Tunable mid-infrared and far-infrared laser output was demonstrated based on BaGa_(4)Se_(7)crystals and an optical parametric oscillator(OPO).With a 1.06μm Nd:YAG laser and a double-pass singly resonant OPO cavity,a ...Tunable mid-infrared and far-infrared laser output was demonstrated based on BaGa_(4)Se_(7)crystals and an optical parametric oscillator(OPO).With a 1.06μm Nd:YAG laser and a double-pass singly resonant OPO cavity,a laser energy output of 2.2 mJ at 10μm was obtained.By tuning the angle and temperature,a tunable laser output covering the wavelength range from 6μm to 17μm was obtained with a tuning precision better than 3 nm.The corresponding optical-to-optical conversion efficiency was 2.8%,and the slope efficiency was 4.4%.The damage effect of the output laser on detectors was also investigated,and point damage to the detector occurred at an output energy of 16.4μJ.The laser system has the advantages of miniaturization,a wide tuning range,high energy and high tuning resolution.Its broadband laser characteristics make it highly valuable for applications in atmospheric detection,infrared spectroscopy and electro-optical countermeasures.展开更多
The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase ...The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase of ICF implosion,the growth of ARTI can be suppressed by using a short-wavelength spatially modulated laser.The ARTI growth rate decreases as the wavelength of the spatially modulated laser decreases,and ARTI is completely suppressed after a certain wavelength has been reached.A spatially uniform laser is introduced to keep the state of motion of the implosion fluid consistent,and it is found that the proportion of the spatially modulated laser required for complete suppression of ARTI decreases as the wavelength continues to decrease.We also optimize the spatial intensity distribution of the spatially modulated laser.In addition,as the duration of the spatially modulated laser decreases,the proportion required for completely suppressing ARTI increases,but the required energy decreases.When the perturbation wavenumber decreases,the wavelength of the spatially modulated laser required for complete suppression of ARTI becomes longer.In the case of multimode perturbation,ARTI can also be significantly suppressed by a spatially modulated laser,and the perturbation amplitude can be reduced to less than 10% of that without a spatially modulated laser.We believe that the conclusions drawn from our simulations can provide the basis for new approaches to control ARTI in ICF.展开更多
The effects of initial spin orientation on the final electron beam polarization in laser wakefield acceleration in a pre-polarized plasma are investigated theoretically and numerically.From the results of variation of...The effects of initial spin orientation on the final electron beam polarization in laser wakefield acceleration in a pre-polarized plasma are investigated theoretically and numerically.From the results of variation of the initial spin direction,the spin dynamics of the electron beam are found to depend on the self-injection mechanism.The effects of wakefields and laser fields are studied using test particle dynamics and particle-in-cell simulations based on the Thomas-Bargmann-Michel-Telegdi equation.Compared with transverse injection,longitudinal injection is found to be preferable for obtaining a highly polarized electron beam.展开更多
Quasi-two-dimensional(quasi-2d)perovskites are promising gain media for micro-nano lasers,yet their uncontrolled crystallization and abundant low-n phases often hinder optical gain and device performance.In this work,...Quasi-two-dimensional(quasi-2d)perovskites are promising gain media for micro-nano lasers,yet their uncontrolled crystallization and abundant low-n phases often hinder optical gain and device performance.In this work,we introduce ethyl acetate(EA)as a green antisolvent to fabricate high-quality quasi-2D PEA_(0.4)MAPbBr_(3)films.The EA-treated films exhibit superior morphology,enhanced crystallinity,and notably inhibited low n-phases.These improvements yield a prolonged photoluminescence lifetime of 26.3 ns and a substantially extended gain lifetime of 129 ps.Consequently,the optimized film exhibits a markedly reduced amplified spontaneous emission(ASE)threshold of 5.6μJ·cm^(-2)and a high net modal gain of 935 cm^(-1).Leveraging these enhanced gain properties,we successfully demonstrate a vertical-cavity surface-emitting laser(VCSEL)based on a dielectric Bragg reflector microcavity,which delivers single-mode lasing at 528.3 nm and a high quality factor of~5886.This work presents a green-solvent-engineering strategy for high-performance perovskite lasers,advancing their prospects for scalable photonic integration.展开更多
Inertial confinement fusion(ICF)requires a constant search for the most effective materials to improve the efficiency of compression of the capsule and of laser-to-target energy transfer.Foams could provide a solution...Inertial confinement fusion(ICF)requires a constant search for the most effective materials to improve the efficiency of compression of the capsule and of laser-to-target energy transfer.Foams could provide a solution,but they require further experimental and theoretical investigation.The new 3D-printing technologies,such as two-photon polymerization,are opening a new era in the production of foams,allowing fine control of material morphology.Very few detailed studies of the interaction of foams with high-power lasers in regimes relevant for ICF have been described in the literature to date,and more investigation is needed.In this work,we present the results of an experimental campaign performed at the ABC laser facility at ENEA Centro Ricerche Frascati in which 3D-printed microstructured materials were irradiated at high power.3D simulations of the laser-target interaction performed with the FLASH code reveal that the laser is scattered by plasma density gradients and channeled into the structure when the center of the focal spot is on the through hole.The time required for the laser to completely ablate the structure given by the simulations is in good agreement with the experimental measurement.Measurements of the reflected and transmitted laser light indicate that scattering occurred during the irradiation,in accordance with the simulations.Two-plasmon decay has also been found to be active during irradiation.展开更多
Laser-driven inertial confinement fusion(ICF)is an important experimental platform for high-energy-density physics research under extreme conditions.In ICF research,high-quality shock waves are key to fusion energy re...Laser-driven inertial confinement fusion(ICF)is an important experimental platform for high-energy-density physics research under extreme conditions.In ICF research,high-quality shock waves are key to fusion energy release.The velocity interferometer system for any reflector(VISAR)is the most important diagnostic technique for measuring quantities such as shock wave and particle velocities with high precision and high spatiotemporal resolution.This paper provides a detailed introduction to the various configurations of VISAR on 10 and 100 kJ-level laser facilities in China,including Line VISAR,Dual-Axis VISAR,Wide-Angle VISAR,and Compressed Ultrafast Photography-VISAR.Recent advances and applications of VISAR diagnostics at these laser facilities are presented,and the future trend of development of high-spatiotemporal-resolution velocity diagnostic technology is described.展开更多
In this study,controllable fabrication of nickel-doped diamond-like carbon(Ni-DLC)films through laser-assisted electrochemical deposition under low-voltage conditions(5 V)is achieved.After substrate polishing,picoseco...In this study,controllable fabrication of nickel-doped diamond-like carbon(Ni-DLC)films through laser-assisted electrochemical deposition under low-voltage conditions(5 V)is achieved.After substrate polishing,picosecond laser irradiation is applied during electrodeposition to precisely control the laser energy and defocus distance during film preparation,with subsequent analysis of surface morphology,composition,and properties in correlation with growth mechanisms.Compared with conventional DLC electrodeposition,the laser-assisted technique significantly improves film quality by maintaining the deposition zone temperature at~52℃,with laser-induced micro-stirring effectively reducing cathode bubble adhesion and suppressing hydrogen evolution.Without laser assistance,the films exhibit poor adhesion,porous structure,and thickness nonuniformity,while increasing the laser energy progressively enhances densification,achieving 3.5μm thickness uniformity.Optimal performance at 8.5μJ laser energy demonstrates an improved deposition rate compared with conventional methods,a minimum corrosion current density(1.116×10^(−6)Amm^(−2)),and a stable friction coefficient(0.143),establishing a novel laser-assisted approach for controllable DLC electrodeposition.展开更多
Combined pulsed laser(CPL),introduced in 1975 for target damage,integrates different lasers to achieve high peak power and pulse energy.However,despite decades of research,CPL remains unused for long-range target dama...Combined pulsed laser(CPL),introduced in 1975 for target damage,integrates different lasers to achieve high peak power and pulse energy.However,despite decades of research,CPL remains unused for long-range target damage due to the challenge of maintaining high peak power density over long distances.We note that a potential solution lies in leveraging the air filament generated by femtosecond laser,which can transmit peak power densities higher than 1014 W/cm^(2)under the power clamping effect.To address this,a concept of a femtosecond laser induced air filament-CW CPL for surface damage of ceramics was introduced.We found no surface changes in ceramic targets when irradiated with a CW laser alone.By way of contrast,the target can be penetrated in a very short time(20 ms)with the assistance of the femtosecond laser induced air filament.In this context,we employ high-speed shadow imaging,cross-timescale simulation models and macro-microscopic characterization,to elucidate the CPL damage mechanism.The optimal CPL,combining a 1 mJ femtosecond laser and a 500 W CW laser,yields a damage rate of 1.51×10^(7)μm^(3)/J,representing an improvement of approximately 175%compared to single femtosecond laser ablation and around 59%enhancement compared to coating-assisted CW laser ablation.Furthermore,the efficacy of the proposed femtosecond-CW CPL method is demonstrated in causing penetration damage of ceramic/metal composite material or direct damage of sapphire,showcasing its versatility in damaging applications.Consequently,the femtosecond-CW CPL ablation method presented in this paper holds great promise as a new type of damage method for transparent hard and brittle materials.展开更多
The process of nuclear fusion in the presence of a laser field was theoretically analyzed.The analysis is applicable to most fusion reactions and different types of currently available intense lasers,from X-ray free-e...The process of nuclear fusion in the presence of a laser field was theoretically analyzed.The analysis is applicable to most fusion reactions and different types of currently available intense lasers,from X-ray free-electron lasers to solid-state near-infrared lasers.Laser fields were shown to enhance the fusion yields,and the mechanism of this enhancement was explained.Low-frequency lasers are more efficient in enhancing fusion than high-frequency lasers.The calculation results show enhancements of fusion yields by orders of magnitude with currently available intense low-frequency laser fields.The temperature requirement for controlled nuclear fusion may be reduced with the aid of intense laser fields.展开更多
White Cyphochilus insulanus beetles,exhibiting both environmental camouflage display and radiative cooling functions,serve as a good prototype for biomimetic fabrication.As inspired,this work presents a femtosecond(fs...White Cyphochilus insulanus beetles,exhibiting both environmental camouflage display and radiative cooling functions,serve as a good prototype for biomimetic fabrication.As inspired,this work presents a femtosecond(fs)laser-based biomimetic fabrication strategy that takes full use of the synthesized radiative cooling nanomaterials for a groundbreaking stimuli-responsive infrared(IR)impressionistic camouflage display.The proposed technique is capable of readily transforming various substrates(quartz glass and metals including Ti,Al,Zr,and W)into self-assembled porous networks(aerogels)consisting of oxygen-vacancy-rich oxide nanoparticles.Surprisingly,the emissions of all as-prepared porous particle-networks in the radiative-cooling long-wavelength infrared(LWIR)band are above 95%,with the SiO_(2) aerogels reaching a maximum of 99.6%.Benefiting from the far-from-equilibrium thermodynamic kinetics,metastable phases of anatase TiO_(2),tetragonal zirconia(t-ZrO_(2)),and monoclinic WO_(3)(Pc)are synthesizable,opening up opportunities for exploring their optical applications.Taking the low-temperature metastable phase WO_(3)(Pc)as representative for systematic studies,it is found that(1)the ratio WO_(3)(Pc)phase to that of room-temperature phase of WO_(3)(P2_(1)/n)can be tailored by modulation of processing parameters;(2)laser synthesized aerogels with hybrid phases of WO_(3)(Pc)and WO_(3)(P2_(1)/n)have a brighter visible whiteness,higher visible/nearinfrared(NIR)spectral selectivity than the natural prototype of white Cyphochilus insulanus beetles but with comparable LWIR emittance.White WO_(3) aerogel in situ deposited during flexibly fs laser artistic patterning can blur the painting features due to its radiative cooling effect,allowing a colorful impressionistic IR display in the heating mode.What's more,invisible painting features concealed by the white deposited WO_(3) aerogel are clearly/faintly distinguishable by introducing external stimuli of a human hand and sample heating,respectively,catalyzing progress in optical encryption and selectively stimuli-responsive decryption display in the infrared band.展开更多
Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challe...Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challenges.In this work,we demonstrate for the firs time that the coherent radiation farfiel patterns from laser–foil interactions can serve as an in situ,real-time,and easy-to-implement diagnostic for an ultraintense laser focus.The laser-driven electron sheets,curved by the spatially varying laser fiel and leaving the targets at nearly the speed of light,produce doughnut-shaped patterns depending on the shapes of the focal spot and the absolute laser intensities.Assisted by particle-in-cell simulations,we can achieve measurements of the intensity and the focal spot,and provide immediate feedback to optimize the focal spots for extremely high intensity.展开更多
We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses.Employing XFEL-based im...We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses.Employing XFEL-based imaging with sub-micrometer spatial and femtosecond temporal resolution,supported by hydrodynamic and particle-in-cell simulations,we reveal how return current density depends precisely on wire diameter,material properties,and incident laser energy.We identify deviations from simple theoretical predictions due to geometrically influenced electron escape dynamics.These results refine and confirm the scaling laws essential for predictive modeling in high-energy-density physics and inertial fusion research.展开更多
To improve the penetration of thick plates,a laser-enhanced plasma arc welding process was developed.However,the current understanding of laser absorption and energy transfer mechanisms is still unclear,limiting its o...To improve the penetration of thick plates,a laser-enhanced plasma arc welding process was developed.However,the current understanding of laser absorption and energy transfer mechanisms is still unclear,limiting its optimization and application.This work establishes mathematical model of this novel heat source including electron density based on the gas state equation,Saha equation,and charge conservation equation.This model reveals the laser transmission characteristics in the plasma controlled by temperature and electron density,as well as the electrical and thermal transfer from the composite arc to the base material.The simulated temperature fields,arc pressure distributions,and arc voltages showed good agreement with experimental measurements,with peak pressure errors within 50 Pa and voltage differences within 0.3 V,validating the accuracy of the model.The results showed that the laser increased the arc temperature inside the keyhole,extending the high-temperature zone downwards.The laser has altered the current density distribution at the keyhole edge,decreasing the upper part but increasing the lower part.The trend of heat flux density change is consistent with the current density.There is a high laser absorption zone in the arc between the tungsten electrode and base metal,whose position changes with laser power,thereby improving the position and axial energy distribution of the plasma arc.展开更多
We put forward a new design of a compact beam transport system for intense laser-driven proton therapy,where instead of using conventional pulsed solenoids,our design relies on a helical coil irradiated by a nanosecon...We put forward a new design of a compact beam transport system for intense laser-driven proton therapy,where instead of using conventional pulsed solenoids,our design relies on a helical coil irradiated by a nanosecond laser pulse to generate strong magnetic fields for focusing protons.A pair of dipole magnets and apertures are employed to further filter protons with large divergences and low energies.Our numerical studies combine particle-in-cell simulations for laser-plasma interaction to generate high-energy monoenergetic proton beams,finite element analysis for evaluating the magnetic field distribution inside the coil,and MonteCarlo simulations for beam transport and energy deposition.Our results show that with this design,a spread-out Bragg peak in a range of several centimeters to a deep-seated tumor with a dose of approximately 16.5 cGy and fluctuation around 2% can be achieved.The instantaneous dose rate reaches up to 10^(9)Gy/s,holding the potential for future FLASH radiotherapy research.展开更多
A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation...A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation source requires relatively ultrashort electron bunches to produce intense coherent THz pulses.Three electron bunch compression processes are utilized in the PCELL accelerator system comprising pre-bunch compression in an alpha magnet,velocity bunching in a radio-frequency(RF)linear accelerator(linac),and magnetic bunch compression in a 180°acromat system.Electron bunch compression in the magnetic compressor system poses considerable challenges,which are addressed through the use of three quadrupole doublets.The strengths of the quadrupole fields significantly influence the rotation of the beam line longitudinal phase space distribution along the bunch compressor.Start-to-end beam dynamics simulations using the ASTRA code were performed to optimize the electron beam properties for generating super-radiant THz-FEL radiation.The operational parameters considered in the simulations comprise the alpha magnet gradient,linac RF phase,and quadrupole field strengths.The optimization results show that 10-16MeV femtosecond electron bunches with a low energy spread(~0.2%),small normalized emittance(~15πmm·mrad),and high peak current(165-247A)can be produced by the PCELL accelerator system at the optimal parameters.A THz-FEL with sub-microjoule pulse energies can thus be obtained at the optimized electron beam parameters.The physical and conceptual design of the THz-FEL beamline were completed based on the beam dynamics simulation results.The construction and installation of this beamline are currently underway and expected to be completed by mid-2024.The commissioning of the beamline will then commence.展开更多
High-energy continuous wave(CW)lasers are mostly used in laser damage applications,but efficient laser ablation of transparent materials is challenging due to low optical absorption.Considering the potential of femtos...High-energy continuous wave(CW)lasers are mostly used in laser damage applications,but efficient laser ablation of transparent materials is challenging due to low optical absorption.Considering the potential of femtosecond(fs)laser-induced air filament for high-peak laser transmission over long distances,femtosecond(fs)laser-induced air filaments are combined with a millisecond(ms)laser to form an fs-ms CPL,enhancing the efficiency of sapphire ablation through synchronized spatial-temporal focusing.Experimental results show that ablation efficiency increases with the ms peak power and duty ratio.Excessive thermal stress leads to fragmentation of the sapphire when the ms duty ratio is over 30%at the peak power of 800 W,or when the peak power is over 500 W at a duty ratio of 100%.Also,the mechanism of high-efficiency damage is revealed through in-situ high-speed imaging.According to it,the ablation process went through 4 stages within 1.5 ms:defect-creating,melting and ablation,spattering,and fragmentation.Finally,the equivalent ablation efficiency of the fs-ms CPL is as high as 1.73×10^(7)μm^(3)/J,about 28 times higher compared to the fs laser only.The CPL damage method explored in this paper can provide theoretical guidance for efficient laser damage of transparent materials.展开更多
The significance of laser-driven polarized beam acceleration has been increasingly recognized in recent years.We propose an efficient method for generating polarized proton beams from a pre-polarized hydrogen halide g...The significance of laser-driven polarized beam acceleration has been increasingly recognized in recent years.We propose an efficient method for generating polarized proton beams from a pre-polarized hydrogen halide gas jet,utilizing magnetic vortex acceleration enhanced by a laser-driven plasma bubble.When a petawatt laser pulse passes through a pre-polarized gas jet,a bubble-like ultra-nonlinear plasma wave is formed.As a portion of the particles constituting this wave,background protons are swept by the acceleration field of the bubble and oscillate significantly along the laser propagation axis.Some of the pre-accelerated protons in the plasma wave are trapped by the acceleration field at the rear side of the target.This acceleration field is intensified by the transverse expansion of the laser-driven magnetic vortex,resulting in energetic polarized proton beams.The spin of energetic protons is determined by their precession within the electromagnetic field,which is described using the Thomas-Bargmann-Michel-Telegdi equation in analytical models and particle-in-cell simulations.Multidimensional simulations reveal that monoenergetic proton beams with an energy of hundreds of MeV,a beam charge of hundreds of pC,and a beam polarization of tens of percent can be produced at laser powers of several petawatts.Such laser-driven polarized proton beams have promise for application in polarized beam colliders,where they can be utilized to investigate particle interactions and to explore the properties of matter under extreme conditions.展开更多
The generation and reconnection of magneticflux ropes in a plasma irradiated by two Laguerre–Gaussian laser pulses with different frequen-cies and opposite topological charges are investigated numerically by particle-...The generation and reconnection of magneticflux ropes in a plasma irradiated by two Laguerre–Gaussian laser pulses with different frequen-cies and opposite topological charges are investigated numerically by particle-in-cell simulations.It is shown that twisted plasma currents and hence magneticflux ropes can be effectively generated as long as the laser frequency difference matches the electron plasma frequency.More importantly,subsequent reconnection of magneticflux ropes can occur.Typical signatures of magnetic reconnection,such as magnetic island formation and plasma heating,are identified in the reconnection of magneticflux ropes.Notably,it is found that a strong axial magneticfield can be generated on the axis,owing to the azimuthal current induced during the reconnection of the ropes.This indicates that in the reconnection of magneticflux ropes,the energy can be transferred not only from the magneticfield to the plasma but also from the plasma current back to the magneticfield.This work opens a new avenue to the study of magneticflux ropes,which helps in understanding magnetic topology changes,and resultant magnetic energy dissipation,plasma heating,and particle acceleration found in solarflares,and magnetic confinement fusion devices.展开更多
Ytterbium(Yb)-based mode-locked fiber lasers have undergone significant development and found widespread applications owing to their high efficiency,compact size,and low cost.However,these lasers typically operate wit...Ytterbium(Yb)-based mode-locked fiber lasers have undergone significant development and found widespread applications owing to their high efficiency,compact size,and low cost.However,these lasers typically operate within the 1030 to 1080 nm range,and expanding their operational wavelength is crucial for applications across various fields.We present the direct generation of a mode-locked laser at 1120.06 nm using an all-polarization-maintaining structure,establishing the longest wavelength reported to date for Yb-doped fiber-based mode-locked lasers.A stable picosecond pulse laser at 1120 nm was realized by combining high-concentration Yb-doping and phase-biasing technology within a figure-9 cavity configuration.The laser delivers a pulse duration of 6.20 ps,a spectral width of 0.19 nm centered at 1120.06 nm,and a repetition rate of 21.52 MHz and reaches a maximum output power of 1.39 W via a double-cladding Yb fiber power amplifier in a master oscillator power amplifier configuration.Furthermore,we present a theoretical investigation of the laser performance,with simulation results aligning well with experimental findings.In addition,a 560.06-nm ultrafast yellow-green laser was generated through frequency doubling in a lithium triborate crystal.We present an approach for long-wavelength Yb-doped mode-locked lasers,with the potential to advance the development and application of Yb-based fiber lasers.展开更多
The rapid advancements of ultrafast intense laser technology have opened new avenues for investigating entanglement in laser-induced systems. However, the application of these advances in quantum technology requires a...The rapid advancements of ultrafast intense laser technology have opened new avenues for investigating entanglement in laser-induced systems. However, the application of these advances in quantum technology requires a reliable and universally applicable method for enhancing and regulating entanglement. Here we demonstrate how a few-cycle intense laser field can significantly enhance the degree of entanglement compared to its multi-cycle counterpart, using the example of electron–electron entanglement of orbital angular momentum(OAM) states in recollision-excitation non-sequential double ionization of Ar atoms. By confining the ionization dynamics to a specific narrow time window, the few-cycle pulse purifies the electron trajectories, thereby ensuring high coherence between entangled OAM channels and enhancing entanglement. Furthermore, the degree of entanglement can be efficiently modulated by varying the carrier envelope phase of the few-cycle laser pulse, which is achieved by altering the population across OAM channels. Optimizing coherence through electron trajectory purification with a designed specific temporal waveform of laser field provides a general pathway for enhancing entanglement in laser-induced systems.展开更多
基金supported by Independent Innovation Science Foundation of National University of Defense Technology(Grant No.23-ZZCX-JDZ-44)。
文摘Tunable mid-infrared and far-infrared laser output was demonstrated based on BaGa_(4)Se_(7)crystals and an optical parametric oscillator(OPO).With a 1.06μm Nd:YAG laser and a double-pass singly resonant OPO cavity,a laser energy output of 2.2 mJ at 10μm was obtained.By tuning the angle and temperature,a tunable laser output covering the wavelength range from 6μm to 17μm was obtained with a tuning precision better than 3 nm.The corresponding optical-to-optical conversion efficiency was 2.8%,and the slope efficiency was 4.4%.The damage effect of the output laser on detectors was also investigated,and point damage to the detector occurred at an output energy of 16.4μJ.The laser system has the advantages of miniaturization,a wide tuning range,high energy and high tuning resolution.Its broadband laser characteristics make it highly valuable for applications in atmospheric detection,infrared spectroscopy and electro-optical countermeasures.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.12074399,12204500,and 12004403)the Key Projects of Intergovernmental International Scientific and Technological Innovation Cooperation(No.2021YFE0116700)+1 种基金the Shanghai Natural Science Foundation(No.20ZR1464400)the Shanghai Sailing Program(No.22YF1455300).
文摘The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase of ICF implosion,the growth of ARTI can be suppressed by using a short-wavelength spatially modulated laser.The ARTI growth rate decreases as the wavelength of the spatially modulated laser decreases,and ARTI is completely suppressed after a certain wavelength has been reached.A spatially uniform laser is introduced to keep the state of motion of the implosion fluid consistent,and it is found that the proportion of the spatially modulated laser required for complete suppression of ARTI decreases as the wavelength continues to decrease.We also optimize the spatial intensity distribution of the spatially modulated laser.In addition,as the duration of the spatially modulated laser decreases,the proportion required for completely suppressing ARTI increases,but the required energy decreases.When the perturbation wavenumber decreases,the wavelength of the spatially modulated laser required for complete suppression of ARTI becomes longer.In the case of multimode perturbation,ARTI can also be significantly suppressed by a spatially modulated laser,and the perturbation amplitude can be reduced to less than 10% of that without a spatially modulated laser.We believe that the conclusions drawn from our simulations can provide the basis for new approaches to control ARTI in ICF.
基金supported by the National Natural Science Foundation of China(Grant Nos.11804348,11775056,11975154,12225505,and 12405281)the Science Challenge(Project No.TZ2018005)+2 种基金supported by the Shanghai Pujiang Program(Grant No.23PJ1414600)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0890203)supported by the Accelerator Technology Helmholtz Infrastructure consortium ATHENA.
文摘The effects of initial spin orientation on the final electron beam polarization in laser wakefield acceleration in a pre-polarized plasma are investigated theoretically and numerically.From the results of variation of the initial spin direction,the spin dynamics of the electron beam are found to depend on the self-injection mechanism.The effects of wakefields and laser fields are studied using test particle dynamics and particle-in-cell simulations based on the Thomas-Bargmann-Michel-Telegdi equation.Compared with transverse injection,longitudinal injection is found to be preferable for obtaining a highly polarized electron beam.
文摘Quasi-two-dimensional(quasi-2d)perovskites are promising gain media for micro-nano lasers,yet their uncontrolled crystallization and abundant low-n phases often hinder optical gain and device performance.In this work,we introduce ethyl acetate(EA)as a green antisolvent to fabricate high-quality quasi-2D PEA_(0.4)MAPbBr_(3)films.The EA-treated films exhibit superior morphology,enhanced crystallinity,and notably inhibited low n-phases.These improvements yield a prolonged photoluminescence lifetime of 26.3 ns and a substantially extended gain lifetime of 129 ps.Consequently,the optimized film exhibits a markedly reduced amplified spontaneous emission(ASE)threshold of 5.6μJ·cm^(-2)and a high net modal gain of 935 cm^(-1).Leveraging these enhanced gain properties,we successfully demonstrate a vertical-cavity surface-emitting laser(VCSEL)based on a dielectric Bragg reflector microcavity,which delivers single-mode lasing at 528.3 nm and a high quality factor of~5886.This work presents a green-solvent-engineering strategy for high-performance perovskite lasers,advancing their prospects for scalable photonic integration.
基金framework of the EUROfusion Consortium,funded by the European Union via the Euratom Research and Training Programme(Grant Agreement No.101052200—EUROfusion)The CRESCO-ENEAGRID High Performance Computing infrastructure is funded by ENEA+3 种基金the Italian National Agency for New Technologies,Energy and Sustainable Economic Developmentby Italian and European research programmesthe framework of the“Universities’Excellence Initiative”programme by the Ministry of Education,Science and Sports of the Republic of Lithuania under an agreement with the Research Council of Lithuania(Project No.S-A-UEI-23-6)support was received through EU LASERLAB-EUROPE JRAextension(Grant Agreement No.871124,Horizon 2020 Research and Innovation Programme).
文摘Inertial confinement fusion(ICF)requires a constant search for the most effective materials to improve the efficiency of compression of the capsule and of laser-to-target energy transfer.Foams could provide a solution,but they require further experimental and theoretical investigation.The new 3D-printing technologies,such as two-photon polymerization,are opening a new era in the production of foams,allowing fine control of material morphology.Very few detailed studies of the interaction of foams with high-power lasers in regimes relevant for ICF have been described in the literature to date,and more investigation is needed.In this work,we present the results of an experimental campaign performed at the ABC laser facility at ENEA Centro Ricerche Frascati in which 3D-printed microstructured materials were irradiated at high power.3D simulations of the laser-target interaction performed with the FLASH code reveal that the laser is scattered by plasma density gradients and channeled into the structure when the center of the focal spot is on the through hole.The time required for the laser to completely ablate the structure given by the simulations is in good agreement with the experimental measurement.Measurements of the reflected and transmitted laser light indicate that scattering occurred during the irradiation,in accordance with the simulations.Two-plasmon decay has also been found to be active during irradiation.
基金supported by the National Key Laboratory of Plasma Physics,Laser Fusion Research Center,China Academy of Engineering Physics under the National Natural Science Foundation of China(Grant Nos.12127810 and 12475242).
文摘Laser-driven inertial confinement fusion(ICF)is an important experimental platform for high-energy-density physics research under extreme conditions.In ICF research,high-quality shock waves are key to fusion energy release.The velocity interferometer system for any reflector(VISAR)is the most important diagnostic technique for measuring quantities such as shock wave and particle velocities with high precision and high spatiotemporal resolution.This paper provides a detailed introduction to the various configurations of VISAR on 10 and 100 kJ-level laser facilities in China,including Line VISAR,Dual-Axis VISAR,Wide-Angle VISAR,and Compressed Ultrafast Photography-VISAR.Recent advances and applications of VISAR diagnostics at these laser facilities are presented,and the future trend of development of high-spatiotemporal-resolution velocity diagnostic technology is described.
基金supported by the National Natural Science Foundation of China(Grant Nos.52275431 and 52075227).
文摘In this study,controllable fabrication of nickel-doped diamond-like carbon(Ni-DLC)films through laser-assisted electrochemical deposition under low-voltage conditions(5 V)is achieved.After substrate polishing,picosecond laser irradiation is applied during electrodeposition to precisely control the laser energy and defocus distance during film preparation,with subsequent analysis of surface morphology,composition,and properties in correlation with growth mechanisms.Compared with conventional DLC electrodeposition,the laser-assisted technique significantly improves film quality by maintaining the deposition zone temperature at~52℃,with laser-induced micro-stirring effectively reducing cathode bubble adhesion and suppressing hydrogen evolution.Without laser assistance,the films exhibit poor adhesion,porous structure,and thickness nonuniformity,while increasing the laser energy progressively enhances densification,achieving 3.5μm thickness uniformity.Optimal performance at 8.5μJ laser energy demonstrates an improved deposition rate compared with conventional methods,a minimum corrosion current density(1.116×10^(−6)Amm^(−2)),and a stable friction coefficient(0.143),establishing a novel laser-assisted approach for controllable DLC electrodeposition.
基金supports from National Natural Science Foundation of China(Grant No.52105498)The science and technology innovation Program of Hunan Province(Grant No.2021RC3074)+2 种基金Advanced Laser Technology Laboratory of Anhui Province(AHL2022KF04)National Key R&D Program of China(Grant No.2023YFB14605500)Changsha Natural Science Foundation(kq2402089).
文摘Combined pulsed laser(CPL),introduced in 1975 for target damage,integrates different lasers to achieve high peak power and pulse energy.However,despite decades of research,CPL remains unused for long-range target damage due to the challenge of maintaining high peak power density over long distances.We note that a potential solution lies in leveraging the air filament generated by femtosecond laser,which can transmit peak power densities higher than 1014 W/cm^(2)under the power clamping effect.To address this,a concept of a femtosecond laser induced air filament-CW CPL for surface damage of ceramics was introduced.We found no surface changes in ceramic targets when irradiated with a CW laser alone.By way of contrast,the target can be penetrated in a very short time(20 ms)with the assistance of the femtosecond laser induced air filament.In this context,we employ high-speed shadow imaging,cross-timescale simulation models and macro-microscopic characterization,to elucidate the CPL damage mechanism.The optimal CPL,combining a 1 mJ femtosecond laser and a 500 W CW laser,yields a damage rate of 1.51×10^(7)μm^(3)/J,representing an improvement of approximately 175%compared to single femtosecond laser ablation and around 59%enhancement compared to coating-assisted CW laser ablation.Furthermore,the efficacy of the proposed femtosecond-CW CPL method is demonstrated in causing penetration damage of ceramic/metal composite material or direct damage of sapphire,showcasing its versatility in damaging applications.Consequently,the femtosecond-CW CPL ablation method presented in this paper holds great promise as a new type of damage method for transparent hard and brittle materials.
基金supported by the National Natural Science Foundation of China(Nos.12405288,12374241,12474484,U2330401,12088101)the Natural Science Foundation of Top Talent of SZTU(No.GDRC202526)。
文摘The process of nuclear fusion in the presence of a laser field was theoretically analyzed.The analysis is applicable to most fusion reactions and different types of currently available intense lasers,from X-ray free-electron lasers to solid-state near-infrared lasers.Laser fields were shown to enhance the fusion yields,and the mechanism of this enhancement was explained.Low-frequency lasers are more efficient in enhancing fusion than high-frequency lasers.The calculation results show enhancements of fusion yields by orders of magnitude with currently available intense low-frequency laser fields.The temperature requirement for controlled nuclear fusion may be reduced with the aid of intense laser fields.
基金financial support received from the Shanghai Pujiang Program(23PJ1406500)。
文摘White Cyphochilus insulanus beetles,exhibiting both environmental camouflage display and radiative cooling functions,serve as a good prototype for biomimetic fabrication.As inspired,this work presents a femtosecond(fs)laser-based biomimetic fabrication strategy that takes full use of the synthesized radiative cooling nanomaterials for a groundbreaking stimuli-responsive infrared(IR)impressionistic camouflage display.The proposed technique is capable of readily transforming various substrates(quartz glass and metals including Ti,Al,Zr,and W)into self-assembled porous networks(aerogels)consisting of oxygen-vacancy-rich oxide nanoparticles.Surprisingly,the emissions of all as-prepared porous particle-networks in the radiative-cooling long-wavelength infrared(LWIR)band are above 95%,with the SiO_(2) aerogels reaching a maximum of 99.6%.Benefiting from the far-from-equilibrium thermodynamic kinetics,metastable phases of anatase TiO_(2),tetragonal zirconia(t-ZrO_(2)),and monoclinic WO_(3)(Pc)are synthesizable,opening up opportunities for exploring their optical applications.Taking the low-temperature metastable phase WO_(3)(Pc)as representative for systematic studies,it is found that(1)the ratio WO_(3)(Pc)phase to that of room-temperature phase of WO_(3)(P2_(1)/n)can be tailored by modulation of processing parameters;(2)laser synthesized aerogels with hybrid phases of WO_(3)(Pc)and WO_(3)(P2_(1)/n)have a brighter visible whiteness,higher visible/nearinfrared(NIR)spectral selectivity than the natural prototype of white Cyphochilus insulanus beetles but with comparable LWIR emittance.White WO_(3) aerogel in situ deposited during flexibly fs laser artistic patterning can blur the painting features due to its radiative cooling effect,allowing a colorful impressionistic IR display in the heating mode.What's more,invisible painting features concealed by the white deposited WO_(3) aerogel are clearly/faintly distinguishable by introducing external stimuli of a human hand and sample heating,respectively,catalyzing progress in optical encryption and selectively stimuli-responsive decryption display in the infrared band.
基金supported by the Guangdong High Level Innovation Research Institute(Grant No.2021B0909050006)the National Grand Instrument Project(Grant No.2019YFF01014402)+1 种基金the National Natural Science Foundation of China(Grant No.12205008)support from the National Science Fund for Distinguished Young Scholars(Grant No.12225501)。
文摘Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challenges.In this work,we demonstrate for the firs time that the coherent radiation farfiel patterns from laser–foil interactions can serve as an in situ,real-time,and easy-to-implement diagnostic for an ultraintense laser focus.The laser-driven electron sheets,curved by the spatially varying laser fiel and leaving the targets at nearly the speed of light,produce doughnut-shaped patterns depending on the shapes of the focal spot and the absolute laser intensities.Assisted by particle-in-cell simulations,we can achieve measurements of the intensity and the focal spot,and provide immediate feedback to optimize the focal spots for extremely high intensity.
基金partially supported by the Center for Advanced Systems Understanding(CASUS)financed by Germany’s Federal Ministry of Education and Research(BMBF)+2 种基金the Saxon State Government out of the State Budget approved by the Saxon State Parliamentfunding from the European Union’s Just Transition Fund(JTF)within the project Röntgenlaser-Optimierung der Laserfusion(ROLF),Contract No.5086999001co-financed by the Saxon State Government out of the State Budget approved by the Saxon State Parliament.
文摘We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses.Employing XFEL-based imaging with sub-micrometer spatial and femtosecond temporal resolution,supported by hydrodynamic and particle-in-cell simulations,we reveal how return current density depends precisely on wire diameter,material properties,and incident laser energy.We identify deviations from simple theoretical predictions due to geometrically influenced electron escape dynamics.These results refine and confirm the scaling laws essential for predictive modeling in high-energy-density physics and inertial fusion research.
基金funded by the National Natural Science Foundation of China(Grant Nos.52275302,52375301 and 52322508)the National Key Research and Development Program of China(Grant No.2023YFB3407701)+1 种基金the HaiYou Industrial Experts Programme(Grant No.CYLJ20241901412)the Open Project of the Key Laboratory of Multiscale Laser Manufacturing Technology,Ministry of Education.
文摘To improve the penetration of thick plates,a laser-enhanced plasma arc welding process was developed.However,the current understanding of laser absorption and energy transfer mechanisms is still unclear,limiting its optimization and application.This work establishes mathematical model of this novel heat source including electron density based on the gas state equation,Saha equation,and charge conservation equation.This model reveals the laser transmission characteristics in the plasma controlled by temperature and electron density,as well as the electrical and thermal transfer from the composite arc to the base material.The simulated temperature fields,arc pressure distributions,and arc voltages showed good agreement with experimental measurements,with peak pressure errors within 50 Pa and voltage differences within 0.3 V,validating the accuracy of the model.The results showed that the laser increased the arc temperature inside the keyhole,extending the high-temperature zone downwards.The laser has altered the current density distribution at the keyhole edge,decreasing the upper part but increasing the lower part.The trend of heat flux density change is consistent with the current density.There is a high laser absorption zone in the arc between the tungsten electrode and base metal,whose position changes with laser power,thereby improving the position and axial energy distribution of the plasma arc.
基金supported by the National Key R&D Program of China(Nos.2022YFA1603200 and 2022YFA1603201)National Natural Science Foundation of China(Nos.12135001,11921006,12475243 and 11825502)+1 种基金Strategic Priority Research Program of CAS(No.XDA25050900)support from the National Natural Science Funds for Distinguished Young Scholar(No.11825502)。
文摘We put forward a new design of a compact beam transport system for intense laser-driven proton therapy,where instead of using conventional pulsed solenoids,our design relies on a helical coil irradiated by a nanosecond laser pulse to generate strong magnetic fields for focusing protons.A pair of dipole magnets and apertures are employed to further filter protons with large divergences and low energies.Our numerical studies combine particle-in-cell simulations for laser-plasma interaction to generate high-energy monoenergetic proton beams,finite element analysis for evaluating the magnetic field distribution inside the coil,and MonteCarlo simulations for beam transport and energy deposition.Our results show that with this design,a spread-out Bragg peak in a range of several centimeters to a deep-seated tumor with a dose of approximately 16.5 cGy and fluctuation around 2% can be achieved.The instantaneous dose rate reaches up to 10^(9)Gy/s,holding the potential for future FLASH radiotherapy research.
基金support from the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research,and Innovation(No.B05F650022),as well as from Chiang Mai University.
文摘A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation source requires relatively ultrashort electron bunches to produce intense coherent THz pulses.Three electron bunch compression processes are utilized in the PCELL accelerator system comprising pre-bunch compression in an alpha magnet,velocity bunching in a radio-frequency(RF)linear accelerator(linac),and magnetic bunch compression in a 180°acromat system.Electron bunch compression in the magnetic compressor system poses considerable challenges,which are addressed through the use of three quadrupole doublets.The strengths of the quadrupole fields significantly influence the rotation of the beam line longitudinal phase space distribution along the bunch compressor.Start-to-end beam dynamics simulations using the ASTRA code were performed to optimize the electron beam properties for generating super-radiant THz-FEL radiation.The operational parameters considered in the simulations comprise the alpha magnet gradient,linac RF phase,and quadrupole field strengths.The optimization results show that 10-16MeV femtosecond electron bunches with a low energy spread(~0.2%),small normalized emittance(~15πmm·mrad),and high peak current(165-247A)can be produced by the PCELL accelerator system at the optimal parameters.A THz-FEL with sub-microjoule pulse energies can thus be obtained at the optimized electron beam parameters.The physical and conceptual design of the THz-FEL beamline were completed based on the beam dynamics simulation results.The construction and installation of this beamline are currently underway and expected to be completed by mid-2024.The commissioning of the beamline will then commence.
基金Project(52105498) supported by the National Natural Science Foundation of ChinaProject(2021RC3074) supported by the Science and Technology Innovation Program of Hunan Province,China+2 种基金Project(2023YFB4605500) supported by the National Key Research and Development Program of ChinaProject(AHL2022KF04) supported by the Advanced Laser Technology Laboratory of Anhui Province,ChinaProject(kq2402089) supported by the Changsha Natural Science Foundation,China。
文摘High-energy continuous wave(CW)lasers are mostly used in laser damage applications,but efficient laser ablation of transparent materials is challenging due to low optical absorption.Considering the potential of femtosecond(fs)laser-induced air filament for high-peak laser transmission over long distances,femtosecond(fs)laser-induced air filaments are combined with a millisecond(ms)laser to form an fs-ms CPL,enhancing the efficiency of sapphire ablation through synchronized spatial-temporal focusing.Experimental results show that ablation efficiency increases with the ms peak power and duty ratio.Excessive thermal stress leads to fragmentation of the sapphire when the ms duty ratio is over 30%at the peak power of 800 W,or when the peak power is over 500 W at a duty ratio of 100%.Also,the mechanism of high-efficiency damage is revealed through in-situ high-speed imaging.According to it,the ablation process went through 4 stages within 1.5 ms:defect-creating,melting and ablation,spattering,and fragmentation.Finally,the equivalent ablation efficiency of the fs-ms CPL is as high as 1.73×10^(7)μm^(3)/J,about 28 times higher compared to the fs laser only.The CPL damage method explored in this paper can provide theoretical guidance for efficient laser damage of transparent materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.12075081 and 12404395)the Innovation Group Project of the Natural Science Foundation of Hubei Province of China(Grant No.2024AFA038)Bin Liu acknowledges the support of Guangdong High Level Innovation Research Institute Project,Grant No.2021B0909050006.
文摘The significance of laser-driven polarized beam acceleration has been increasingly recognized in recent years.We propose an efficient method for generating polarized proton beams from a pre-polarized hydrogen halide gas jet,utilizing magnetic vortex acceleration enhanced by a laser-driven plasma bubble.When a petawatt laser pulse passes through a pre-polarized gas jet,a bubble-like ultra-nonlinear plasma wave is formed.As a portion of the particles constituting this wave,background protons are swept by the acceleration field of the bubble and oscillate significantly along the laser propagation axis.Some of the pre-accelerated protons in the plasma wave are trapped by the acceleration field at the rear side of the target.This acceleration field is intensified by the transverse expansion of the laser-driven magnetic vortex,resulting in energetic polarized proton beams.The spin of energetic protons is determined by their precession within the electromagnetic field,which is described using the Thomas-Bargmann-Michel-Telegdi equation in analytical models and particle-in-cell simulations.Multidimensional simulations reveal that monoenergetic proton beams with an energy of hundreds of MeV,a beam charge of hundreds of pC,and a beam polarization of tens of percent can be produced at laser powers of several petawatts.Such laser-driven polarized proton beams have promise for application in polarized beam colliders,where they can be utilized to investigate particle interactions and to explore the properties of matter under extreme conditions.
基金supported by the National Natural Science Foundation of China(Grant Nos.12375236 and 12135009)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA25050100 and XDA25010100).
文摘The generation and reconnection of magneticflux ropes in a plasma irradiated by two Laguerre–Gaussian laser pulses with different frequen-cies and opposite topological charges are investigated numerically by particle-in-cell simulations.It is shown that twisted plasma currents and hence magneticflux ropes can be effectively generated as long as the laser frequency difference matches the electron plasma frequency.More importantly,subsequent reconnection of magneticflux ropes can occur.Typical signatures of magnetic reconnection,such as magnetic island formation and plasma heating,are identified in the reconnection of magneticflux ropes.Notably,it is found that a strong axial magneticfield can be generated on the axis,owing to the azimuthal current induced during the reconnection of the ropes.This indicates that in the reconnection of magneticflux ropes,the energy can be transferred not only from the magneticfield to the plasma but also from the plasma current back to the magneticfield.This work opens a new avenue to the study of magneticflux ropes,which helps in understanding magnetic topology changes,and resultant magnetic energy dissipation,plasma heating,and particle acceleration found in solarflares,and magnetic confinement fusion devices.
基金supported by the National Natural Science Foundation of China(Grant No.92477133)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515011662)+1 种基金the National Natural Science Foundation of Fujian Province(Grant No.2025J01060)the National Natural Science Foundation of Xiamen(Grant No.3502Z202571016).
文摘Ytterbium(Yb)-based mode-locked fiber lasers have undergone significant development and found widespread applications owing to their high efficiency,compact size,and low cost.However,these lasers typically operate within the 1030 to 1080 nm range,and expanding their operational wavelength is crucial for applications across various fields.We present the direct generation of a mode-locked laser at 1120.06 nm using an all-polarization-maintaining structure,establishing the longest wavelength reported to date for Yb-doped fiber-based mode-locked lasers.A stable picosecond pulse laser at 1120 nm was realized by combining high-concentration Yb-doping and phase-biasing technology within a figure-9 cavity configuration.The laser delivers a pulse duration of 6.20 ps,a spectral width of 0.19 nm centered at 1120.06 nm,and a repetition rate of 21.52 MHz and reaches a maximum output power of 1.39 W via a double-cladding Yb fiber power amplifier in a master oscillator power amplifier configuration.Furthermore,we present a theoretical investigation of the laser performance,with simulation results aligning well with experimental findings.In addition,a 560.06-nm ultrafast yellow-green laser was generated through frequency doubling in a lithium triborate crystal.We present an approach for long-wavelength Yb-doped mode-locked lasers,with the potential to advance the development and application of Yb-based fiber lasers.
基金supported by the National Natural Science Foundation of China (Grant Nos.12274273and 12450402)the Innovation Program for Quantum Science and Technology (Grant No.2021ZD0302101)。
文摘The rapid advancements of ultrafast intense laser technology have opened new avenues for investigating entanglement in laser-induced systems. However, the application of these advances in quantum technology requires a reliable and universally applicable method for enhancing and regulating entanglement. Here we demonstrate how a few-cycle intense laser field can significantly enhance the degree of entanglement compared to its multi-cycle counterpart, using the example of electron–electron entanglement of orbital angular momentum(OAM) states in recollision-excitation non-sequential double ionization of Ar atoms. By confining the ionization dynamics to a specific narrow time window, the few-cycle pulse purifies the electron trajectories, thereby ensuring high coherence between entangled OAM channels and enhancing entanglement. Furthermore, the degree of entanglement can be efficiently modulated by varying the carrier envelope phase of the few-cycle laser pulse, which is achieved by altering the population across OAM channels. Optimizing coherence through electron trajectory purification with a designed specific temporal waveform of laser field provides a general pathway for enhancing entanglement in laser-induced systems.
