low intensity (relative to the pump pulse). The frequency difference between the pump pulse and the seed pulse is equal to the plasma characteristic frequency corresponding to the plasma density, which corresponds to the Raman forward scattering phase matching condition.

[0079] The vacuum target chamber is used to provide a vacuum environment for the interaction between laser and matter, that is, the vacuum target chamber is used to provide the input and output vacuum environment for two laser pulses before and after laser pulse amplification;

[0080] A plasma target generating device is disposed in the vacuum target chamber, wherein the plasma target generating device is used to encapsulate a gas at a specific pressure and ionize it through a capillary high-voltage discharge to form the required plasma target.

[0081] The laser system is configured to propagate the pump pulse and the seed pulse in the same direction along the plasma target. The laser system is also configured such that the pump pulse and the seed pulse are spatially positioned within the plasma target, with the seed pulse located at the leading edge of the pump pulse. Utilizing the Raman forward scattering mechanism in the plasma, the energy of the pump pulse is transferred to the seed pulse, thereby amplifying the seed pulse. The amplified pulse further propagates within the plasma target, and the temporal pulse width of the amplified pulse is further compressed, thereby generating ultra-high power, near-single-cycle, high temporal contrast near-infrared and mid-infrared pulses.

[0082] Initially, the pump pulse and seed pulse are injected into the plasma target along the same propagation direction, with the seed pulse positioned at the leading edge of the pump pulse. The two pulses superimpose in the plasma via beat frequency, generating an electron plasma wave. The higher-frequency pump pulse has a higher group velocity than the seed pulse in the plasma. Therefore, during propagation, the higher-frequency pump pulse gradually surpasses the signal region of the seed pulse, and the shorter-pulse-width seed pulse is eventually completely overtaken by the pump pulse. During the overlapping propagation of the two, the pump pulse, seed pulse, and plasma wave undergo three-wave coupling resonance, resulting in Raman forward scattering. This causes the energy of the pump pulse to continuously transfer to the seed pulse, achieving dynamic intensity amplification of the latter. The amplified low-frequency seed pulse further propagates in the plasma and induces self-phase modulation. That is, the seed pulse then propagates independently in the plasma and triggers self-phase modulation, thereby further compressing the time-domain pulse width of the seed pulse. Using the above seed pulse amplification and compression mechanism, ultra-high power, near-single-cycle, and high-contrast near-infrared and mid-infrared pulses can be generated. This laser pulse is currently unattainable by traditional optical devices and has potential for wide-ranging applications in basic scientific research, medicine, and industrial applications.

[0083] Preferably, the pump light pulse and the seed light pulse are in the same direction.

[0084] Preferably, the plasma target has a substantially uniform axial density distribution along the axial direction (the direction of laser propagation).

[0085] In another preferred embodiment, the spectral components of the seed light pulse satisfy the difference between the center frequency of the pump light pulse and the plasma characteristic frequency corresponding to the plasma density of the plasma target, which corresponds to the Raman forward scattering phase-matching condition. That is, this application can use a seed light pulse with a very wide spectrum, whose spectrum covers the frequency values ​​required to satisfy the phase-matching condition; rather than a specific monochromatic light (single frequency component) that satisfies the phase-matching condition.

[0086] Preferably, the seed light pulse is positioned at the leading edge of the pump light pulse in the space at the initial moment.

[0087] Preferably, the pump light pulse and the seed light pulse are injected into the plasma target chamber simultaneously in time, or the pump light pulse signal is delayed by tens of femtoseconds compared to the seed light pulse.

[0088] Preferably, the peak power of the pump light pulse is 0.1 terawatt to 10 petawatts.

[0089] Preferably, the peak power of the seed light pulse is 10 megawatts to 1 terawatt.

[0090] Preferably, the pump light pulse focused on the plasma target has a beam waist radius of 100 micrometers to 1 centimeter.

[0091] Preferably, the lateral characteristic distribution of the pump light pulse spot is Gaussian or super-Gaussian.

[0092] Preferably, the lateral characteristic distribution of the seed pulse spot can be one of the following types: Gaussian, super-Gaussian, Laguerre-Gaussian, Bessel-Gaussian, Hermite-Gaussian, or Airy.

[0093] Preferably, the length of the plasma target along the laser propagation direction is 100–1000 micrometers, and the lateral dimension is greater than 100 micrometers. The lateral dimension refers to the width of the plasma target, which is perpendicular to the laser propagation direction and is generally required to be greater than the laser spot diameter. This application only requires a very short plasma target to achieve amplification of the seed light pulse.

[0094] Preferably, the electron number density of the plasma target is 10. 18 ~10 21 Each cubic centimeter, thereby enabling the amplified light pulse generated to propagate further in the plasma target, induces self-phase modulation, and the time-domain pulse width of the amplified light pulse is further compressed.

[0095] laser system

[0096] In this invention, the laser system includes a laser and related optical path devices. The laser can be a commercially available, stable, and cost-effective high-power laser device with a certain repetition frequency, used to generate pump pulses and seed pulses with appropriate parameters. Depending on the requirements for amplifying the output parameters of the seed pulse, the laser can also be a self-built high-power laser device.

[0097] In one embodiment, the pump pulse with terawatt / petawatt power is output from a terawatt / petawatt laser device, and then a small portion of the beam is intercepted to split a weak beam. Then, the frequency of the weak beam is changed (or broadband light is generated) through conventional nonlinear optical means to meet the amplification conditions. Finally, the weak beam is used as a seed light pulse.

[0098] In one embodiment, the pump light pulse is output by one laser device, and the seed light pulse is output by another laser device.

[0099] In one embodiment, the pump light pulse is the seed light pulse output after the previous stage amplification, and the newly amplified seed light pulse can be generated in the manner mentioned in the above embodiments.

[0100] In one embodiment, the laser system is used to generate pump pulses and seed pulses. It can employ a commercially available femtosecond short-pulse high-power laser device. The output mid-infrared pulse parameters, including pulse energy, center frequency, and spectral width, can be modulated by changing the parameters of the pump pulse, seed pulse, or plasma target.

[0101] In one embodiment, the pump pulse is a terawatt or petawatt-level laser system, and is a long pulse with high intensity and relatively high frequency (relative to the seed pulse); wherein the seed pulse is a gigawatt-level or higher laser system, and is a short pulse signal with low power and relatively low frequency (relative to the pump pulse), or a low-power broadband short pulse signal.

[0102] In one embodiment, when the initial pump light power is determined, the initial seed light power can be 4 to 5 orders of magnitude less than the pump light power.

[0103] Pump light pulse and seed light pulse

[0104] In this invention, the pump light pulse and seed light pulse can be commonly used Gaussian beams or have a special spatial structure. Changes in the seed light pulse, pump light pulse, or plasma density parameter can be used to control the parameters of the generated seed light pulse.

[0105] To meet the requirements of higher power and beam quality while satisfying general practical application conditions, in one embodiment, the beam waist radius of the pump light pulse and seed light pulse on the target is generally set to 100 micrometers to 1 centimeter. The pulse width of the pump light pulse is 20 to 200 seed light pulse oscillation cycles, preferably 20 to 60 seed light pulse oscillation cycles; the pulse width of the seed light pulse is 10 to 60 seed light pulse oscillation cycles, preferably 10 to 30 seed light pulse oscillation cycles. The pulse width of the seed light pulse is generally required to be less than or equal to half the pulse width of the pump light pulse to obtain higher amplification efficiency.

[0106] In one embodiment, the peak power of the pump light pulse can be 0.1 terawatt to 10 petawatts, and the peak power of the seed light pulse can be 10 times the peak power of the corresponding pump light pulse. -5 ~10 -3 The pump light peak power is preferably 1 terawatt to 1 petawatt, and the seed light pulse peak power is preferably 100 megawatts to 100 gigawatts. The amplification capability of this application refers to amplifying the seed light pulse power to the order of magnitude of the pump light pulse power, with the initial power difference between the two preferably controlled within 10... -4 .

[0107] The time interval between the pump light pulse and the seed light pulse entering the plasma has a certain tolerance, and the seed light pulse can enter the plasma tens of femtoseconds before the pump light pulse.

[0108] Plasma target

[0109] In this invention, a gas target is ionized under high voltage to form a plasma target along the propagation direction of the pump light pulse and the seed light pulse. The plasma target can be generated by methods such as gas capillary channel discharge, but is not limited to these methods. The formed plasma target has adjustable density and length, and is suitable for use at high repetition frequencies. The changes in the plasma target parameters can be used to control the parameters of the amplified seed light pulse.

[0110] In one embodiment, the plasma target generating device includes a gas generating device, an electrode device, and a capillary channel device. The capillary channel device includes a capillary tube. An appropriate gas is introduced into the capillary channel through the gas generating device, and then the gas inside the tube is ionized by a high-voltage current provided by the electrode device, thereby generating a plasma target that is substantially uniform along the axial direction of the capillary tube. Furthermore, the generated plasma parameters can be adjusted and controlled by changing the shape of the capillary tube, the amount of gas introduced, and the power supply voltage, thereby generating the desired target.

[0111] The gas may consist of a single gas or a mixture of gases with low atomic numbers, preferably hydrogen, helium, nitrogen, or a mixture thereof.

[0112] In one embodiment, the plasma formed after capillary ionization contains an electron number density of 10. 18 ~10 21 10 units per cubic centimeter, preferably 10 19 ~10 20 Each cubic centimeter.

[0113] In one embodiment, the length of the plasma target along the laser propagation direction is 100 to 1000 micrometers, and the lateral dimension is greater than 100 micrometers, preferably 200 to 600 micrometers.

[0114] In one embodiment, the plasma target has a substantially uniform density along the direction of laser propagation.

[0115] A method for generating ultra-high power, near-single-cycle, high-contrast near-infrared and mid-infrared pulses.

[0116] This invention provides a method for amplifying near-infrared and mid-infrared laser pulse power to terawatts and above, and compressing the pulse width to near a single cycle, comprising the following steps:

[0117] (a) Providing a plasma target, said plasma target being generated by high-voltage discharge of a gas (e.g., capillary gas);

[0118] (b) Pump light pulses and seed light pulses are provided, which are injected into the plasma in the same direction and superimposed by beat frequency to excite plasma waves; the high-frequency pump light with a higher group velocity will gradually exceed the signal region of the seed light pulse in space, during which the three-wave coupling resonance condition of pump light, seed light and electron plasma wave is satisfied, namely Raman forward scattering condition, so that the energy of pump light pulse is continuously transferred to seed light pulse, realizing the dynamic light intensity amplification of the latter;

[0119] (c) After being removed from the pump pulse, the amplified seed pulse continues to propagate independently in the plasma, further triggering self-phase modulation, achieving time-domain pulse width compression, and further enhancing the light intensity.

[0120] Characteristics of output seed light pulse

[0121] In this application, the amplified, tunable, ultrashort, ultra-intense near-mid-infrared seed light pulse has the following characteristics:

[0122] (a) Peak intensity is 10 times the initial intensity 3 ~10 5 Its power is on the same order of magnitude as the pump laser pulse;

[0123] (b) The pulse width is as short as a single optical cycle at half maximum width at half maximum light intensity;

[0124] (c) The center wavelength is 1 to 2 times the center wavelength of the pump light pulse.

[0125] To make the objectives, technical solutions, and advantages of the present invention clearer, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. It should be understood that these are merely examples provided to the reader of possible implementations of the present invention and are not intended to limit the scope of the invention.

[0126] Figure 1 This is a schematic diagram of the plasma optical pulse amplification device, i.e., the laser pulse amplification device of the present invention. Figure 1 As shown, the device includes a laser 2 and a vacuum target chamber 1.

[0127] The vacuum target chamber 1 is used to provide a vacuum environment for the interaction between laser and matter. In addition, the vacuum target chamber houses a plasma target generating device for generating an adjustable plasma target 8. The plasma target generating device includes a controllable capillary channel device 5, a gas generating device 6, and a high-voltage power supply 7. The capillary channel device 5 includes a capillary tube, and the generated plasma target has adjustable density, length, etc., and has a high reusability.

[0128] First, a suitable gas is introduced into the capillary tube through the gas generating device 6. Then, the gas inside the tube is ionized by a high-voltage discharge provided by the high-voltage power supply 7, thereby generating a plasma with a uniform density distribution along the axial direction of the capillary tube. In addition, the plasma parameters generated can be adjusted and controlled by changing the shape of the capillary tube, the amount of gas introduced, and the power supply voltage, thereby generating the desired plasma target 8.

[0129] The generated plasma target 8 preferably has a length of 200–600 micrometers along the laser propagation direction. The gas target can be composed of a single or mixture of gases with low atomic numbers, preferably hydrogen, helium, nitrogen, or mixtures thereof. The desired plasma target is generated by ionizing the gas target through capillary high-voltage discharge, and preferably contains an electron number density of 10-1. 19 ~10 20 Each cubic centimeter.

[0130] Laser 2 is used to input the initial pump pulse 3 and the seed pulse 4, both of which enter the plasma region in the same direction. The seed pulse 4 is spatially positioned at the leading edge of the pump pulse 3. After the two pulses enter the plasma, the pump pulse 3, having a higher group velocity, gradually surpasses the seed pulse 4 in space. At this point, the beat frequencies of the pump pulse 3 and the seed pulse 4 superimpose, exciting an electron plasma wave. Subsequently, the pump pulse 3, the seed pulse 4, and the electron plasma wave undergo three-wave coupling resonance and Raman forward scattering, during which the pump pulse is consumed. Figure 1 In 10), the seed light pulse is amplified ( Figure 1 (9 in the text). The amplified seed light pulse continues to propagate independently in the plasma, further inducing a self-phase modulation process. Its pulse is significantly compressed to a near-single cycle, ultimately outputting an amplified and pulse-width-compressed seed light pulse. Figure 1 11).

[0131] The difference between the center frequency of pump pulse 3 and the center frequency of seed pulse 4 is equal to the plasma characteristic frequency corresponding to the uniform density of the plasma target. The pump pulse and seed pulse can be common Gaussian beams, super-Gaussian beams, or beams with special spatial structures. The beam waist radius of the pump pulse and seed pulse on the target is generally set to 200 micrometers to 1 centimeter. The pulse width of the pump pulse is preferably 30 to 60 seed pulse oscillation cycles; the pulse width of the seed pulse is preferably 10 to 30 seed pulse oscillation cycles. The pulse width of the seed pulse is generally required to be less than or equal to half the pulse width of the pump pulse to obtain higher amplification efficiency. The peak power of the pump pulse is preferably 10 terawatts to 1 petawatt, and the peak power of the seed pulse is preferably 100 megawatts to 100 gigawatts. For a more significant amplification effect, the initial peak power difference between seed pulse 4 and pump pulse 3 is preferably controlled to 10... -4 There is a certain tolerance for the time interval between the pump light pulse 3 and the seed light pulse 4 entering the plasma; the seed light pulse can enter the plasma tens of femtoseconds before the pump light pulse.

[0132] Furthermore, the present invention can adjust the parameters of the amplified seed light pulse, such as pulse energy, peak intensity, wavelength, and number of oscillation periods, by changing the parameters of the plasma target 8, the seed light pulse 4, or the pump light pulse 3, thereby realizing an adjustable high-power, near-single-cycle near-infrared or mid-infrared light pulse.

[0133] The present invention will be further described below with reference to specific embodiments 1 and 2. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer.

[0134] Example 1

[0135] This embodiment adopts Figure 1 The aforementioned implementation scheme includes a laser, a vacuum target chamber, and a plasma target.

[0136] The laser provides an initial pump pulse and a seed pulse, wherein the pump pulse has a wavelength of 1.0 micrometers and the seed pulse has a wavelength of 1.8 micrometers; both are Gaussian beams with the same spot radius of 200 micrometers; the peak intensity of the pump pulse is 3.0 × 10⁻⁶. 16The peak intensity of the seed light pulse is 1.0 × 10⁻⁶ watts per square centimeter. 12 Watts per square centimeter; pump light pulse width is 240 femtoseconds, seed light pulse width is 120 femtoseconds.

[0137] Vacuum target chambers are used to provide a vacuum environment for the interaction of lasers and matter.

[0138] The plasma region generated by ionizing the gas target via capillary high-voltage discharge has a length of 130 micrometers along the laser propagation direction, and its spatial extent is calibrated as shown by the gray dashed line in Figure 2(a). Hydrogen gas was used, and the electron number density of the ionized plasma along the axis (laser propagation direction) was set to be approximately 2.2 × 10⁻⁶. 20 Each cubic centimeter is used to match the center frequencies of the pump light pulse and the seed light pulse used in this embodiment, thus satisfying the phase matching requirement.

[0139] In this embodiment, the pump light pulse and the seed light pulse are simultaneously injected into the plasma along the same direction. The initial spatial positions and intensity distributions of the two laser pulses are shown in Figure 2(a) at 0.48 ps on the left. The seed light pulse value is multiplied by 10 from the original data. 4 To make this clearer in the figure, when the pump pulse and the seed pulse enter the plasma, they beat at the same frequency, exciting an electron plasma wave. Correspondingly, the pump pulse, due to its greater group velocity in the plasma, continuously surpasses the seed pulse in space. During this process, the energy of the pump pulse is continuously transferred to the seed pulse through the three-wave coupling mechanism of Raman forward scattering, thus amplifying the intensity of the seed pulse, as shown in the middle of Figure 2(a) at 0.84 ps. After the seed pulse leaves the pump pulse region, it continues to propagate independently in the plasma, inducing a self-phase modulation process, achieving a further significant compression of the pulse width and a further increase in intensity, as shown on the right side of Figure 2(a) at 1.65 ps.

[0140] Figure 2(b) shows the distribution of the electric field over time after amplification and compression of the seed light pulse. Figure 2(c) shows the initial spectrum of pump light pulse 3 and the spectral distribution of seed light pulse 4 before and after energy amplification and pulse width compression. Numerical simulation results show that the peak light intensity of the 1.8 μm near-infrared seed light pulse increases from the initial 1.0 × 10⁻⁶. 12 The watts per square centimeter were magnified to 8.9 × 10⁻⁶. 16 The time-domain pulse width is compressed from an initial 120 femtoseconds to 9.19 femtoseconds per square centimeter, while the center frequency of the output seed light pulse remains unchanged. This demonstrates that the present invention can significantly and effectively amplify and compress infrared laser pulses. Furthermore, the amplification effect can be further adjusted by changing the initial plasma target or laser pulse parameters.

[0141] Example 2

[0142] This embodiment adopts Figure 1 The aforementioned implementation scheme includes a laser, a vacuum target chamber, and a plasma target.

[0143] The laser will provide an initial pump pulse and a seed pulse, wherein the pump pulse wavelength is 1.0 micrometer and the seed pulse wavelength is 1.8 micrometers; the pump pulse is a conventional super-Gaussian beam with a spot radius of 40 micrometers; the seed pulse is a Laguerre-Gaussian laser with a special spatial structure, a spot radius of 40 micrometers, and a topological kernel number of 1; the peak intensity of the pump pulse is 2.0 × 10⁻⁶. 16 The peak intensity of the seed light pulse is 1.0 × 10⁻⁶ watts per square centimeter. 12 Watts per square centimeter; pump light pulse width is 180 femtoseconds, seed light pulse width is 90 femtoseconds.

[0144] Vacuum target chambers are used to provide a vacuum environment for the interaction of lasers and matter.

[0145] The plasma region generated by ionizing the gas target via capillary high-voltage discharge has a length of 200 micrometers along the laser propagation direction. Hydrogen gas is used, and the electron number density of the ionized plasma along the axis (laser propagation direction) is set to be approximately 2.2 × 10⁻⁶. 20 Each cubic centimeter is used to match the pump light pulse and seed light pulse frequencies used in this embodiment, thus satisfying the phase matching requirement.

[0146] In this embodiment, the pump light pulse and the seed light pulse simultaneously enter the plasma in the same direction, generating a plasma wave and causing three-wave coupling resonance to amplify the light pulse. In the early stage, as shown in the upper part of Figure 3(a), the intensity of the seed light pulse begins to increase, but the pump light pulse does not significantly diminish at this time. The seed light pulse value is multiplied by 10 from the original data to make it more obvious in the figure. In the overlapping region of the pump light pulse and the seed light pulse, the electrostatic field corresponding to the generated electron plasma wave has a helical three-dimensional spatial distribution, as shown in the lower part of Figure 3(a). As time progresses further, in the middle stage, as shown in the upper part of Figure 3(b), as the seed light pulse gradually leaves the pump light pulse region due to its smaller group velocity, its intensity rapidly increases to 1.5 × 10⁻⁶. 16Watts per square centimeter. At this point, the pump light is significantly consumed, exhibiting pulse train characteristics in the longitudinal distribution. Simultaneously, the outer edges of the transverse spot are also significantly consumed, corresponding to a Laguerre-Gaussian type seed light pulse, i.e., low intensity in the middle and high intensity on the outer edges. Therefore, the seed light pulse mainly consumes the outer region of the pump light. Later, as shown in Figure 3(c), the magnified seed light pulse propagates independently in the plasma, inducing self-phase modulation, achieving pulse compression to a quasi-single cycle, while the light intensity further increases to 1.0 × 10⁻⁶. 17 Watts per square centimeter. Furthermore, as shown in Figure 3(c), the amplified output seed light pulse still maintains a spirally wound three-dimensional spatial structure, and the corresponding topological kernel number is 1, consistent with the initial input Laguerre-Gaussian seed light pulse. It should be noted that due to the computational limitations of the three-dimensional particle simulation program, the two light pulse spots used in Example 2 are relatively small; in practice, larger spots can be used to achieve amplification.

[0147] This invention has at least one of the following advantages

[0148] (a) The plasma optical pulse amplification device of the present invention is an efficient, compact optical device that can operate at a high repetition rate. Specifically, the device of the present invention is simple, compact and low cost. The required laser device can be a commercially available terawatt-level small laser. The compact size and low purchase and operating costs, the vacuum target chamber can be ordered directly from the manufacturer. The technology of this device is already very mature. The capillary device technology for generating gas targets is also very mature and has been widely used in experiments such as laser plasma acceleration.

[0149] (b) The plasma optical pulse amplification device and method of the present invention can generate highly efficient, ultra-intense, ultra-short, and high-contrast near-(mid-)infrared pulses. However, optical technologies based on traditional nonlinear crystal materials are limited by factors such as the material's frequency bandwidth, damage threshold, and energy gain, making it difficult to generate high-power, short-cycle infrared optical pulses. Furthermore, they lack effective and universal modulation methods; that is, for optical amplification of a single wavelength band, independent design or reliance on specially customized amplification gain crystals is required. Currently, short-cycle mid-infrared pulses generated based on nonlinear crystal material technology are generally limited to low intensity (megawatts to gigawatts). Using the plasma optical pulse amplification method of the present invention, since plasma has no material loss threshold limitations, it can withstand extremely high power, intensity, and energy laser pulses. It can efficiently amplify and output terawatt-level or higher high-power, high-energy, and high-intensity near-single-cycle near-(mid-)infrared pulses within a spatiotemporal scale of hundreds of micrometers or hundreds of femtoseconds, achieving an initial light intensity increase of approximately 4 to 5 orders of magnitude. For example, it can amplify the intensity of an initial low-power near-(mid-)infrared laser pulse by 10... 4With power ranging from terawatts and above, and compressible to near single-cycle pulse width, and with adjustable frequency and other pulse parameters, it breaks through the limitations of traditional optical techniques.

[0150] (c) The method of the present invention is simple to operate. It only requires pump light pulse and signal light pulse to be injected into a set plasma target in the same direction. Through the interaction between laser and plasma and the generated electron plasma wave, the three-wave coupling process is triggered to realize the energy transfer and amplification of laser. Combined with self-phase modulation, pulse width compression is realized. No other optical modulation equipment is required. Therefore, the method of the present invention is a simple all-optical generation method. The laser used has a kilohertz-level operating repetition frequency. The plasma target is obtained by continuously replenishing gas, which has a very high reusability.

[0151] (d) The apparatus and method of the present invention have strong versatility and scalability, and possess advantages and characteristics such as high efficiency, low cost, small size and compactness, and strong practicality. Specifically, the pump light pulse in the present invention can be a commercially available terawatt-level small laser (wavelength in the 1-micron band), or a laser pulse in any high-power band, or even a seed light pulse amplified by the present method, to serve as the pump light pulse for the next stage of amplification. Since the initial power of the seed light pulse is very low, it can be completely prepared based on the current traditional nonlinear crystal method, and the wavelength can be selected; at the same time, the seed light pulse can also be a broadband laser, as long as it contains frequency components that meet the phase matching conditions, the corresponding amplification can be achieved;

[0152] (e) Furthermore, the method of the present invention can amplify seed light pulses of different wavelengths by simply changing the plasma density, while the pump light pulse does not need to be changed. In addition, the beam participating in the amplification can be a common Gaussian beam or a spatial structure beam with a specific spatial distribution. Since it propagates in the same direction, the output pump light pulse and the amplified seed light pulse can be further focused into a small spot with an intensity of ultra-high relativistic intensity. The corresponding laser pulse can then be used in research such as wake field acceleration and high harmonic generation.

[0153] The specification of this invention describes numerous technical features distributed across various technical solutions. Listing all possible combinations of these technical features (i.e., technical solutions) would make the specification excessively lengthy. To avoid this problem, the various technical features disclosed above, in the following embodiments and examples, and in the accompanying drawings can be freely combined to form various new technical solutions (all of which are considered to have been described in this specification), unless such a combination of technical features is technically infeasible. For example, one example discloses feature A+B+C, and another example discloses feature A+B+D+E. Features C and D are equivalent technical means that serve the same function, and technically only one needs to be used; they cannot be used simultaneously. Feature E can technically be combined with feature C. Therefore, the solution A+B+C+D should not be considered as described because it is technically infeasible, while the solution A+B+C+E should be considered as described.

[0154] All references to this invention are considered to be incorporated integrally into the disclosure of this invention so as to serve as a basis for modifications if necessary. Furthermore, it should be understood that after reading the foregoing disclosure of this invention, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope of protection claimed by this invention.

Claims

1. A plasma optical pulse amplification device, characterized in that, include: A laser system for generating pump pulses and seed pulses, wherein the pump pulses are light pulses having a first pulse width and including a first center frequency, and the seed pulses are light pulses having a second pulse width and including a second center frequency, wherein the first center frequency is higher than the second center frequency, and the first pulse width is greater than the second pulse width. A vacuum target chamber, which provides a vacuum environment for the interaction of laser and matter; A plasma target generating device is disposed in the vacuum target chamber, wherein the plasma target generating device is used to provide a plasma target; The laser system is configured to cause the pump pulse and the seed pulse to propagate in the same or substantially in the same direction along the plasma target. The laser system is also configured such that the pump pulse and the seed pulse are spatially positioned within the plasma target, with the seed pulse located at the leading edge of the pump pulse. Utilizing the Raman forward scattering mechanism of the pump pulse in the plasma, the energy of the pump pulse is transferred to the seed pulse, thereby amplifying the seed pulse. The further propagation of the amplified seed pulse within the plasma target further compresses the temporal pulse width, thereby generating ultra-high power, near-single-cycle, high-contrast near-infrared and mid-infrared light pulses.

2. The apparatus as claimed in claim 1, characterized in that, The statement that the pump light pulse and the seed light pulse propagate in the same direction along the plasma target means that the pump light pulse and the seed light pulse propagate in the same direction.

3. The apparatus as described in claim 1, characterized in that, The difference between the first center frequency of the pump light pulse and the second center frequency of the seed light pulse is equal to the plasma characteristic frequency corresponding to the plasma density of the plasma target.

4. The apparatus as claimed in claim 1, characterized in that, The first pulse width is the oscillation period corresponding to 20 to 200 seed light pulse wavelengths, and / or the second pulse width is the oscillation period corresponding to 10 to 60 seed light pulse wavelengths.

5. The apparatus as claimed in claim 1, characterized in that, The second pulse width of the seed light pulse is less than or equal to half the first pulse width of the pump light pulse.

6. The apparatus as claimed in claim 1, characterized in that, The initial peak power of the seed light pulse is 10 times the initial peak power of the corresponding pump light pulse. -5 ~10 -3 Magnitude.

7. The apparatus as claimed in claim 1, characterized in that, The plasma target typically has a length of 100–1000 micrometers along the laser propagation direction and a lateral dimension greater than 100 micrometers.

8. The apparatus as claimed in claim 1, characterized in that, The electron number density of the plasma target is 10. 18 ~10 21 Each cubic centimeter.

9. The apparatus as claimed in claim 1, characterized in that, The obtained near-infrared and mid-infrared pulses have one or more characteristics selected from the group consisting of: (a) The peak intensity of the amplified seed light pulse is 10 times the initial peak intensity of the seed light pulse. 3 ~10 5 times; (b) The pulse width is as short as a single optical cycle at half maximum width at half maximum light intensity; (c) The center wavelength is 1 to 2 times the center wavelength of the pump light pulse.

10. A method for generating ultra-high power, near-single-cycle, high-contrast near-infrared and mid-infrared pulses, characterized in that, Includes the following steps: (a) Provide a plasma target; (b) A pump light pulse and a seed light pulse, the pump light pulse having a first pulse width and including a light pulse having a first center frequency, the seed light pulse having a second pulse width and including a light pulse having a second center frequency, the first center frequency being higher than the second center frequency, and the first pulse width being greater than the second pulse width; (c) The pump light pulse and the seed light pulse are made to propagate in the same direction along the plasma target, and the pump light pulse and the seed light pulse are positioned in the plasma target with the seed light pulse at the leading edge of the pump light pulse. Using the Raman forward scattering mechanism of the pump light pulse in the plasma, the energy of the pump light pulse is transferred to the seed light pulse, thereby amplifying the seed light pulse. The amplified light pulse further propagates in the plasma target, and the time-domain pulse width of the amplified pulse is further compressed, thereby generating ultra-high power, near-single-cycle, high-contrast near-infrared and mid-infrared light pulses.

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