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2026 Year 6 Volume 1 Issue
- Abstract：Attosecond x-ray pulses are a critical tool for tracking ultrafast electron dynamics in condensed matter, molecular systems, and strongly correlated materials. Recent breakthroughs have pushed x-ray free-electron lasers (XFELs) into the attosecond domain, substantially surpassing their previous femtosecond capabilities. Building on these advancements, this work investigates the potential of the Shanghai HIgh repetitioN rate XFEL and Extreme light facility (SHINE), China’s first continuous-wave (CW) XFEL, to generate intense attosecond x-ray pulses, thereby offering transformative capabilities for x-ray science. Through comprehensive start-to-end simulations, we show that SHINE is capable of producing terawatt-scale pulses at both soft and hard x-ray ranges. This is achieved using a self-chirping scheme within the existing machine configuration, requiring no additional hardware. We further find that superradiant behavior in the postsaturation regime plays a central role in attosecond XFEL, enabling higher peak power and shorter attosecond pulses. Our results illustrate the wide applicability of the self-chirping scheme and demonstrate that CW XFELs can generate intense attosecond x-ray pulses at megahertz repetition rates, opening new opportunities for real-time studies of electronic dynamics in complex systems.2|0|0Updated：2026-03-12
- Abstract：High-repetition-rate, high-power, ultrashort pulse fiber lasers are highly attractive and promising light sources in various fields of high-precision scientific research and industrial applications. Here, we demonstrate a compact Yb-doped soliton oscillator gain-managed nonlinear amplifier (SO-GMNA) system that delivers pulses at a fundamental repetition rate of 171 MHz with an average power of 8.26 W, compressible to 40.8 fs. The use of an intracavity chirped fiber Bragg grating enables direct generation of chirp-optimized, sideband-free soliton pulses suitable for the subsequent GMNA stage, which substantially simplifies the system structure and enhances its robustness. Leveraging this system, we further explored the intriguing noise characteristics and spectral coherence evolution during the nonlinear amplification processes. Our findings offer valuable insights for the development of cost-effective, highly reliable, and high-performance ultrashort fiber laser systems.2|0|0Updated：2026-03-12
- Abstract：Extremely high axial magnetic fields above the gigagauss level are supposed to exist in neutron stars, which may be a one of the critical parameters for their internal structures and be responsible for the x-ray and gamma-ray emission from these stars. Here, we show that such ultrahigh magnetic fields can be produced by multiple petawatt-class lasers interacting with a cuboid solid target with a cylindrical microtube in the middle. It is found that the obliquely incident intense lasers at the target surfaces enable the produced hot electrons to form an azimuthal current and subsequently induce a seed magnetic field along the cylindrical axis inside the microtube as the hot electrons transport into it. This current–field configuration is similar to a theta-pinch device. When the hot electrons and energetic ions produced via target normal sheath acceleration converge toward the microtube axis, the seed magnetic field is dramatically amplified. This process continues until the magnetic pressure near the axis becomes comparable to the thermal pressure contributed both by hot electrons and by energetic ions. Later on, as the plasma in the center starts to be expelled outward by the magnetic pressure, an electron current ring with extremely high densities is formed, leading to a further boost of the magnetic fields to well above the gigagauss level. A scaling of the magnetic field strength with laser intensities, pulse durations, incident angles, and target sizes is presented and verified by numerical simulations, which demonstrates the robustness of our scheme. Our scheme is well suited for experimental realization on 100-TW-class to PW-class femtosecond or picosecond laser facilities with multiple linearly polarized laser beams.2|0|0Updated：2026-03-12
- Abstract：We present the experimental features of second harmonic emission from an air plasma coexcited by 2 ultrafast laser pulses and propose a theoretical model that describes the observed properties. The dual-beam optical nonlinear process was discovered to depend on the optical polarization of both fundamental pulses simultaneously, and the output emissions coincided with the propagation directions of the 2 input laser beams. These attributes of the ultrafast phenomenon are reconciled by incorporating the action of plasma grating into the interaction picture. When the diffractive property of the laser-induced grating is considered, each of the fundamental beams is diffracted onto the direction of the other. The collinear fundamental components can then generate a second harmonic radiation that fulfills the phase matching condition. The ensuing theoretical simulation fits well against the experimental observations. Finally, we analyze the effective nonlinear susceptibility tensor of the air plasma to facilitate future research on the hidden symmetries within plasmas induced by intense ultrafast lasers.2|0|0Updated：2026-03-12
- Abstract：High-intensity mid-infrared femtosecond lasers in the 5- to 11-μm spectral range flexibly delivered through fibers exhibit exceptional potential for biomedical applications due to their alignment with fundamental molecular vibrational modes. However, the key issue is that no solid-core fiber is available that can deliver such intense mid-infrared femtosecond laser without suffering from high nonlinearity, low damage thresholds, and pulse distortion. To solve this problem, we successfully developed chalcogenide glass antiresonant hollow-core fibers that exhibit superior capabilities for delivering intense mid-infrared femtosecond pulses. The fiber achieves high transmission with loss as low as ~1 dB/m, excellent bending insensitivity, and near-diffraction-limited beam quality ( < 1.1). Notably, it supports the delivery of femtosecond pulses with peak powers exceeding 15 MW without introducing any observable pulse distortion or structural damage, surpassing conventional solid-core chalcogenide glass fibers by over an order of magnitude in damage threshold. Experimental validation demonstrates efficient murine corneal tissue dissection at a record-low power threshold of 60 mW (40% reduction compared to that of free-space systems), leveraging the characteristic amide I absorption band at 6.1 μm. This work pioneers the use of chalcogenide glass antiresonant hollow-core fibers for mid-infrared ultrafast laser applications, establishing a transformative platform for next-generation photonic medical technologies. Key advancements include broadband mid-infrared transmission with tailored spectral refinement, unprecedented power-handling capacity, and excellent spatial–temporal fidelity. The developed antiresonant hollow-core fiber paves the way for compact, flexible, and high-precision surgical tools, bridging the gap between laboratory innovation and clinical treatment.2|0|0Updated：2026-03-12
- Abstract：Collisionless shocks are crucial mechanisms for energetic particle generation in the universe. Recent advances in ultraintense laser technology have enabled laboratory investigations of shock-driven ion acceleration, yet the observed directional asymmetries of ion beams remain poorly understood. Here, using particle-in-cell simulations supported by a theoretical model, we reveal that the intrinsic asymmetry of proton beams generated in near-critical-density plasmas is determined by the carrier-envelope phase () of the laser. This asymmetry originates from the -dependent formation of magnetic islands, which deflect refluxing electrons and induce imbalanced transverse currents and charge separation. The resulting asymmetric electrostatic shocks accelerate proton beams preferentially toward the side with larger magnetic islands, with the deflection direction reversing upon a -shift in the . Our results provide a mechanistic understanding of directional ion beam generation and suggest a new framework for interpreting the origin of high-energy cosmic rays, while offering a potential method for retrieval in ultraintense laser–matter interactions.2|0|0Updated：2026-03-12
- Abstract：The ultrafast time-integrated diagnosis of ions plays a vital role in high-energy-density physics research. However, it is extremely challenging to measure in experiment. Here, we demonstrate a reliable approach for investigating the dynamics of deuterium ions in dense plasma. By irradiating a heavy water stream with the hundred Hertz repetitive intense femtosecond laser pulses, the neutrons from the reaction can be detected via a single time-of-flight detector to accumulate the spectrum with a fine energy resolution. This spectrum has been utilized to calculate the temperature and angular distribution of deuterium ions transported in plasma. The calculated results are well verified by particle-in-cell simulations of deuterium ions dynamics. Our method paves a new way for diagnosing ions’ picosecond time-integrated dynamics in plasma and holds great potential for understanding the ions’ transport process in high-energy-density matters and studying laser plasma ion acceleration.2|0|0Updated：2026-03-12
- Abstract：With the rapid global advancement of relativistic ultrafast electron diffraction systems, the impact of relativistic effects on electron scattering efficiency has attracted renewed attention. Recent reviews emphasize the scaling of the differential elastic-scattering cross-section with increasing electron energy. Although such observations are not formally incorrect, they can lead to a misperception of the relative scattering efficiency of relativistic electrons compared to that of their nonrelativistic counterparts. The scaling originates from analyses conducted in the angular domain, where the compression of the scattering angle (or solid angle ) with increasing energy creates an enhancement of the differential elastic-scattering cross-section, . In this work, we recast the problem in momentum-transfer space , where scattering is accurately accounted for. This transformation eliminates the angular compression artifact and reveals that high-energy scaling follows a simple dependence, with no intrinsic relativistic gain. We demonstrate this by directly integrating relativistic differential elastic-scattering cross-sections from ELSEPA and by applying a straightforward transformation of the well-known Mott–Massey formalism into -space. The results are general, with calculations performed for elements from carbon to gold and for energies between 50 and 5,000 keV. They reproduce the long-established trend in total elastic-scattering cross-sections, in which scattering strength decreases with increasing electron kinetic energy. Practically, at energies above roughly 50 keV, scattering is already dominated by the forward direction, and most of the scattered intensity falls within the acceptance range of typical ultrafast electron diffraction detectors.1|0|0Updated：2026-03-12
- Abstract：Quantum tunneling, a quintessential quantum phenomenon, challenges classical intuitions by allowing particles to pass through seemingly insurmountable barriers. This study delves into the intricate dynamics of electron tunneling, focusing on the critical role of sub-barrier interactions and complex time processes. Through a combination of experimental measurements and simulations based on Feynman’s path integral of complex time trajectories, we reveal that the sub-barrier potential interaction introduces an asymmetric electron wave packet probability distribution along the real time axis and a marked delay at the tunneling exit. The energy-dependent behavior of this delay in electronic tunneling agrees with that observed in the previous atomic tunneling studies, suggesting a universal mechanism underlying quantum tunneling across different scales. Our findings underscore the necessity of incorporating both the wave and particle aspects of quantum entities to fully comprehend tunneling dynamics, which holds promise for an intuitive interpretation of complex-number quantum processes.2|0|0Updated：2026-03-12
- Abstract：Reflecting light off a mirror moving near light speed offers a powerful method for generating bright, ultrashort pulses in the extreme ultraviolet range. Several investigations show that dense relativistic electron mirrors can be created by striking a nanometer-scale foil with a high-intensity, sharp-fronted laser pulse, forming a single relativistic electron sheet (RES). This RES coherently reflects and upshifts a counterpropagating laser beam from the infrared to the extreme ultraviolet with efficiency exceeding incoherent scattering by over several orders of magnitude. Here, we demonstrate that optimizing the drive laser waveform can reliably produce a single RES, leading to the generation of isolated attosecond pulses enhancing both the intensity and temporal compression of the back-reflected light in a controlled manner. Simulations reveal that tuning parameters like timing delay enables control over the amplitude, duration, and bandwidth of the resulting attosecond Thomson backscattering pulse. Together, these advances meet key experimental challenges and pave the way for compact, tunable sources of isolated attosecond pulses for probing ultrafast phenomena.0|0|0Updated：2026-03-12
- Abstract：Ultra-broadband near-zero-dispersion mirrors (UbZdMs) are the essential component for pulse reflection and beam transport in ultra-intense ultrafast lasers. By combining and optimizing the metal-dielectric hybrid structure, the TM-polarization UbZdM presented here has a high-reflection bandwidth of one octave (600 to 1,200 nm) and, more importantly, a dispersion-free bandwidth of nearly 300 nm, which could also be increased to one octave with a commercial dispersion management device, much broader than those of current dielectric mirrors. The measured laser-induced damage threshold is around 0.40 J/cm, which is similar to that of dielectric mirrors and twice that of metal mirrors. The damage results and mechanism are successfully explained with a proposed integral electric field intensity model, which could help improve the damage resistance for an even higher performance. The designed film structure of UbZdM is quite robust to deposition errors, making it very suitable to meter-size coatings for high-energy lasers. UbZdM, introduced in this article, can be directly applied to current 100-petawatt laser projects and future single-cycle exawatt lasers. Our work is of great value for next steps in the development of both ultra-intense and ultrafast lasers, as well as related important applications such as physics in the exawatt and attosecond/zeptosecond regimes.2|0|0Updated：2026-03-12
- Abstract：Upconversion photoluminescence lifetime imaging has emerged as a transformative analytical tool by leveraging the temporal signatures of luminescent probes to resolve molecular interactions. While compressed ultrafast photography offers distinct advantages for high-speed imaging, its utility in quantitative applications, such as food safety, remains constrained by reconstruction artifacts, particularly spatial distortion and edge detail loss. To address these limitations, we present a method of single-shot compressed upconversion photoluminescence lifetime imaging (sCUPLI) empowered by a multi-prior physics-enhanced neural (mPEN) network. This framework synergizes physical models of photoluminescence dynamics and imaging processing, subpixel information loss of the compressed encoding, extended sampling priors, sparsity constraints, and deep learning to achieve precise quantification of upconversion photoluminescence lifetimes. To demonstrate its potential in beverage additive detection, we apply mPEN–sCUPLI to analyze synthetic colorants using rare-earth-doped upconversion nanoprobes. The system excels at resolving subtle optical heterogeneities in beverage matrices, achieving superior spatiotemporal resolution and artifact suppression compared to conventional methods. It attains a spatial resolution of 90.5 lp/mm at a frame rate of 33,000 fps, achieving a spatial resolution improvement of approximately 3.56 times. Quantitative analysis shows that mPEN–sCUPLI reconstruction improves the average peak signal-to-noise ratio by 4 dB and enhances the sharpness and fidelity of imaging by 1.85 times. Given its ability to achieve high-fidelity and high-throughput photoluminescence lifetime imaging from single-shot 2-dimensional measurements, the proposed mPEN–sCUPLI approach is expected to be widely adopted in food safety detection applications.0|0|0Updated：2026-03-12
Research Article
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