Laser

Unlike solar panels, solar thermoelectric generators can convert heat from any source into electricity. But poor efficiency has held the technology back – until now.

arXiv:2508.16533v1 Announce Type: new Abstract: High laser intensities enable the production of electron-positron pairs from bright gamma rays passing through strong fields. Potentially the most promising approach for all-optical experiments in the near term uses dense but higher divergence electron beams from laser wakefield acceleration to produce gamma rays through inverse Compton scattering. Achieving many-photon collisions between these gamma rays and the high intensity laser pulse in practice is extremely difficult, however, due to significant shot-to-shot jitter in laser pointing and timing. We model these practical difficulties using simulated Monte-Carlo experiments. By using a more efficient algorithm for sampling infrequent pair production with particle splitting, we enable the exploration of a multi-dimensional parameter space. Using Gaussian Process Regression we then efficiently find optimal conditions for maximising pair production by changing the laser spot size, the

arXiv:2508.16278v1 Announce Type: new Abstract: Frequency-modulated lasers (FMLs) are widely used in spectroscopy, biology, and LiDAR. The performance of these applications highly depends on the fast and precise tracking of the FMLs' absolute frequency, which remains a challenge. Here we demonstrate integrated lithium niobate electro-optic frequency combs with arbitrarily tunable repetition rates and a 29.45-nm bandwidth, enabling precise tracking of the absolute frequency of an FML with a chirp rate as high as $2\times10^{18}\,\mathrm{Hz/s}$, which is over three orders of magnitude above the state of the art. This method enables frequency-modulated continuous-wave ranging using an FML with severe mode hops, unlocking great potential for improving the ranging resolution and acquisition rate. Our method lays the foundation for FML-based high-precision measurements of frequency, distance, and time, leading to profound implications in fundamental science and engineering applications.

arXiv:2508.15984v1 Announce Type: new Abstract: The self-sustained or avalanche-type cascade is an intriguing prediction of strong-field quantum electrodynamics (QED) that has yet to be observed in laboratories. It is accompanied by the conversion of electromagnetic energy into gamma photons and electron-positron ($e^-e^+$) pairs, whose number increases exponentially over time. We investigate a simple configuration to initiate a QED cascades: it is based on the superposition of an incident multipetawatt laser pulse and its reflection from a solid target. The incident laser pulse > the initially flat target surface, creating a parabolic mirror that focuses the reflected radiation. For the considered setup the threshold laser power is about $7\,\text{PW}$. With a $27\,\text{PW}$ laser pulse, positron production exhibits clear signatures of an avalanche-type cascade, including exponential growth and more than 15 positron generations with similar energy spectra. Therefore,

arXiv:2508.16459v1 Announce Type: new Abstract: We present a novel Simultaneous Localization and Mapping (SLAM) method that employs Gaussian Process (GP) based landmark (object) representations. Instead of conventional grid maps or point cloud registration, we model the environment on a per object basis using GP based contour representations. These contours are updated online through a recursive scheme, enabling efficient memory usage. The SLAM problem is formulated within a fully Bayesian framework, allowing joint inference over the robot pose and object based map. This representation provides semantic information such as the number of objects and their areas, while also supporting probabilistic measurement to object associations. Furthermore, the GP based contours yield confidence bounds on object shapes, offering valuable information for downstream tasks like safe navigation and exploration. We validate our method on synthetic and real world experiments, and show that it delivers

The ultrabroadband infrared frequency comb could be used for chemical detection in portable spectrometers or high-resolution remote sensors.

Valence electrons, located in the outermost shell of an atom, play an important role in driving chemical reactions and forming bonds with other atoms.

arXiv:2508.14592v1 Announce Type: new Abstract: Generation of ultrashort X-ray pulses in a free-electron laser relies on high-density electron bunches with a precisely adjusted current and energy distribution. To this end, robust and flexible electron bunch manipulation techniques are required that allow a high degree of control over the phase space density of the bunch. This paper reports on the demonstration of ultrashort current spikes with femtosecond duration, created by compressing an electron bunch after a laser-induced energy modulation with linearly varying envelope. This scheme is implemented at the free-electron laser FLASH, where the energy modulation is created early in the linear accelerator before the bunch is accelerated to its final energy. Formation of the spikes is observed in measurements of the longitudinal phase space density. It is demonstrated that, in conjunction with conventional compression techniques, this laser-based scheme allows to create two spikes with

arXiv:2508.14463v1 Announce Type: new Abstract: Bubble detectors are widely used to measure neutron flux from laser-driven sources employing a pitcher-catcher setup, due to their insensitivity to intense $\gamma$-ray backgrounds and strong electromagnetic pulses (EMP).\\ This paper presents a method to account for the neutron energy-dependent response of bubble detectors, enabling accurate conversion of bubble counts into neutron flux at the detector location. The proposed method is based on the accurate reconstruction of the response function using a surrogate model. The resulting model is convoluted with the (normalized) expected/measured neutron spectrum to obtain an effective measure of the bubble detector's response, herein referred to as effective $c$ or $c_\text{eff}$. This effective value for the response is energy-independent after the convolution. In this way, our approach includes the spectral distribution of neutrons arriving at the detector to determine the integral

They are barely thicker than a human hair—yet they could significantly improve the effectiveness of inhaled medications: carrier particles in dry powder inhalers transport the active ingredient and ensure it can be efficiently inhaled into the lungs. How well this works depends strongly on their shape.

For years, engineers have sought better ways to build tiny, efficient lasers that can be integrated directly onto silicon chips, a key step toward faster, more capable optical communications and computing.

Optical frequency combs are specially designed lasers that act like rulers to accurately and rapidly measure specific frequencies of light. They can be used to detect and identify chemicals and pollutants with extremely high precision.

arXiv:2508.13649v1 Announce Type: new Abstract: We present the ultra-fast dynamics of the interaction between a high-intensity extreme contrast (expected to be around 1e-18 at hundreds of picoseconds timescale) femtosecond laser and a solid. Simultaneous measurements of probe Doppler spectrometry and reflectivity in pump-probe experiments reveal the presence of extreme pressure in the solid density region, which triggers a long-lived (about 15 ps) strong inward shock. Hydrodynamic simulations accurately replicate these observations, providing a detailed explanation of the underlying physics

arXiv:2508.13492v1 Announce Type: new Abstract: Keyhole-induced (KH) porosity, which arises from unstable vapor cavity dynamics under excessive laser energy input, remains a significant challenge in laser powder bed fusion (LPBF). This study presents an integrated experimental and data-driven framework using airborne acoustic emission (AE) to achieve high-resolution quantification of KH porosity. Experiments conducted on an LPBF system involved in situ acquisition of airborne AE and ex situ porosity imaging via X-ray computed tomography (XCT), synchronized spatiotemporally through photodiode signals with submillisecond precision. We introduce KHLineNum, a spatially resolved porosity metric defined as the number of KH pores per unit scan length, which serves as a physically meaningful indicator of the severity of KH porosity in geometries and scanning strategies. Using AE scalogram data and scan speed, we trained a lightweight convolutional neural network to predict KHLineNum with

arXiv:2508.12442v1 Announce Type: new Abstract: Laser propulsion has been proposed for relativistic interstellar flights, but it faces the significant challenge of requiring extremely powerful laser radiation due to the inherently low momentum transfer between the beam and the sail. The photon-recycling technique enhances thrust by transferring momentum through multiple reflections within a cavity setup, formed by the lightsail and a ground-based mirror in a laser system array. In this work, a delay differential model is developed to describe the evolution of the beam and thrust, incorporating both the Doppler effect and the round-trip time delay experienced by each beam component. With optimized multilayer reflectors, the thrust performance gain is shown to be significant for interstellar flight, though limited by diffraction and the necessity of removing harmful redshifted radiation that could overheat the lightsail. By balancing thrust performance with thermal stability, we derive

arXiv:2508.12437v1 Announce Type: new Abstract: Reducing the size and complexity of high-performance timekeeping devices is an ever-growing need for various applications, such as 6G wireless technology, positioning, navigation and timing (PNT), Internet of Things (IoT), and ultrafast spectroscopy. This work presents a distributed feedback (DFB) laser-pumped Rb atomic clock, which features extraordinary frequency stability, small size and low power consumption. The DFB laser head employs a built-in isolator with a linewidth of approximately 1 MHz. For complete optical pumping of the atoms in the absorption cell, the laser beam is expanded to a diameter of 10 mm by using an optical diffuser-based beam expander. The physics package is based on a magnetron microwave cavity and surrounded by two layers of magnetic shielding. The overall volume of the optical system combined with the physics package is 250 cm$^3$. The proposed atomic clock is also designed to operate at a low temperature,

arXiv:2508.11852v1 Announce Type: new Abstract: Beam energy compression via chicane magnets has been proved to be an effective method to reduce the slice energy spread of electron beams generated by laser wakefield accelerators (LWFAs). This technique has been widely adopted by leading research teams in experiments targeting future compact, high-gain free electron lasers (FELs). However, after energy compression, a strong beam energy chirp is introduced into the electron beam, which substantially hinders the microbunching process and impairs spectral coherence. Here, we present a detailed, unaveraged three-dimensional simulation that examines the effects of this energy chirp, and the results can be applied to the design of a proposed LWFA-driven VUV FEL. The energy chirp in a LWFA-produced electron beam causes FEL interactions at multiple resonant frequencies across the entire electron bunch, simultaneously, which prevents sustained radiation power growth at the designed frequency

arXiv:2508.12089v1 Announce Type: new Abstract: We propose a multi-stage convolutional neural network (MSCNN) based integrated method for reducing uncertainty of 3D point accuracy of lasar scanner (LS) in rough indoor rooms, providing more accurate spatial measurements for high-precision geometric model creation and renovation. Due to different equipment limitations and environmental factors, high-end and low-end LS have positional errors. Our approach pairs high-accuracy scanners (HAS) as references with corresponding low-accuracy scanners (LAS) of measurements in identical environments to quantify specific error patterns. By establishing a statistical relationship between measurement discrepancies and their spatial distribution, we develop a correction framework that combines traditional geometric processing with targeted neural network refinement. This method transforms the quantification of systematic errors into a supervised learning problem, allowing precise correction while

Scientists directly observed tiny lattice deformations in quantum dots caused by electron-hole pairs, key for advancing solar cells and LEDs.

arXiv:2508.11417v1 Announce Type: new Abstract: We investigate the propagation and nonlinear self-focusing of TW power laser pulses that create 10-m-scale, highly homogeneous plasma channels in rubidium vapor. Using computational solutions of the relevant propagation equations, we study the effects of the ionizing pulse central wavelength in relation to the resonance frequencies of atomic rubidium. Recent experiments show that pulse propagation and plasma channel creation is distinctly different for 780 nm laser pulses (resonant with the rubidium $D_2$ line) and 810 nm laser pulses. We study pulse propagation in a $\pm$30 nm range around the $D_2$ resonance and find that the results are distinctly different when tuning to sub-resonant wavelengths from those obtained for super-resonant wavelengths. For pulse wavelengths below the resonance the behavior is similar to the resonant case, characterized by strong self-focusing and a sharp plasma boundary. Pulse wavelengths above 780 nm on

arXiv:2508.11238v1 Announce Type: new Abstract: Preformed plasma channels are essential for guiding high-power laser pulses over extended distances in laser wakefield accelerators, enabling the generation of multi-GeV electron beams for applications such as free-electron lasers and particle colliders. Above-threshold ionization heating provides a robust mechanism for creating laser-matched plasma channels across a wide parameter range, owing to its density- and geometry-independent heating effect. Establishing predictive scaling laws between channel parameters and formation conditions is critical for designing channels optimized for electron acceleration across energies spanning hundreds of MeV to tens of GeV. Through combined timescale analysis and numerical simulations, hydrodynamic expansion is identified as the dominant mechanism governing density profile evolution during ATI channel formation. Remarkably, this process maintains effective laser-guiding channel structures across a

arXiv:2508.11148v1 Announce Type: new Abstract: Plasma-based acceleration of positrons attracts extensive interests due to the ultrahigh accelerating gradient and ultrashort duration, while generating wakefield positron beam by the inherent injection is still a great challenge. Here, we put forward a superponderomotive injection method of positrons in the blowout regime of laser wakefield acceleration. In this method, transverse laser fields facilitate the trapping of positrons into the laser-modulated longitudinal wakefield which dominates the subsequent energy gaining, that is distinct from the electrostatic induced superponderomotive electrons. Particle-in-cell simulations demonstrate that this method can be implemented by the collision between a donut wake and a pair jet, resulting in the multi-cycle positron beam with hundreds of pC charge and brightness of $10^{13}~\rm{Am}^{-2}$. Such a collisional setup is available in the current laser-plasma experiments, and the generated

For the first time, researchers at Umeå University have demonstrated the full capabilities of their large-scale laser facility. In a study published in Nature Photonics, the team reports generating a combination of ultrashort laser pulses, extreme peak power, and precisely controlled waveforms that make it possible to explore the fastest processes in nature.

Some of science’s biggest mysteries unfold at the smallest scales. Researchers investigating super small phenomena – from the quantum

arXiv:2508.10855v1 Announce Type: new Abstract: This paper presents a rigorous analytical framework for quantitatively evaluating space-based laser power beaming from lunar-orbiting spacecraft to surface receivers, addressing the critical need for continuous, high-density energy to sustain lunar exploration and habitation. The framework integrates physics-based models of spacecraft photovoltaic generation, precise orbital geometries, time-dependent link availability and slant-range variations, coherent beam propagation (including transmitter aperture diameter, beam quality factor, path losses, and pointing jitter), and photonic-to-electrical conversion at the lunar surface. Particular emphasis is placed on phased-array transmitter systems, whose large effective apertures significantly reduce beam divergence relative to single-aperture designs, resulting in orders-of-magnitude increases in delivered surface power under equivalent orbital and power conditions. Parametric sensitivity

arXiv:2508.10829v1 Announce Type: new Abstract: We report the first experimental observation of carrier-envelope phase-driven energy bunching in laser wakefield acceleration. Using a few-cycle (~9 fs), multi-terawatt laser pulse and ionization injection in a helium-nitrogen gas mixture, we observe electron spectra composed of multiple quasi-monoenergetic peaks with regular narrow energy spacing. This comb structure arises from intermittent injection from successive half-cycles of the laser field, enabled by the evolving carrier-envelope phase during propagation in the plasma. These findings establish sub-cycle ionization injection as a potential route to attosecond control in plasma acceleration, enabling injection and beam structuring synchronized to the optical waveform on sub-femtosecond timescales.

arXiv:2508.10685v1 Announce Type: new Abstract: This study explores nanoparticle-assisted electron injection as a method for controlling beam charge in laser wakefield acceleration through particle-in-cell simulations. We systematically investigate how the material (Li through Au) and size (50-200 nm) of nanoparticles influence electron injection dynamics and beam charge. Our results demonstrate that beam charge (10-600 pC) can be effectively controlled by adjusting these parameters. We identify a saturation threshold in the nanoparticle electric field strength, beyond which beam charge depends on the total number of atoms in the nanoparticle rather than on the electron density after ionization. Significant electron injection occurs across multiple plasma wave periods with distribution patterns influenced by nanoparticle properties leading to increased beam charge but a broader energy spread. These findings offer practical guidelines for experimental implementation of

arXiv:2508.10475v1 Announce Type: new Abstract: The paper presents results and discussion of electron dynamics in molecules in which intense ultrafast pulse drives multiphoton ionization, high harmonic generation, and charge resonance due to the Rabbi flopping in the regime of Charge Resonance Enhanced Ionization (CREI) for the ground state molecular nitrogen cation. We show how ionization rates oscillate with oscillations of envelope reflecting modulation of the population of the excited molecular orbital. We observe the increase in ionization due to mechanisms analogous to Charge Resonance Enhanced Ionization (CREI) and also uncover also the time periods of suppressed ionization. Electronic flux calculations illustrate these changes and help reveal multiple ionization bursts which are for the first time reported for a multielectron non-stretched/ non-dissociating molecule. Furthermore, we discuss the effects of ultrafast intense laser pulses on the bonding properties of a nitrogen

arXiv:2508.10288v1 Announce Type: new Abstract: Clock atom interferometry is an emerging technique in precision measurements that is particularly well suited for sensitivity enhancement through large momentum transfer (LMT). While current systems have demonstrated momentum separations of several hundreds of photon momenta, next-generation quantum sensors are targeting an LMT enhancement factor beyond $10^4$. However, the viability of LMT clock interferometers has recently come into question due to the potential impact of laser frequency noise. Here, we resolve this concern by analyzing the cumulative fidelity of sequential state inversions in an LMT atom interferometer. We show that the population error from $n$ pulses applied from alternating directions scales linearly with $n$. This is a significant advantage over the $n^2$ scaling that occurs when probing a two-level system $n$ times from the same direction. We further show that contributions to the interferometer signal from

An international team of scientists led by Nanyang Technological University, Singapore (NTU Singapore) has developed a new type of ultracompact laser that is more energy efficient and consumes less power.

A team led by scientists at the Department of Energy's SLAC National Accelerator Laboratory have generated a highly exotic type of light beam, called a Poincaré beam, using the FERMI free-electron laser (FEL) facility in Italy, marking the first time such a beam has been produced with a FEL.

Researchers at the Optics and Photonics Research Center (CePOF) have succeeded in increasing the susceptibility of the fungus Candida albicans to drug treatment through light-activated therapy. The results of the study offer a promising alternative in the fight against antimicrobial resistance, a growing global problem that occurs when bacteria, viruses, fungi, and other parasites develop genetic mutations that render them resistant to drugs.

arXiv:2508.09048v1 Announce Type: cross Abstract: The advantage of attosecond measurements is the possibility of time-resolving ultrafast quantum phenomena of electron dynamics. Many such measurements are of interferometric nature, and therefore give access to the phase. Likewise, weak measurements are intrinsically interferometric and specifically take advantage of interfering probability amplitudes, therefore encoding the phase information of the process. In this work, we show that attosecond interferometry experiments can be seen as a weak measurement, which unveils how this notion is connected to strong field physics and attosecond science. In particular, we show how the electron trajectory picks up a new phase, which occurs due to the weak measurement of the process. This phase can show significant contributions in the presence of spectral features of the measured system. Furthermore, extending this approach to include non-classical driving fields shows that the generated

Компания Hisense, производитель телевизионной и бытовой техники, представляет на российском рынке ультракороткофокусный...

arXiv:2508.07698v1 Announce Type: cross Abstract: We have developed an operando laser-based photoemission electron microscope (laser-PEEM) with a ferroelectric characterization system. A Sawyer-Tower circuit was implemented to measure the polarization-voltage ($P-V$) characteristics of ferroelectric devices. Using this system, we successfully obtained the well-defined $P-V$ hysteresis loops for a ferroelectric capacitor incorporating Hf$_{0.5}$Zr$_{0.5}$O$_2$ (HZO), reproducing the typical field-cycling characteristics of HZO capacitors. After dielectric breakdown caused by field-cycling stress, we visualized a conduction filament through the top electrode without any destructive processing. Additionally, we successfully observed polarization contrast through the top electrode of an oxide semiconductor (InZnO$_x$). These results indicate that our operando laser-PEEM system is a powerful tool for visualizing conduction filaments after dielectric breakdown, the ferroelectric

arXiv:2508.07500v1 Announce Type: new Abstract: The optical cycle-averaged ionization rate of Ar, O$_{2}$, and N$_{2}$ vs. local instantaneous laser intensity $I$ for linear polarized $800$ nm light is determined up to approx. $300$ TW/cm$^{2}$ by numerically inverting published time-of-flight ion spectrometer data. The published Ar$^{+}$ collection efficiency of the microchannel plate (MCP) at the end of the spectrometer and its $I_{0}$ scale are recalibrated by fitting it to its high $I_{0}$ solution. The relative collection efficiencies of the other species are determined by published MCP cathode data. Results for O$_2$ are consistent with a reevaluation of published data used to determine its cross section $\sigma_8$ in the multiphoton (low $I$) regime.

arXiv:2508.06989v1 Announce Type: new Abstract: High-energy, narrow-linewidth nanosecond pulses are highly demanding for many applications that require high temporal and spatial coherence. However, the amplification of narrow-linewidth pulses is primarily limited by stimulated Brillouin scattering, which causes pulse instabilities, back-reflected pulses, and catastrophic damage effects on optical components. In this work, we present a 1.6 mJ narrow-linewidth nanosecond pulsed fiber laser system based on all-glass spun tapered double-clad fibers without employing any mitigating technique for the stimulated Brillouin scattering effect. The system delivers pulses with an 8 ns duration at a 100 kHz repetition rate, over 97.5% degree of polarization, a beam quality factor of M2 = 1.3, a spectral linewidth of 53.8 MHz, a 160 W average power, and 188 kW peak power with a slope efficiency of 97.6%. The degree of spatial coherence of the amplified signal was measured to be 0.94. Our results

arXiv:2508.06733v1 Announce Type: new Abstract: High-lying Rydberg and autoionizing (AI) states of thorium (Th) have been studied via resonance laser ionization spectroscopy at both TRIUMF Canada's particle accelerator centre and Oak Ridge National Lab (ORNL). Multiple Rydberg series converging to the ionization potential (IP) were observed via different stepwise laser excitation schemes and were assigned to be the $6d^27s (^4F_{3/2})$ $np$, $nd$, and $nf$ series. Analysis of these series enabled the determination of the IP to be 50868.735(54) cm$^{-1}$, which improved the precision by two orders of magnitude over the current adopted NIST value of 50867(2) cm$^{-1}$. Additionally, four AI Rydberg series were identified and assigned to $nf$ and $nd$ series converging to the $6d^27s$ $^4F_{5/2}$ and $6d^27s$ $^2D_{3/2}$ metastable states of Th$^+$. The measured energies of the Rydberg and AI Rydberg states are reported, and observed perturbations within the series are discussed.

arXiv:2508.06462v1 Announce Type: new Abstract: Compact, stable, and versatile laser-driven ion sources hold great promise for applications ranging from medicine to materials science and fundamental physics. While single-shot sources have demonstrated favorable beam properties, including the peak fluxes necessary for several applications, high repetition rate operation will be necessary to generate and sustain the high average flux needed for many of the most exciting applications of laser-driven ion sources. Further, to navigate through the high-dimensional space of laser and target parameters towards experimental optima, it is essential to develop ion acceleration platforms compatible with machine learning learning techniques and capable of autonomous real-time optimization. Here we present a multi-Hz ion acceleration platform employing a liquid sheet jet target. We characterize the laser-plasma interaction and the laser-driven proton beam across a variety of key parameters

arXiv:2508.06045v1 Announce Type: new Abstract: The interaction of an ultraintense Nd:glass laser pulse with a near-critical plasma self-organizes into a highly efficient $\gamma$-ray source. Three-dimensional particle-in-cell simulations demonstrate that relativistic self-focusing, aided by a self-generated electron cavity, enhances the laser intensity by more than an order of magnitude, driving the system into the radiation-reaction-dominated regime, i.e. one where the electrons lose a substantial amount of their energy as hard radiation. Peak photon emission occurs near $0.5$ times the relativistic critical density, with a $\gamma$-photon yield exceeding $20\%$ of the laser energy. Compared to Ti:Sa lasers of the same power, the longer duration of Nd:glass laser pulses leads to an order of magnitude increase in $\gamma$-photon number in the extreme conversion efficiency regime, making them particularly well-suited for photonuclear physics applications. These findings point to a

It’s a reminder of the research that has defined the start of her professional career – exploring meteorite

With a suite of reimagined instruments at SLAC's LCLS facility, researchers see massive improvement in data quality and take up scientific inquiries that were out of reach just one year ago.

arXiv:2508.05412v1 Announce Type: new Abstract: Extreme ultraviolet (EUV) coherent sources below 120nm are of paramount significance for promoting next-generation nano-scale lithography,precision spectroscopy, and exploring the emerging physical phenomena in quantum materials. Nonlinear optical conversion serves as the only feasible approach to obtain solid state EUV lasers, yet the intrinsic strong absorption at EUV and giant phase mismatch among light waves have hindered the realization of highly-efficient EUV light sources. Herein, we propose a random additional periodic phase (RAPP) strategy in third-order nonlinear crystals to overcome these problems, that an artificially designed random phase grating at micrometer-scales is embedded in the homogeneous bulk crystal, thus adaptively compensating the phase mismatch between fundamental-wave and third-harmonic waves. For the first time, the EUV laser at 118nm is demonstrated in the RAPP lithium fluoride (LiF) crystals with wide

Critical mineral lithium—the lightest of all metals—had long eluded geologists by slipping through the cracks of traditional analysis.

A team of physicists has discovered a method to temporarily halt the ultrafast melting of silicon using a carefully timed sequence of laser pulses. This finding opens new possibilities for controlling material behavior under extreme conditions and could improve the accuracy of experiments that study how energy moves through solids.

arXiv:2508.04544v1 Announce Type: new Abstract: Laser-induced phase transitions offer pathways of phase transitions that are inaccessible by conventional stimuli. In this study, we conduct ab initio simulations to numerically demonstrate a novel laser-induced structural transformation: converting a bulk crystal into a layered van der Waals material using intense light pulses. The transition is driven by a nonlinear phononic mechanism, where selectively exciting polar and anti-polar phonon modes with polarized terahertz light breaks targeted interlayer bonds while preserving intralayer ones. We identify that strong anisotropy in bond sensitivity where interlayer bonds are significantly more susceptible to excitation than intralayer bonds is the critical prerequisite. Our findings pave the way for on demand transformations from bulk to 2D materials, facilitate the design of advanced phase-change devices, and suggest a potential optical exfoliation method to expand the range of

arXiv:2508.02735v1 Announce Type: new Abstract: The quantitative modeling and design of modern short-pulse fiber lasers cannot be performed with averaged models because of large variations in the pulse parameters within each round trip. Instead, lumped models obtained by concatenating models for the various components of the laser are required. Since the optical pulses in lumped models are periodic, their linear stability is investigated using the monodromy operator, which is the linearization of the roundtrip operator about the pulse. A gradient-based optimization method is developed to discover periodic pulses. The computation of the gradient of the objective function involves numerical computation of the action of both the round trip operator and the adjoint of the monodromy operator. A novel Fourier split-step method is introduced to compute solutions of the linearization of the nonlinear, nonlocal, stiff equation that models optical propagation in the fiber amplifier. This method

arXiv:2508.03476v1 Announce Type: new Abstract: This thesis presents the development and characterisation of a polarisation-multiplexing ring-cavity fibre laser for dual-comb generation. It explores the underlying physics, implementation, and potential uses of this innovative laser system, especially in LIDAR technology. Conventional dual-frequency comb systems for metrology use two optical frequency combs synchronised via complex feedback loops, which suffer from phase-locking issues and raise system cost and fragility. In contrast, single-cavity dual comb systems generate two combs with slightly different repetition rates in the same cavity, ensuring mutual coherence and noise cancellation. However, these systems often display unstable regimes and are typically demonstrated only in laboratories. This thesis aims to design, build, characterise, and optimise a single-cavity polarisation multiplexed fibre laser that produces dual optical frequency combs with enough stability and

arXiv:2508.03309v1 Announce Type: new Abstract: The increasing availability of high-power Yb-based ultrafast laser-amplifier systems has opened the possibility of air filamentation at high repetition rates >1 kHz. In this new regime, accumulation effects cannot be ruled out, therefore, characterizing the plasma parameters and afterglow plasma-chemical kinetics becomes increasingly relevant. In this work, we use optical emission spectroscopy to measure nanosecond dynamics of gas temperature and electron temperature, species-specific decay times, and electron density of an atmospheric air laser filament produced by high average power femtosecond laser at a high repetition rate of 10 kHz. The molecular excitation mechanisms behind the nitrogen photoemissions are derived from vibrational distributions and temporal behavior of the studied emission bands. The presented diagnostic technique offers a complementary but more holistic measurement approach to optical probe schemes to characterize

arXiv:2508.03152v1 Announce Type: new Abstract: Cross-beam energy transfer (CBET) between two lasers is investigated through both analytical theory and two-dimensional simulations, with particular attention to its linear and nonlinear evolution under various laser-plasma conditions over timescales from several hundred picoseconds to one nanosecond. Based on the dispersion relation of stimulated Brillouin scattering driven by two laser beams, we obtain a laser frequency difference range within which CBET occurs. In the nonlinear regime, high harmonic of ion acoustic wave (IAW) leads to the reduction of saturation level at high laser intensities ($I\gtrsim 10^{15}\,\mathrm{W/cm^2}$). The wave breaking of harmonic IAW causes the second growth and final saturation of CBET. At low intensities, the linear saturation level slowly varies over time. Compared to Gaussian beams, smoothed lasers with speckles can mitigate CBET saturation level by reducing the effective overlap region. The maximum

arXiv:2508.02847v1 Announce Type: cross Abstract: Laser directed energy deposition (DED) additive manufacturing struggles with consistent part quality due to complex melt pool dynamics and process variations. While much research targets defect detection, little work has validated process monitoring systems for evaluating melt pool dynamics and process quality. This study presents a novel multimodal monitoring framework, synergistically integrating contact-based acoustic emission (AE) sensing with coaxial camera vision to enable layer-wise identification and evaluation of geometric variations in DED parts. The experimental study used three part configurations: a baseline part without holes, a part with a 3mm diameter through-hole, and one with a 5mm through-hole to test the system's discerning capabilities. Raw sensor data was preprocessed: acoustic signals were filtered for time-domain and frequency-domain feature extraction, while camera data underwent melt pool segmentation and

arXiv:2508.02735v1 Announce Type: new Abstract: The quantitative modeling and design of modern short-pulse fiber lasers cannot be performed with averaged models because of large variations in the pulse parameters within each round trip. Instead, lumped models obtained by concatenating models for the various components of the laser are required. Since the optical pulses in lumped models are periodic, their linear stability is investigated using the monodromy operator, which is the linearization of the roundtrip operator about the pulse. A gradient-based optimization method is developed to discover periodic pulses. The computation of the gradient of the objective function involves numerical computation of the action of both the round trip operator and the adjoint of the monodromy operator. A novel Fourier split-step method is introduced to compute solutions of the linearization of the nonlinear, nonlocal, stiff equation that models optical propagation in the fiber amplifier. This method

arXiv:2508.01945v1 Announce Type: cross Abstract: Adding spin-polarized carriers to semiconductor lasers strongly changes their properties and, through the transfer of angular momentum, leads to the emission of the circularly polarized light. In such spin-lasers the polarization of the emitted light can be modulated an order of magnitude faster than its intensity in the best conventional lasers. This ultrafast operation in spin-lasers relies on the large linear birefringence, usually viewed as detrimental in spin and conventional lasers, which couples the two linearly-polarized emission modes. We show that the dynamical properties of birefringent spin-lasers under intensity and polarization modulation are accurately described as coupled harmonic oscillators. Our model agrees with the intensity-equation description which, unlike the common complex field components describing the role of birefringence in laser dynamics, uses simpler real quantities and allows analytical solutions. We

arXiv:2508.01734v1 Announce Type: cross Abstract: We report on the photoinduced spin crossover (SCO) transition from a 2HS-2LS to a 3HS-1LS state in a [2x2] Fe(II) metallogrid complex using molecular crystals with static photocrystallography at a first ever attempt in the beamline P11 of the PETRA III synchrotron, DESY. A class 3B diode laser was used to induce the transition under controlled irradiation conditions. Structural characterization was achieved through single-crystal X-ray diffraction (SCXRD) measurements post-irradiation, revealing significant changes in average Fe-N distances, consistent with SCO behavior. Our experimental setup enables precise alignment necessary for photo-excitation using a class 3B diode laser along with a compact focusing optics. The longest dimension of the combined setup of the diode head and the focusing optics is not more than 32cm. The setup showcasing the utility of a compact diode laser system which can even be conveniently used in

arXiv:2508.02568v1 Announce Type: new Abstract: Frequency-agile lasers operating in the ultraviolet-to-blue spectral range (360-480 nm) are critical enablers for a wide range of technologies, including free-space and underwater optical communications, optical atomic clocks, and Rydberg-atom-based quantum computing platforms. Integrated photonic lasers offer a compelling platform for these applications by combining low-noise performance with fast frequency tuning in a compact, robust form factor through monolithic integration. However, realizing such lasers in the blue spectral range remains challenging due to limitations in current semiconductor materials and photonic integration techniques. Here, we report the first demonstration of a photonic integrated blue laser at around 461 nm, which simultaneously achieves frequency agility and low phase noise. This implementation is based on the hybrid integration of a gallium nitride-based laser diode, which is self-injection locked to a

arXiv:2508.02395v1 Announce Type: new Abstract: We present a study of second harmonic generation (SHG) and third harmonic generation (THG) in lithium triborate (LBO) crystals using a high-energy, 10-J-class, 10 Hz Yb:YAG laser system. We achieved high conversion efficiencies of 75\% for SHG and 56\% for THG for Gaussian-like temporal pulse shapes and top-hat-like beam profiles. The angular and temperature dependence of the LBO crystals were measured and validated through numerical simulations. The SHG process exhibited an angular acceptance bandwidth of 1.33 mrad and a temperature acceptance bandwidth of 2.61 K, while the THG process showed 1.19 mrad and 1.35 K, respectively. Additionally, long term stability measurements revealed RMS energy stabilities of 1.3\% for SHG and 1.24\% for THG. These results showcase the reliability of LBO crystals for high-energy, high-average-power harmonic generation. The developed system offers automated switching between harmonics provided at the

arXiv:2508.02259v1 Announce Type: new Abstract: We demonstrate real-time wavefront correction in a high-energy high-average-power DiPOLE100/Bivoj laser using adaptive optics. A bimorph deformable mirror and Shack-Hartmann wavefront sensor reduced wavefront error tenfold and improved the Strehl ratio elevenfold. Design aspects such as deformable mirror actuator geometry, optimal placement, and loop frequency are discussed for integration into next-generation high-energy high-average-power lasers.

arXiv:2508.01000v1 Announce Type: new Abstract: The permutation entropy (PE) is a statistical indicator that allows to quantify the complexity of a signal. Here we show that it is able to {identify and anticipate} the threshold bifurcation of a complex laser, where thousands of modes compete for gain at the onset of lasing. In our experimental setup, the cavity roundtrip time is several orders of magnitude longer than the temporal resolution of the detection system, which enables a high statistical sampling of the intensity dynamics per roundtrip. We show that the permutation entropy experiences a clear decrease far below the threshold and reaches a sharp minimum at the threshold bifurcation point, which reveals an abrupt increase of the temporal correlations. The evolution of the entropy is compared with standard quantifiers of approaching bifurcations. While lag-1 autocorrelation gradually grows as the threshold is approached, PE shows a steep decrease that captures the emergence of

arXiv:2508.00455v1 Announce Type: new Abstract: The ability to arbitrarily dial in amplitudes and phases enables the fundamental quantum state operations pioneered for microwaves and then infrared and visible wavelengths during the second half of the last century. Self-seeded X-ray free-electron lasers (FELs) routinely generate coherent, high-brightness, and ultrafast pulses for a wide range of experiments, but have so far not achieved a comparable level of amplitude and phase control. Here we report the first tunable phase-locked, ultra-fast hard X-ray (PHLUX) pulses by implementing a recently proposed method: A fresh-bunch self-seeded FEL, driven by an electron beam that was shaped with a slotted foil and a corrugated wakefield structure, generates coherent radiation that is intensity-modulated on the femtosecond time scale. We measure phase-locked (to within a shot-to-shot phase jitter corresponding to 0.1 attoseconds) pulse triplets with a photon energy of 9.7 keV, a pulse energy

arXiv:2508.00145v1 Announce Type: new Abstract: Laser-plasma accelerators offer a compact means of producing high-energy electron beams, but their performance is fundamentally limited by dephasing between the accelerated electrons and the plasma wave. To overcome this limitation, we investigate the combination of plasma density tapering and optical guiding to extend the effective acceleration length. Using a Joule-class femtosecond laser coupled into an optical-field-ionized plasma waveguide with a controlled density gradient, we experimentally achieve electron beam energies exceeding 1.6 GeV, a 40% increase compared to the constant-density case. Particle-in-cell simulations reproduce the main experimental features and reveal the central roles of delayed injection, nonlinear laser evolution, and self-focusing in enhancing energy gain.

arXiv:2507.23617v1 Announce Type: new Abstract: We demonstrate a quasi-continuous sub-$\mu$K strontium source achieved without the use of a high-finesse cavity-locked laser. Our frequency reference is based on a dispersion-optimized, fiber-based frequency comb that enables sub-kHz linewidths. The long-term stability of the comb is defined by an external RF reference: either a 10 MHz RF signal from the Dutch Metrology Institute (VSL), or a tunable RF source whose long-term stability is maintained by monitoring and stabilizing the position of a narrow-line magneto-optical trap (MOT). The comb-stabilized system is benchmarked against a conventional cavity-locked laser and achieves comparable performance in broadband and single-frequency MOTs using the narrow $^1$S$_0$ $\rightarrow$ $^3$P$_1$ laser cooling transition. We generate high-flux, sub-$\mu$K samples of all three bosonic strontium isotopes and demonstrate quasi-continuous outcoupling from the MOT. These results highlight the

Researchers have developed a novel laser-assisted synthesis method to fabricate platinum (Pt) colloidosomes (Cs) with promising applications in near-infrared (NIR) photocatalytic and enzyme-mimicking cancer therapy.

arXiv:2507.21918v1 Announce Type: cross Abstract: The control of material properties at the atomic scale remains a central challenge in materials science. Transition metal dichalcogenides (TMDCs) offer remarkable electronic and optical properties, but their functionality is largely dictated by their stable crystalline phases. Here we demonstrate a single-step, ligand-free strategy using femtosecond laser ablation in liquid to transform crystalline, stoichiometric palladium diselenide (PdSe$_{\mathrm{2}}$) into highly stable, amorphous, and non-stoichiometric nanoparticles (PdSe$_{\mathrm{2-x}}$, with x$\approx$1). This laser-driven amorphization creates a high density of selenium vacancies and coordinatively unsaturated sites, which unlock a range of emergent functions absent in the crystalline precursor, including plasmon-free surface-enhanced Raman scattering with an enhancement factor exceeding 10$^\mathrm{6}$, a 50-fold increase in photocatalytic activity, and near-infrared

arXiv:2507.22021v1 Announce Type: new Abstract: Organic electrochemical transistors (OECTs) are key bioelectronic devices, with applications in neuromorphics, sensing, and flexible electronics. However, their microfabrication typically relies on precious metal contacts manufactured via cleanroom processes. Here, we present a high-throughput additive-subtractive microfabrication strategy for metal-free, flexible OECTs using biodegradable materials and room-temperature processing. Additive manufacturing of large features is achieved via extrusion printing of a water-dispersed graphene ink to fabricate electrode contacts, and spin-coating of a cellulose acetate ink to form both the substrate and encapsulation layer. Combined with femtosecond laser ablation, this approach enables micrometer-resolution patterning of free-standing OECTs with channel openings down to 1 um and sheet resistance below 10 Ohm/sq. By tuning laser parameters, we demonstrate both selective and simultaneous ablation

arXiv:2507.21979v1 Announce Type: new Abstract: Q-switched lasers are compact, cost-effective, and highly pulse energy-scalable sources for nanosecond-scale laser pulses. The technology has been developed for many decades and is widely used in scientific, industrial and medical applications. However, their inherently narrow bandwidth imposes a lower limit on pulse duration - typically in the few-hundred-picosecond range - limiting the applicability of Q-switched technology in fields that require ultrafast laser pulses in the few-picosecond or femtosecond regime. In contrast, mode-locked lasers can produce broad-band, ultrafast (

arXiv:2507.21891v1 Announce Type: new Abstract: Intracavity laser-based systems are emerging as key enablers for next-generation wireless communications, positioning, and wireless power transfer (WPT). Distributed coupled-cavity laser (DCCL) systems, as a representative configuration, have been proposed to expand the field of view (FoV) and enhance safety. This paper investigates the safety assessment of DCCL-WPT systems through three case studies: skin safety, eye safety, and small-object intrusion sensitivity. First, we establish a safety analysis model to quantify irradiation levels on intruding objects in the beam path, which simulates intracavity beam propagation using diffraction modeling and gain-loss dynamics under case-specific boundary conditions. Next, we formulate an eye safety evaluation tailored for DCCL-WPT systems using a human head model to identify potential exposure angles and distances. Ray tracing confirms that intracavity beams are not focused onto the retina,

arXiv:2507.20401v1 Announce Type: new Abstract: Endovenous laser therapy (ELT) as a minimally invasive procedure for ablation of large superficial veins, nevertheless, can cause complications of thrombotic nature. In this regard, the study of the main patterns of thrombus formation during ELT and modelling of endovenous heat-induced thrombosis (EHIT) is relevant. Based on the assumption of diffusion limiting of biochemical processes occurring during the coagulation of blood, by recalculating the reaction rates according to the Stokes-Einstein equation, a simple point model of blood coagulation during ELT was built in this paper. As a result of the use of this model, it was demonstrated that blood heating entails an increase in the rate of thrombin production, a decrease in the time for achieving the peak of its concentration by 5-6 times with its almost constant amplitude. Heating leads to the rapid formation of fibrin clusters and the appearance of a fibrin-polymer network with a

arXiv:2507.20748v1 Announce Type: new Abstract: Helium metastable species play a critical role in sustaining radio-frequency (RF) driven micro atmospheric pressure plasma jets through Penning ionization and for the generation of reactive oxygen and nitrogen species (RONS). Their densities are typically measured using tunable diode laser absorption spectroscopy (TDLAS). Most spatially resolved TDLAS approaches rely on mechanical scanning of a narrow laser beam across the plasma, which is time-consuming and limits spatial resolution. In this work, we present an advanced two-dimensional (2D) TDLAS method that enables direct spatial mapping of helium metastable densities without the need for mechanical scanning. A rotating optical diffuser is employed to suppress speckle interference and generate uniform illumination across the plasma region. The absorption profile is captured using a short-wavelength infrared camera equipped with a telecentric lens, achieving high spatial resolution

As technology advances, photonic systems are gaining ground over traditional electronics, using light to transmit and process information more efficiently. One such optical system is laser beam scanning (LBS), where laser beams are rapidly steered to scan, sense, or display information.

A team of researchers at the Max Born Institute and collaborating institutions has developed a reliable method to create complex magnetic textures, known as skyrmion bags, in thin ferromagnetic films. Skyrmion bags are donut-like, topologically rich spin textures that go beyond the widely studied single skyrmions.

arXiv:2507.19449v1 Announce Type: new Abstract: The exceptionally low-energy isomeric transition in $^{229}$Th at around 148.4 nm offers a unique opportunity for coherent nuclear control and the realisation of a nuclear clock. Recent advances, most notably the incorporation of large ensembles of $^{229}$Th nuclei in transparent crystals and the development of pulsed vacuum-ultraviolet (VUV) lasers, have enabled initial laser spectroscopy of this transition. However, the lack of an intense, narrow-linewidth VUV laser has precluded coherent nuclear manipulation. Here we introduce and demonstrate the first continuous-wave laser at 148.4 nm, generated via four-wave mixing (FWM) in cadmium vapor. The source delivers 100 nW of power with a linewidth well below 100 Hz and supports broad wavelength tunability. This represents a five-orders-of-magnitude improvement in linewidth over all previous single-frequency lasers below 190 nm, marking a major advance in laser technology. We develop a

arXiv:2507.18599v1 Announce Type: new Abstract: Research on silicon nitride (SiN) nanomechanical resonators produces an exceptionally rich variety of resonator geometries, for which there is currently no available rapid prototyping solution. Experimental advances in nanobeam, trampoline, phononic bandgap, and soft-clamping structures all rely on conventional nanofabrication involving e-beam or photolithography, followed by various etching steps. These techniques are typically time-consuming, relatively inflexible, and often result in spurious residual SiN overhang that can degrade mechanical quality factors. In contrast, recent work has shown that simple resonant structures, such as nanobeams, can be prototyped by direct laser ablation of free-standing SiN membranes using a spatially distributed sequence of microholes that limits stress concentration. However, these early demonstrations were restricted to basic shapes, created by manually combining ablation routines for circles and

Researchers from Trinity College Dublin's School of Engineering have built a powerful new machine that lets us watch precisely what happens when tiny particles—far smaller than a grain of sand—hit a surface at extremely high speeds. It's the only machine like it in Europe, and it took over two years to design and build.

arXiv:2507.17719v1 Announce Type: new Abstract: A continuous-wave laser source at 148.4 nm based on second-harmonic generation in randomly quasi-phase matched strontium tetraborate, SrB4O7, is demonstrated. It provides (1.3-0.6+0.7) nW of VUV power in a single pass for an incident UV laser power of 325 mW. The laser system is developed for the resonant laser excitation of the 229Th nucleus to its low-energy isomeric state. For a frequency-stabilized laser system we expect to reach similar VUV power spectral densities as in previous pulsed laser excitation experiments of the nuclear transition in 229Th-doped crystals.

arXiv:2507.17100v1 Announce Type: new Abstract: Femtosecond (fs) laser sintering enables ultrafast and spatially localized energy deposition, making it attractive for additive manufacturing of metal nanoparticles. However, undesired ablation during fs irradiation of copper (Cu) nanoparticles often disrupts uniform sintering, and the underlying ablation mechanisms remain poorly understood. In this work, we investigate the fragmentation and coalescence behavior of Cu nanoparticles subjected to fs laser scanning under fluence conditions relevant to sintering applications. Particle size distributions extracted from scanning electron microscopy reveal a bimodal transformation: emergence of sub-60\,nm debris and formation of large aggregates up to 750 nm. We evaluate two candidate mechanisms -- Coulomb explosion and hot electron blast -- by estimating electron emission, electrostatic pressure, and hot electron temperature using the Richardson--Dushman equation and two-temperature modeling.

arXiv:2507.17046v1 Announce Type: new Abstract: In high-intensity laser-plasma interactions, particles can lose a substantial fraction of their energy by emitting radiation. Using particle-in-cell simulations, we study the impact of radiation reaction on the dynamics of an underdense plasma target struck by counterpropagating circularly polarized laser pulses. By varying the relative wavelengths and intensities of the pulses, we find a range of parameters where radiation reaction can detrap electrons from the interference beat wave. The resulting charge separation field and the dominant direction of ion expulsion are thus reversed by radiative effects. Based on the electron dynamics during the interaction, we estimate the bounds on the parameter regime where the reversal occurs. The bounds take the form of three simple inequalities which depend only on the wavelength, normalized vector potential, and pulse duration ratios of the two lasers as well as the product of the pulse duration

arXiv:2507.16949v1 Announce Type: new Abstract: Reflecting light off a mirror moving near light speed, as first envisioned by Einstein, offers a powerful method for generating bright, ultrashort pulses in the extreme ultraviolet range. Recent breakthroughs show that dense relativistic electron mirrors can be created by striking a nanometre-scale foil with a high-intensity, sharp-front laser pulse, forming a single relativistic electron sheet (RES). This RES coherently reflects and upshifts a counter-propagating laser beam from the infrared to the extreme ultraviolet with efficiency exceeding incoherent scattering by over several orders of magnitude. Here we demonstrate that optimizing the drive laser waveform can reliably produce a single RES, leading to generation of isolated \emph{attosecond} pulses enhancing both intensity and temporal compression of the back reflected light in a controlled manner. Simulations reveal that tuning parameters like timing delay enables control over the

arXiv:2507.16082v1 Announce Type: cross Abstract: Interfacing superconducting microwave resonators with optical systems enables sensitive photon detectors, quantum transducers, and related quantum technologies. Achieving high optical pulse repetition is crucial for maximizing the device throughput. However, light-induced deterioration, such as quasiparticle poisoning, pair-breaking-phonon generation, and elevated temperature, hinders the rapid recovery of superconducting circuits, limiting their ability to sustain high optical pulse repetition rates. Understanding these loss mechanisms and enabling fast circuit recovery are therefore critical. In this work, we investigate the impact of optical illumination on niobium nitride and niobium microwave resonators by immersing them in superfluid helium-4 and demonstrate a three-order-of-magnitude faster resonance recovery compared to vacuum. By analyzing transient resonance responses, we provide insights into light-induced dynamics in these

arXiv:2507.16299v1 Announce Type: new Abstract: The investigation of coherent phenomena in strong-field processes requires interferometric measurement schemes with high selectivity to disentangle the complex nonlinear response of the system. Interferometers combining acousto-optical phase modulation with lock-in detection feature excellent dynamic range and highly selective detection, thus providing a promising solution. However, acousto-optical modulators (AOMs) cause several issues when operated with intense, ultrashort, near infrared (NIR) laser pulses. The AOMs introduce temporal and angular dispersion, self-phase modulation and reduced acousto-optic efficiency at NIR wavelengths. Here, we present an acousto-optical phase modulation interferometer design that solves these issues. The presented solutions pave the way for the investigation of strong-field processes with phasemodulated interferometry and are also useful to improve the performance of phase-modulation interferometers

arXiv:2507.16227v1 Announce Type: new Abstract: This work presents predictive hydrodynamic simulations empowered by artificial intelligence (AI) for laser driven implosion experiments, taking the double-cone ignition (DCI) scheme as an example. A Transformer-based deep learning model MULTI-Net is established to predict implosion features according to laser waveforms and target radius. A Physics-Informed Decoder (PID) is proposed for high-dimensional sampling, significantly reducing the prediction errors compared to Latin hypercube sampling. Applied to DCI experiments conducted on the SG-II Upgrade facility, the MULTI-Net model is able to predict the implosion dynamics measured by the x-ray streak camera. It is found that an effective laser absorption factor about 65\% is suitable for the one-dimensional simulations of the DCI-R10 experiments. For shot 33, the mean implosion velocity and collided plasma density reached 195 km/s and 117 g/cc, respectively. This study demonstrates a

arXiv:2507.16227v1 Announce Type: cross Abstract: This work presents predictive hydrodynamic simulations empowered by artificial intelligence (AI) for laser driven implosion experiments, taking the double-cone ignition (DCI) scheme as an example. A Transformer-based deep learning model MULTI-Net is established to predict implosion features according to laser waveforms and target radius. A Physics-Informed Decoder (PID) is proposed for high-dimensional sampling, significantly reducing the prediction errors compared to Latin hypercube sampling. Applied to DCI experiments conducted on the SG-II Upgrade facility, the MULTI-Net model is able to predict the implosion dynamics measured by the x-ray streak camera. It is found that an effective laser absorption factor about 65\% is suitable for the one-dimensional simulations of the DCI-R10 experiments. For shot 33, the mean implosion velocity and collided plasma density reached 195 km/s and 117 g/cc, respectively. This study demonstrates a

A new review highlights a powerful, cleaner route to produce ultra-clean, customizable nanoparticles—key building blocks for artificial sensory systems that mimic human perception and power emerging technologies like extended reality (XR) and advanced human–machine interfaces.

Multi-wavelength light sources are required for optical transceivers to increase data. However, scaling the laser array size increases thermal crosstalk, which may affect laser efficiency and reliability.

arXiv:2507.13976v1 Announce Type: new Abstract: In this letter, we report the measurement of the coefficient of thermal expansion (CTE) of single-crystal silicon from 655 mK to 16 K using an ultra-stable laser based on a single-crystal silicon Fabry-Perot cavity. Below 1 K temperatures, the CTE is in the $10^{-13}$ K$^{-1}$ range with a lowest point at $\boldsymbol{\alpha(}655$ mK$ \boldsymbol{)=} 3.5 \pm 0.4 \times 10^{-13}$ K$^{-1}$. We produce a theoretical model based on Debye and Einstein models to effectively approximate the CTE measured in this temperature range. This is the lowest-temperature CTE measurement of silicon to date, as well as the lowest operating temperature for an ultra-stable Fabry-Perot cavity for laser frequency stabilization.

arXiv:2507.13907v1 Announce Type: new Abstract: Laser-plasma based experiments are always more demanding about the plasma characteristics which need to be generated during the interaction. This is valid for laser-plasma acceleration as well as for inertial confinement fusion experiments. Most of these experiments are moving toward high repetition rate operation regimes, making even more demanding the requests on the plasma sources and the diagnostics to be implemented.\\ Interferometry is one of the most used methods to characterize these sources, since it allows for non-perturbative, single-shot measurements either of the neutral gas or the plasma density. The design of the interferometric setup is non-trivial and needs to be shaped on the actual conditions of the experiment. Similarly, the analysis of the raw data is a complex task, prone to many sources of error and dependent on the manual inputs.\\ In this work, we will present the techniques we are developing for the analysis of

arXiv:2507.13982v1 Announce Type: new Abstract: Reliable energy delivery is a critical requirement for long-term lunar missions, particularly in regions with limited solar access, such as polar craters and during extended lunar nights. Optical Power Beaming (OPB) using high-power lasers offers a promising alternative to conventional solar power, but the effects of suspended lunar dust on beam propagation remain poorly understood. This study introduces a detailed simulation model that incorporates both diffraction and height-dependent scattering by the electrostatically suspended lunar regolith. Un like prior approaches, which assumed uniform dust layers or center-to-center transmission loss, our model uses generalized diffraction theory and refractive index gradients derived from particle density to assess beam deformation and attenuation. The results show that even in ground-to-ground scenarios, lunar dust significantly degrades energy transfer efficiency,

arXiv:2507.12899v1 Announce Type: cross Abstract: The experimental verification of the quantum nature of gravity represents a milestone in quantum gravity research. Recently, interest has grown for testing it via gravitationally induced entanglement (GIE). Here, we propose a space-based interferometer inspired by the LISA Pathfinder (LPF). Unlike the LPF, our design employs two smaller gold-platinum test masses, each weighing the milligram scale, surrounded by a shield below 2 K, and positioned side by side with a millimeter scale separation. This configuration enables the detection of GIE through simultaneous measurements of differential and common-mode motions. We simulate quantum measurements of these modes taking into account gas damping, black-body radiation, and cosmic-ray collisions to estimate the integration time for GIE detection. Our results show that GIE can be demonstrated with a few modifications to the LPF setup.

arXiv:2507.12109v1 Announce Type: new Abstract: We present the first systematic experimental validation of return-current-driven implosion scaling in micrometer-sized wires irradiated by femtosecond laser pulses. Employing XFEL-based imaging with sub-micrometer spatial and femtosecond temporal resolution, supported by hydrodynamic and particle-in-cell simulations, we reveal how return current density depends precisely on wire diameter, material properties, and incident laser energy. We identify deviations from simple theoretical predictions due to geometrically influenced electron escape dynamics. These results refine and confirm the scaling laws essential for predictive modeling in high-energy-density physics and inertial fusion research.

arXiv:2507.11656v1 Announce Type: new Abstract: A comprehensive numerical study has been conducted to investigate the feasibility of efficient terahertz wave generation in two-dimensional MXene layers excited by near-infrared femtosecond laser pulses.

A powerful new technique harnesses swirling plasma inside laser-blasted microtubes to produce record-breaking magnetic fields—rivaling those near neutron stars—all within a compact laboratory setup. This innovation promises to transform astrophysics, quantum research, and fusion energy experiments by unleashing megatesla-level forces using nothing more than targeted laser pulses and clever engineering.

After 10 years of gravitational-wave research, the LIGO Lab team at MIT is getting ready for the next generation of detectors.

arXiv:2507.11501v1 Announce Type: new Abstract: Ultrafast laser-driven terahertz sources are gaining in popularity in an increasingly wide range of scientific and technological applications. However, many fields continue to be severely limited by the typically low average power of these sources, which restricts speed, signal-to-noise ratio, and dynamic range in numerous measurements. Conversely, the past two decades have seen spectacular progress in high average power ultrafast laser technology based on Ytterbium lasers, rendering hundreds of watts to kilowatts of average power available to this community to drive THz sources. This has opened the young field of high-average-power laserdriven THz time-domain spectroscopy, which holds the potential to revolutionize the applications of THz time-domain systems. In this perspective article, we discuss this young field and emphasize recent advancements in broadband terahertz sources utilizing high-power Yb-based ultrafast lasers as drivers,

Researchers have created an ultrasensitive laser the size of a penny that could improve lidar technology, boosting autonomous vehicles in the process.

arXiv:2507.10153v1 Announce Type: new Abstract: Ever since the advent of high-order harmonic generation, one of the main goals has been to maximize the high harmonic yield. This is due to the wide range of applications in multidisciplinary research fields, including nonlinear XUV optics and ultrafast science. Nowadays, intense laser-atom interactions are one of the primary sources of high-order harmonic generation, emitting radiation in the extreme ultraviolet (XUV) range. Although the scaling laws for XUV photon numbers have been extensively studied in the past, their dependence on the duration of the driving laser pulse has remained largely unexplored experimentally. This is because, in each of these studies, the XUV photon yield was optimized according to the specific characteristics of the lasers used and the corresponding XUV beamlines. In other words, there have been no systematic measurements on the dependence of XUV yield on the duration of the driving laser pulse. Here, by

arXiv:2507.10064v1 Announce Type: new Abstract: This work developed an accurate and robust absorption-based method for spatially resolved measurements of gas temperatures in flames and reacting flows, with typical single-measurement uncertainties on the order of 1\%. This method exploits narrow-linewidth laser absorption of hot CO$_2$ molecules, which can be generated from combustion or artificially seeded into the flow. A collinear dual-laser setup allowed for periodic scans over tens of CO$_2$ absorption transitions near the $\nu_3$ bandhead every 100 $\mu s$, from which gas temperatures (as well as CO$_2$ concentrations) were determined with high sensitivity and robustness. Spatially resolved measurements were achieved using an electrically driven high-speed beam scanning system consisting of a 2-D galvo scanner and a pair of off-axis parabolic mirrors. An effective spatial resolution of 1 mm was achieved at a planar field measurement speed of 200 Hz and a volumetric field

arXiv:2507.08825v1 Announce Type: new Abstract: How can one design complex systems capable of learning for a given functionality? In the context of ultrafast laser-surface interaction, we unravel the nature of learning schemes tied to the emergence of complexity in dissipative structures. The progressive development of learning mechanisms, from direct information storage to the development of smart surfaces, originates from the network of curvatures formed in the unstable fluid under thermoconvective instability, which is subsequently quenched and resolidified. Under pulsed laser irradiation, non-equilibrium dynamics generate intricate nanoscale patterns, unveiling adaptive process mechanisms. We demonstrate that the imprints left by light act as a form of structural memory, encoding not only local effects directed by laser field polarization but also a cooperative strategy of reliefs that dynamically adjust surface morphology to optimize light capture. By investigating how apparent