Laser

arXiv:2605.30933v1 Announce Type: new Abstract: This paper presents generation of Fourier-limited pulses from a periodically phase-modulated CW laser field by phase manipulation of its spectral components. Phase modulation in the form of modulus function of sine (MFS) is considered. It allows to produce pedestal-free pulses with controllable repetition rate and duty cycle. Sidelobes of these pulses can be excluded by choosing a proper modulation index. The proposed method allows to produce pulses with 50\% duty ratio. It is shown that three-tone modulation of phase allows to simulate MFS phase modulation.

Nonlinear interactions between light and matter are at the heart of some of the most powerful tools in modern optics, but pushing these processes to their limits has long been hampered by a fundamental constraint: the stronger you make the laser, the more likely it is to destroy whatever it illuminates.

A research group led by Assistant Professor Takafumi Tomita and Professor Kenji Ohmori at the Institute for Molecular Science, National Institutes of Natural Sciences, has developed a new microscopy technique called the Atom Camera, which uses a single ultracold atom at near absolute zero temperature trapped in an optical tweezer as a camera to visualize the intensity and polarization distributions of light at the nanometer (one-millionth of a millimeter) scale.

arXiv:2605.28370v1 Announce Type: new Abstract: We develop an analytical theory of coherent (scaled quadratically with the number of particles) radiation and coherent radiation friction in a head-on collision of a dense charged particle bunch with an intense laser pulse. We demonstrate that the low-frequency coherent radiation in the forward and backward directions dominates the energy-momentum losses of a mildly relativistic bunch and can result in a substantial enhancement of the overall radiation friction as compared to the incoherent case. We derive the scaling laws for the average momentum losses of the bunch over the collision with respect to laser intensity, pulse duration, and particle bunch parameters, and show their robustness with respect to laser polarization and the shape of the particle distribution in the bunch.

arXiv:2605.27821v1 Announce Type: new Abstract: High-repetition-rate, fully coherent extreme-ultraviolet (EUV) and X-ray free-electron lasers (FELs) are essential for advanced time-resolved ultrafast spectroscopies. While external seeding serves as the standard technique to achieve precise temporal coherence, conventional methods demand hundred-megawatt peak-power laser systems. Furthermore, advanced configurations like echo-enabled harmonic generation (EEHG) introduce the severe complexities of dual-laser synchronization. Together, these requirements fundamentally restrict operations to kilohertz repetition rates and compromise overall system stability. Here, we experimentally demonstrate a fully coherent EEHG-FEL driven by a single, sub-microjoule seed laser. By employing a direct-amplification enabled harmonic generation technique, we utilize an initial 0.4 microJ (2 MW peak power) ultraviolet seed to directly drive coherent lasing at nanometer wavelengths. By eliminating the need

arXiv:2605.27603v1 Announce Type: new Abstract: We present a theoretical description of atomic strong-field photoionization. Specifically, we consider an atom driven by a combination of two electromagnetic fields: a high-frequency field assisted by an intense, low-frequency laser. We investigate the photoelectron spectrum (PES) as the sum of two contributions: direct ionization due to the laser field and the photoionization term associated with the high-frequency field. We identify the contributions of above-threshold ionization (ATI) and laser-assisted photoemission (LAPE) structures in the total spectra, even when they overlap. As a particular case, we investigate the situation where an ATI-peak coincides with a sideband. Our theoretical scheme for the hydrogen initially in the 1s quantum state and based on strong field approximation, is general enough to be applied to other atomic species and field configurations.

A new experimental treatment could finally offer hope for millions of people with dry age-related macular degeneration — one of the leading causes of blindness in older adults. Researchers at Aalto University discovered a way to gently heat tissue at the back of the eye using near-infrared light, triggering the cells’ natural “cleanup and repair” systems before major damage occurs.

arXiv:2605.26708v1 Announce Type: new Abstract: Frequency-stable lasers enable high-fidelity quantum state manipulation, which forms the basis of optical atomic clocks, quantum sensing, and quantum computation. Performing state manipulations at increasingly high speeds requires attention to laser frequency noise at high Fourier (carrier-offset) frequencies that cannot be addressed by traditional cavity stabilization alone. Scalable operations also benefit from device miniaturization. Here, we demonstrate a hybrid laser stabilization approach that combines ultrahigh frequency stability of a cryogenic silicon cavity with high-Fourier-frequency noise suppression of an integrated Brillouin laser. The combined system suppresses frequency noise over a Fourier span of more than 7 decades, yielding a

arXiv:2605.26148v1 Announce Type: new Abstract: A rainbow is a captivating natural phenomenon resulting from the refraction, dispersion, and reflection of sunlight within water droplets. Traditional classroom demonstrations often focus on qualitative explanations of the formation of rainbows using prisms or water bowls. This study presents a simple experimental approach to analysing the process of rainbow formation through quantitative analysis using a cylindrical glass filled with water, graph paper, and three semiconductor laser sources emitting red, green, and blue light. By measuring the angles of minimum deviation for different wavelengths, we have found that the experimental values closely match the theoretical predictions. This method offers a hands-on, cost-effective approach to enhance students' understanding of the physics behind rainbows.

arXiv:2605.25697v1 Announce Type: new Abstract: The importance of investigating magnetized plasmas/solids in extreme conditions has grown over the last decades, particularly in the field of high energy density physics (HEDP), such as laboratory astrophysics and inertial confinement fusion. However, up to now, the unique capabilities of an X-ray free-electron laser (XFEL), such as high brilliance and low divergence have never been exploited for this type of research. In this paper, we present the first platform developed at SACLA, Japan, that combines a high-power optical laser for generating matter under extreme conditions of pressure and temperature, an XFEL probe, and an external magnetic field. The high current is produced using a 2 kV, 4.8 kJ pulsed power system giving a maximum current of 10 kA which is synchronized with the optical laser and XFEL in a vacuum environment. It flows through a split-pair coil to generate a high magnetic field (10 T at 6 kA) which has 1 cm access

arXiv:2605.25471v1 Announce Type: new Abstract: We have demonstrated broadband frequency-noise suppression in a laser stabilization system by augmenting a conventional proportional-integral-derivative (PID) controller with a digital disturbance observer (DOB) implemented on a field-programmable gate array (FPGA). The DOB employs a first-order exponential moving average filter as its Q-filter, replacing multi-parameter frequency-domain plant identification with a single one-dimensional gain sweep. Using modulation transfer spectroscopy on the 87Rb D2 line at 780.24 nm, we have measured the frequency-noise power spectral density and the Allan deviation of the beat note between two independently stabilized lasers. The integrated rms frequency noise below 40 kHz decreased by 16.9 dB compared with PID alone, corresponding to a reduction from approximately 140 kHz to 20 kHz. The short-term fractional frequency instability improved from sigma_y(1 ms) = $7.9 \times 10^{-12}$ to $4.6 \times

arXiv:2605.25063v1 Announce Type: new Abstract: Reinforcement learning offers a promising approach for scan-order optimisation in laser additive manufacturing, where sequential scan decisions critically influence thermal accumulation, residual stress, distortion, and final part quality. A central challenge in applying RL to this domain lies in reward and world-model fidelity: full finite-element analysis is computationally prohibitive for dense in-the-loop evaluation, while cheap thermo-inspired proxy metrics, though efficient, may capture only partial aspects of the true thermo-mechanical objectives. This paper investigates a bilevel Proxy--FEA diagnostic framework for reward and world-model diagnosis in reinforcement-learning-guided scan-order optimisation. The lower level employs lightweight scan-path and thermo-inspired proxies for rapid candidate generation and preliminary policy-side screening, while the upper level utilises sparse Abaqus FEA simulations to provide

Flashes of femtosecond laser light, lasting just a few trillionths of a second, have made it possible to observe new magnetic structures for the first time. By using light as a remote control, researchers were able to switch magnetism into previously unseen three-dimensional states at the nanoscale.

Recently, UV laser engraving became an indispensable technology in modern industries where accuracy and precision in surface modification

arXiv:2605.23620v1 Announce Type: new Abstract: Laser-induced cavitation under nanosecond optical breakdown is central to applications such as laser-induced forward transfer, microsurgery, and microfluidic actuation, yet the physical origin of the earliest cavity and its connection to subsequent bubble growth remain unresolved. Existing models typically describe bubble formation either as a plasma-driven mechanical response or as a thermally driven nucleation process, without resolving how these mechanisms interact during inception. Here, we developed a coupled plasma-thermal framework that unifies free-electron dynamics, plasma absorption, thermoelastic acoustic response, residual thermal energy retention, and post-inception bubble evolution within a single description. The model shows that bubble inception is governed primarily by plasma-induced thermoelastic acoustic relaxation, which generates transient tensile rarefaction pressures sufficient for cavitation on nanosecond

arXiv:2605.22835v1 Announce Type: new Abstract: Technologies that require surface wetting or evaporative cooling require the ability to efficiently spread fluids across large areas, as increased wetted surface area increases evaporative flux. However, the intrinsic surfacial and bulk properties of most engineered materials substantially limit the rate and magnitude of surface wetting and lack control of flow direction, preventing them from rapidly wetting large surfaces. Here, we introduce our approach for rapid and controlled wetting of surfaces by laser-engraving channel networks that provide pathways for rapid, long-distance (cm-dm scale) capillary fluid propagation across the area, while the intrinsic material properties enable slow, short-distance (mm-cm scale) surface wetting. We investigated this approach on hardened cement paste and showed that laser engraving is a fabrication-friendly, scalable, and reproducible solution for creating channels with properties conducive to

arXiv:2605.22577v1 Announce Type: new Abstract: In this work, we introduce a non-volatile heterogeneous quantum dot (QD) III-V/Al2O3/Si distributed feedback (DFB) laser exhibiting optical memristive behavior. The device operates in the O-band (~1300 nm) with a threshold current density of 234 A/cm2 and a side-mode suppression ratio exceeding 48 dB. Co-integrated Al2O3-based memristors produce bipolar resistive switching, yielding non-volatile wavelength shifts of ~ 46 pm and ~ 17 dB peak power contrast with zero static holding power. The III-V/Al2O3/Si heterojunction memristor I-V hysteresis is also modeled. This new device enables simultaneous coherent light generation and persistent optical state storage, establishing a new class of active photonic memory for neuromorphic and reconfigurable WDM applications.

arXiv:2605.22152v1 Announce Type: new Abstract: Controlled interaction of laser light with electron beams is fundamental for ultrafast electron microscopy and electron-based quantum optics, yet their direct coupling is forbidden in free space. Here we use longitudinally polarized light at a thin membrane and show that the emerging focal fields can modulate the electron beam in a direct, coherent and linear way, without the need for nanostructured materials or slanted interaction geometries. Also, we use vectorial polarizations to excite and probe three-dimensional nanophotonic near-fields in metallic mesocrystals by coherent electron energy gain and loss. We find that longitudinal electric fields excite axial near-fields in a direct way while longitudinal magnetic fields excite oscillating ring currents via azimuthal electric fields. These possibilities enable tilt-free, collinear generation of attosecond electron pulses or free-electron qubits and provide novel imaging modes in

arXiv:2605.22033v1 Announce Type: new Abstract: We study theoretically the lasing synchronization of the two arrays of lasers with the complex mode dispersion, separated by a spectrally detuned barrier. We demonstrate that for lasing at the Dirac point, the synchronization persists for an order of magnitude higher barriers than in the arrays with a usual parabolic dispersion or a purely dissipative coupling. We interpret this effect as the Klein tunneling of the laser coherence through the barrier. Our numerical findings are supported by an analysis of the delocalization of the linearized eigenmodes of the arrays, which enhances the synchronization.

arXiv:2605.21073v1 Announce Type: new Abstract: Thin-film lithium niobate (TFLN) electro-optic modulators are attractive for high-speed optical interconnects, but scalable transmitter architectures require not only high modulation bandwidth but also multi-channel optical power distribution and practical laser-to-chip integration. Here, we demonstrate a hybrid-integrated 1 * 8 TFLN electro-optic modulator array passively butt-coupled to a 1550 nm distributed-feedback laser. The chip integrates a three-stage cascaded 1 * 2 multimode-interference splitter, spot-size converters, eight traveling-wave Mach-Zehnder modulators, thermal tuning electrodes, and on-chip 50 {\Omega} terminations. The cascaded splitter provides uniform optical power distribution with a maximum normalized power deviation of 9.7%, while the optimized electrodes enable electro-optic 3 dB bandwidths exceeding 40 GHz for all channels. The measured half-wave voltages are 3.60-3.83 V, corresponding to V{\pi}L products of

arXiv:2605.20647v1 Announce Type: new Abstract: Achieving diffraction-limited focusing of high-power laser pulses to generate ultra-high intensities is crucial for developing compact laser-driven particle accelerators and exploring strong-field quantum electrodynamics. However, accurately diagnosing and optimizing the focal spots of petawatt (PW) laser pulses remains a significant challenge. In this work, we present an experimental methodology utilizing a twin-focus scheme to precisely characterize the intensity distribution and wavefront of focused PW femtosecond laser pulses, and employ it to elucidate their power-dependent evolution. Furthermore, we optimized the focal spots at full power via our in-situ wavefront correction method termed ``HotLoop', achieving a Strehl ratio of 0.80 for 1 PW laser pulses. Consequently, the cutoff proton energies in laser proton acceleration experiments were significantly enhanced. The success of this approach underscores the necessity of in-situ

arXiv:2605.19318v1 Announce Type: cross Abstract: Amorphization of silicon is crucial to applications in photonics, microelectronics and solar cell technologies. Ultrafast lasers have been used to generate amorphous silicon from crystalline silicon using rapid nonthermal melting and solidification in room temperature. As material temperature can affect cooling rates significantly, adding temperature control in ultrafast laser modification of silicon may allow a new degree of freedom in ultrafast laser modification. In this work, we investigate the role of cryogenic temperature in governing ultrafast damage pathways via single-shot femtosecond laser irradiation of silicon from room temperature down to 24K at 1030nm. Across this temperature range, we observe a pronounced enhancement of amorphization at lower temperatures, revealed through optical microscopy, Raman spectroscopy, and Kelvin probe force microscopy (KPFM). Raman analysis identifies this ring as an amorphous surface layer,

arXiv:2605.20042v1 Announce Type: new Abstract: The present study considers the operation of a laser that incorporates a photonic time crystal (PTC), the purpose of which is to generate a field characterised by multiple widely separated optical frequencies. This laser is the subject of both a proposal and theoretical investigation. The laser comprises an active medium and a PTC within a small cavity constructed from two photonic crystals that are positioned in an overlapping configuration. PTC is modulated by an external field. The spikes in the laser field spectrum are separated by the PTC modulation frequency. The development of a quantum model of the laser with PTC has been achieved, and the analysis of a lasing mode with multi-frequency spikes has been made. The investigation focused on the study of lasing conditions, output power, and the lasing field spectra. The experimental realization of the multi-frequency laser with PTC under realistic conditions is discussed.

arXiv:2605.18969v1 Announce Type: new Abstract: We report the first experiment investigating ion acceleration and neutron generation irradiating thin plastic targets (CH2) and deuterated plastic targets (CD2) of thickness ranging from 30nm to 160nm using the 4PW (0.1 Hz) laser at CoReLS in South Korea. Thin wedge-shaped filters exploiting differing stopping ranges were designed to distinguish carbon 6+ ions from deuterons in shots with CD2 targets. The maximum energies of all ion species from both CH2 and CD2 targets were found to increase linearly with the laser intensity. The highest observed energy of each ion species scales as q (charge)^2/mass, which is more similar to the scaling expected for ponderomotive acceleration than to the scaling expected for TNSA. The maximum ion energies were also found to increase with target thickness. Utilizing the secondary interactions of the deuteron beam, we created a fast neutron source via deuteron breakup reactions on a copper converter. The

arXiv:2605.18968v1 Announce Type: new Abstract: Laser-driven neutron sources offer ultrashort pulse durations and extreme peak fluxes inaccessible to conventional facilities, enabling novel time-of-flight(TOF) spectroscopy and nuclear astrophysics measurements. We present the first complete start-to-end simulation comparison of deuterium-deuterium (DD) bulk fusion and laser wakefield acceleration-driven photonuclear neutron sources, evaluated for fast neutron capture relevant to the r-process. The simulation chain couples particle-in-cell modeling of the laser-plasma interaction, Geant4 Monte Carlo neutron transport with shielding and background characterization, and a NON-SMOKER-based event generator for multi-neutron capture on Au197 and Rh103. We derive scaling laws for neutron yield, pulse duration, and peak flux from 1J terawatt to 250J petawatt-class systems, including DD bulk fusion scaling laws specific to the short-pulse regime where volumetric ion heating via plasma

In the HiPEQ project, a consortium of industry and research partners has developed new laser-based approaches to enable miniaturized, robust beam sources for quantum technology. Among others, the consortium also used lasers to grow novel optical insulator crystals. The project achieved significant progress from November 2021 to July 2025. Fraunhofer ILT in Aachen played a key role by co-developing the laser processes needed.

Gold nanoparticles, which are about one-thousandth the width of a human hair, can convert light they receive from a laser into heat. This capacity, known in medicine as photothermal therapy, is effective at destroying cancer cells without harming the surrounding healthy tissue. It's one of the techniques the scientific community is exploring in depth as an alternative chemotherapy, as it is less aggressive.

arXiv:2605.17363v1 Announce Type: cross Abstract: Single-layer molybdenum disulfide ($MoS_2$) possesses significant potential for nanoscale optoelectronics, but achieving high-intensity, long-term-stable photoluminescence (PL) emission remains a challenge. In this work, we demonstrate a remarkably robust, more than 8-fold maximum enhancement in the PL intensity of exfoliated and CVD-grown single-layer $MoS_2$ via a non-destructive ultraviolet (UV) laser treatment method. This substantial increase in radiative efficiency is accompanied by a trion-to-neutral exciton transition in the PL signal and a corresponding blue shift of the Raman $E_{2g}^1$ and $A_{1g}$ vibrational modes, signaling successful electron depletion (p-doping) and formation of Mo-O bonds, respectively. Furthermore, we demonstrate precise spatial control over PL properties by confining PL treatment exclusively to the UV laser-treated area. Crucially, the enhanced PL performance shows exceptional longevity; the CVD

arXiv:2605.18527v1 Announce Type: new Abstract: We present a systematic experimental comparison of single-pass second-harmonic generation (SHG) in bismuth triborate (BiBO) and lithium triborate (LBO) nonlinear crystals, driven by a 1.3 ps, 91 kHz laser at 1030 nm with up to 57 W of average input power. Both crystals yielded 32 W of second harmonic (SH) output at 515 nm, corresponding to a conversion efficiency of 56 %, which to the best of our knowledge represents the highest SH output power reported in the green spectral region using a BiBO crystal. Power dependence, long-term stability, beam quality, pulse duration, spectral properties, thermal effects, and angular acceptance bandwidth are characterized and directly compared for both crystals. These results provide quantitative performance benchmarks to guide the selection of nonlinear crystals for high-average-power, ultrashort-pulse frequency conversion near 1030 nm.

arXiv:2605.18336v1 Announce Type: new Abstract: Plasma wakefield excitation driven by two color Laguerre Gaussian laser pulses carrying orbital angular momentum is investigated analytically and through quasi-cylindrical particle in cell simulations. Using a perturbative framework together with the quasistatic approximation, the influence of the transverse laser mode structure on the longitudinal and transverse wakefields in an underdense plasma is examined in the weakly relativistic regime. The results show that drivers with finite azimuthal index produce reduced and less regular on-axis longitudinal wakefields compared to conventional Gaussian drivers. However, radial longitudinal field distributions reveal that this reduction originates from a redistribution of the wakefield energy toward finite radii rather than a simple loss of wake excitation. Orbital angular momentum carrying modes generate hollow and ring shaped wake structures accompanied by strongly modified transverse

arXiv:2605.16763v1 Announce Type: new Abstract: We have experimentally investigated the spectral characteristics and spatial structure of femtosecond pulses from a titanium:sapphire laser during filamentation in an optical cell filled with argon at pressures up to 40 atm under pressure shock-drop conditions. This leads to the development of strong jet flows and vortex gas turbulence, which in turn triggers the early onset of multiple filamentation of the optical pulse and largescale broadening of its spectrum throughout the entire duration of the pressure drop. The magnitude of this spectrum broadening can reach 80 nm and is proportional to the initial gas pressure. Using computational fluid dynamics simulations, we studied the dynamics of the emergence, development, and relaxation of stimulated turbulence in compressed gas in the region of the cell outlet valve and assessed the effect it exerts on the propagating femtosecond pulse. The revealed regularities may serve as the basis for

arXiv:2605.16039v1 Announce Type: cross Abstract: The creation and exploration of new materials under extreme pressure-temperature conditions has become increasingly reliant on laser-heated diamond anvil cell (LHDAC) techniques, which provide direct access to previously unexplored regions of multinary phase diagrams. Whereas numerous high-pressure phases have been identified in situ, systematic recovery and post-synthesis physical property characterization of these materials remain significant challenges. In this work, we present the development of an integrated LHDAC synthesis and demonstrate a practical LHDAC-based synthesis workflow that enables stabilization and recovery of metastable intermetallic phases for subsequent structural and transport studies. Using this approach, we successfully achieved LHDAC synthesis of high-pressure MnSb2 and YbZn2 phases under moderate pressures. Synchrotron X-ray diffraction and spatial mapping confirm dominant formation of the targeted phases,

arXiv:2605.16206v1 Announce Type: new Abstract: We present fully kinetic two-dimensional, three-velocity-component (2D3V) PIConGPU simulations of a three-beam direct-drive interaction with a 15 $\mu$m solid-density cryogenic hydrogen cylinder, establishing a predictive numerical baseline for the operational DRACO ($\tau=30$ fs) and upcoming PENELOPE ($\tau=150$ fs) laser facilities at HZDR. The simulations resolve charge-separation fields on the order of 3 TV/m and reveal a robust kinematic bifurcation of the accelerated population into a fast (1-5 MeV) ion beam and a slower bulk (1-100 keV) flow. We demonstrate analytically and numerically that the charge-separation front ($v_{hb}$) is an intrinsically non-quasi-neutral electrostatic double layer that lies outside the closure assumptions of radiation-hydrodynamic models. A simple $2v_{hb}$ reflection scaling derived directly from the front trajectory tracks the centroid of the constant-energy fast-ion band under the impulsive 30 fs

arXiv:2605.16014v1 Announce Type: new Abstract: From the synthesis and evolution of the elements to the celestial nuclear processes of stellar explosions and neutron star mergers, nuclear physics is the foundation of our understanding of the universe. After more than a century of progress, the field of nuclear physics remains vibrant. The rapid advancement of laser technology has opened unprecedented avenues in nuclear physics, driven by the interdisciplinary convergence of laser physics, nuclear structure, plasma science, and quantum dynamics. This emerging field enables studies on laser-induced nuclear excitation, laser assisted nuclear decay, and precision manipulation of nuclear isomers for optical clocks. This review comprehensively examines the research achievements over the past decade regarding the influence of lasers on radioactive charged particle emissions and nuclear excitation. Regarding theoretical developments, the review details various methods used to evaluate the

Carbon dioxide laser resurfacing plus isotretinoin is safe and effective for treating rhinophyma, new research suggests, despite past warnings about combining the modalities.

arXiv:2605.14129v1 Announce Type: new Abstract: Merging direct and indirect-drive has long been viewed as an optimal hybrid laser-fusion scheme that combines the uniformity of x rays with the efficiency of direct illumination. We present the first integrated 2D simulations of hybrid shock drive (HSD) targets for the OMEGA laser. The HSD scheme [L. Ceurvorst et al., Phys. Rev. E 101 063207 (2020)] uses x rays from a thin Au-coated x-ray converter outer shell to drive the initial shock into a standard direct-drive capsule. Direct illumination is used to implode the target after the first shock. The design effectively suppresses laser-imprint seeding of hydrodynamic instabilities, maintaining shell integrity during the implosion. This scheme will enable fielding low-adiabat, high-convergence implosions on OMEGA with expected performance greatly exceeding those of current designs. HSD targets are projected to significantly enhance fusion yields, potentially increasing the record Lawson

The use of CO2 laser to excise lesions in patients with severe hidradenitis was effective and well-tolerated in a small retrospective review.

arXiv:2605.13327v1 Announce Type: new Abstract: Laser ablation in liquids enables the synthesis of surfactant-free nanoparticles but remains limited in productivity due to intrinsic constraints imposed by the liquid environment. These constraints include nonlinear optical losses, material redeposition, and cavitation bubble-induced shielding. Temporal intensity shaping of the incident laser pulse offers a potential route to mitigate these limitations. Here, ultrashort GHz-burst ablation is applied to laser ablation of gold in water. By distributing the pulse energy into a sequence of picosecond sub-pulses arriving within the nanosecond time window preceding cavitation bubble formation, GHz-burst irradiation enables energy delivery before the onset of bubble-induced shielding. This increases the threshold fluence for nonlinear losses and yields an ablation efficiency enhancement of up to a factor of three compared to single-pulse ablation. Importantly, this efficiency gain is not

arXiv:2605.13191v1 Announce Type: new Abstract: Achieving reliable joining between transparent materials and metals under non-optical-contact conditions remains challenging due to limited energy coupling and uncontrolled interfacial reaction across $\mu$m-scale gaps. Burst-mode ultrafast lasers provide a potential solution for large-gap welding through temporally distributed energy deposition. However, the underlying interaction mechanisms and achievable joining limits remain unclear. In this study, burst-mode ultrafast laser welding of sapphire to Invar alloy was investigated under controlled interfacial gaps from 3 to 10 $\mu$m. Cross-sectional microscopy, elemental mapping, white-light interferometry, and shear testing were employed to analyze joint morphology, elemental distribution, fracture behavior, and mechanical performance.After optimization of the processing parameters for burst-mode ultrafast laser welding, the interfacial morphological evolution and joint strength under

arXiv:2605.13118v1 Announce Type: new Abstract: We report on a feasibility study conducted at the ELBA facility at ELI Beamlines in 2025 to investigate the possible production of muons from high-energy electron beams generated by extended laser-plasma interactions in optically generated plasma waveguides. Our team operated a portable, autonomous, and compact telescope based on Resistive Plate Chamber (RPC) detectors, positioned to detect high-penetration charged particles originating from the beam dump. The campaign demonstrated that RPC detectors can operate reliably and safely in the ELBA environment, even under intense radiation and electromagnetic conditions. The collected datasets, though statistically limited and affected by lack of beam control, allow detailed characterization of the background and validated the detectors' stability and tracking performance. These results confirm the feasibility of the approach and provide the foundation for a dedicated future run under

A research team led by Hee-jung Lee, senior researcher at Korea Institute of Materials Science (KIMS), in collaboration with Professor Sunghwan Park of Kyungpook National University and Professor Mingyu Kim of Yeungnam University, has developed a technology that enhances CO₂ adsorption performance in metal–organic frameworks (MOFs) by up to 75% through precise laser-based control of their internal structure.

Until now, it has been technically nearly impossible to rotate highly sensitive samples in all directions under a microscope without making contact. Researchers at the Karlsruhe Institute of Technology (KIT) have developed a new laser-based technique that allows microscopic samples such as cells to be rotated contact-free in all three spatial directions. The laser creates tiny temperature differences in the liquid, which trigger gentle fluid flows that move the sample. This protects delicate samples and enables more accurate three-dimensional images—an important step for basic medical research.

Until now, it has been technically nearly impossible to rotate highly sensitive samples in all directions under a microscope without making contact.

arXiv:2605.10222v1 Announce Type: cross Abstract: Test-mass thermal noise is a limiting noise source for current and next-generation ground-based gravitational-wave observatories. Uniform-intensity higher-order laser beams, including Laguerre-Gaussian (LG) and Hermite-Gaussian (HG) modes, have been proposed as alternatives to the fundamental Gaussian beam due to their thermal-noise advantages. As interferometer power increases toward the megawatt regime, thermal aberrations from absorption in the test-mass coatings become increasingly significant. In this work, we quantify the robustness of higher-order modes against absorption-induced thermal deformation. We show that, under identical operating conditions, higher-order modes produce substantially more uniform thermal distortions than the fundamental mode, requiring significantly less thermal compensation power. The optimal curvature correction is reduced to 33% for the LG$_{2,2}$ mode and 24% for the HG$_{3,3}$ mode relative to the

arXiv:2605.09816v1 Announce Type: new Abstract: High brightness and low coherence laser sources with wideband tunability are essential for many full-field imaging applications aiming for high contrast and speckle free performance. However, this combination of parameters is challenging to achieve. The current solutions focus on decreasing spatial coherence or generation of time-varying speckle patterns, while suppression of temporal coherence typically compromises brightness. Here we demonstrate a wideband pulsed laser source with low temporal coherence and the absence of phase correlation between pulses as an alternative approach with simultaneous time and frequency diversity. The full gain spectrum of a Tm doped fiber laser (1650 nm 2000 nm) is operated in a tunable noise like pulse regime, which by nature is composed of countless structured elementary events with uncorrelated phases randomly varying from bunch to bunch. The measured spectral widths range from 13.8 nm to 18.8 nm,

arXiv:2605.09574v1 Announce Type: new Abstract: Laser-plasma acceleration produces ultrashort, high-brightness ion beams reaching tens of MeV, yet their large divergence and broad energy spread require dedicated capture elements for beam transport. Using laser-accelerated protons from the GSI PHELIX laser to the LIGHT beamline as a reference, we developed a framework to optimize and assess such combined capture and transport systems, with emphasis on injection into conventional accelerators. In addition to our numerical analysis we derive scaling laws linking transmission and chromatic emittance growth to the initial half-opening angle, showing that the present performance is primarily divergence-limited. We also estimate and predict the longitudinal bunch quality and quantify the divergence reduction needed to approach injector-relevant intensities.

arXiv:2605.09191v1 Announce Type: new Abstract: The energy distribution of energetic protons inside a solid target is a key quantity governing nuclear reaction yields and energy deposition in high-intensity laser-driven fusion, including nonthermal proton--boron (p--B) schemes and proton fast ignition. Yet it has remained inaccessible to conventional particle diagnostics, which detect only ions escaping the target and are perturbed by intense plasma electromagnetic fields. Here we establish a quantitative diagnostic that uses nuclear activation reactions occurring within the target itself as an internal probe of the in-solid proton energy distribution. Applied to laser-driven p--B fusion experiments on the kJ-class laser, the method reconstructs an exponential-equivalent in-solid proton energy distribution from the absolute yields of $^{11}\mathrm{C}$ and $^{7}\mathrm{Be}$ produced via $\mathrm{^{11}B(p,n)^{11}C}$ and $\mathrm{^{10}B(p,\alpha)^{7}Be}$, and yields the absolute number

A novel technology using nano-sized ultrafine water clusters is associated with significant reduction in the erythema that occurs post-laser treatment, new research shows.

arXiv:2605.07216v1 Announce Type: cross Abstract: This paper presents a high-precision gravitational redshift test using the China Space Station (CSS) Laser Time Transfer (CLT) system. We develop a comprehensive observation equation based on a c^{-3} order relativistic model for space-ground clock comparison. While the CSS optical clock system is currently in the orbital debugging phase, our simulation using actual CSS orbit data achieves a gravitational redshift verification precision of (1.8 \pm 47)*10^{-7} -- approximately one order of magnitude improvement over previous experiments. Our work represents the first application of laser-based time transfer for gravitational redshift verification at such precision, and the first use of the CSS CLT link for testing this fundamental aspect of General Relativity. Unlike microwave-based methods, our laser approach avoids ionospheric effects and first-order Doppler shifts. Residual analysis identifies tropospheric delay variations and

MIT researchers discovered a paradoxical phenomenon in optical physics that could enable a new bioimaging method that’s faster

Over the past few decades, some physicists worldwide have been investigating unusual particle-like magnetic structures known as topological solitons. These structures could potentially be leveraged to develop new cutting-edge technologies, such as new magnetic memory devices and computing systems.

arXiv:2605.05762v1 Announce Type: new Abstract: Optical microcavities with rotational symmetry have been widely used for narrowing linewidth and reducing frequency noise, however, the narrow but wavelength dependent optical feedback restricts the narrow linewidth laser works only at some discrete wavelength matching the resonance of the microcavity. Here, we demonstrate a narrow linewidth semiconductor laser with continuous wavelength tunability by hybrid integrating a DFB laser chip with a deformed microcavity fabricated on a 220 nm SOI wafer. The deformed microcavity with vortex radius demonstrates the unique characteristics of unidirectional energy storage, wavelength self-adaptivity, and self-focusing of the Rayleigh scattering based distributed feedback. In addition, the strength of Rayleigh scattering is also significantly enhanced by the high numerical aperture silicon waveguide. The optical feedback signal measured by the optical frequency domain reflectometry (OFDR) shows

arXiv:2605.05614v1 Announce Type: new Abstract: Proton radiography of laser direct-drive spherical implosions has shown anomalous structures that correspond to strong electric or magnetic fields extending throughout the corona. These fields have the ability to affect laser-target interactions and act as an energy sink. To better understand the these fields, simplified experiments were conducted in planar geometry on the OMEGA EP laser at the Laboratory for Laser Energetics. Varying target material, target size, pulse shape, and intensity, and measured the field structure using dual-axis proton radiography and a 4w probe. Proton radiographs were analyzed and quantitatively demonstrate that the growth of these features is dominated by laser energy and target Z. The data strongly supports that a secondary instability as a consequence of the expansion driven Weibel instability in these interactions is the primary driver for these fields.

arXiv:2605.05465v1 Announce Type: new Abstract: The prediction of aircraft icing is conventionally performed using multishot simulation frameworks that fail to predict the progressive roughening of the ice surface. To understand roughness formation, we investigate droplet impingement on clean and laser-scanned rough ice shapes using a high-fidelity computational framework based on wall-modeled large-eddy simulations and Lagrangian particle tracking. This methodology is validated against experimental data for a NACA 23012 airfoil and a NACA 64A008 swept tail, accurately predicting collection efficiency and supercooled large droplet splashing. The framework is subsequently applied to laser-scanned rime ice geometries to quantify the impact of surface roughness on local impingement distributions. The results reveal that physical roughness induces a highly nonuniform collection efficiency, with droplet impingement intensely concentrated on upstream-faces of roughness elements, creating

Quantum batteries can be charged remotely and could allow for far better energy density than conventional batteries used in devices today.

Why Ink-Based Branding Creates Waste on Stainless Hardware Stainless hardware is built to last. Handles, brackets, plates, tags,

arXiv:2605.03918v1 Announce Type: new Abstract: The centroid oscillation of an offset laser pulse propagating in a preformed plasma channel is investigated through theoretical analysis and three-dimensional particle-in-cell simulations. For non-relativistic laser pulses, the mode leakage of a finite channel and the temporal walk-off between the fundamental and high order modes of a finite-duration laser induce a decay in the laser centroid oscillation. An analytical model characterizing these decay mechanisms is derived and validated by simulations. For relativistic laser pulses, the slice-based centroid oscillation frequency develops an axial chirp due to relativistic channel modification and photon deceleration. This chirp leads to phase mixing across different axial slices of the pulse, resulting in a rapid damping of the overall centroid oscillation. Understanding this oscillation damping is crucial for mitigating electron beam pointing jitter and maintaining beam quality in

arXiv:2605.03296v1 Announce Type: new Abstract: We develop a microscopic open-quantum-system theory for a radiation-balanced solar laser (RBSL) based on ytterbium-doped yttrium aluminum garnet (Yb:YAG), in which optical gain, thermal redistribution among sublevels of the electronic ground and excited manifolds, and lattice-temperature dynamics are treated within a unified framework. Starting from a Lindblad master equation for a multilevel gain medium coupled to a cavity mode, we include incoherent solar pumping, spontaneous emission, cavity loss, and phonon-assisted intra-manifold relaxation obeying detailed balance. In the regime of fast thermalization within each electronic manifold, a compact temperature-dependent two-level model is derived, in which the gain, inversion, and lasing threshold are controlled by Boltzmann occupation factors and partition functions of the electronic sublevels. This microscopic reduction is then coupled self-consistently to a thermal balance equation

arXiv:2605.03157v1 Announce Type: new Abstract: Spectroscopy of laser-produced plasmas offers an avenue for real-time, standoff and non-preparatory sensing of rare-earth elements (REEs) within a mineralogical context with applications spanning exploration geology to ore body mapping to ore sorting. Demonstrations of laser-induced breakdown spectroscopy (LIBS) in rock samples have employed both atomic and molecular detection for REE sensors. In this work we evaluate a complementary technique of absorption spectroscopy, realized with dual-frequency combs. This approach provides multi-THz (nm) spectral coverage with simultaneous sub-GHz (pm) resolution. It can improve accuracy and line identification confidence in congested multi-species spectra, which makes it ideal for multi-species evaluations present within mineralogical samples. We analyze REE signatures in calibrated reference materials (CRMs) and a synthesized, REE-containing alloy for atomic, ionic and molecular (oxide)

arXiv:2605.02406v1 Announce Type: new Abstract: Optical clocks require an ultra-stable laser to probe and precisely measure the frequency of the narrow-linewidth clock transition. We introduce a portable ultraviolet (UV) laser system for use in an aluminum quantum logic clock, demonstrating a fractional frequency instability of approximately $\mathrm{mod}\,\sigma_\mathrm{y} = 2 \times 10^{-16}$. The system is based on an ultra-stable cavity with crystalline AlGaAs/GaAs mirror coatings, alongside with a frequency quadrupling system employing two single-pass second harmonic generation (SHG) stages. Its acceleration sensitivity, measured in all three axes, does not exceed $4(2) \times 10^{-12}$/(ms$^{-2}$) and is among the lowest recorded for transportable systems to date. Additionally, partial cancellation between photo-thermal noise and photo-birefringence noise is used to effectively mitigate noise induced by intra-cavity optical power fluctuation at lower Fourier frequencies.

arXiv:2605.01840v1 Announce Type: new Abstract: Wakefield structures are critical for beam manipulation in free-electron lasers (FELs), particularly when serving as dechirpers, where beam-induced longitudinal wakefields compensate the energy chirp introduced during beam magnetic compression. However, conventional planar structures also generate time-dependent quadrupole wakefields due to their asymmetric geometry, which can cause beam mismatch and projected emittance growth. To address this limitation, we propose a quadripartite wakefield structure comprising four identical corrugated plates, able to fully suppress quadrupole wakefields while preserving strong longitudinal wakefields. To accurately evaluate its performance, we calculate wake potentials based on the Panofsky-Wenzel theorem using three-dimensional simulation software and extract the corresponding wake functions by deconvolution. We further adopt a particle-to-particle (P2P) tracking method incorporating these wake

arXiv:2605.01306v1 Announce Type: new Abstract: Laser absorption spectroscopy (LAS) is a well-established technique for non-intrusive measurement of gas species in combustion and atmospheric environments, but conventional methods struggle with multi-species mixtures under dynamic or interference-laden conditions. Overlapping spectral features, noise, and incomplete reference data limit reliability when unknown or weakly absorbing species are present. This dissertation develops diagnostics combining LAS with machine learning (ML) to address these limitations. Deep denoising autoencoders (DDAEs) are applied to shock-tube measurements during high-speed hydrocarbon pyrolysis, improving signal fidelity and detection limits for trace species. A structured unsupervised framework, HT-SIMNet, then mitigates interference from unknown species without full calibration data, using spectral augmentation and a Noise2Noise-inspired scheme to isolate species in reactive systems. Where reference

arXiv:2605.01125v1 Announce Type: new Abstract: Rapid and controllable reduction of graphene oxide (GO) remains a critical challenge for realizing its full technological potential. Here, we report efficient reduction of GO by a synergistic electron-beam-assisted single-pulse near-infrared (NIR) laser process. Time-resolved electron energy-loss spectroscopy measured with a dynamic transmission electron microscope (DTEM) is used to locally track the oxygen concentration evolution after NIR laser pulse irradiation. This finds an oxygen diffusivity of 1.6 +/- 0.4 x 10$^{-8}$ m$^2$/s, which corresponds to 90% reduction of a 46-nm thick film within 960 ns. Electron beam irradiation is found to change the optical absorptivity of GO in the NIR region and the thermal heating cycle resulting from the laser pulse is simulated. Structural characterization via selected-area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) finds localized restoration of

arXiv:2605.01306v1 Announce Type: cross Abstract: Laser absorption spectroscopy (LAS) is a well-established technique for non-intrusive measurement of gas species in combustion and atmospheric environments, but conventional methods struggle with multi-species mixtures under dynamic or interference-laden conditions. Overlapping spectral features, noise, and incomplete reference data limit reliability when unknown or weakly absorbing species are present. This dissertation develops diagnostics combining LAS with machine learning (ML) to address these limitations. Deep denoising autoencoders (DDAEs) are applied to shock-tube measurements during high-speed hydrocarbon pyrolysis, improving signal fidelity and detection limits for trace species. A structured unsupervised framework, HT-SIMNet, then mitigates interference from unknown species without full calibration data, using spectral augmentation and a Noise2Noise-inspired scheme to isolate species in reactive systems. Where reference

arXiv:2605.02201v1 Announce Type: new Abstract: Airborne Laser Scanning (ALS) can collect point clouds across large areas, enabling large-scale forest inventory. However, ALS point clouds are sparse and noisy, resulting in inaccurate individual-tree-level forest inventory, such as stem localization and tree size estimation. To overcome this problem, we propose a deep learning model, 3D Forest Super Resolution (3DFSR), to simultaneously improve point density and reduce noise for ALS forest point cloud. 3DFSR is a voxel-based CNN with a U-Net architecture. The proposed 3DFSR is evaluated on ALS point clouds collected in both temperate forests in the U.S. and boreal forests in Germany. Experimental results demonstrate that 3DFSR can generate finer point clouds of tree structure than other state-of-the-art point cloud super-resolution algorithms, achieving 0.249 m Chamfer Distance and 2.711 m Hausdorff Distance. Furthermore, to verify the effectiveness of 3DFSR point clouds in forest

arXiv:2605.01100v1 Announce Type: new Abstract: This work presents a knowledge-driven decision-support system that integrates structured defect knowledge with LLM-based reasoning to provide explainable defect diagnosis and mitigation guidance in manufacturing, using LPBF as a representative, safety-critical case study. The proposed ontology-integrated LLM-based decision support system for LPBF defect analysis and mitigation guidance is built on a knowledge base containing 27 known LPBF defect types organized into hierarchical categories and causal relationships. The developed system supports fuzzy natural language queries for systematic knowledge retrieval, literature-supported explanation of defects, and guidance on defect causes and mitigation strategies derived from encoded process knowledge. Furthermore, a multimodal image-assessment module based on foundation models enables descriptor-guided interpretation of representative microscopic defect images through semantic alignment

arXiv:2605.00527v1 Announce Type: cross Abstract: Lissajous confocal laser endomicroscopy (CLE) is a promising solution for high speed in vivo optical biopsy for handheld scenarios. However, Lissajous scanning traces a resonant trajectory and samples only the visited pixels per frame; at high frame rates, many pixels remain unvisited, creating structured holes. In this work, we introduce the first benchmark for high-rate Lissajous CLE, consisting of low-quality video clips paired with high-quality reference images. The reference images are wide-FOV mosaics obtained by stitching stabilized, slow-scan frames of the same tissue, enabling temporally aligned supervision. Using this dataset, we propose MIRA, a lightweight recurrent framework for Lissajous CLE restoration that iteratively aggregates temporal context through feature reuse and displacement alignment. Our experiments demonstrate that MIRA outperforms both lightweight and high-complexity baselines in restoration quality while

In a striking glimpse into extreme physics, scientists have captured the split-second chaos that unfolds when powerful laser flashes blast matter into a superheated plasma. By combining two cutting-edge lasers, researchers were able to track how copper atoms lose and regain electrons in trillionths of a second, creating and dissolving highly charged ions in a rapid, almost cinematic sequence.

Millions of people watched the historic launch of Artemis II and were captivated by the mission's 10-day journey around the moon as NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen ventured farther into space than any human before. Part of the public's ability to experience the mission in high-definition was due to laser communications.

arXiv:2604.27941v1 Announce Type: new Abstract: The colonisation of extraterrestrial planets requires sustainable food production independent of Earth-based supplies. Due to the high costs and complicated logistics of food transport, in-situ cultivation will be essential. Growing plants directly in regolith offers a practical approach to achieve sustainable long-term human habitation beyond Earth. In this study, Laser-Induced Breakdown Spectroscopy (LIBS) technique was employed for bioimaging of broccoli (Brassica oleracea) and salad (Lactuca sativa) plants grown in Lunar regolith simulant and control substrate. For this purpose, the potential of the 2090 nm laser wavelength for bioimaging of plant tissue was studied compared to the conventional 1064 nm. The signal-to-noise ratio (SNR), total emissivity ($\epsilon_{\mathrm{tot}}$), and Mg II / Mg I intensity ratio (ionisation degree) were all higher when using the 2090 nm laser wavelength compared to 1064 nm. These findings indicate

arXiv:2604.27799v1 Announce Type: new Abstract: The excitation of plasma wakefields driven by chirped laser pulses is investigated using a reduced relativistic fluid Poisson model supported by fully relativistic particle in cell (PIC) simulations. The study considers exponential, linear, quadratic, and unchirped phase-modulated laser drivers propagating in an underdense plasma. Numerical solutions of the governing equations demonstrate that exponential chirping produces enhanced wakefield amplitudes compared to polynomial and unchirped cases due to nonlinear phase variation across the pulse envelope. The analytical predictions are validated using quasi cylindrical PIC simulations performed under identical plasma and laser parameters. The simulations reveal strong chirp dependent wakefield modification, with positively chirped pulses generating peak accelerating fields exceeding 58 GV per m, accompanied by pronounced density compression and enhanced electron momentum gain. These

arXiv:2604.27614v1 Announce Type: new Abstract: We present a comprehensive theoretical investigation of hyperfine-resolved excitation and detection of the low-energy isomeric state of $^{229}$Th in trapped $^{229}\mathrm{Th}^{3+}$ ions. Using a quantum master equation approach, we analyze the dependence of the isomeric population on laser linewidth, detuning, and irradiation time, showing that their proper matching is essential for efficient excitation. We further propose two nuclear-state detection schemes based on three hyperfine-resolved electronic fluorescence channels at 690, 984, and 1088 nm. Our analysis shows that the 690-nm and 984-nm scheme yields detectable photon rates on the order of $10^4~\mathrm{s}^{-1}$ per ion for each wavelength, whereas the 1088-nm scheme achieves a higher rate on the order of $10^5~\mathrm{s}^{-1}$ per ion. By quantifying the trade-off between irradiation time and scan-step size, we show that the nuclear transition can be located within one month

arXiv:2604.27165v1 Announce Type: new Abstract: The standard architecture for a high-peak-power femtosecond laser is chirped pulse amplification using diffraction gratings for compression; the damage threshold of the compression gratings limits current lasers to multi-petawatt peak power. Plasma gratings have orders-of-magnitude higher damage tolerance than conventional optics, so plasma gratings with sufficiently high optical quality could allow the construction of ultra-high-power femtosecond lasers. Here, we present experimental measurements of the angular dispersion, angular bandwidth, and diffraction angles of ionization-based plasma transmission gratings and show that both the dispersive and the diffractive properties of these gratings are in close agreement with optical theory and simulations. Gratings with a period of 10.2 microns are found to have an angular dispersion of approximately 0.005 degrees/nm. The dispersion and bandwidth of these gratings suggest plausible designs

arXiv:2604.27036v1 Announce Type: new Abstract: Storage ring-based steady-state microbunching (SSMB) is a promising approach for generating high-average-power coherent radiation, while the instabilities driven by coherent undulator radiation in the laser modulator (LM) is important for the ring performance. In this paper we investigate the longitudinal single-bunch multi-turn LM instability using cavity mode decomposition techniques. The evolution of the wakefield in the longitudinal beam dynamics equations are derived, and the instability growth rates are analyzed. Numerical simulations show excellent agreement with the theoretical model, validating the mode decomposition approach. These findings provide critical insights into the design and operation of SSMB storage rings, suggesting effective mitigation strategies to suppress the instability and enhance the overall performance.

Particle accelerators such as those at the European Organization for Nuclear Research (CERN) in Geneva are typically highly complex large-scale devices. In these ring-shaped facilities, which are often several kilometers in length, magnets and radio-frequency cavities are used to accelerate elementary particles. An alternative approach is now emerging: compact laser–plasma accelerators that can be built and operated at a fraction of the cost. These accelerators can achieve acceleration gradients up to around 1,000 times higher than those of conventional accelerators. Researchers at HHU contributed significantly to this development.

XPP, the X-ray Pump Probe instrument at the Linac Coherent Light Source (LCLS), is back online and welcoming researchers after a complete rebuild. The overhaul has readied XPP for the significant increase in X-ray output expected from the ongoing high-energy upgrade to LCLS at the Department of Energy's SLAC National Accelerator Laboratory. LCLS is a pioneering X-ray free-electron laser facility used by scientists around the world to capture ultrafast snapshots of natural processes.

arXiv:2604.26718v1 Announce Type: cross Abstract: Laser annealing offers a promising route to back end of the line fabrication of ferroelectric thin film transistors based on hafnium-zirconium oxide (HZO). Due to the wide band gap of this material, previous reports have studied the crystallization of HZO using ultraviolet or infrared light. In contrast, we monitor its crystallization in a Si3N4/TiN/Hf0.5Zr0.5O2 thin film heterostructure upon irradiation with visible nanosecond laser pulses. This geometry mimics the structure of CMOS devices and harnesses the absorption of TiN in the visible regime to generate the heat necessary for the transformation. Through a series of local in situ measurements using a modified transmission electron microscope, we quantify the relationship between the HZO film thickness, critical laser energy density and the ferroelectric HZO phase fraction, finding a sharp threshold behavior in the laser pulse energy necessary to crystallize HZO. The optimal

arXiv:2604.26705v1 Announce Type: new Abstract: We present a classical theory of relativistic surface plasmon (RSP) excitation at a smooth plasma-vacuum interface driven by either a ponderomotive force or an electric field of an intense laser pulse. Starting from Maxwell equations coupled to a cold-fluid plasma response, we derive a general driven wave equation for the RSP and solve it analytically. We show that an infinite planar surface enforces conservation of the in-plane wavevector. A finite longitudinal interaction length or axial modulation supplies a finite kz spectrum, while cylindrical curvature replaces one continuous transverse in-plane wavenumber by a discrete azimuthal mode index m. This partially relaxes the planar in-plane constraint, while axial phase matching remains controlled by the longitudinal spectrum of the drive. The excitation strength is controlled by the overlap between the drive and the surface eigenfield, which is determined by the surface geometry. This

arXiv:2604.26486v1 Announce Type: new Abstract: Achieving high-quality electron beams from laser wakefield accelerators critically relies on density tailoring to control electron dynamics during injection, acceleration, and extraction. We report on the experimental observation of electron beam acceleration and shaping, in transverse momentum and longitudinal phase space, controlled by plasma density tailoring in a gas cell. Electron beams with a FWHM charge of 40 pC at an energy of 190 MeV, 3.4\% energy spread and an rms divergence of 0.46 mrad, corresponding to a transverse momentum spread of 0.2 $m_e c$, have been measured. These beams have a peak spectral brightness of up to 8 pC/MeV/mrad. Simulations using experimental parameters as input show that acceleration in the plasma plateau leads to chirped electron beams which then undergo transverse momentum spread reduction in a plasma down-ramp followed by dechirping in a 10~mm long plasma tail, leading to the measured peaked spectra.

arXiv:2604.26377v1 Announce Type: new Abstract: Solving large, sparse linear systems is a fundamental workload in scientific computing and engineering simulations, often dominating runtime and energy consumption in high-performance computing (HPC) applications. In this work, we explore an alternative computing paradigm based on analog optical processing, implemented through the Laser Processing Unit (LPU). The LPU encodes linear systems into the dynamics of coupled lasers within an optical cavity, where the steady-state phases of the optical fields correspond to the solution of $Ax=b$. We present a mapping of general linear systems, both dense and sparse, onto the LPU architecture and evaluate its performance using representative matrices from the SuiteSparse collection. Using an LPU emulator, we benchmark convergence behavior and time-to-solution for sparse, multi-banded matrices against established Krylov subspace methods (CG, GMRES, BiCGSTAB, and others) executed on a modern GPU

The idea of sending a swarm of tiny laser-sail powered spacecraft to our nearest exoplanet won't go away. While complex and punctuated with tough problems, the idea is the only realistic way of reaching another solar system this century, according to researchers. But the scientific benefits would be huge.

Intravitreal brolucizumab is superior to panretinal laser photocoagulation in preserving visual acuity for patients with proliferative diabetic retinopathy, clinical trial data show.

arXiv:2604.25823v1 Announce Type: new Abstract: Guiding relativistically intense laser pulses in low-density plasmas enables extended acceleration lengths in laser-plasma accelerators (LPAs), allowing for the production of multi-GeV electron beams. Quantitative interpretation of such experiments is often limited by substantial uncertainties in key plasma parameters, particularly the transverse density profile of hydrodynamic optically field-ionized channels. Distinct plasma density distributions can produce similar terminal beam energies, complicating efforts to infer the underlying interaction physics from measurements at the accelerator exit alone. By combining longitudinally resolved electron beam diagnostics with independent measurements of laser spectral evolution in a 10 GeV LPA, we establish a multi-observable constraint on plasma density profiles. Once plasma downramps are taken into account, excellent agreement is observed with simulation over the entire accelerator length

Scientists at MIT discovered that chaotic laser light can spontaneously form a highly focused beam instead of scattering—if the conditions are just right. This “pencil beam” enabled them to image the blood-brain barrier in 3D at speeds 25 times faster than existing techniques. The method also lets researchers watch how drugs move into brain cells in real time. It could dramatically accelerate the development of treatments for neurological diseases.

arXiv:2604.24669v1 Announce Type: new Abstract: The microstructure of Ti-6Al-4V has a decisive impact on its mechanical performance; however, controlling phase composition during Laser Powder Bed Fusion (LPBF) remains difficult because of the inherent localized and cyclic thermal history. To fully leverage the design flexibility of LPBF while maintaining an efficient process, it is desirable to tailor the microstructure directly through process-parameter optimization rather than relying on post-processing or in-situ heat treatments. Nevertheless, the large and multidimensional parameter space, combined with the limited availability of experimental data, makes this task particularly challenging. In this work, we develop an efficient computational framework that links process conditions to microstructure evolution by coupling a phase transformation model with a fast 1D finite-difference thermal model, enabling comprehensive insights into process-microstructure relations. The framework

arXiv:2604.24417v1 Announce Type: new Abstract: Radiotherapy with Very High Energy Electron (VHEE) beams is being extensively investigated for the treatment of deep-seated tumours, even in view of novel protocols based on the so-called FLASH effect. Laser WakeField Acceleration (LWFA) provides a compact and affordable accelerator technology for VHEE electron beams, featuring ultra-high instantaneous dose rates and holding the promise to provide Ultra-High (average) Dose Rates (UHDRs) needed to activate the FLASH effect, with major efforts ongoing worldwide to fulfill this promise. Therapeutic doses are already at reach, using pencil beams produced via LWFA. These beams typically exhibit significant energy spread, and small transverse size. These features are rather different from those of other beams considered so far in radiotherapy studies. In view of a rapid clinical translation of LWFA-VHEE beams it is therefore of paramount importance to assess the role of these properties in the

arXiv:2604.24282v1 Announce Type: new Abstract: Hybrid laser plasma radiofrequency (RF) acceleration architectures signify a promising advancement in addressing the stability challenges associated with traditional laser wakefield accelerators. A thorough theoretical and numerical analysis of the three-dimensional dynamics of ultra-relativistic electron bunches in these hybrid systems is presented, clearly explaining how transverse beam stability, betatron oscillation polarisation, and radiative cooling work. By combining analytical models of spatiotemporal plasma wakefield modulation and phase dependent RF-driven oscillations with fully self-consistent 3D particle in cell (PIC) simulations, incorporating classical radiation reaction (RR) via the Landau Lifshitz model (with quantum parameter to account for synchrotron like losses during betatron oscillations. The findings indicate that the external RF fields operate as a tunable lattice, allowing for exact adjustment of amplitude,

arXiv:2604.24221v1 Announce Type: new Abstract: We demonstrate a compact scheme for generating sub-20-fs pulses from a commercial ytterbium femtosecond laser delivering 80 fs pulses at 76 MHz repetition rate with 1 W average power. Spectral broadening is achieved in a photonic crystal fiber (PCF), followed by dispersion compensation using broadband chirped mirrors. By systematically varying the fiber length and coupled power, we investigate the interplay between nonlinear spectral broadening and higher-order dispersion. While the spectral bandwidth increases monotonically with fiber length, the achievable pulse duration exhibits a clear minimum due to accumulation of uncompensated higher-order phase, primarily third-order dispersion. An optimal fiber length of 80 mm yields nearly transform-limited 15.4 fs pulses. Shorter fibers provide insufficient broadening, whereas longer fibers, despite offering larger bandwidth, compromise the pulse temporal quality. Stable sub-20-fs operation is

arXiv:2604.23998v1 Announce Type: new Abstract: Molecular cavity optomechanics (COM) leverages ultrastrong interactions between confined optical fields and high-frequency molecular vibration, providing a unique platform for exploring high-frequency phonon dynamics. In this work, we theoretically propose the use of a hybrid molecular COM system for realizing an ultra-low-threshold mid-infrared (MIR) phonon laser. Despite an optical quality factor of only $Q_a=100$, an ultra-low threshold power of $\mathrm{P}_{\mathrm{th}} = 17.5~\mathrm{nW}$ is achieved, enabled by giant single-photon optomechanical coupling and molecular collective effect. Moreover, the mechanical gain and threshold power can be further tuned by adjusting the distance between mirrors of the Fabry-P\'{e}rot cavity. Our findings establish the first direct connection between molecular COM and MIR phonon lasers, with potential applications in MIR acoustics and biomedical imaging.

arXiv:2604.23913v1 Announce Type: new Abstract: We report on an experimental demonstration of efficient neutron generation based on direct laser acceleration in microwire-array targets irradiated by ultrashort (tens of femtoseconds) laser pulses. The optimal array period was identified, at which the maximum proton energy and the number of protons with energies exceeding $1~\mathrm{MeV}$ were significantly increased. Using a $1~\mathrm{PW}$, $\sim25~\mathrm{fs}$ laser at a moderate intensity of $\sim10^{20}~\mathrm{W/cm^2}$, a high neutron yield of up to $(8.33\pm0.84)\times10^{6}~\mathrm{n/sr/J}$ was detected from the LiD converter via $^7\mathrm{Li}(p,n)$ and $\mathrm{D}(p,n)^3\mathrm{He}$ nuclear reactions. Self-consistent integrated simulations reproduced the experimental results and predicted that with a Be converter, a forward pulsed neutron source with an unprecedented yield per joule of $3.67\times10^{7}~\mathrm{n/sr/J}$ can be obtained under identical laser conditions. This

arXiv:2604.24370v1 Announce Type: new Abstract: The shift from stand-level to individual-tree-level forest assessments supports improved biodiversity mapping, particularly in boreal ecosystems where tree species like aspen (Populus tremula L.) play a keystone role. While airborne laser scanning (ALS) is the standard for such inventories, a major limitation is the small number of publicly available ALS datasets containing high-quality, field-validated reference data. Furthermore, open multispectral ALS datasets with high-quality field reference data are completely lacking despite the potential of multispectral ALS data for tree species classification. This paper presents and details an open multispectral ALS dataset used in a recent international benchmarking study of machine learning and deep learning methods for tree species classification by Taher et al. (2026). The dataset comprises 6326 segment-level point clouds of individual trees representing nine species in Southern Finland.

arXiv:2604.24234v1 Announce Type: new Abstract: The technological maturity of in situ inspection and monitoring methods in additive manufacturing is steadily increasing, enabling more efficient and practical qualification procedures. In this context, image segmentation of powder bed images in Laser Powder Bed Fusion (L-PBF) has been investigated by various authors, leveraging both edge detection and machine learning approaches to identify deviations from nominal geometry. Despite these developments, several challenges remain, including the sensitivity of segmentation performance to industrial illumination conditions and layer-to-layer variability in pixel intensity patterns. The study addresses these limitations by proposing a graph-augmented segmentation approach. The underlying principle consists of preserving the geometrical information at a global level rather than at pixel-wise level, modeling dependencies and relational information among spatial regions with a Graph Neural

Pharma is especially interested in using human-based models to screen for drugs that effectively cross the blood-brain barrier, as animal models often fail to predict what happens in humans. The post Pencil Beam Laser Could Help Researchers Design Brain-Targeted Therapies appeared first on GEN - Genetic Engineering and Biotechnology News.

Pharma is especially interested in using human-based models to screen for drugs that effectively cross the blood-brain barrier, as animal models often fail to predict what happens in humans. The post Pencil Beam Laser Could Help Researchers Design Brain-Targeted Therapies appeared first on GEN - Genetic Engineering and Biotechnology News.

MIT researchers discovered a paradoxical phenomenon in optical physics that could enable a new bioimaging method that's faster and higher-resolution than existing technology. They discovered that, under the right conditions, a chaotic mess of laser light can spontaneously self-organize into a highly focused "pencil beam."

arXiv:2604.22443v1 Announce Type: cross Abstract: We investigate a bi-directionally coupled system consisting of a Kerr-nonlinear microresonator and a continuous-wave single-mode semiconductor laser. Inside the resonator, a forward-propagating and a backscattered field interact nonlinearly, while a fraction of the backscattered field is fed back into the laser cavity. We show in this paper that the interaction of the laser with the feedback opens up new ways of stabilizing $1$-solitons. Using numerical bifurcation analysis, we systematically identify existence ranges of time-harmonic 1-soliton states in the anomalous dispersion regime. We demonstrate that, in contrast to the uni-directional configuration, the bi-directional coupling introduces a dynamic self-correcting response of the laser frequency that stabilizes $1$-solitons. These enhanced stability properties of $1$-solitons thus enable robust and self-started frequency-comb generation, consistent with the existing experimental

arXiv:2604.22443v1 Announce Type: new Abstract: We investigate a bi-directionally coupled system consisting of a Kerr-nonlinear microresonator and a continuous-wave single-mode semiconductor laser. Inside the resonator, a forward-propagating and a backscattered field interact nonlinearly, while a fraction of the backscattered field is fed back into the laser cavity. We show in this paper that the interaction of the laser with the feedback opens up new ways of stabilizing $1$-solitons. Using numerical bifurcation analysis, we systematically identify existence ranges of time-harmonic 1-soliton states in the anomalous dispersion regime. We demonstrate that, in contrast to the uni-directional configuration, the bi-directional coupling introduces a dynamic self-correcting response of the laser frequency that stabilizes $1$-solitons. These enhanced stability properties of $1$-solitons thus enable robust and self-started frequency-comb generation, consistent with the existing experimental

arXiv:2604.22397v1 Announce Type: new Abstract: Rare-earth-doped materials constitute the foundation of conventional solid-state lasers, but their bulk-crystal form is inherently incompatible with photonic integration, making it challenging to realize compact, high performance nanoscale laser sources. Lithium niobate on insulator (LNOI), with its exceptional electro-optic and nonlinear optical properties, has emerged as one of the most promising platforms for integrated photonics. Combining Nd3+ doping with LNOI offers the unique possibility of uniting the efficient gain provided by Nd3+ ions with the excellent characteristics of LNOI. However, on-chip laser emission from Nd:LNOI has not been demonstrated previously. In this work, we report the first realization of an integrated Nd:LNOI microdisk laser, demonstrating lasing at 1094.17 nm under 785.10 nm pumping with a low threshold of 146 uW and a slope efficiency of 1.962*10^(-5). Beyond continuous-wave operation, we further observe

arXiv:2604.21418v1 Announce Type: new Abstract: Chip-scale semiconductor laser frequency combs offer remarkable prospects for compact and power-efficient optical sensors. For the laser to be suitable for typical comb applications, its degree of coherence must first be assessed from a microwave self-mixing signal. Unfortunately, such measurements require scarcely available high-speed photodetectors with multi-GHz bandwidths and radio-frequency electronics. However, in this work, we demonstrate a simplified approach to comb coherence assessment for interband cascade lasers based on a relationship between easily-accessible MHz-frequency (baseband) noise and the multi-GHz-frequency intermode beat note. The downconversion of microwave noise to near-DC frequencies is found to originate intrinsically from the laser, which simultaneously acts as a frequency mixer due to electrical nonlinearities and a phase-to-amplitude noise converter due to the linewidth enhancement factor. Correlation

Researchers in the US and Germany have unveiled a theoretical blueprint for an atomic clock driven by a highly synchronized laser, where atoms work in concert rather than independently. Publishing their results in Physical Review Letters, Jarrod Reilly at the University of Colorado, Simon Jäger at the University of Bonn, and their colleagues in the US and Germany revived an idea first proposed in the 1990s—possibly charting a course toward the narrowest-linewidth lasers ever achieved.