Phase delay self-compensating vector polarized light parametric chirped pulse amplifier
By using a nonlinear crystal orthogonally placed at 90° and orthogonally polarized pump light in a vector polarized light parametric chirped pulse amplifier, the phase delay problem of vector polarized light during amplification was solved, achieving vector polarized light amplification with high polarization purity and high peak power.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-04-03
AI Technical Summary
In the existing technology, vector polarized light undergoes polarization distortion due to dynamic phase delay during the parametric chirped pulse amplification process, making it difficult to achieve high polarization purity and high peak power in vector polarized light parametric chirped pulse amplification.
Two identical nonlinear crystals, placed orthogonally at 90°, are used to perform two-stage optical parametric chirped pulse amplification. Two orthogonally polarized pump beams are used to amplify the vector polarized signal light. Self-compensation of phase delay is achieved through polarization identity swapping and phase delay design.
The problem of nonlinear phase delay compensation was effectively solved, and vector polarized light parametric chirped pulse amplification with high polarization purity and high peak power was achieved, while maintaining the polarization purity and temporal pulse quality of vector polarized light.
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Figure CN121790902A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of laser technology, and more particularly to a vector polarization parametric chirped pulse amplifier with phase delay self-compensation. Background Technology
[0002] Vector light fields, especially radially polarized light with a cylindrically symmetric spatial polarization structure, have significant application value in particle acceleration, high-order harmonic generation, and other strong-field physics research because they can break the diffraction limit under tight focusing conditions and generate a strong longitudinal electric field component at the focal point. Therefore, they have attracted widespread attention.
[0003] Converting linearly polarized light into vector-polarized light with a specific spatial polarization structure using polarization optical elements such as spatial light modulators or vortex half-wave plates outside the laser cavity is currently the main technical solution for generating vector-polarized femtosecond pulsed lasers. However, this method is limited by the damage threshold, operating bandwidth, and spectral characteristics of existing polarization optical elements, and it is still difficult to directly obtain vector-polarized femtosecond pulsed lasers with high peak power.
[0004] Optical parametric chirped pulse amplification (OPA) technology has become an important means of generating high peak power femtosecond pulsed lasers due to its advantages such as high gain and wide wavelength tunability. In particular, under wavelength degenerate type II phase-matching conditions, optical parametric amplification that is insensitive to the polarization of the incident signal light can be achieved. This insensitivity to the polarization of the incident signal light provides a potential technical approach for improving the peak power of vector-polarized light.
[0005] An ideal laser amplifier for vector-polarized light should not only provide the same broadband gain for two orthogonal polarization components of the vector-polarized signal light, but also maintain the relative phase between the two polarization components within its gain bandwidth.
[0006] However, in the process of optical parametric chirped pulse amplification, the nonlinear crystal, acting as a waveplate, will affect the vector polarization of the signal light. e polarization and o The polarization component introduces a linear phase delay that varies with frequency; more importantly, in broadband optical parametric chirped pulse amplification, due to imperfect phase matching (Δ... k The presence of factors such as (≠0) inevitably introduces an additional nonlinear phase delay. This nonlinear phase delay is strongly correlated with the gain of the parametric amplification, exhibiting a "dynamic" waveplate effect. The superposition of linear and nonlinear phase delays results in different polarization states for different frequency components of the amplified vector-polarized signal light, thus compromising its overall polarization purity and temporal pulse quality. How to accurately compensate for or eliminate this phase delay in the vector-polarized signal light is a key challenge. e polarization and oPhase delay between polarization components, especially nonlinear phase delay that changes "dynamically" with the parametric amplification state, is a key technical challenge for achieving high polarization purity and high peak power vector polarized parametric chirped pulse amplification. Summary of the Invention
[0007] This invention provides a vector polarized light parametric chirped pulse amplifier with phase delay self-compensation, aiming to solve the polarization distortion problem caused by "dynamic" phase delay during vector polarized light parametric chirped pulse amplification in the prior art, so as to achieve vector polarized light parametric chirped pulse amplification with high polarization purity and high peak power.
[0008] The technical solution provided by this invention is as follows: A phase-delay self-compensated vector polarization parametric chirped pulse amplifier includes: a narrowband pulsed laser, a broadband pulsed laser generating device, a half-wave plate, a polarization beam splitter, a pulse stretcher, a laser mode converter, a first nonlinear crystal, a second nonlinear crystal, and a pulse compressor. The narrowband pulsed laser is used to generate pump light, and the broadband pulsed laser generating device is used to generate signal light. The pump light and the signal light are wavelength degenerate or nearly degenerate, that is, the wavelength of the signal light is twice or nearly twice the wavelength of the pump light. The signal light is time-domain broadened by the pulse stretcher, and then passes through the laser mode converter, which changes the polarization of the signal light to obtain the desired vector-polarized signal light with a specific spatial polarization distribution. The pump light passes sequentially through the half-wave plate and the polarization beam splitter, decomposing into a first pump light and a second pump light. The first nonlinear crystal and the second nonlinear crystal are two identical nonlinear crystals, placed at a 90° angle to each other, with the optical axis of the second nonlinear crystal perpendicular to the optical axis of the first nonlinear crystal; the first pump light and the second pump light are polarized orthogonally. The vector-polarized signal light and the first pump light enter the first nonlinear crystal together, and the first pump light performs a first-stage optical parametric chirped pulse amplification on the vector-polarized signal light. The vector-polarized signal light after the first-stage optical parametric chirped pulse amplification enters the second nonlinear crystal together with the second pump light, and the second pump light performs a second-stage optical parametric chirped pulse amplification on the vector-polarized signal light. The first-stage optical parametric chirped pulse amplification and the second-stage optical parametric chirped pulse amplification satisfy type II phase matching or type II quasi-phase matching in the first nonlinear crystal and the second nonlinear crystal. In the first nonlinear crystal and the second nonlinear crystal, the two orthogonally polarized linear polarization components of the vector polarized signal light are respectively used as the first nonlinear crystal. o polarization and e Polarized light, and the second nonlinear crystal e polarization and o Polarized light; the phase delay accumulated in the second-stage optical parametric chirped pulse amplification of the vector polarized signal light by the two orthogonally polarized linearly polarized components has the opposite sign to the phase delay accumulated in the first-stage optical parametric chirped pulse amplification, and can cancel each other out; The vector-polarized signal light, amplified by the first and second stages of optical parametric chirped pulses, passes through the pulse compressor to obtain a high-peak-power vector-polarized femtosecond pulse laser.
[0009] In an optional embodiment, the broadband pulsed laser generating device can be a broadband pulsed laser that is time-synchronized with the narrowband pulsed laser, or it can be a nonlinear broadband pulsed laser generating device that uses the narrowband pulsed laser output by the narrowband pulsed laser as the driving light source of the nonlinear broadband pulsed laser generating device to generate the signal light through nonlinear frequency conversion.
[0010] In an optional embodiment, the phase delay accumulated by the two orthogonally polarized linear polarization components of the vector polarized signal light in the first-stage optical parametric chirped pulse amplification and the second-stage optical parametric chirped pulse amplification will change with the different gains of the first-stage optical parametric chirped pulse amplification and the second-stage optical parametric chirped pulse amplification, respectively.
[0011] In an optional embodiment, the phase delay self-compensating vector polarized parametric chirped pulse amplifier further includes: a first beam expander and a second beam expander. Before entering the second nonlinear crystal, the second pump light and the vector polarized signal light amplified by the first-stage parametric chirped pulse amplifier are expanded by the first beam expander and the second beam expander, respectively, so as to adjust the gain of the second-stage parametric chirped pulse amplifier to be comparable to the gain of the first-stage parametric chirped pulse amplifier, thereby obtaining a better phase delay self-compensation effect.
[0012] In an optional embodiment, the phase delay self-compensated vector polarized light parametric chirped pulse amplifier further includes: a first delayed optical path and a second delayed optical path, the first delayed optical path and the second delayed optical path being respectively disposed on the optical paths of the first pump light and the second pump light. By introducing a preset time delay, the vector polarized signal light and the first pump light are time-synchronized when entering the first nonlinear crystal, and the vector polarized signal light and the second pump light are time-synchronized when entering the second nonlinear crystal.
[0013] In an optional embodiment, the pulse stretcher is a grating pair or a prism pair, used to stretch the pulse width of the signal light to the pulse width of the pump light.
[0014] In an optional embodiment, the pulse compressor is composed of polarization-insensitive optical elements, including isotropic dielectric materials or chirped volume Bragg gratings, for compressing the pulse width of the amplified vector-polarized signal light to the femtosecond level.
[0015] In an optional embodiment, the laser mode converter is a vortex half-wave plate used to convert the signal light into the vector-polarized signal light.
[0016] Compared with the prior art, the basic principles and beneficial effects of the present invention are as follows: This invention uses two identical nonlinear crystals, placed at 90° orthogonal, as the first and second stages of optical parametric chirped pulse amplification, respectively. Correspondingly, two pump beams with orthogonal polarization are used to amplify the vector polarized signal light in two stages of optical parametric chirped pulse amplification.
[0017] Because the first and second nonlinear crystals are placed orthogonally at 90°, the horizontal and vertical polarization components of the vector polarized signal light are interchanged in the two-stage optical parametric chirped pulse amplification, resulting in the first nonlinear crystal being... o polarization( e The linear polarization component (polarization) will be transformed accordingly in the second nonlinear crystal. e polarization( o (Polarization) state. This design allows the phase delay introduced during the second-stage optical parametric chirped pulse amplification process between the horizontal and vertical polarization components of the vector polarized signal light to cancel each other out, thus achieving self-compensation for phase delay.
[0018] This design cleverly utilizes the symmetry of the parametric process itself. The phase delay introduced by the second-stage optical parametric chirped pulse amplification on the two orthogonal polarization components of the vector polarized signal light is used to offset the "dynamic" phase delay accumulated in the first-stage optical parametric chirped pulse amplification process. This effectively solves the nonlinear phase delay compensation problem in the vector polarized optical parametric chirped pulse amplification process, thereby achieving high polarization purity and high peak power vector polarized optical parametric chirped pulse amplification. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and not all embodiments. For those skilled in the art, other drawings can be obtained based on the provided drawings without any creative effort.
[0020] Figure 1 A schematic diagram of a phase delay self-compensating vector polarization parametric chirped pulse amplifier provided for an embodiment of the present invention; Figure 2 is a schematic diagram of the spectral and phase delay evolution of radially polarized signal light in a two-stage amplification process of a vector polarized parametric chirped pulse amplifier with phase delay self-compensation provided in an embodiment of the present invention. Figure 3 A schematic diagram illustrating the phase delay residual under different second-stage pump light intensities of a vector polarized parametric chirped pulse amplifier with phase delay self-compensation, provided for an embodiment of the present invention. Figure 4 is a schematic diagram of the pulse time-domain envelope of two orthogonal polarization components of a radially polarized signal light after amplification by a phase-delay self-compensating vector polarized parametric chirped pulse amplifier provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the spot outline and polarization projection of the radially polarized signal light after amplification by a vector polarized parametric chirped pulse amplifier with phase delay self-compensation, provided as an embodiment of the present invention. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0022] In vector-polarized optical parametric chirped pulse amplification (OPP), the orthogonal e-polarized and o-polarized components of the vector-polarized signal light are synchronously amplified by the same pump light. In a polarization-insensitive POP configuration with simple wavelength and type II phase matching, both components can always achieve the same broadband gain. However, a key technical challenge in this type of broadband POP is that the birefringence effect of the nonlinear crystal and the imperfect phase matching together introduce linear and nonlinear phase delays that vary with frequency. This phase delay has dynamic characteristics and is closely related to operating parameters such as parametric gain. It causes relative walk-off and pulse profile distortion in the time domain of the two orthogonal polarization components of the vector-polarized light, thus compromising the polarization purity and temporal pulse quality of the vector-polarized light.
[0023] To address the aforementioned technical problems, this invention provides a vector polarization parametric chirped pulse amplifier with phase delay self-compensation. The theoretical basis for the technical solution provided by this invention is described below: The phase delay self-compensated vector polarized parametric chirped pulse amplifier includes two sequentially arranged parametric chirped pulse amplification units for amplifying vector polarized chirped pulse laser light—that is, vector polarized signal light.
[0024] Both stages of the optical parametric amplification unit satisfy type II phase matching or type II quasi-phase matching, and the signal light wavelength is set to twice or nearly twice the pump light wavelength, satisfying the wavelength degeneracy or near-degeneracy condition. The two amplification units use a first nonlinear crystal and a second nonlinear crystal as optical parametric amplification crystals, respectively. The two are identical, but are placed at 90° orthogonal to each other—their optical axes are 90° orthogonal.
[0025] During the first-stage optical parametric chirped pulse amplification process, the vector-polarized signal light is incident on the first nonlinear crystal. Depending on its relationship with the crystal's optical axis, its two mutually orthogonal linearly polarized components serve as the crystal's polarization parameters. o Light and e The light is synchronously parametrically amplified by the first pump light on two mutually orthogonal linearly polarized components.
[0026] Subsequently, the amplified vector-polarized signal light enters the second nonlinear crystal. Since the optical axis of the second nonlinear crystal is orthogonal to that of the first nonlinear crystal, the polarization "identities" of the two orthogonal linear polarization components in the vector-polarized signal light are reversed compared to the first nonlinear crystal: the polarization "identities" of the two components that were originally orthogonal in the first nonlinear crystal are now reversed. o The polarization component of light is transformed into e Light, and the origin e The light component then transforms into o Light. In the second nonlinear crystal, the second pump light continues to synchronously parametrically amplify the two orthogonally polarized linearly polarized components of the vector-polarized signal light. To cooperate with the above polarization interchange mechanism, the polarization directions of the two pump light beams incident on the two-stage nonlinear crystal are also orthogonal to each other.
[0027] Through the above design, the two orthogonal polarization components of the vector polarized signal light undergo polarization identity swapping during the two-stage amplification process, causing the nonlinear phase delays introduced by the two stages of optical parametric amplification to have opposite signs, thus canceling each other out. At the same time, the two stages of nonlinear crystals with orthogonal optical axes and equal lengths act as "non-zero order waveplates," introducing linear phase delays of equal magnitude but opposite signs, thereby achieving synchronous compensation for linear and nonlinear phase delays.
[0028] Since the nonlinear phase delay varies with the gain of the pump light on the vector polarized signal light, in practical applications, the operating parameters of the two-stage amplification units—including the pump light intensity and the initial signal light intensity—can be actively controlled to make the gains of the two-stage amplification units comparable. Consequently, the phase delay introduced by the second-stage amplification is numerically equal to that of the first-stage amplification, but with the opposite sign, thus achieving the optimal phase delay compensation effect.
[0029] The following describes in detail a phase-delay self-compensating vector polarization parametric chirped pulse amplifier provided by an embodiment of the present invention. Please refer to [link to relevant documentation]. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 , Figure 1 A schematic diagram of a vector polarized light parametric chirped pulse amplifier with phase delay self-compensation provided by the present invention; Figure 2 shows the spectral and phase delay evolution of radially polarized signal light during the two-stage amplification process; Figure 3 The phase delay residue under different second-stage pump light intensities is shown; Figure 4 shows the pulse time-domain envelope of the two orthogonal polarization components of the radially polarized signal light after magnification; Figure 5 The magnified outline of the radially polarized signal light spot and its polarization projection are shown.
[0030] like Figure 1 As shown in the figure, an embodiment of the present invention provides a vector polarization parametric chirped pulse amplifier with phase delay self-compensation, comprising: a narrowband pulsed laser 1; a broadband laser pulse generating device 2; a half-wave plate 3; a polarization beam splitter 4; a pulse stretcher 5; a laser mode converter 6; a first nonlinear crystal 7; a second nonlinear crystal 8; a pulse compressor 9; a first beam expander 10; and a second beam expander 11.
[0031] In this embodiment, the devices are configured as follows: the narrowband pulsed laser 1 is a picosecond laser that outputs a Gaussian beam with a pulse width of 3 ps and a wavelength of 1030 nm as pump light; the broadband laser pulse generating device 2 is a supercontinuum laser generating device that uses the 1030 nm pulsed laser output from the narrowband pulsed laser 1 as pump light and outputs a broadband Gaussian beam with a spectral half-width of 100 nm and a center wavelength of 2060 nm as signal light. Pulse stretcher 5 is a ZnSe crystal with positive dispersion characteristics in the 2 μm band, which stretches the pulse width of the signal light to approximately 2 ps, comparable to the pulse width of the pump light; the first nonlinear crystal 7 and the second nonlinear crystal 8 are two identical 1.5 mm thick KTA crystals, cut at an angle of... θ =48.8°, φ=0°, satisfying Type II phase matching; for the center wavelength of the signal light at 2060 nm, its function as a waveplate is approximately the same as that of a full-wave plate; the optical axis of the second nonlinear crystal 8 is 90° orthogonal to the optical axis of the first nonlinear crystal 7; the laser mode converter 6 is a vortex half-wave plate, which can convert linearly polarized signal light into radially polarized signal light; the pulse compressor 9 is an isotropic fused silica with negative dispersion characteristics in the 2 μm band, to ensure that the polarization characteristics of the compressed radially polarized signal light are not affected.
[0032] The optical path and workflow of this embodiment are as follows: First, the pump light is split into a first pump light and a second pump light with mutually orthogonal polarization directions by a half-wave plate 3 and a polarization beam splitter 4. At the same time, the signal light passes sequentially through a pulse stretcher 5 (broadening its pulse width to be comparable to that of the pump light), and then is converted into radially polarized signal light by a laser mode converter 6.
[0033] Next, the first stage of optical parametric chirped pulse amplification is performed: the first pump light and the radially polarized signal light are jointly incident on the first nonlinear crystal 7. Under the condition of satisfying type II phase matching, the radially polarized signal light is amplified by the first pump light. In this process, the two mutually orthogonal linearly polarized components of the radially polarized signal light serve as the first nonlinear crystal 7. o Light and e The light is synchronously amplified by the first pump light, and corresponding idler light is obtained accordingly. During this process, the pump light affects the radially polarized signal light... o polarization and e The broadband gains of the polarization components are basically the same.
[0034] Then, a second-stage optical parametric chirped pulse amplification is performed: the second pump light and the radially polarized signal light, which has been amplified in the first stage, are both incident on the second nonlinear crystal 8. The radially polarized signal light is amplified in the second stage by the second pump light. This crystal is exactly the same as the first nonlinear crystal 7, but is placed at a 90° orthogonal angle in space—their optical axes are at a 90° orthogonal angle.
[0035] To facilitate the separation of the amplified signal light from the pump light and idler light, a non-collinear phase matching method can generally be used.
[0036] To optimize the phase delay compensation effect, the second pump light and the radially polarized signal light amplified by the first stage can be beam expanded by the first beam expander 10 and the second beam expander 11, respectively, to adjust the operating parameters of the second stage amplification (such as pump light intensity, initial signal light intensity, etc.) so that the gains of the two amplification units are comparable. As a result, the phase delay introduced by the second stage amplification is equal in value to that of the first stage amplification, but with opposite signs, thereby achieving the optimal phase delay compensation effect.
[0037] Finally, the radially polarized signal light, amplified by two stages, enters the pulse compressor 9, which compresses its pulse width to the femtosecond level, resulting in a radially polarized femtosecond pulsed laser with high peak power.
[0038] Based on the nonlinear coupled-wave equation and taking radially polarized signal light as an example, we present a full-spacetime numerical simulation of the operation of a vector-polarized parametric chirped pulse amplifier with phase delay self-compensation provided by this invention. The pump light is a linearly polarized Gaussian beam with a center wavelength of 1030 nm, and the signal light is radially polarized light with a center wavelength of 2060 nm. Spatially, the 1030 nm Gaussian pump light coincides with the center of the annular 2060 nm radially polarized signal light. The peak intensity of the pump light... I p ~60 GW / cm 2 Peak intensity of incident signal light I s ~0.6 GW / cm 2 Between the two amplification units, the peak intensity of the second-stage pump light is increased by expanding the second pump light and the radially polarized signal light amplified by the first stage. I p and the peak intensity of the incident signal light. I s Same as the first-stage amplification, ~60 GW / cm 2 and ~0.6 GW / cm 2 .
[0039] Taking the 45° linearly polarized component in radially polarized signal light as an example, Figure 2 shows the spectral and phase delay evolution of radially polarized signal light during the two-stage amplification process: Figure 2a The spectrum and phase delay after the first stage of amplification are shown in the figure. e polarization and o There is a phase delay that varies non-linearly with frequency between the polarization components; Figure 2b In the case of two nonlinear crystals placed in parallel (optical axes parallel), the spectrum and phase delay after two-stage amplification can be seen that the phase delay introduced by the two-stage optical parametric amplification is superimposed, which further accumulates and enhances the phase delay. Figure 2c In the case of two nonlinear crystals placed orthogonally (optical axes at 90°), the spectrum and phase delay after two-stage amplification show that the phase delay introduced by the first-stage amplification is effectively compensated in the second-stage amplification, and the phase delay between the two orthogonal polarization components of the radially polarized signal light approaches 0.
[0040] Furthermore, the intensity of the pump light used in two-stage optical parametric chirped pulse amplification has a significant impact on the phase delay compensation effect. For example... Figure 3 As shown, the peak intensity of the pump light, amplified by the first stage, is maintained at 60 GW / cm². 2 The pump intensity of the second stage amplification is kept constant, but the intensity of the second stage amplification is changed. When the pump intensity of the second stage amplification is 60 GW / cm², 40 GW / cm², and 20 GW / cm², the residual phase delay will increase as the deviation between the pump intensities of the two stages of amplification increases. When the pump intensities of the two stages of amplification are consistent, the optimal phase delay compensation effect can be obtained.
[0041] The residual phase delay will ultimately manifest as an inconsistency in the time-domain pulses of the two orthogonally polarized components of the radially polarized signal light. As shown in Figure 4, Figure 4a The pulse time-domain envelope of radially polarized signal light after compression by pulse compressor 9 is shown in the state of parallel placement of two nonlinear crystals (optical axes parallel). It can be seen that the two orthogonal polarization components of the radially polarized signal light exhibit obvious pulse walk-off in the time domain. Figure 4b The results are shown in the case of two nonlinear crystals placed orthogonally (optical axes are 90° orthogonal). In this case, the two orthogonal polarization components of the radially polarized signal light do not show any difference in pulse envelope and completely coincide in the time domain.
[0042] Finally, the effect of phase delay compensation needs to be considered in the entire spatial domain. For example... Figure 5 As shown, Figure 5 The magnified radially polarized signal light spot outline and polarization projection are shown. The magnified radially polarized light still maintains a complete annular spot, and after passing through the linear polarizer, it presents a "double-lobed" structure. Furthermore, the spot rotates synchronously with the rotation of the polarizer axis, indicating that its radial polarization characteristics are well preserved throughout the entire spatial domain.
[0043] In summary, this embodiment provides a vector polarized light parametric chirped pulse amplifier with phase delay self-compensation, which can effectively compensate for the phase delay between orthogonal polarization components introduced during the amplification process while broadband amplifying the vector polarized signal light. This allows the amplified vector polarized signal light to maintain good vector polarization characteristics in the frequency, time, and spatial domains, making it suitable for generating vector polarized femtosecond pulse lasers with ultra-high peak power.
[0044] It should be understood that the above embodiments are merely one specific implementation of the present invention, and while the description is relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A vector polarization parametric chirped pulse amplifier with phase delay self-compensation, characterized in that, include: Narrowband pulsed laser, broadband pulsed laser generating device, half-wave plate, polarization beam splitter, pulse stretcher, laser mode converter, first nonlinear crystal, second nonlinear crystal, and pulse compressor; The narrowband pulsed laser is used to generate pump light, and the broadband pulsed laser generating device is used to generate signal light. The pump light and the signal light are wavelength degenerate or nearly degenerate. The signal light is time-domain broadened by the pulse stretcher, and then passes through the laser mode converter, which changes the polarization of the signal light to obtain the desired vector-polarized signal light with a specific spatial polarization distribution. The pump light passes sequentially through the half-wave plate and the polarization beam splitter, decomposing into a first pump light and a second pump light. The first nonlinear crystal and the second nonlinear crystal are two identical nonlinear crystals, placed at a 90° angle to each other, with the optical axis of the second nonlinear crystal perpendicular to the optical axis of the first nonlinear crystal; the first pump light and the second pump light are polarized orthogonally. The vector-polarized signal light and the first pump light enter the first nonlinear crystal together, and the first pump light is used to perform first-stage optical parametric chirped pulse amplification on the vector-polarized signal light. The vector polarized signal light, after being amplified by the first-stage optical parametric chirped pulse, enters the second nonlinear crystal together with the second pump light, and the vector polarized signal light is amplified by the second pump light in the second stage of optical parametric chirped pulse amplification. The first-stage optical parametric chirped pulse amplification and the second-stage optical parametric chirped pulse amplification satisfy type II phase matching or type II quasi-phase matching in the first nonlinear crystal and the second nonlinear crystal; In the first nonlinear crystal and the second nonlinear crystal, the two orthogonally polarized linearly polarized components of the vector polarized signal light are respectively the o-polarized and e-polarized light of the first nonlinear crystal and the e-polarized and o-polarized light of the second nonlinear crystal; the phase delay accumulated by the two orthogonally polarized linearly polarized components of the vector polarized signal light in the second-stage optical parametric chirped pulse amplification has the opposite sign to the phase delay accumulated in the first-stage optical parametric chirped pulse amplification, and can cancel each other out; The vector-polarized signal light, amplified by the first and second stages of optical parametric chirped pulses, passes through the pulse compressor to obtain a high-peak-power vector-polarized femtosecond pulse laser.
2. The vector polarization parametric chirped pulse amplifier with phase delay self-compensation according to claim 1, characterized in that, The broadband pulsed laser generating device is either a broadband pulsed laser that is time-synchronized with the narrowband pulsed laser, or a nonlinear broadband pulsed laser generating device; the narrowband pulsed laser output from the narrowband pulsed laser is used as the driving light source of the nonlinear broadband pulsed laser generating device, and the signal light is generated through nonlinear frequency conversion.
3. The vector polarization parametric chirped pulse amplifier with phase delay self-compensation according to claim 1, characterized in that, The phase delay accumulated by the two orthogonally polarized linearly polarized components of the vector polarized signal light in the first-stage and second-stage optical parametric chirped pulse amplification will change with the different gains of the first-stage and second-stage optical parametric chirped pulse amplification, respectively.
4. The vector polarization parametric chirped pulse amplifier with phase delay self-compensation according to claim 1, characterized in that, The phase delay self-compensated vector polarization parametric chirped pulse amplifier further includes: a first beam expander and a second beam expander. Before entering the second nonlinear crystal, the second pump light and the vector polarization signal light amplified by the first stage of parametric chirped pulse amplification are expanded by the first beam expander and the second beam expander, respectively, so as to control the gain of the second stage of parametric chirped pulse amplification.
5. The vector polarization parametric chirped pulse amplifier with phase delay self-compensation according to claim 1, characterized in that, The phase-delay self-compensated vector polarized parametric chirped pulse amplifier further includes: a first delayed optical path and a second delayed optical path, which are respectively disposed on the optical paths of the first pump light and the second pump light. By introducing a preset time delay, the vector polarized signal light and the first pump light are time-synchronized when entering the first nonlinear crystal, and the vector polarized signal light and the second pump light are time-synchronized when entering the second nonlinear crystal.
6. The vector polarization parametric chirped pulse amplifier with phase delay self-compensation according to claim 1, characterized in that, The pulse stretcher is a grating pair or a prism pair, used to stretch the pulse width of the signal light to the pulse width of the pump light.
7. The vector polarization parametric chirped pulse amplifier with phase delay self-compensation according to claim 1, characterized in that, The pulse compressor is composed of polarization-insensitive optical elements, including isotropic dielectric materials or chirped volume Bragg gratings, used to compress the pulse width of the amplified vector polarized signal light to the femtosecond level.
8. The vector polarization parametric chirped pulse amplifier with phase delay self-compensation according to claim 1, characterized in that, The laser mode converter is a vortex half-wave plate used to convert the signal light into the vector polarized signal light.