Laser

arXiv:2610.21839v1 Announce Type: new Abstract: Micro light-emitting diodes (micro-LEDs) offer superior performance for next-generation displays, yet their scalable manufacturing is severely bottlenecked by the mass transfer process from donor to receiver substrates. The existing laser-induced forward transfer (LIFT) methods are restricted by low throughput, limited selectivity, and long reaction times. In this study, we introduce a novel defocused direct laser ablation transfer (D-DLAT) method utilizing polyimide as a dynamic release layer. Whereas most indirect laser transfer methods trigger chip release followed by passive descent toward the receiver, D-DLAT directly ablates the release layer to actively propel the small-sized chips towards the receiver via ablation shock. By optimizing the ablation profiles and scanning paths, this method achieves high-speed transfer with significantly enhanced precision and robustness. We demonstrate the successful transfer of micro-LEDs ranging

arXiv:2610.21766v1 Announce Type: new Abstract: Compact ultrafast laser combs around the 2 $\mu$m atmospheric transmission window are of growing interest for direct spectroscopy and as drivers for nonlinear conversion to otherwise hard-to-reach spectral regions. Dual-comb systems in this region remain very scarce: existing implementations rely mostly on nonlinear conversion, resulting in complex systems with poor conversion efficiency and overall low average and peak power. In this paper, we report on a watt-level dual-comb laser directly emitting at 2.1 $\mu$m. The system is based on a single-cavity, soft-aperture Kerr-lens mode-locked (KLM) laser using a broadband holmium (Ho)-doped CaAlGdO$_4$ (CALGO) gain crystal. The laser delivers a total output power exceeding 2 W (1 W per comb) with a sub-100-fs pulse duration (50 nm bandwidth) at a repetition rate of 96.5 MHz, corresponding to a pulse energy of 10 nJ and a peak power of 100 kW per comb. To assess the source's potential for

arXiv:2610.21430v1 Announce Type: new Abstract: A machine-learning surrogate model based on a multi-layer perceptron neural network is used to predict six laser performance metrics for an indium gallium arsenide quantum well laser given epitaxial layer parameters as inputs. The surrogate model was trained on simulation data from a set of 4999 designs which were generated by varying epitaxial layer parameters and simulating each design with Harold to extract performance metrics. The model predicts all 6 chosen metrics with a coefficient of determination, $R^2$, greater than 0.91 on a held-out test set and demonstrates a $\sim 10^6 \times$ speed up compared to full device simulations. The model is used to search across 1 million potential epitaxial designs in the parameter space and find designs that minimize threshold current and internal loss. Using the surrogate, rather than full device simulation, reduces computation time for a million designs from 231 days to $\sim$2 minutes on a

arXiv:2610.21839v1 Announce Type: cross Abstract: Micro light-emitting diodes (micro-LEDs) offer superior performance for next-generation displays, yet their scalable manufacturing is severely bottlenecked by the mass transfer process from donor to receiver substrates. The existing laser-induced forward transfer (LIFT) methods are restricted by low throughput, limited selectivity, and long reaction times. In this study, we introduce a novel defocused direct laser ablation transfer (D-DLAT) method utilizing polyimide as a dynamic release layer. Whereas most indirect laser transfer methods trigger chip release followed by passive descent toward the receiver, D-DLAT directly ablates the release layer to actively propel the small-sized chips towards the receiver via ablation shock. By optimizing the ablation profiles and scanning paths, this method achieves high-speed transfer with significantly enhanced precision and robustness. We demonstrate the successful transfer of micro-LEDs

Physicists at Auburn University have used flashes of laser light to bring order to tiny electrically charged "islands" inside a crystal. The discovery helps answer a decades-old question about how the material organizes itself and shows how light could be used to control its behavior—a step toward exploring new technologies for processing and storing information.

When IPG Photonics introduced the LightWELD series in 2020, it helped redefine the handheld laser welding market. By

Surface preparation has long been one of the dirtiest steps in manufacturing. Abrasive grit, solvent baths and compressed-air

Researchers at Friedrich Schiller University Jena and the University of Regensburg have developed a method for determining, using light, a quantum property of electrons that has hitherto been difficult to access. The focus is on what is known as Berry curvature—a quantity that describes certain geometric properties of the quantum mechanical states of electrons. The researchers measured it in a layer of the semiconductor tungsten diselenide, just one atomic layer thick, using ultrashort laser pulses. The results have been published in the latest issue of the journal Nature Photonics.

arXiv:2610.13251v1 Announce Type: cross Abstract: Ultrafast laser-assisted field emission from metallic nanotips is a promising route for generating coherent electron pulses. However, existing theoretical models often neglect many-body strong correlation effects in the emitter's electronic structure and its response to the optical field. In this work, we propose a theoretical framework based on the non-equilibrium Green's function formalism to simulate the out-of-equilibrium electron dynamics across a strongly driven matter-vacuum interface, in a one-dimensional model. Treating the tip-vacuum coupling perturbatively, we find that the interplay between strong-field emission and multi-photon emission regimes can be described in terms of a filtering of the emitter's local density of occupied states through field-dressed vacuum propagators. By including electron-electron interactions via the second-Born approximation, we show that correlation-induced modifications in the electronic

arXiv:2610.13427v1 Announce Type: new Abstract: We report a soft-aperture Kerr-lens mode-locked Tm:Y2O3 ceramic laser stabilized by suppressing wavelength competition under high population-inversion conditions. The laser delivers an average output power of 0.5 W with a pulse duration of 112 fs at a repetition rate of 90 MHz and a central wavelength of 2.08 um. Further optimization for shorter pulses yields a pulse duration of 107 fs, through with a reduced output power of 0.22 W. These results demonstrate that spectral-control is an effective approach for achieving stable mode-locking in such laser with strong spectral competition.

arXiv:2605.08098v2 Announce Type: replace Abstract: Kirigami is an increasingly useful fabrication method to produce shape-programmable metamaterial structures. However, inverse design remains difficult because deployment is nonlinear, and feasible cut layouts must satisfy discrete compatibility rules, avoid overlap, and map one target shape to valid designs. We present RL-Kirigami, an inverse design framework that combines optimal-transport conditional flow matching (OT-CFM) with reinforcement learning to generate compatible ratio fields for compact reconfigurable parallelogram quad kirigami. A marching decoder enforces global geometric compatibility, and Group Relative Policy Optimization (GRPO) aligns the generator with nondifferentiable rewards for silhouette matching, feasibility, and ratio-field regularity. Across procedurally generated target shape instances, a single sample from the pretrained OT-CFM prior reached $94.2\%~\mathrm{sIoU}$ and outperformed solver baselines while

When we think about a diamond, we often think about a material whose value comes from its perfection. In my research, however, I am interested in something almost opposite: the tiny imperfections inside diamonds. These atomic-scale defects can give diamonds new optical and electronic properties, and some of them can serve as quantum systems. The challenge is learning how to control these defects without disturbing the others.

Scientists have demonstrated a remarkable new antenna that resembles a lightsaber, using a laser to create a tunable beam of plasma capable of transmitting radio waves. The technology could revolutionize wireless communications by allowing antennas to change their size and direction on demand, with promising applications in satellites, radar, and space exploration.

arXiv:2610.11729v1 Announce Type: cross Abstract: The prospect of imaging single biomolecules, viruses and cells with intense, ultrashort X-ray pulses has driven the development of X-ray free-electron lasers (XFELs). However, the weak scattering from small particles is easily swamped by background from residual gas, which has so far limited applications to strongly scattering targets such as viruses, cell organelles and cells. Here we report a three-dimensional (3D) reconstruction of an isolated 1-MDa membrane-protein complex, photosystem I (PS I), from single-particle diffraction data. PS I trimers were aerosolised by charge-reduction electrospray ionisation and injected into the European XFEL beam, with partial helium gas exchange reducing background scattering by 80%. From 32 788 diffraction patterns of single trimers in random orientations, we reconstructed the 3D electron density to a resolution of 3.8 nm, limited by the detector geometry. The disc-shaped density, about 22 nm

arXiv:2610.11892v1 Announce Type: new Abstract: The extremely intense pulses of X-ray free-electron lasers (XFELs) have enabled imaging of radiation-sensitive samples, such as macromolecular microcrystals, beyond radiation damage limits. These sources have the potential to deliver biomolecular single-particle imaging, similar to cryo-electron microscopy but without the need for cryo-fixation and with temporal resolution from femtoseconds to milliseconds. While this possibility was recognized before XFELs were built, the biological single-particle imaging work-flow has previously only been demonstrated on large virus particles. Based on decades of improvements in X-ray beam focusing, particle delivery, diffraction detection, and advanced analysis, here we demonstrate imaging of a single molecular complex, the giant-hemoglobin erythrocruorin (Ery) with X-ray laser pulses. Two-dimensional classes of diffraction patterns could be reconstructed to 15 Angstrom resolution, and 3D images to

arXiv:2610.11856v1 Announce Type: new Abstract: We report, to the best of our knowledge, the first controlled, like-for-like experimental mapping of how four practical design parameters--seed-cavity topology, seed power, amplifier pumping geometry, and seed-cavity free spectral range (FSR)--jointly shape the radio-frequency (RF)-resolved relative intensity noise (RIN) of high-power continuous-wave (CW) Yb-doped fiber lasers. We compare a standalone bidirectional fiber Bragg grating (FBG) oscillator, an FBG-seeded master-oscillator power amplifier (MOPA), and unidirectional ring-seeded MOPAs with FSRs of approximately 11.5 and 5 MHz, all near 1064 nm at a common 72 W output, with RIN measured from 10 kHz to 1 GHz. Across all settings, the low-frequency RIN is technical-noise limited and nearly architecture-independent, whereas RIN above 160 kHz is governed by the seed-cavity topology and its transfer through the amplifier. Higher seed power suppresses the mid- and high-frequency RIN,

arXiv:2610.11729v1 Announce Type: new Abstract: The prospect of imaging single biomolecules, viruses and cells with intense, ultrashort X-ray pulses has driven the development of X-ray free-electron lasers (XFELs). However, the weak scattering from small particles is easily swamped by background from residual gas, which has so far limited applications to strongly scattering targets such as viruses, cell organelles and cells. Here we report a three-dimensional (3D) reconstruction of an isolated 1-MDa membrane-protein complex, photosystem I (PS I), from single-particle diffraction data. PS I trimers were aerosolised by charge-reduction electrospray ionisation and injected into the European XFEL beam, with partial helium gas exchange reducing background scattering by 80%. From 32 788 diffraction patterns of single trimers in random orientations, we reconstructed the 3D electron density to a resolution of 3.8 nm, limited by the detector geometry. The disc-shaped density, about 22 nm

arXiv:2610.11603v1 Announce Type: new Abstract: A novel diagnostic is proposed for active probing of doped inertial confinement fusion (ICF) spherical shells, enabling direct measurements of mix and burn dynamics at next-generation implosion facilities via resonant absorption imaging with an X-ray free-electron laser (XFEL). The charge-state-sensitive imaging of embedded dopants provides spatiotemporally resolved constraints on ionization, opacity, and material mix seeded by hydrodynamic instabilities in stagnated plasmas. Proof-of-principle experiments demonstrating resonant XFEL probing of hot spot in coated copper wires driven by an ultra-short relativistic laser pulse, have established the feasibility of this approach. Furthermore, atomic and radiation-hydrodynamic simulations, combined with synthetic resonant X-ray absorption imaging, extend the diagnostic concept to laser-driven direct-drive ICF shells with copper-doped ablators and radiation-driven indirect-drive shells with

arXiv:2610.08989v1 Announce Type: cross Abstract: While offline reinforcement learning (RL) enables policy optimization from static datasets without costly online interaction, it remains bottlenecked by the risk of executing out-of-distribution (OOD) actions. Recent approaches mitigate this by learning a behavior-cloning policy through flow matching and then performing RL within its constrained latent space. However, naively optimizing the latent policy can easily cause the policy to collapse into a brittle mode or exploit sharp artifacts of the learned critic. In this work, we find that entropy regularization is essential in latent-space RL for addressing these challenges. We introduce LASER, a novel offline RL algorithm that applies latent-space adjoint matching to achieve entropy-regularized latent-space RL with expressive flow policies while avoiding backpropagation through time. Through comprehensive experiments on 40 challenging OGBench tasks with varying dataset qualities, we

arXiv:2610.08989v1 Announce Type: cross Abstract: While offline reinforcement learning (RL) enables policy optimization from static datasets without costly online interaction, it remains bottlenecked by the risk of executing out-of-distribution (OOD) actions. Recent approaches mitigate this by learning a behavior-cloning policy through flow matching and then performing RL within its constrained latent space. However, naively optimizing the latent policy can easily cause the policy to collapse into a brittle mode or exploit sharp artifacts of the learned critic. In this work, we find that entropy regularization is essential in latent-space RL for addressing these challenges. We introduce LASER, a novel offline RL algorithm that applies latent-space adjoint matching to achieve entropy-regularized latent-space RL with expressive flow policies while avoiding backpropagation through time. Through comprehensive experiments on 40 challenging OGBench tasks with varying dataset qualities, we

arXiv:2610.10193v1 Announce Type: new Abstract: A comprehensive (start-to-end) simulation was performed regarding the formation of a front-tilted laser pulse and the subsequent acceleration of non-relativistic electrons moving along a reflective grating structure. The laser pulse tilt was formed using another diffraction grating -- either reflective or transmissive. The pulse had a spectral range (FWHM) of 803--863 nm and an initial duration of approximately 17 fs. Acceleration under normal laser pulse incidence was also calculated for comparison. Research results indicate that the use of a femtosecond laser pulse with a front, tilted by means of a reflective diffraction grating, significantly enhances the efficiency of laser acceleration of non-relativistic electrons compared to the case of a pulse at normal incidence. Furthermore, it was found that using a transmissive diffraction grating to shape the tilted pulse front also increases acceleration efficiency relative to normal

arXiv:2610.09435v1 Announce Type: new Abstract: We report, for the first time, a fully integrated Ho$^{3+}$-doped fluoride glass waveguide laser incorporating a femtosecond laser-inscribed waveguide and waveguide Bragg grating. The compact 12.4 mm cavity achieves stable single-frequency lasing at 2062.21 nm with a line width of better than 5 MHz. The laser emits linearly polarized light, which is efficiently delivered through an SM1950 single-mode fiber. This alignment-free architecture provides a compact and robust platform for integrated mid-infrared single-frequency laser sources.

arXiv:2610.08989v1 Announce Type: new Abstract: While offline reinforcement learning (RL) enables policy optimization from static datasets without costly online interaction, it remains bottlenecked by the risk of executing out-of-distribution (OOD) actions. Recent approaches mitigate this by learning a behavior-cloning policy through flow matching and then performing RL within its constrained latent space. However, naively optimizing the latent policy can easily cause the policy to collapse into a brittle mode or exploit sharp artifacts of the learned critic. In this work, we find that entropy regularization is essential in latent-space RL for addressing these challenges. We introduce LASER, a novel offline RL algorithm that applies latent-space adjoint matching to achieve entropy-regularized latent-space RL with expressive flow policies while avoiding backpropagation through time. Through comprehensive experiments on 40 challenging OGBench tasks with varying dataset qualities, we

A new type of advanced microscope (wide-field coherent multidimensional microscopy) has been developed. It uses a carefully designed sequence of ultrashort light pulses to study the behavior of high-tech materials, with potential practical applications in the study of innovative materials such as those used to build solar panels. This is the result of work by a research group of physicists from the Faculty of Sciences, Mathematics, Physics, and Natural Sciences at Università Cattolica's Brescia campus who, for the first time, have developed a "multidimensional microscope" that, in a sense, records the behavior of materials.

arXiv:2610.08453v1 Announce Type: new Abstract: Phonon lasers amplify mechanical vibrations, serving as key tools for coherent acoustics research and applications such as ultrasensitive sensing and information processing, which has been extensively studied in Markovian systems but remains unexplored in non-Markovian ones. In this paper, we propose the nonreciprocal phonon laser in a coupled cavity system composed of nonlinear optomechanical resonator and degenerate optical parametric amplifier (DOPA) under the Markovian approximation. The mechanical gain and threshold power of the phonon laser are influenced by Sagnac-Fizeau effects, which leads to the unidirectional phonon laser and enhances the phonon laser performance via DOPA. Moreover, we generalize the nonreciprocal phonon laser to non-Markovian regimes. We find that non-Markovian effects can lead to the further enhancement of the phonon laser at a lower phonon laser threshold power with DOPA fixed. Our work reveals connections

arXiv:2610.08223v1 Announce Type: new Abstract: Dispersion is a key limiting factor in ultrafast systems as it modifies the temporal structure of ultrashort optical pulses. Conventional dispersion compensation techniques, though widely used, rely on a combination of several bulky optical components and complex, long propagation paths, posing challenges for integration into compact photonic platforms. All-dielectric resonant metasurfaces operating in the Huygens' regime of spectrally overlapping electric and magnetic dipolar resonances offer a promising route to low-loss dispersion control at the sub-wavelength scale; however, the achievable dispersion from a single layer remains fundamentally limited by its phase gradient and spectral bandwidth. Here, we experimentally demonstrate in-line dispersion control of femtosecond laser pulses using a multilayer architecture of dielectric Huygens' metasurfaces, without requiring spatial separation of their spectral components, as typically

arXiv:2610.07951v1 Announce Type: new Abstract: Hyperspectral imaging (HSI) enables spatial mapping of haemoglobin oxygenation and cytochrome-c-oxidase (CCO) redox changes in exposed neural tissue. In this study, we present a technical upgrade of an existing HSI platform by the integration of laser speckle contrast imaging (LSCI), enabling contemporaneous assessment of oxygenation, oxidative metabolism, relative perfusion and a derived relative oxygen metabolic index in exposed spinal cord in a rat preclinical model. The upgraded system (hNIR+) uses a shared optical path and a single camera to acquire HSI and LSCI images from the same field of view using a sequential acquisition workflow. Hyperspectral images are acquired at 11 discrete wavelengths (600, 630, 665, 784, 800, 818, 835, 851, 868, 881, and 894 nm) to estimate changes in oxygenated haemoglobin (HbO2), deoxygenated haemoglobin (HHb) and oxidized CCO (oxCCO). LSCI is implemented using 632.8-nm coherent illumination to

arXiv:2610.07813v1 Announce Type: new Abstract: We present a rapid, mask-free fabrication workflow for the Paul wheel trap chip based on selective laser etching (SLE) of fused silica. The complete process - femtosecond laser writing, wet-chemical etching in KOH ($\sim$230 $\mu$m/h, releasing the trap geometry from a 500 $\mu$m wafer in approximately 2 h), RF magnetron sputtering of silver electrodes, and direct femtosecond laser ablation for electrode patterning - is carried out in-house, bypassing photolithographic processing and custom shadow masks entirely. Nine chips per 4-inch wafer can be produced in a single working day, reducing the fabrication lead time by more than one order of magnitude relative to the outsourced CVD diamond design. The functionality of the fabricated wheel trap chip is confirmed by a proof-of-concept microparticle trapping demonstration, in which a single microparticle was confined continuously for 72 h at atmospheric pressure. This establishes SLE of

Creating a quantum device often begins by intentionally damaging a crystal. Scientists fire an ultrafast laser pulse into a material, knocking atoms out of place and leaving behind tiny imperfections called vacancies. Far from being flaws, these vacancies can behave as qubits—the fundamental building blocks of quantum information.

arXiv:2610.06655v1 Announce Type: cross Abstract: We report the growth and physical properties of HoCo$_2$ thin films on Si substrate by pulsed laser deposition. Well-defined Kiessig fringes in the x-ray reflectivity data yield a film thickness of $35 \pm 1$~nm and demonstrate smooth film surface and interface profiles. Atomic force microscopy confirms the high morphological quality of the films, revealing subnanometer surface roughness of $\sim$170~pm. Two independently prepared films exhibit a reproducible ferrimagnetic transition at $T_{\mathrm{C}}=77\pm3$~K, demonstrating retention of the characteristic magnetic ordering of bulk HoCo$_2$. However, the absence of resolvable thermal hysteresis indicates a predominantly continuous, second-order like transition in the films, in contrast to the first-order transition of bulk HoCo$_2$. At 5~K, the films exhibit clear magnetic hysteresis with a coercive field of $\sim$600~Oe, substantially larger than the negligible coercivity of bulk

arXiv:2610.05895v1 Announce Type: new Abstract: We show that an intense low-frequency laser field can qualitatively modify the local extremal structure of an interband energy gap in a crystal. Using an instantaneous laser-dressed basis obtained from the nonperturbative diagonalization of the multiband crystal Hamiltonian, we derive a quartic normal form for the dressed gap near a high-symmetry point. At a critical field, the quadratic part of this normal form changes sign, and the gap experiences a bifurcation: a single symmetric minimum splits into two symmetry-related minima separated by a local maximum. We identify the microscopic origin of this bifurcation by decomposing the quadratic part into a homogeneous Stark contribution and a field-modified band-curvature contribution. The latter originates from the multiband redistribution of interband polarizations and provides the mechanism for the field-induced change of the gap extrema. A realization for the Kronig--Penney model

A laser reveals hidden vascular pathology, ocular findings signal cancer recurrence, and a possible link between eating disorders and retinal hemorrhage.

Researchers have demonstrated a technique that uses a laser to produce a plasma beam antenna capable of transmitting radio waves. The article, "Laser-Induced-Plasma-Filament Antenna Transmitting 30 MHz VHF," is published in the IEEE Journal of Microwaves.

arXiv:2610.03416v1 Announce Type: cross Abstract: We extend the Bethe--Floquet formalism of Joachain and coworkers, originally developed for laser-assisted electron--atom collisions, to inelastic scattering of fast electrons from a many-body condensed-matter target in a time-periodic light field. At first order in the projectile--target interaction, the general Floquet--Fourier cross section separates into exact laser-dressed projectile kernels and a matrix-valued Floquet density response of the target. For spatially structured or translationally non-invariant systems, the latter is the bi-momentum Floquet structure factor; its momentum diagonal defines the Floquet generalization of the dynamic structure factor, constrained by Hermiticity, positivity, and sum rules. As a controlled realization of the general projectile kernel, an eikonal--Volkov approximation for slowly varying inhomogeneous fields yields a finite-momentum-resolution convolution of the target response. In the

arXiv:2610.03552v1 Announce Type: new Abstract: We are developing an experimental platform at Lawrence Livermore National Laboratory's Jupiter Laser Facility to characterize X-ray emission from highly charged ions in the high-density ($n_e > 10^{23}$ cm$^{-3}$), high-temperature ($T_e \sim 1$ keV) regime, leveraging the recently upgraded frequency-doubled short-pulse Titan laser. These measurements will provide experimental benchmarks for high electron density effects on atomic structure, including Stark broadening, ionization potential depression, density-dependent line shifts, and suppression of dielectronic recombination, effects that are relevant to spectral modeling packages used by both the high-energy-density and astrophysics communities. Here, we describe the current status of the platform and present results from first experiments using the upgraded frequency-doubling capability, including calibrated K-shell spectra acquired from five time-integrated X-ray channels.

arXiv:2610.03376v1 Announce Type: new Abstract: The Any Light Particle Search II employs a highly sensitive heterodyne detection system to measure an ultra-weak electromagnetic field that is reconverted from axions inside a regeneration cavity (RC). The initial design of the heterodyne system utilized a local oscillator laser (LO) that was resonant with the RC to form an interference beatnote with the weak signal field exiting the cavity. A weakness of this design is that it is possible for the out-of-mode field component of the LO to be larger than the in-mode component, allowing its noise to dominate the optical component of the noise budget and reducing the SNR of the experiment. This problem can be addressed by introducing a second, non-resonant laser as the LO. Since the in-mode light of this laser does not couple to the cavity, significantly more of its power is reflected than when the LO is resonant. We present a model for the measurement noise that predicts these design

EPFL researchers have developed a chip-based laser that keeps a very stable frequency across its tested operating range, without needing active electronic control. Their research is published in the journal Nature Photonics.

arXiv:2610.01183v1 Announce Type: cross Abstract: The negatively charged nitrogen-vacancy ($\mathrm{NV}^-$) defect in diamond can be used for quantum information processing via the readout of the radiative decay of the excited state into the ground state. The large refractive index mismatch of diamond and air causes low photon extraction efficiency due to total internal reflection losses. Here, we investigate the photon extraction numerically and report additive solid immersion lenses (SILs) consisting of the high-k dielectric yttria-stabilized-zirconia (YSZ) for surface modification and enhanced light extraction of shallow implanted nitrogen-vacancy centers. We demonstrate an average increase of 63% in saturation intensity using a scalable bottum up room temperature pulsed laser deposition and photolithography structurization process. The average necessary laser intensity for saturation is reduced by 33% by the SILs.

arXiv:2610.01597v1 Announce Type: new Abstract: The Rayleigh-Plateau instability predicts that infinitesimal perturbations of a liquid jet grow only for kR < 1, with kR = 1 marking the classical stability boundary. Here, we show that femtosecond-laser-induced cavitation generates a localized, impulsive recoil perturbation on a flowing liquid jet, enabling a two-dimensional map of jet breakup across the (kR, epsilon/R) plane. The perturbation's spacing (wavelength) and strength (amplitude) are set independently by the laser repetition rate and pulse energy, respectively. At low amplitudes, tuning the repetition rate recovers the classical Rayleigh-Plateau dispersion relation and its kR = 1 cutoff, while increasing the wavelength enables controlled generation of monodisperse droplet trains, bidisperse droplet populations, and ultimately isolated single droplets. Along the amplitude axis, low pulse energies produce a seed that amplifies only the imposed wavenumber, whereas above a

arXiv:2610.01485v1 Announce Type: new Abstract: The plasma channel of the AWAKE plasma wakefield acceleration experiment is created by laser ionization of rubidium vapor in a 10~m long vapor source. Verifying the properties of the channel --- the radius of its fully ionized core and the width of its boundary sheath --- that are vital for ensuring good-quality wakefields is important as is validating numerical models of ionizing pulse propagation. Near-resonant schlieren imaging can detect the plasma channel in the low-density vapor, but there is no direct inversion to obtain channel parameters from the images. We use symbolic regression to find compact analytical formulas that connect measurable properties of the schlieren signal to plasma profile parameters. Using databases of simulated signals generated with three different plasma edge-profile families, we obtain formulas with one and two fitting constants to predict the equivalent channel radius with an accuracy below twice the

The U.S. National Science Foundation provides $33M to make key upgrades and keep the laser in service for

arXiv:2609.40130v1 Announce Type: new Abstract: The nuclear electromagnetic moments and mean-square charge radii of several silver (Ag) isotopes deduced from recent laser spectroscopy studies in the mass region $A=$ 96-121 are determined using high-accuracy electronic structure calculations performed in this work. We report hyperfine structure and isotope-shift atomic factors calculated with the relativistic coupled cluster approach, including single, double, triple, and perturbative quadruple excitations, CCSDT(Q). Following a systematic theoretical uncertainty analysis, we show that at the precision now achieved (sub-percent uncertainties in some cases), quantum electrodynamic effects become significant. We also show that the isotope-dependent effect in the hyperfine structure due to the non-point-like nuclear magnetization distribution can be extracted with negligible dependence on the assumed nuclear magnetization model at the present level of precision. This also yields a nuclear

arXiv:2609.39928v1 Announce Type: new Abstract: Generally, ultrafast laser glass dicing is governed by explosive material removal, which restricts the achievable surface roughness. Here we report single-step dicing of aluminosilicate glass with residual interface roughness below 5 nm, producing optical-quality surfaces without post-processing, using near-field-enhanced 0th-order Bessel-Gauss beams. This exceptional interface quality cannot be explained by a conventional laser ablation mechanism, such as phase explosion, melt expulsion, or fracture-dominated material removal. Instead, quantitative analysis of local thermal dynamics indicates that material removal is consistent with a Hertz-Knudsen-type evaporation process, enabling layer-by-layer removal with precision approaching a few molecular layers. These results suggest that nanoscale optical confinement fundamentally alters the response of transparent materials to ultrafast laser irradiation and establish a route toward

arXiv:2609.39298v1 Announce Type: new Abstract: Practical O-band quantum-dot (QD) mode-locked comb sources must combine wide flat-top bandwidth, low radio-frequency (RF) timing noise, error-correctable bare-line modulation, and feedback tolerance, yet these functions are usually optimized separately and their relation to comb-formation dynamics remains unclear. Here we map the gain-current/saturable-absorber-bias plane of a simple two-section InAs/GaAs QD mode-locked laser to resolve distinct application-specific regimes. A low-injection, high-reverse-bias regime produces 0.80 ps pulses, consistent with amplitude-modulated operation, whereas a high-injection, intermediate-bias regime yields a 16.16 nm (2.75 THz) flat-top comb with 110 lines and a 14.98 ps extended waveform, consistent with a stronger frequency-modulated contribution. To our knowledge, this is the broadest reported 3 dB bandwidth among QD mode-locked comb sources. At a separate low-noise bias, the beatnote exhibits a

arXiv:2609.39850v1 Announce Type: new Abstract: Laser-based deorbiting has long been proposed as a promising technique for mitigating the growing population of orbital debris, particularly decimetre-scale objects -- large enough to cause catastrophic collisions yet too small to be economically captured by current active debris removal (ADR) missions. However, the practical implementation of laser-based approaches remains constrained by several factors. Ground-based systems suffer from atmospheric absorption, scattering, and turbulence, which degrade beam quality and limit effective energy delivery. Space-based platforms benefit from superior propagation efficiency, enabling more compact and lower-power systems, but require complex, high-cost orbital infrastructure with demanding deployment, maintenance, and scalability challenges. This paper proposes a stratospheric balloon-based concept for laser debris removal, exploring the intermediate regime between ground-based and space-based

Muons are constantly being created as cosmic rays collide with molecules in Earth's upper atmosphere. With their ability to penetrate far into dense, solid materials, these cosmic muons are often used to image the insides of objects that are otherwise hidden from view. However, the flow of these natural particles is far too slow for the technique to become both fast and reliable in practical settings.

arXiv:2609.37228v1 Announce Type: new Abstract: Laser polarization affects both the production of betatron x rays and their angular distribution, which together determine the photon yield collected within a fixed angular acceptance. We investigate these effects using particle-in-cell simulations of laser-wakefield acceleration with linearly polarized (LP) and circularly polarized (CP) pulses of equal energy in helium--nitrogen targets of two different lengths. In the longer target, CP produces more photons early in propagation, whereas LP produces more later. For 20--60-keV photons transmitted through 2 mm of aluminum, the LP/CP yield ratio before angular selection changes from 0.88 early on to 1.91 in a late stage. Late-emitting LP electrons develop pronounced transverse oscillations along the laser polarization direction, accompanied by angular broadening of the radiation. This broadening largely removes the late LP production advantage within a central $\pm5$-mrad acceptance, where

arXiv:2609.36592v1 Announce Type: new Abstract: Photons from ultrastable lasers can remain coherent over distances approaching the Earth-Sun separation, enabling optical clocks projected to lose less than one second over the age of the Universe. Yet characterizing these photons poses an identifiability problem: a two-laser heterodyne measurement produces a single beatnote linewidth that conflates contributions from both lasers. For more than half a century, the standard solution has been the three-cornered-hat (TCH) method, which requires three independent ultrastable lasers. Here we derive the mathematical form and elucidate the physical origin of asymmetric beatnote-linewidth distributions arising from finite photon wave trains, a long-observed feature not captured by canonical Gaussian or Lorentzian statistics. This finding accurately recovers two linewidths hidden in laser beatnote statistics without a third laser. The framework consistently captures the observed coherence-length

arXiv:2609.36528v1 Announce Type: new Abstract: In direct-drive inertial confinement fusion (ICF), cross-beam energy transfer (CBET) redirects a significant fraction of the incident laser energy out of the plasma. We report the experimental demonstration that broadband lasers reduce CBET-enhanced reflected-light return, performed at the low-coherence Kunwu laser facility with two crossed beams of 0.6% bandwidth and up to 550J at $\sim$2.6$\times$10$^{14}$ W/cm$^{2}$. A coupled ray-tracing model shows that the strong CBET amplification of narrowband reflected light is much weaker under broadband illumination. In symmetric incidence condition of two orthogonal beams, the total fractional scattered energy decreases from 7.57% to 4.64%; in asymmetric incidence condition, which separates stimulated Brillouin scattering (SBS) from specular reflection, the SBS fraction decreases from 3.75% to 0.46% and the specular-reflection fraction decreases from approximately 2.2% to 1.3%. These results

arXiv:2609.36284v1 Announce Type: new Abstract: We have developed a computer code that models the three dimensional nature of a sodium plasma created by laser resonance saturation. This was accomplished by taking account of the temporal and spatial distortion suffered by the laser pulse as it propagates through a nonuniform sodium atom distribution. We have also undertaken the first measurements of the radial and axial electron density and temperature profiles arising in such a plasma and have been able to demonstrate that our computer code predictions are in reasonable agreement with these results. Absorption of the laser pulse is found to be quite significant for even a few centimeters of $10^{16}$~cm$^{-3}$ sodium atom density and that as a result quite low temperature plasmas can be produced for modest energy laser pulses.

arXiv:2609.36085v1 Announce Type: new Abstract: Electron Stark broadening of the $4^2D$--$3^2P$ multiplet transition in a sodium plasma produced by laser resonance saturation has provided a means of undertaking the first spatial measurements of the free electron density across and along the plasma channel created in sodium vapor of density $10^{15}$--$5\times10^{16}$~cm$^{-3}$. From these measurements and measurements of the neutral sodium density within a heat sandwich oven, we are able to deduce the corresponding electron temperature. These temperatures compare favourably with the electron temperature estimated from a Boltzmann analysis of line intensities and suggest that a highly ionized ($>$10\%) plasma of electron temperature $

An international team of physicists has developed a new method for determining the precise color of laser light using an image that rotates as the laser's frequency shifts.

arXiv:2609.35401v1 Announce Type: new Abstract: The Qprop 3.0 package for the solution of the time-dependent Schr\"odinger equation for an electron in a laser field and atomic potential is extended to incorporate nondipole effects related to the laser wave propagation. The developed code can be used for the simulation of strong field atomic phenomena in the nondipole regime, such as above-threshold ionization, ionization stabilization in high-frequency laser fields, high-order harmonic generation, when the effects connected with the magnetic field are non-negligible or when the laser wavelength is comparable with the atomic size. Similar to the dipole Qprop the wave function is expanded in spherical harmonics, the time-propagation of the wave functions is performed using the Crank- Nicolson approach, and the photoelectron spectra are calculated employing the t-SURFF or i- SURFV methods. The validity and accuracy of the implementation are demonstrated through several illustrative

arXiv:2609.35284v1 Announce Type: new Abstract: We demonstrate stimulated Raman spectroscopy on dipole-forbidden fine-structure transitions in a fast ion beam. It is applied to the $\mathrm{S}_{1/2}\rightarrow\mathrm{D}_{5/2}$ clock transition in $^{88}\mathrm{Sr}^{+}$ and combined with a subsequent E1 transition to allow for its detection by standard fluorescence detection. Building on this, the $\mathrm{D}_{3/2}\rightarrow\mathrm{D}_{5/2}$ fine-structure splitting is measured directly using a Doppler-free scheme employing two subsequent Raman transitions. These measurements demonstrate a path toward precision collinear laser spectroscopy of narrow transitions on short-lived isotopes beyond the linewidth limit of conventional electric-dipole spectroscopy, which can be used to probe fundamental aspects of atomic and nuclear physics.

arXiv:2609.34476v1 Announce Type: new Abstract: Continuous monitoring of intraocular pressure (IOP) is essential for the diagnosis and management of glaucoma, yet existing clinical methods rely on intermittent in-clinic measurements that miss critical diurnal fluctuations. Smart contact lenses are an attractive platform for continuous IOP tracking, and optical strain sensors are particularly promising thanks to their high sensitivity and natural readout. Most such optical sensors infer strain from the period of a regular structure - a grating or photonic crystal - whose deformation is read out optically. However, the precision of all sensors based on the period of regular structures is fundamentally bounded by the uncertainty principle, which severely limits performance at the millimeter length scales available inside a contact lens. Here, we address this limitation by integrating a distributed-feedback (DFB) laser, based on a surface-modulated ultrathin F8BT dye layer, into a soft

arXiv:2609.33483v1 Announce Type: new Abstract: Laser-driven proton-boron fusion offers a path for generation of $\alpha$ particles on a compact scale. Conventional solid-target experiments, however, are fundamentally limited by target degradation and low shot-repetition capacity. Here, we demonstrate a continuous laser-driven $\alpha$ particle source utilizing target-normal sheath acceleration from a continuously replenishable ultrathin water-leaf jet target. The proton beam interacts with a downstream boron nitride converter, driving the $^{11}\text{B}(p,\alpha)^{8}\text{Be}$ reaction which yields three $\alpha$ particles. The measurement was repeated across $18{,}000$ consecutive shots at a rate of $10\,\text{Hz}$. The outgoing $\alpha$-particle yield and spectral fluence were measured and benchmarked against comprehensive particle-transport simulations. The numerical and experimental results reveal a pronounced flattening in the energy-differential $\alpha$-particle spectrum

arXiv:2609.33056v1 Announce Type: new Abstract: We report on hyperfine structure measurements of the $1s2s\,{}^{3\!}S_1 \rightarrow 1s2p\,{}^{3\!}P_{0,2}$ fine-structure transitions in the spectrum of $^{11}$B$^{3+}$ ions. The helium-like ions were created in an electron beam ion trap (EBIT) and ejected after a short production period of 15 ms. A challenge of the experiment was the treatment of the complex energy-time-profile of the created ion bunches and the sensitivity of the collinear laser spectroscopy to the starting potential inside the EBIT. Despite these complications and the low statistics of the experiment, we were able to confirm and improve the results of a previous measurement of these transitions. While we find moderate tension in the results for the hyperfine parameters of the $^{3\!}P_{0,2}$ levels, their fine-structure level energies are in reasonable agreement between experiments and with theory.

arXiv:2609.32089v1 Announce Type: new Abstract: Multiple internal reflections enhance laser absorption in vaporization-induced cavities, but connecting ray histories, cavity geometry, and absorptance typically requires full ray tracing. We develop a reduced-order framework based on Beer-Lambert-type attenuation governed by an effective per-reflection optical depth (EPROD). A power-weighted formulation defines an absorptance-equivalent interaction count under constant effective single-interaction absorptance, while a cumulant expansion separates the EPROD-independent mean interaction count from ray-path heterogeneity corrections. Across nine simulation groups spanning three alloys and three spot diameters, the mean interaction count follows a unit-intercept linear depth relation with R-squared values of 0.7824-0.9843. Its slope varies by only 3.4%-6.3% across alloys at fixed spot diameter and decreases with increasing spot diameter. Fixing this slope from ray statistics yields an

A tiny device that can be reprogrammed using a laser could lead to adaptable devices for computing, imaging and telecommunications. Most devices are built to perform a particular job. If you want them to do something different, you generally need to replace a component, rewire the system or manufacture a new one. For example, every time you ask a large language model like ChatGPT or Claude a question, many electrical signals race through computer chips, carrying information and performing calculations. This takes energy, and lots of it.

arXiv:2609.31534v1 Announce Type: new Abstract: Attosecond pulses provide direct access to electron dynamics in atoms, molecules, and solids on their natural timescales. While table-top sources have achieved attosecond pulse durations at moderate intensities, extending attosecond science to high peak powers in the x-ray regime requires free-electron lasers (FELs). Here we report the generation of soft-x-ray pulses with a duration of $\sim\!100$ as and peak power on the order of 10 TW at the European XFEL. The unprecedented combination of pulse duration and peak power is enabled by operation of a soft-x-ray undulator at high electron energy together with five-stage bunch compression, producing ultrahigh peak currents. These millijoule-level attosecond x-ray pulses establish a new regime for attosecond science.

arXiv:2609.31333v1 Announce Type: new Abstract: Ultrashort X-ray pulses, as provided by X-ray Free Electron Lasers (XFELs), offer unique opportunities to probe the formation of laser-induced nanostructures with sizes even below the optical diffraction limit, with sub-micometer and sub-picosecond spatial and temporal resolution. Using ultrafast small-angle X-ray scattering (SAXS), we probe the formation of nanoscatterers and nanocracks in reciprocal space as they evolve into different types of laser-induced periodic surface structures (LIPSS) on silica films. Our focus is on the dynamics and evolution of nanoscatterers and high spatial frequency LIPSS (HSFL), with spatial periods below 100 nm. Our experiments include an in-situ analysis of the pulse-by-pulse evolution of HSFL at a fixed sample location, as well as fs time-resolved delay and fluence scans using an ultrafast pump-probe scheme. We find that nanoscatterers and periodic nanocracks form at delay times of hundreds of

arXiv:2609.31132v1 Announce Type: new Abstract: Fog and clouds remain major obstacles to free-space optical (FSO) communications because micron-sized droplets can impose tens of decibels of attenuation. Ultrashort laser filamentation can transiently clear fog in laboratory-scale experiments, but its extension to atmospheric-scale propagation has remained uncertain. Here we demonstrate laser-assisted fog clearing under atmospheric-scale propagation conditions over a 140-m optical path using a high-energy, high-average-power picosecond laser and weak focusing to sustain extended multifilamentation. A steady-state transparent channel approximately 2 cm in diameter restores up to 12 dB of transmission for an independent optical beam. Increasing the clearing-laser pulse energy primarily extends the multifilament region while maintaining a nearly constant longitudinally averaged deposited energy per unit length of ~2 mJ/m over the measured bundle length. This low average deposition,

arXiv:2609.30907v1 Announce Type: new Abstract: Laser-induced white (light) emission was observed from transparent Cr:YAG ceramics irradiated with a focused continuous wave beam of light from an infrared laser diode. The laser-induced white emission is detected only on the surface of the sample and is not observed in volume. It is found that the intensity of the emission increases exponentially with the laser power density above the threshold. The impact of broadband emission on the power of the transmitted laser beam through the sample was measured. The disappearance of broadband emission due to displacement of the laser beam or an increase in ambient pressure leads to a decrease in the power of transmitted laser beam. Origins of the laser-induced white light emission along with its characteristic features are discussed in terms of multiphoton absorption, intervalence charge transfer and ionic space charge models.

arXiv:2609.30584v1 Announce Type: new Abstract: Experimental Fluid-Structure Interaction (FSI) often involves phenomena that occur simultaneously across vastly different spatial and temporal scales. For example, the separation bubble behind a cylinder and the vortex interactions in its wake, or the flow produced by an individual swimmer and the flow generated by the movement of the entire swarm. Imaging-based flow studies of such FSI phenomena are challenging and often lead to separate analyses of different flow regions. This work introduces simultaneous shadow and laser-based Particle Image Velocimetry (PIV) to obtain concurrent near-wall and far-field flow velocity measurements. The experimental setup developed here enables the first simultaneous comparison between shadow- and laser-based PIV, demonstrating that shadow velocimetry can achieve accuracy comparable to laser-based measurements at the macro scale. We then use this new combined flow measurement technique to fully capture

Mazda начала продажи кроссовера EZ-60 Laser Edition 2027 модельного года в Китае (в Европе модель известна как CX-6e). Линейка включает девять комплектаций с последовательной гибридной и полностью электрической силовой установкой, а новые версии Laser Edition впервые получили лидар. В рамках ограниченной акции цены составляют от 114 до 167 тыс. юаней — примерно 1,43–2,10 млн рублей.

Researchers often use antibodies to detect specific molecules or biological markers because they are remarkably precise at recognizing their targets. However, finding the faint signals of cancer in blood samples is a challenge even for the most reliable techniques.

Researchers often use antibodies to detect specific molecules or biological markers, as they are remarkably precise at recognizing their targets.

arXiv:2609.29325v1 Announce Type: new Abstract: Monte Carlo sampling of strong-field quantum electrodynamics processes underpins simulations of high-intensity laser experiments and of astrophysical compact-object magnetospheres. Sampling an event requires the total rate of the process together with the cumulative probability that determines how energy is partitioned between the produced particles. Simulations typically tabulate both in advance and invert the tabulated probability numerically. Here we replace this procedure with elementary-function approximations for synchrotron radiation and the nonlinear Breit--Wheeler process. For each process, we approximate the auxiliary function that sets the total rate, as well as the cumulative probability, with Pad\'e approximants chosen so that the inversion reduces to a quartic equation. This yields the sampled quantum parameter---electron $\chi_e$ or photon $\chi_\gamma$---in closed form. The approximations and the particle spectra sampled

arXiv:2609.28788v1 Announce Type: new Abstract: Artificially generated muon beams, with tunable parameters, are highly valuable in imaging objects that are opaque to any other scanning technique. Lower-energy muon beams are currently produced at accelerator facilities, while higher energies have only recently been observed as a result of the interaction of laser-wakefield-accelerated electrons and solid targets. This work focuses on using muography imaging detectors to measure the profile of a muon beam generated via the Bethe-Heitler process and to perform muon imaging in an experimental setup extending up to 42 meters from the muon source. By comparing the data with Monte Carlo simulations, we confirm that the measured beam profile and object imaging are consistent with artificially produced muons of energy of a few GeV. To our knowledge, this represents the first demonstration of imaging dominated by an artificial, laser-driven muon beam.

arXiv:2609.28734v1 Announce Type: new Abstract: The thermal history of the melt pool in laser powder bed fusion (LPBF) additive manufacturing processes governs the solidification microstructure and the mechanical properties of the resulting 3D-printed parts. Dual-laser systems offer additional degrees of freedom to control the cooling profile by reheating material behind the melt pool, but calibrating process parameters is challenging due to the complex physics of the process. We present an optimization-based iterative learning controller that determines optimal power, velocity, and offset settings by judiciously combining simulations and experiments: the model supplies search directions while feedback obtained from experiments on the real plant corrects for parameter errors, enabling convergence despite model inaccuracies. The approach is validated in simulation using a high-fidelity thermal model as a plant surrogate, with deliberate mismatches in absorption coefficient, latent heat

arXiv:2609.27447v1 Announce Type: cross Abstract: Numerous quantum devices require lasers strictly locked to atomic transitions. Atom-filtered lasers (AFLs) are considered a leading candidate for quantum device laser sources due to their ability to self-align to atomic transitions. However, the sub-GHz sharp transmission spectra of conventional atomic filters impose constraints on both laser miniaturization and output stability. Herein, we demonstrate a micro Faraday anomalous dispersion optical filter ({\mu}FADOF) operating within the extreme hyperfine Paschen-Back regime, generating a 7.5 GHz flat-top transmission window. By integrating this filter, the miniaturization bottleneck of the AFLs is overcome, achieving a 30-fold volume reduction to a compact package volume of 75 mL. Simultaneously, investigations into the optical self-feedback characteristics of the {\mu}FADOF reveal a stable operating regime, where the optical self-feedback of the atomic filter acts as a stabilizing

arXiv:2609.27215v1 Announce Type: new Abstract: Kerr photonic integrated circuit optical parametric oscillators (PIC OPOs) provide a promising platform for coherent visible-light generation, offering broad wavelength accessibility and low frequency noise for applications in quantum information processing, precision metrology, spectroscopy, and sensing. However, achieving large fiber-coupled output powers and high conversion efficiency remains challenging, impacting the practical deployment of these sources. Here we demonstrate optical injection locking of a commercially available visible Fabry-P\'erot (FP) laser diode to a PIC OPO, realizing a hybrid laser that combines the complementary strengths of nonlinear frequency conversion with those of semiconductor laser technologies. Using 25 $\mu$W of injected PIC OPO signal, we generate coherent visible-light at 635 nm with a fiber-coupled output power of $\approx$ 40 mW and side-mode suppression ratio $\gtrsim$ 36.3 dB. The

arXiv:2609.27838v1 Announce Type: new Abstract: This paper proposes the formation keeping control law for deorbiting debris by a laser ablation. Laser ablation is vital technology for contactless active debris removal, where a chaser satellite with a laser system irradiates laser pulses to a target object to generate the ablation force for deorbiting. The deorbiting force decelerates the target, and the chaser must maintain its relative position and continue irradiating. In other words, both the chaser and the target are supposed to be deorbited simultaneously, where both have accelerations. Although conventional formation flying missions assume that only a chaser maneuvers, the formation flying in this paper considers that both a chaser and a target have accelerations. Thus, this paper derives the relative equations of motion between the chaser and the target in powered flight and their analytical solution using relative orbital elements. A control law based on the analytical

arXiv:2609.27006v1 Announce Type: new Abstract: We present a laser-tracker-assisted hand-eye calibration method for camera-equipped mobile robots. The method combines laser-tracker-based 3D metrology with camera-based 2D observations. Building on our previous laser-tracker-assisted camera-to-robot calibration method for ground-observing mobile robots, we present a generalized formulation for calibrating the camera pose in the coordinate system of tracker-localized mobile robots. The new approach relaxes assumptions of our previous method on robot and camera configuration by chaining multiple calibration targets resulting in a more general approach supporting various camera-equipped mobile robot systems.

Recommendations from an expert focus on protecting the eyes during laser treatments.

arXiv:2609.26390v1 Announce Type: new Abstract: We demonstrate a laser-wakefield accelerator driven by a high-repetition-rate optical parametric chirped-pulse amplification (OPCPA) laser, producing stable, quasi-monoenergetic electron beams at 100 Hz. Using 70 mJ, 8.1 fs laser pulses, we obtain 47 MeV electron beams with 15 pC charge and an intrinsic energy spread below 10%. Measurements over 10,000 consecutive shots show rms fluctuations of only 1.4% in peak energy and 12% in charge, together with low pointing jitter. Principal-component analysis reveals that the beam fluctuations are described by five physically interpretable modes, dominated by slow variations below 1 Hz. Particle-in-cell simulations reproduce the measured spectrum and show that nonlinear self-focusing localizes ionization injection, resulting in the observed narrow energy distribution. The demonstrated combination of electron energy, charge, beam quality, and stability represents a significant step toward

arXiv:2609.24798v1 Announce Type: new Abstract: Coupling between laser cavities provides a means of controlling optical modes through their gain, loss, and hybridization. Here we demonstrate electrically controlled mode locking in a monolithic InP dual ring laser operating in the L band without a dedicated saturable absorber. Independent biasing of the two rings accesses single mode emission, mode locking, and hybridized supermode operation, with a measured intermode beat frequency of 542 MHz in the latter regime. The laser generates 7.9 ps pulses at 18.11 GHz. A coupled cavity model describes how differential nonlinear detuning modifies the modal gain loss contrast, and time domain simulations yield pulse durations and spectral widths close to those measured experimentally. In a device incorporating saturable absorbers, reverse bias enables 3.1 ps pulses and reduces the integrated timing jitter from 9.06 to 2.46 ps relative to the unbiased condition. These results connect electrical

arXiv:2609.23654v1 Announce Type: new Abstract: Extending the orbital angular momentum (OAM) degree of freedom to slow electrons would open a distinct regime of low-energy electron-matter interactions. Using time-dependent density-functional theory, we demonstrate that laser-driven armchair carbon nanotubes (CNTs) can emit OAM-carrying slow electrons. A circularly polarized OAM-writing pulse promotes circumferential electronic motion and generates OAM about the tube axis; a delayed linearly polarized extraction pulse releases slow electrons carrying the injected angular momentum. We find much higher ionization yields and net emitted axial OAM in representative CNTs than in oriented CO2 and benzene under identical laser conditions. Increasing the tube diameter enhances the ionization yield and OAM substantially, and moreover, reversing the helicity of the OAM-writing pulse flips the sign of the emitted OAM. Together, these findings establish CNTs as a platform for slow-electron

Neutrinos are the pervasive yet intangible particles that permeate the universe, streaming through whole planets, stars, and our

Magnetic reconnection is a process that occurs when the magnetic fields of a conductive plasma quickly rearrange and release massive amounts of stored magnetic energy. It is widely thought to be the underlying mechanism behind cosmic events such as solar flares and substorms in Earth's magnetosphere.

arXiv:2609.19756v1 Announce Type: new Abstract: Carrier-envelope-phase (CEP) stabilized few-cycle pulses make the sub-cycle field structure a control parameter for laser-driven polarized electron sources, yet spin solvers for such pulses are rarely tested against exact results. We show that for an electron initially at rest in a linearly polarized plane-wave pulse the rest-frame polarization angle follows the instantaneous vector potential, $\Sigma = 2\arctan(a_x/2) + a_e a_x$ with $a_e$ the electron anomaly: the net rotation vanishes for every CEP, while the peak intra-pulse angle varies over the CEP by 3.02 degrees for a two-cycle and by 0.22 degrees for an eight-cycle pulse. The result follows from the Volkov orbit in longitudinal and transverse rapidities. We use it to validate a light-front reference integrator and a physics-informed neural network trained only on the light-front equations, which reaches $4\times10^{-5}$ in the spin sector and carries over to elliptical

arXiv:2609.19571v1 Announce Type: new Abstract: Kilojoule-class short-pulse (

Nanodiamonds are tiny diamond particles that usually measure mere millionths of a millimeter. They are extremely hard, stable and heat-resistant and highly adaptable for various purposes in medicine, new materials, catalysis and energy technology. By compressing plastic with lasers, researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Rostock are now able to systematically produce high-purity, ultra-small diamonds with a narrow size distribution. This is impossible to achieve with conventional methods such as explosions. As a scalable technology, laser compression offers great potential for improved, clean and sustainable production of ultra-small nanodiamonds.

About 40 years ago, researchers found ancient ship carvings on a temple wall in Cyprus, possibly all carved at once at the tail end of the Bronze Age, around the time of the infamous Bronze Age collapse. Then, decades later, a new study revealed they had missed nearly two dozen ancient carvings.

arXiv:2609.18775v1 Announce Type: new Abstract: Despite many experimental attempts, laboratory pair-beam sources have not yet reached the charge, collimation, and density needed to observe kinetic pair-plasma instabilities. Here we show that an optimised direct-laser-acceleration (DLA) regime in a gas target can close this gap in the regime of kilojoule-class petawatt lasers. Quasi-3D PIC and Geant4 simulations show that DLA-accelerated electron bunches carry tens of nC at GeV-scale energies with low divergence. Converted in a high-Z target, they generate up to 3x10^12 positrons with tunable energy spectra and transverse sizes of several skin depths in the beam rest frame. A proof-of-principle PIC simulation of the pair beam propagating through background gas shows the growth of a current-filamentation instability. This provides direct numerical evidence that kinetic pair dynamics are within reach of near-term facilities such as ELI-L4. The same electron driver also generates 6.5x10^5

arXiv:2609.18725v1 Announce Type: new Abstract: High-power, continuously tunable terahertz sources based on free-electron lasers require precise control of electron-beam microstructures. Quantitative prediction of the modulation amplitude across a broad frequency range remains challenging because the laser-induced distribution and its collective evolution must be treated together. To describe this coupled evolution, a nonlinear model is developed for microbunching seeded by a frequency-beating laser heater. The non-Gaussian heater-exit distribution is obtained by optical phase averaging and propagated through multistage compression in six-dimensional phase space. Source-induced correlations are retained, with space charge, coherent synchrotron radiation, and radio-frequency wakefields evaluated self-consistently. The wavelength-dependent bunching response is thereby connected to the laser beat frequency, laser power, and compression partition. The short-wavelength double peak is found

arXiv:2609.18493v1 Announce Type: new Abstract: Semantic labels for indoor mobile laser scanning (MLS) frames remain largely absent from current point cloud semantic segmentation benchmarks, which mainly focus on reconstructed indoor scenes or outdoor LiDAR perception. This paper introduces Semantic-ITC, to the best of our knowledge the first public dataset and benchmark for frame-wise indoor MLS semantic segmentation. The dataset contains 52 indoor sequences, 79,108 MLS frames, and 1.23 billion labeled points collected in classrooms, corridors, meeting rooms, offices, and study areas. Labels are attached directly to measured LiDAR points in each frame using 16 semantic classes covering structural elements, furniture, room equipment, vegetation, and other indoor objects. Semantic-ITC preserves the sparse, non-uniform, and frame-wise sampling pattern of indoor MLS, making it distinct from scene-level reconstructed point clouds and mesh-based indoor datasets. The annotations are

Laser scanning, often referred to as lidar, has rapidly transformed how tropical forest regions are studied, monitored and understood across academic disciplines. The technology enables researchers to peer through dense forest canopies, rapidly providing high-resolution scans of the landscape below. This growing observational power is central to the scientific value of remote sensing technologies but also brings into focus the conditions, interests and power structures under which they are used.

Launched on Oct. 20, 2018, the joint ESA/JAXA BepiColombo mission has traveled for almost eight years, using a carefully planned but eventful sequence of planetary flybys and solar-electric propulsion to gradually approach its destination, Mercury. The mission is now entering the final stage of its journey to the smallest and innermost planet of our solar system.

arXiv:2609.13467v1 Announce Type: cross Abstract: Laser Powder-blown Directed Energy Deposition (LP-DED) offers flexibility for process and materials and high productivity (~5 kg/h), but process-induced pores often compromise mechanical properties. This study utilizes in-situ X-ray synchrotron imaging to compare pore formation mechanisms in Ti-6Al-4V (Ti64) and stainless steel 316L (SS316L), focusing on the interplay between particle dynamics and thermophysical properties. Four distinct pore formation mechanisms were identified, with most large pores originating from the closure of cavities formed behind incident particles impinging on the melt pool. High Weber number (We >> 1) governs this behavior, indicating that particle inertia, rather than thermophysical property differences, is the primary driver of large pore formation. The study demonstrates that increased energy density leads to larger melt pool volumes, facilitating deeper particle penetration. This greater penetration

arXiv:2609.15968v1 Announce Type: new Abstract: Laser-plasma accelerators have demonstrated the ability to produce ultrashort relativistic electron bunches with peak currents suitable for compact light sources, ultrafast diffraction, and strong-field studies. However, their performance critically depends on preserving the longitudinal phase-space density of the beam as it exits the plasma accelerator. Here, we report the first direct observation of a previously unresolved process in which a highly charged electron bunch undergoes significant longitudinal expansion and progressively loses electrons during extraction from a laser-driven wakefield accelerator, a phenomenon we refer to as electron shedding. Using femtosecond relativistic electron microscopy, we tracked the evolution of the beam far beyond the accelerator exit and observed the bunch stretching over many plasma wavelengths before shedding electrons during propagation. Particle-in-cell simulations reproduce the observed

arXiv:2609.15421v1 Announce Type: new Abstract: Ultrashort laser pulses can induce order out of chaos. A femtosecond pulse melts a metal surface for about a hundred picoseconds; under photoexcitation with no net polarization axis, the resolidifying film nonetheless organizes into regular nanoscale patterns. Here we derive from first principles the nonlinear hydrodynamics responsible for it and show it accounts for the full phase diagram of morphologies from measurable laser and material parameters. Starting from the Navier-Stokes equations in the lubrication limit, the molten film obeys a damped Kuramoto-Sivashinsky equation that reduces to a Swift-Hohenberg formalism near threshold, with every coefficient fixed by the laser fluence, melt thickness, optical skin depth, and thermocapillary response. The ratio of melt depth to optical skin depth sets the pattern wavelength, while the inter-pulse delay, via post-pulse damping, gates the route from flat surface to ordered pattern to

arXiv:2609.15304v1 Announce Type: new Abstract: Lithium niobate on insulator (LNOI) combines the outstanding optical properties of lithium niobate (LN) with strong optical confinement, scalable fabrication and high-density integration, making it a leading platform for integrated photonic chips. Recent advances in LNOI photonics have mainly centred on passive and electro-optic components, including couplers, waveguides, microcavities and modulators, whereas efficient on-chip laser sources remain insufficiently developed, limiting the realization of fully integrated LN photonic systems. Because LN is an indirect-bandgap material, lasing on LNOI generally relies on photoluminescence from rare-earth-ion doping, yet the conversion efficiency of doped LNOI lasers has remained low. By comparing LNOI microcavity lasers with fibre lasers and waveguide amplifiers, we identify the limited number of rare-earth ions participating in stimulated emission as a key factor responsible for inefficient

arXiv:2609.13554v1 Announce Type: new Abstract: Accurate detection and quantification of light-element isotopes, particularly hydrogen (H) and lithium (Li), are essential across chemistry, materials science, geology, nuclear energy, forensics, and defense applications. Their isotopic compositions provide insight into fuel cycles, materials degradation, mass transport, and environmental processes. Hydrogen and Li isotopes are especially relevant in nuclear environments because neutron-induced reactions directly connect their isotopic inventories. Despite their importance, analysis of these light isotopes remains challenging due to their low atomic mass, high mobility, and, in some cases, radiological constraints. While some existing analytical techniques can detect and measure H and/or Li, they typically require extensive sample preparation, laboratory-based instrumentation, or extended analysis times that preclude real-time monitoring capabilities. To address these limitations,

arXiv:2609.13538v1 Announce Type: new Abstract: We investigate the structural information retained in the distribution of explosion ion trajectories from proteins subjected to strong ionization. Using molecular-dynamics simulations and machine-learning analysis benchmarked against an analytical approach, we show that low-resolution structural information can be retrieved from the explosion distributions alone. An ensemble of convolutional neural networks trained on simulated spherical ion maps recovers the radius of gyration and the three semi-axes of an ellipsoidal molecular envelope with prediction errors of 1.2~\text{\AA} and 1.5~\text{\AA}, respectively, while an analytical ellipsoid charge model returns similar estimates and performs best for globular structures. We further investigate how higher-level structural information and symmetries can be extrapolated from ion measurements. This study supports the viability for structural determination of single proteins without

Laser blended vision is a treatment for presbyopia, the natural deterioration of our ability to see things close up, that develops in people aged 40 and over.

Extremely short, intense light flashes are in high demand to investigate atoms, molecules and new materials. Free-electron lasers (FELs) produce these flashes. But around the world, beam time available at large-scale user facilities is in short supply, and waiting times are long.

The Japan Aerospace Exploration Agency's (JAXA) Hayabusa2 spacecraft reached another milestone this summer, a first for space agencies. On Sunday, July 5, the probe conducted the first successful laser-ranging experiment during a flyby of asteroid Torifune, the first exploration target of Hayabusa2's Extended Mission. This latest milestone will advance the capabilities of JAXA and other space agencies as they pursue future missions involving near-Earth asteroids (NEAs) and other deep-space objects.

Scientists blasted diamonds with lasers to get the best measurement of the mineral's melting point yet. The new, more accurate numbers could help improve fusion experiments and studies of giant planets.