Advanced Laser Research Articles

Validation of stone-kidney size score to predict outcome and complications of pediatric percutaneous nephrolithotomy

The prevelance of urinary system stone disease in children is emphasizing the need for minimally invasive treatments to decrease morbidity and recurrence risk. Percutaneous nephrolithotomy (PCNL) has emerged as a preferred approach for pediatric patients with complex stones due to its minimally invasive nature, including miniaturized and vacuum-assisted access sheaths, advanced laser technology and tubeless and outpatient procedures. However, adult scoring systems have proven ineffective in predicting success and complications in pediatric PCNL. This highlights the need for specialized scoring systems, such as the Stone-Kidney Size (SKS) scoring system, tailored to pediatric patients and will be evaluated in our study for its association with the stone-free rate (SFR) and complications. The data of 144 patients aged <17 years who had undergone PCNL between January 2008 and December 2019 were evaluated retrospectively. Demographics, stone characteristics, perioperative/postoperative outcomes were recorded for each patient. The SKS scoring system comprises the stone kidney index (SKI) and the number of stones, assigns one or two points based on single or multiple stones and an SKI value of <0.3 or ≥0.3, respectively. The SKI is computed by dividing the stone's longest axis by the kidney's longest axis. Residual stones less than 4mm on non-contrast computed tomography are considered clinically insignificant residual fragments (CIRFs). Stone-free and CIRF patients were considered successful results. The relationship between the SKS scoring system and SFR, success, and complication rates after surgery was investigated. Statistical analyses were conducted using SPSS 22.0 software. The SFR was 67.36% and 74.31% when CIRF patients were included, respectively, with a complication rate of 27%. In multivariate analysis, stone treatment history, stone burden, and SKS score were statistically significantly associated with SFR (p<0.001, p=0.032, p<0.001, respectively). Furthermore, the SKS score was the only variable that showed a statistically significant relationship with success. No significant association was found between SKS score and complications (p=0.342). Our study demonstrates a relationship between the SKS scoring system and SFR in pediatric PCNL patients. However, shortcomings have been observed in its capacity to accurately predict post-PCNL complications. Despite being a retrospective analysis and having a single-center design, our study externally validates the relationship between the SKS scoring system and SFR after pediatric PCNL. The SKS scoring system is associated with SFR in pediatric patients undergoing PCNL; however, this relationship has not been established for complications.

Phase-matched five-wave mixing in zinc oxide microwire

Abstract High-order wave mixing in solid-state platforms gather increasing importance due to the development of advanced lasers and integrated photonic circuit for both classical and quantum information. However, the high-order wave mixing is generally inefficient in solids under weak pump. Here, we observed the presence of phase matching of five-wave mixing (5WM) propagating in a zinc oxide (ZnO) microwire. The 5WM signal is enhanced by 2–3 orders of magnitude under the phase matching conditions, reaching an absolute conversion efficiency of 1.7 × 10−13 when the peak pumping power density is about 106 W/cm2. The propagation of multiple nonlinear signals, including sum frequency generation, third harmonic generation, four-wave mixing etc., benefited from both the large nonlinear coefficients and the wide transparent window of ZnO, implies the possibility of developing cascaded nonlinear process under higher pumping. This study enriches the ZnO platform for integrated nonlinear nanophotonics.

Design framework of a computer-generated hologram that performs volumetric beam shaping for advanced laser processing

Axial beam shaping is very effective for material laser processing, typically laser cutting, drilling, and grooving. We demonstrate a framework for designing a computer-generated hologram (CGH) that performs volumetric beam shaping. The procedure performs axial beam shaping with a continuous intensity distribution, unlike our previous research in which only discrete focal points were arranged three-dimensionally. This research is the more general approach for volumetric beam shaping. An important point in this research is finding an optimal interval in the optical axis direction and in calculating the CGH design. The design interval is half of the focusing length (the full width at half-maximum of the laser beam profile in the axial direction) given by the diffraction limit of the optical system. The optimal value is obtained using an axially shaped beam that is the reconstruction of the CGH calculated from Zernike polynomials. We also demonstrate that the optimal interval for evaluating the axially shaped beam is also half of the beam length. Following the CGH design procedure, we demonstrate CGHs that generate long-focus beams with an arbitrary axially shaped beam. We found a tradeoff relation between the focusing length and the intensity of the long-focus beam, suggesting that the use of a focused beam with an appropriate length according to the purpose will lead to improved processing efficiency.

Mirror-assisted 360° panoramic 3D measurement system based on rotary laser profilometer

Abstract The full surface digitization of real samples plays a crucial role in fields such as object recognition, industrial quality control, and reverse modeling. To achieve panoramic three-dimensional (3D) reconstruction of samples in complex scenes, we propose an advanced panoramic laser scanning system, consisting of a laser rotation scanning system and a pair of plane mirrors. With the assistance of mirrors, the projected line laser beam can illuminate the sample from full angles in a single scanning sequence, and the camera can capture the 3D information of the sample from several specific viewpoints. The scanning method of rotating allows us to achieve more efficient and larger-scale 3D scanning. After obtaining the sample’s 3D information from different viewpoints using the same calibration parameters, the sample’s full-surface 3D data in the global coordinate can be obtained using mirror reflections. We conducted precision and effectiveness tests on samples with different sizes, materials, shapes, and textures to demonstrate the ability of the proposed method to perform full-surface 3D reconstruction under different scenarios. The experimental results of accuracy evaluation demonstrate that the proposed system can achieve a measurement accuracy at the level of 100 μm. Additionally, the robust experimental results in different scenarios also indicate that the proposed panoramic laser scanning system is capable of accurately obtaining full-surface 3D data of various types of samples, providing a cost-effective, easy-to-use, efficient, high-resolution, and effective approach for achieving panoramic 3D reconstruction.

Microstructure evolution and crack prevention in TiC nanoparticles-enhanced 2195 Al[sbnd]Li alloy joint fabricated by coaxial fiber-diode hybrid laser wire-feeding welding

High hot crack susceptibility (HCS) in laser-welded 2195 AlLi alloy poses a considerable challenge that restricts its widespread application. Nonetheless, the utilization of advanced laser beam shaping technology and nano-technology presents novel approaches to modify the melting and solidification procedures, enabling precise control over microstructure and crack. Herein, a crack-free and well-formed weld seam (WS) of 2195 AlLi alloy was successfully achieved by employing a coaxial “Gussies + Flat top” hybrid laser source and introducing TiC nanoparticles. The contrast experiments were performed to comprehensively investigate the effect of TiC nanoparticles on the microstructure evolution and hot cracks in welded joints of 2195 AlLi alloy. The results indicated that the crack propagation occurs linearly along the grain boundaries of columnar dendrites and laterally along the grain boundaries of equiaxed dendrite utilizing the conventional AlCu filling wire. With the assistance of TiC nanoparticles, the crack-free WS with homogeneously equiaxed dendrites is facilitated. The elimination of cracks by introducing TiC nanoparticles is attributed to the ameliorative liquid feeding channels, grain refinement, as well as the the pinning effect of TiC nanoparticles.

Efficacy and Safety of 577-nm Yellow Laser in the Treatment of Pigmented Epidermal Lesions.

Freckles and lentigines are common pigmented problems which not only cause substantial cosmetic morbidity but also create psychosocial concern. The available modalities for the treatment of pigmented lesions are often unsatisfactory for patients, require a long treatment period, and often cause skin irritation. With the advent of lasers, safe and effective treatment options for epidermal pigmentation have become more varied for different Fitzpatrick skin types. We aimed to evaluate the efficacy and safety of 577-nm yellow laser in the treatment of pigmented epidermal lesions. This study was carried out on 50 patients presented with pigmented epidermal lesions (25 presented with freckles and 25 presented with lentigines). Each patient received four treatment sessions with a 577-nm diode laser at 2-week intervals. There was significant improvement in freckles and lentigines, as 23 out of 50 patients showed marked improvement, 11 patients showed moderate improvement, 10 patients showed mild improvement, and only six patients had no changes. Moreover, 23 patients were very satisfied, 18 patients were satisfied, and nine patients were not satisfied. As regards the safety of the 577-nm yellow laser, there was no significant adverse effect among patients except pain, erythema, and hyperpigmentation, which resolved within one month after treatment. This study showed that the 577-nm yellow laser is an effective, safe, and well-tolerated device in the treatment of freckles and lentigines.

Dual‐Wavelength Controllable and Exciplex Emission for Laser Concealment

AbstractAs an advanced signal source, laser is very suitable for various photonic devices but implementing tunability of wavelength is more challenging. Herein, the study designs and synthesizes boron difluoride derivative tBuBF2, systematically studying the impact of assembly behavior on laser performance. The laser test results indicate that the emission wavelength of tBuBF2 microcrystals can be controlled by varying the length of the microcrystals, with the shorter wavelength of 0–1 vibronic lasing emission at 444 nm and the longer wavelength of 0–2 lasing emission at 468 nm. Mechanistic studies reveal that laser color change comes from an increase in optical propagation losses due to self‐absorption at the 0–1 vibronic band. Furthermore, CBP@tBuBF2 microcrystals constructed by doping with 4,4′‐bis(9‐carbazolyl)‐1,10‐biphenyl (CBP) as the guest molecule, which primarily exhibits 580 nm exciplex yellow emission while retaining weak blue emission. Moreover, it is demonstrated that the laser emission only occurred within the 0–2 vibronic band in the blue region owing to the increased self‐absorption phenomenon with 0–1 band, thus achieving controllable dual‐wavelength and exciplex emission for laser concealment. This work expands novel regulation strategy available for laser behavior control by enhancing the self‐absorption process, describing structure‐property relationships that will guide the design of advanced laser materials.

Linewidth Measurement of a Narrow-Linewidth Laser: Principles, Methods, and Systems.

Narrow-linewidth lasers mainly depend on the development of advanced laser linewidth measurement methods for related technological progress as key devices in satellite laser communications, precision measurements, ultra-high-speed optical communications, and other fields. This manuscript provides a theoretical analysis of linewidth characterization methods based on the beat frequency power spectrum and laser phase noise calculations, and elaborates on existing research of measurement technologies. In addition, to address the technical challenges of complex measurement systems that commonly rely on long optical fibers and significant phase noise jitter in the existing research, a short-delay self-heterodyne method based on coherent envelope spectrum demodulation was discussed in depth to reduce the phase jitter caused by 1/f noise. We assessed the performance parameters and testing conditions of different lasers, as well as the corresponding linewidth characterization methods, and analyzed the measurement accuracy and error sources of various methods.

Climate Change and Cultural Heritage: A Global Mapping of the UNESCO Thematic Indicators in Conjunction with Advanced Technologies for Cultural Sustainability

This study investigates the relationship between cultural heritage and climate change, assessing the global implementation of advanced technologies in line with UNESCO’s Thematic Indicators for Cultural Sustainability. Few studies have been conducted on this topic; hence, theoretical background examines the keywords related to cultural heritage preservation, conservation, restoration, climate change mitigation, and adaptation, as well as the intersection of culture and climate change. It also analyses the definitions provided by leading global organizations and explores the use of advanced technologies in protecting cultural heritage. The research methodology is based on an analytical method consisting of a bibliometric assessment and a scientometric assessment. The bibliometric and scientometric analyses map occurrences, frequencies, and intercorrelations of these keywords with UNESCO Thematic Indicators and advanced technology utilization. The findings reveal a predominance of conservation-related Thematic Indicators, suggesting a conservative approach to cultural sustainability, particularly for environmental resilience, wealth, and livelihoods. In terms of advanced technologies, laser scanning and photogrammetry are used for both conservation and restoration purposes, while chromatography and virtual tours are mainly applied to conservation and preservation practices. Otherwise, infrared thermography, X-ray imaging, and online platforms are used, respectively, for heritage preservation, restoration, and conservation. On the other hand, ground-penetrating radar and remote sensing exhibit fewer connections to heritage protection. The mapping of culture and climate change also highlights the importance of conservation in responding to changing climate conditions. Climate adaptation is closely linked to both conservation and preservation efforts, highlighting the critical role of cultural heritage in fostering climate resilience.

High-performance flexible p-type Ce-filled Fe3CoSb12 skutterudite thin film for medium-to-high-temperature applications

P-type Fe3CoSb12-based skutterudite thin films are successfully fabricated, exhibiting high thermoelectric performance, stability, and flexibility at medium-to-high temperatures, based on preparing custom target materials and employing advanced pulsed laser deposition techniques to address the bonding challenge between the thin films and high-temperature flexible polyimide substrates. Through the optimization of fabrication processing and nominal doping concentration of Ce, the thin films show a power factor of >100 μW m−1 K−2 and a ZT close to 0.6 at 653 K. After >2000 bending cycle tests at a radius of 4 mm, only a 6 % change in resistivity can be observed. Additionally, the assembled p-type Fe3CoSb12-based flexible device exhibits a power density of 135.7 µW cm−2 under a temperature difference of 100 K with the hot side at 623 K. This work fills a gap in the realization of flexible thermoelectric devices in the medium-to-high-temperature range and holds significant practical application value.

Beyond 99.5% Geometrical Fill Factor in Perovskite Solar Minimodules with Advanced Laser Structuring

AbstractPerovskite solar cells, known for high efficiency and compatibility with various photovoltaic (PV) applications, have garnered significant attention from academia and industry. Scaling up these cells conventionally involves fabricating modules with series‐connected cells using a monolithic interconnection based on the P1‐P2‐P3 scheme, a common approach for thin‐film PV modules. The Geometrical Fill Factor (GFF), representing the ratio between active area and aperture area, typically ranges from 90% to 95%. This study introduces an advanced laser manufacturing process to minimize interconnection area by reducing scribe width and minimizing distances between them, achieving an interconnection width of 45 µm with a GFF of 99.1%. Additionally, a discontinuous P2 design further reduces the dead area to an average of 19.5 µm, resulting in a record GFF of 99.6%. Using this interconnection in a highly efficient p‐i‐n stack, the study demonstrates the feasibility of the discontinuous P2 by fabricating 2.6 cm2 minimodules with an aperture area efficiency of 20.7%. The research highlights how proper design can minimize intrinsic losses during the scaling process from cell to module to a negligible level. Experimental studies, coupled with cell‐to‐module loss simulations and electroluminescence mapping for layer deposition uniformity, provide insights into the potential of the new P2 design.

Recent advances in high-order harmonic generation from laser-ablated plumes at the advanced laser light source laboratory

High-order harmonic generation is a nonlinear optical frequency conversion process that occurs during intense ultrafast laser-matter interaction. At the Advanced Laser Light Source laboratory, we use ultrafast laser pulses having diverse wavelengths, spanning visible, near- and mid-infrared ranges, to generate high-order harmonics from laser-ablated plumes in the extreme ultraviolet or soft X-ray region of the electromagnetic spectrum. The Advanced Laser Light Source Laboratory is situated within the Énergie Matériaux Télécommunications Center of the Institut national de la recherche scientifique in Montréal, Quebec, Canada. We focus on generating bright and broadband harmonics by exploiting various types of ultrafast resonances in different species within the laser-ablated plume, and use them for applications in ultrafast spectroscopy, imaging, and AMO science. We are also actively exploring previously unknown physics governing the harmonic generation from different resonances. In this review article, we provide an overview of the recent advancements made in these directions.

A 3D tailored monolithic glass chip for stimulating and recording zebrafish neuronal activity with a commercial light sheet microscope

Microfluidic technology is unrivaled in its ability to apply soluble chemical stimuli with high spatiotemporal precision. Analogous, light–sheet microscopy is unmatched in its ability of low phototoxic but fast volumetric in vivo imaging with single cell resolution. Due to their optical translucency during the larval stages, zebrafish (Danio rerio) are an ideal model to combine both techniques; yet, thus far this required light–sheet microscopes, which were in most cases custom–built and adapted to the available softlithographic chip technology. Our aim was to use a commercial light–sheet microscope to illuminate a microfluidic chip from two opposite lateral directions and to record images with the detection objective placed orthogonally above the chip. Deep tissue penetration can be achieved by superimposing beams from opposite directions to form a single light sheet. But a microfluidic chip that allows a) targeted stimulus application in a closed microenvironment, b) interference–free incoupling of excitation light from two directions and c) outcoupling of fluorescence in the perpendicular direction through an optically perfect cover glass was not known until now. Here, we present a monolithic glass chip with the required plane-parallel sidewalls and cover slide closure at the top, constructed by advanced femtosecond laser ablation, thermal bonding and surface smoothing processes. In addition, the 3D shape of a fish fixator unit was tailored to match the body shape of a zebrafish larva to ensure stable positioning during whole–brain recording. With hydrodynamic focusing a targeted partial exposure of the larva’s head to chemical stimuli and fast position switching (in less than 10 s) was possible. With the capabilities of this unique monolithic glass chip and its up–scalable wafer–level fabrication process, the new NeuroExaminer is prone to become an excellent addition to neurobiology laboratories already equipped with high–quality commercial light sheet microscopes.

Controlling the Glassy State toward Structural and Mechanical Enhancement: Additive Manufacturing of Bulk Metallic Glass Using Advanced Laser Beam Shaping Technology (Adv. Funct. Mater. 12/2024)

Controlling the Glassy State toward Structural and Mechanical Enhancement: Additive Manufacturing of Bulk Metallic Glass Using Advanced Laser Beam Shaping Technology (Adv. Funct. Mater. 12/2024)

Macroscopic quantum entanglement between an optomechanical cavity and a continuous field in presence of non-Markovian noise

Probing quantum entanglement with macroscopic objects allows us to test quantum mechanics in new regimes. One way to realize such behavior is to couple a macroscopic mechanical oscillator to a continuous light field via radiation pressure. In view of this, the system that is discussed comprises an optomechanical cavity driven by a coherent optical field in the unresolved sideband regime where we assume Gaussian states and dynamics. We develop a framework to quantify the amount of entanglement in the system numerically. Different from previous work, we treat non-Markovian noise and take into account both the continuous optical field and the cavity mode. We apply our framework to the case of the Advanced Laser Interferometer Gravitational-Wave Observatory and discuss the parameter regimes where entanglement exists, even in the presence of quantum and classical noises. Published by the American Physical Society 2024

On-Chip Meta-Optics for Engineering Arbitrary Trajectories with Longitudinal Polarization Variation.

On-chip integrated meta-optics promise to achieve high-performance and compact integrated photonic devices. To arbitrarily engineer the optical trajectory along the propagation path in an on-chip integrated scheme is of significance in fundamental physics and various emerging applications. Here, we experimentally demonstrate an on-chip metasurface integrated on a waveguide to enable predefined arbitrary optical trajectories in the visible regime. By transformation of the transverse phase to generate longitudinal mapping, the guided waves are extracted and molded into any different optical trajectories (parabola, hyperbola, and cosine). More intriguingly, predefined polarization states with longitudinal variation are also successfully imparted along the trajectory. Owing to the on-chip propagation scheme, the trajectories are uniquely free from zero-order diffraction interference, naturally having a higher signal-to-noise ratio beyond conventional free-space forms. Overall, such on-chip optical trajectory engineering allows for miniaturized integration and can find paths in potential applications of complex optical manipulation, advanced laser fabrication, and microscopic imaging.

Effects of pulsed laser ablation on magnetic losses of GO electrical steels along various excitation directions

Surface laser treatment is an effective way of improving magnetic properties of Grain-Oriented Electrical Steels (GOES). However, these enhancements generally only concern their easy magnetization axis aligned with their Rolling Direction (RD). In this work, the effects of an ablation laser process (implemented with advanced UltraShort Pulse Lasers (USPL)) on the magnetic properties of GOES are investigated for various excitation configurations. Both conventional and non-conventional laser patterns are also used and compared. Experimental results show that the ablation process can improve performances of GOES not only along the RD but also along other excitation directions providing an adaptation of laser patterns when the excitation direction changes.

Parametric investigation of ultrashort pulsed laser surface texturing on aluminium alloy 7075 for hydrophobicity enhancement

Hydrophobicity plays a pivotal role in mitigating surface fouling, corrosion, and icing in critical marine and aerospace environments. By employing ultrafast laser texturing, the characteristic properties of a material’s surface can be modified. This work investigates the potential of an advanced ultrafast laser texturing manufacturing process to enhance the hydrophobicity of aluminium alloy 7075. The surface properties were characterized using goniometry, 3D profilometry, SEM, and XPS analysis. The findings from this study show that the laser process parameters play a crucial role in the manufacturing of the required surface structures. Numerical optimization with response surface optimization was conducted to maximize the contact angle on these surfaces. The maximum water contact angle achieved was 142º, with an average height roughness (Sa) of 0.87 ± 0.075 µm, maximum height roughness (Sz) of 19.4 ± 2.12 µm, and texture aspect ratio of 0.042. This sample was manufactured with the process parameters of 3W laser power, 0.08 mm hatch distance, and a 3 mm/s scan speed. This study highlights the importance of laser process parameters in the manufacturing of the required surface structures and presents a parametric modeling approach that can be used to optimize the laser process parameters to obtain a specific surface morphology and hydrophobicity.

Research on the Causes and Treatment of Weld Zone Fracture in Cold Rolled High Strength Steel Rolling Process

In response to the poor quality of laser welding of cold-rolled advanced high-strength steel and the problem of easy fracture at the weld seam during the rolling process, the reasons for the fracture at the weld seam were first analysed using scanning electron microscopy and other equipment, to clarify the fracture characteristics and organizational distribution. Combined with the characterization results of mechanical properties, the reasons for the fracture at the weld seam during the rolling process were elucidated; Then, the influence of welding process on weld quality is studied from four aspects: laser power, welding speed, pre heat power, and post heat power; Based on the above analysis, a typical cold rolled advanced high-strength steel laser welding technology has been developed. By optimizing welding parameters such as welding power, speed, and preheating before and after, the quality of the weld seam and the cup protrusion effect have been ensured. At the same time, a reasonable rolling process optimization plan has been proposed; After applying the research results to the site, the quality of the weld seam has been significantly improved, and the occurrence rate of band breakage at the high-strength steel weld seam has decreased from an average of 3.6% per month to 0.13%. The band breakage defect at the weld seam has been effectively treated.

Suppression of Microbunching Instability based on optimized velocity bunching in linac-driven FELs

The microbunching instability (MBI) driven by beam collective effects can cause significant electron beam quality degradation in advanced x-ray free electron lasers. Typically, multiple stage magnetic bunch compressors used to generate high peak current electron beam will dramatically amplify the microbunching instability. In this paper, by redesigning the solenoid elaborately and adopting a dual-mode buncher cavity with the third harmonic mode used to correct the RF curvature, it is potential for the electron beam to be further compressed in velocity bunching (VB) process. Therefore, a VB plus one bunch compressor could be a promising alternative scheme to achieve moderate peak current beam for high-repetition-rate X-ray FELs to suppress the additional MBI gain due to multi-stage magnetic bunch compressors.