Gas-phase laser spectroscopy employing nanosecond lasers has traditionally been constrained to analyzing the conformational landscape of isomers with relatively long excited-state lifetimes. The approach proposed here addresses this limitation by introducing infrared-triggered isomerization to detect previously "invisible" isomers. Molecules such as 2-acetaminophen (2-AAP), 2-hydroxyformanilide (2-HFA), and 2-aminophenol (2-AP) exhibit multiple isomeric forms, among which the ortho-substituted isomers form strong intramolecular hydrogen bonds, rendering them undetectable in conventional resonant two-photon ionization (R2PI) spectra. Infrared (IR) excitation induces intramolecular vibrational energy redistribution (IVR), enabling the transformation of these "invisible" isomers into "visible" ones. This transformation manifests as new peaks in IR-dip spectra, representing a population transfer detectable through the technique. This advancement significantly enhances the capability of laser spectroscopy to detect and analyze short-lived isomers in the gas phase, thereby broadening its applicability for structural analysis.

Noncontact pulsed laser-scanning laser Doppler vibrometer (PL-SLDV) phased array imaging for damage detection in composites.

Investigation on nanosecond laser processing of superhydrophobic microstructures on SiCp/Al

Large-area Si/Pt nanoscale structures on amorphous silicon films via nanosecond laser induced

Nanosecond pulsed deep-red Raman laser operating at 735 and 750 nm

Abstract The high-strength and lightweight properties of carbon fiber reinforced polymer (CFRP) have led to its widespread application across numerous fields, making CFRP surface treatment an indispensable key step in its industrial processing. Using a combination of infrared (IR) nanosecond and ultraviolet (UV) picosecond pulsed lasers to treat the CFRP surface, with the total power of the two pulsed lasers fixed while varying their power proportions, the changes in the surface physicochemical properties were investigated. Experimental results demonstrate that the nanosecond–picosecond combined pulsed laser can effectively improve the physicochemical properties of the CFRP surface; when the IR nanosecond laser power proportion is higher, the CFRP surface roughness increases by 60.8%, whereas when the UV picosecond laser power proportion is higher, the CFRP surface hydrophilicity improves, with oxygen-containing groups such as C=O increasing by 6.43% and 28.15%. By adjusting the power proportions of the IR nanosecond and UV picosecond lasers in the combined laser system, selective modification of the physicochemical properties of the CFRP surface was achieved, while also elucidating the mechanisms by which the IR nanosecond-UV picosecond combined pulsed laser selectively modifies the CFRP surface, providing a solid foundation for efficient, high-quality, and selective processing of CFRP.

Abstract This paper proposes a novel method for detecting trace uranium in water, based on the synergistic coupling of the copper electrode surface microstructure with electrochemical enrichment. Microstructures were fabricated on the copper electrode surface using a nanosecond laser (10 ns, 1064 nm), after which the surface oxide layer was removed using dilute hydrochloric acid. Trace uranium in water was enriched using electrochemical enrichment technology and subsequently analyzed using laser-induced breakdown spectroscopy. The U II 409.013 nm characteristic emission line was selected as the analytical target. We systematically investigated the influence of the microstructure fabrication parameters, electrochemical enrichment parameters, and laser excitation parameters on the enhancement of the U II 409.013 nm line signal, with particular emphasis on analyzing the relationship between the microstructure morphology and spectral line intensity. The experimental results demonstrated that the microstructures on the electrode surface enhanced the characteristic uranium emission line intensity by nearly one order of magnitude, achieving a detection limit of 20.0 μ g l −1 (relative standard deviation, RSD = 4%). By characterizing the microstructure morphology and calculating plasma parameters, the enhancement mechanism of the uranium characteristic spectral line was identified as a threefold effect: (1) the microstructures significantly increased the effective surface area of the electrode; (2) the field enhancement effect of the microstructures effectively reduced the plasma excitation threshold and improved the ionization efficiency; (3) the microstructures enhanced the electrochemical enrichment effect by improving the hydrophilicity of the electrode surface. This method provides an innovative analytical approach for monitoring heavy metal pollution in water bodies and for detecting radioactive elements in marine environments.

In recent years, laser-structured titanium dioxide (TiO 2 ) surfaces have attracted considerable attention due to their combination of high specific surface area, biocompatibility, and unique optical properties, offering promising opportunities for photonics, sensing, and energy applications. Of particular interest is the study of the optical manifestations of porous Ti/TiO 2 films fabricated via laser structuring, with potential evidence of plasmonic resonances and anomalous dispersion. The samples were prepared from titanium foil subjected to anodization in potassium hydroxide solution, followed by nanosecond laser structuring at the wavelength of 1064 nm and an energy density of (3.2 ± 0.2)∙10 3 J/cm 2 . Surface morphology was analyzed using scanning electron microscopy and optical profilometry, while optical characteristics were investigated by spectrophotometry and ellipsometry. To interpret the spectral data, a modified Adachi-Forouhi model within the dipole approximation was applied, enabling quantitative description of the contributions of interband transitions and plasmonic modes. The surfaces produced by laser structuring exhibited pronounced porosity (pore sizes of 300–1100 nm, depth ~200 nm), submicron cracks, and nanoparticles of the laser-structured material. Reflection spectra revealed minima corresponding to the excitation of surface plasmons and interference modes. Dielectric permittivity spectra displayed a region of anomalous dispersion and field localization at a wavelength of 625 nm. Calculated parameters included the skin layer thickness, Purcell factor for a nanopore, damping length of plasmon oscillations on the surface, propagation length of surface plasmons, and the critical value of polarizability enhancement in the plasmon resonance localization region. Modeling indicated a narrowing of the bandgap to 1.016 eV. Contributions to the dielectric permittivity of the semiconductor component from interband absorption saturation, changes in band structure, and free carriers were determined. While the bandgap narrowing played a decisive role, the dominant contribution to the experimentally observed dielectric behavior arose from the generation of resonant plasmonic modes. It was established that the key mechanism of the optical response is the resonant localization of the electromagnetic field within the nanopores, confirming the manifestation of hyperbolic metamaterial behavior. The material obtained exhibited significant bandgap narrowing due to the nanosecond laser treatment. The results highlight the potential of porous laser-structured anodized titanium surfaces for photonic and sensing devices, as well as for use in waveguiding structures.

In this study, we developed a reusable low-adhesion metallic cell culture surface having microscale structures using nanosecond pulsed laser processing. Titanium alloy disks were mirror-polished and laser-processed to create microstructures with a pitch of 15μm, smaller than typical cell size. The cytocompatibility of the developed surfaces was confirmed, showing comparable viability to standard plastic dishes. On the other hand, the cells on the laser-processed surfaces exhibited suppressed lamellipodia formation and maintained a rounded morphology and the area of adhered cells was significantly inhibited compared to polished surfaces, indicating reduced adhesion. Further, by applying PBS jet flow to the culture surface, it has been demonstrated that the cells on the micro-structured surfaces formed significantly larger detachment zones under PBS jet flow, confirming weakened adhesion strength. Furthermore, intact cell sheets could be detached from the laser-processed surfaces by pipetting, whereas cells on polished surfaces remained adherent. These results suggest that the developed culture surface enables on-demand cell detachment through physical stimuli without enzymatic treatment, maintaining cell-cell junctions and extracellular matrix integrity. This technology offers potential for applications in cell sheet engineering and enzyme-free cell harvesting, contributing to cost-effective and sustainable cell-based applications. Future work should investigate cell proliferation and migration behavior to further validate its utility for industrial tissue engineering platforms.

In this paper, ultra-fast laser lift-off (LLO) of carbon nanotube (CNT)-integrated polyimide film (PI) was investigated by different laser burst mode and pulse intervals using the two-temperature model. By comparing the temperature field distributions of nanosecond, picosecond, and femtosecond lasers at different pulse intervals, it can be found that picosecond lasers cause a higher lattice temperature increase at the PI interface with specific pulse interval conditions. With the increase in the pulse interval, the lattice temperature of the three kinds of lasers decreased, indicating that the heat accumulation effect was weakened. In addition, under picosecond laser irradiation, the lattice temperature at the PI/glass interface of integrated CNTs could be significantly increased, which was significantly different from the system without integrated CNTs. The simulation results show that the picosecond laser is more suitable for LLO with an appropriate pulse interval, and the integration of CNTs at the PI/glass interface can effectively reduce the laser energy threshold required for the LLO process. Our work presents a new PI/CNT/glass model for ultra-fast laser low-threshold LLO and promotes the laser debonding technology in the fields of OLED and other optoelectronic chips.

The polar oxide Lithium Niobate Tantalate is probed using time-resolved luminescence spectroscopy with the goal of revealing an initial structural insight into the solid solution by analyzing the spectral properties and dynamics of radiatively decaying self-localization phenomena. A blue-green luminescence band can be induced by ultraviolet nanosecond laser pulses with a temperature-dependent intensity and spectral width, pointing to the radiative decay of optically generated self-trapped excitons as its origin, i.e., electron–hole pairs with strong coupling to either the NbO6- or TaO6-octahedra. The luminescence decay takes place in the microsecond time range and deviates significantly from a single exponential behavior, so the determined lifetime constants of up to ≈70 μs and stretching factors (1/3–1/5) are validated in more detail using alternative evaluation methods. We discuss our findings, considering the interplay of radiative and non-radiative decay channels, the transition from self-trapped to free excitons, and the presence of a structural disorder of the oxygen octahedra in the solid solutions. Overall, our results suggest self-trapped excitons as local probes for an initial structural elucidation and provide essential information about further experimental and theoretical studies on the atomic structure of Lithium Niobate Tantalate, but also for improving the crystal quality in the framework of applications in photonics and quantum optics.

Abstract A narrow-bandwidth, short-pulse, equal-intensity dual-beam monochromatic soft X-ray source based on laser-produced gold plasma was developed. It utilizes soft X-ray radiation of plasma generated by nanosecond laser irradiation of a gold planar target, with two mirror-symmetric one-dimensional reflective zone plates (1D RZPs) serving as monochromating elements. Measurements of parameters demonstrate that these twin beamlines exhibit an energy bandwidth of about 34 eV @ 395.4 eV and a pulse width of about 13.2 ns, with an intensity ratio of 0.98 : 1. Three different 1D RZPs were fabricated on a single silicon substrate, enabling switching between different energies (395.4 eV, 1.96 eV and 524.9 eV) via translation. This source holds significant potential for rapid testing and online calibration of soft X-ray components such as filters, mirrors, detectors and so on.

Accurate evaluation of mechanical properties in steels under ageing or service conditions remains a major challenge. We propose a thermo-mechanical coupling framework for nanosecond laser ablation based on energy conservation, which is embedded into a physics-informed neural network (PINN) to enable simultaneous inversion of multiple mechanical properties. A thermo-mechanical coupling coefficient is defined to uniformly describe the dynamic allocation of input laser energy among thermal diffusion, mechanical work, and plasma shielding across different deformation stages under laser irradiation. Furthermore, hard-to-measure physical characteristics in the coupled equation are replaced with experimentally accessible features obtained through the simultaneous acquisition of spectroscopic, shockwave, and surface-wave signals. Using 210 experimental datasets, the framework simultaneously recovers Young's modulus, yield strength, ultimate tensile strength, and micro-Vickers hardness with high accuracy (R2 = 0.9927, 0.9912, 0.9916, and 0.9959, respectively), significantly outperforming the baseline method (ultrasonic velocity regression for E, R2 = 0.0012). Comparisons with linear normalization and unconstrained neural networks demonstrate that PINN achieves near-unity accuracy through the embedding of conservation-law constraints. Partial dependency analysis further uncovers the nonlinear coupling laws between input features and mechanical properties. The proposed paradigm, integrating conservation laws, measurable features, and physics-informed learning, offers a universal approach for non-contact, high-precision, and physically consistent multi-to-multi inversion of multiple material properties under nanosecond laser ablation conditions.

The paper considers the mechanisms of mass transfer in an In/CdTe system under nanosecond pulsed laser irradiation, which are caused by nonstationarity, nonequilibrium, physical and geometric nonlinearity, high rate and simultaneity of various physical processes. Moreover, threshold processes such as phase transitions and ablation in the metal/CdTe heterosystem, under powerful nanosecond laser irradiation at normal conditions and in a liquid medium are analyzed. The melting and ablation thresholds under nanosecond laser irradiation of the metal (In)/CdTe film structures in water are found and their change due to appearance of nonlinearities (caused by changes in the physical characteristics of In) and pressure generation is studied. It is found out that the pressure in the energy release region under irradiation of the In/CdTe with a neodymium laser (pulse = 7 ns) in water is 17 times greater in the case of the photothermoacoustic effect and 90 times greater in the case of indium melting.

We report experimental observations of extremely high levels of above-threshold ionization (ATI) and extensive delayed ionization of photoelectrons from argon clusters in moderately intense nanosecond laser fields at 532 nm. We have successfully projected the cluster explosion and expansion process onto the time-of-flight axis of the photoelectrons. The photoelectron spectra can be separated into three groups: a fast group that reaches as high as 3500 times the ponderomotive energy (Up) of the laser field, an ATI group that shows the addition of up to 8 photons (over 200Up), and a delayed group that are ionized ∼100 ns after laser excitation ∼1 mm downstream from the excitation spot. The delayed electrons are tentatively attributed to field ionization of near-threshold electrons contained in the expanding nanoplasma after an initial Coulomb explosion; hence, the delay times of these electrons demonstrate a dependence on the strength of the extraction field. These surprising discoveries demonstrate that the intermediate intensity regime is not a simple extrapolation of strong fields, and new phenomena warrant detailed investigation.

We report a low-temperature fabrication strategy for silicon nanosheet (SiNS) field effect transistors (FETs) that relies on single-step nanosecond laser annealing to enable an upper-tier integration in monolithic three-dimensional (3D) (M3D) architectures. Via the use of amorphous silicon (a-Si) as the channel material, we simultaneously achieved crystallization and source/drain dopant activation through nanosecond-pulsed Nd:YAG laser annealing, all within a sub-450 °C thermal budget. This single-step approach simplifies the fabrication process while minimizing thermal diffusion to the underlying layers, thus addressing key constraints in M3D integration. Through systematic control of the laser fluence, we identified an optimized process window that maximized the crystalline quality, minimized the interface trap density, and improved key electrical metrics, such as carrier mobility and subthreshold swing. Structural and electrical analyses, including transmission electron microscopy (TEM) imaging, interface trap extraction, and series resistance evaluation, confirmed that the laser-annealed devices achieved performance on par with that of those treated by conventional thermal processes. This scalable and thermally compatible technique offers a promising platform for the integration of high-performance logic devices in future 3D semiconductor systems.

Realizing the full potential of optical actuation for high-speed phase-change radio-frequency (RF) switches requires a shift to single-pulse operation. This work presents a systematic investigation of reversible phase transitions in GeTe thin films induced by single 10 ns laser pulses, utilizing spatially resolved characterization techniques, including atomic force microscopy (AFM) and micro-spectroscopy. Precise laser fluence windows for crystallization (12.7–16 mJ/cm2) and amorphization (25.44–41.28 mJ/cm2) are established. A critical finding is that the amorphization process is governed by rapid thermal accumulation, which creates a direct trade-off between achieving the phase transition and avoiding detrimental surface morphology. Specifically, we observe that excessive energy leads to the formation of laser-induced ridges and ablation craters, which are identified as primary causes of device performance degradation. This study elucidates the underlying mechanism of single-pulse-induced phase transitions and provides a practical processing window and design guidelines for developing high-performance, optically actuated GeTe-based RF switches.

Nanosecond-pulsed Nd:YAG laser ablation was investigated as a method for removing Al Ti-based hard coatings deposited on WC–Co hardmetal inserts. Systematic variation in laser parameters identified conditions for complete coating removal while preserving substrate integrity. The laser was operated at 532 nm, under a range of fluences (0.1–11.7 J/cm2), pulse delays (20–180 µs), and pulse numbers (1–300). LIBS qualitative monitoring enabled precise ablation progress by identifying Ti, Al, and O layers, and later the detection of Co and W signals. Scanning electron microscopy (SEM/EDS) and optical profilometry confirmed that 5–10 pulses at intermediate delays (60–80 µs, 4.8–7.1 J/cm2) provided complete removal of ~18 µm-thick coatings while maintaining substrate integrity. In contrast, higher energies and excessive pulses caused localized melting and surface irregularities. These results demonstrate that Nd:YAG laser ablation, especially when coupled with LIBS, offers a precise, fast, and environmentally alternative to conventional chemical stripping methods for the refurbishment and recycling of cutting tools.

Study on surface modification of 4H-SiC wafers induced by nanosecond laser

Defect-related optical properties of KDP crystals caused by nanosecond laser