Search Results (302)

This work focuses on the design of non-Hermitian DFB lasers incorporating phase-shifted dielectric and metallic gratings, emphasizing the symmetry aspects of the complex refractive index profile. Conventional DFB lasers featuring dielectric Bragg gratings and metallic gratings are also investigated. The impact of the phase shift between the gratings, as well as facet boundary conditions, was analyzed in terms of threshold gain and gain contrast relative to the next-higher-order laser pole. Significant performance improvements were predicted for complex-coupled DFB lasers wherein the dielectric and metallic gratings are either in-phase or out-of-phase. In contrast, for PT-symmetric configurations, we found that reflection asymmetry, which was expected to further enhance DFB laser performance, is compromised by facet reflections. To address this issue, lasing must occur at the Bragg wavelength, and the contribution of the PT-symmetry-induced asymmetric reflection must be enhanced. The solution involves using high-reflectivity and anti-reflective facet coatings. Modeling results show a threshold gain as low as 26 dB/cm, with laser emission occurring exactly at the Bragg wavelength. The gain contrast relative to the next-higher mode reached 72 dB/cm. Such gain contrast should ensure extremely robust single-mode laser operation. These results also suggest better tolerance of optical feedback and, as a potential outcome, operation without an optical isolator. Full article

High-power laser systems impose stringent requirements on the laser-induced damage threshold of optical thin films. Post-deposition thermal annealing has been demonstrated as an effective approach to enhancing the LIDT of HfO₂-based coatings; however, its effects on antireflection coatings—particularly those employing non-quarter-wave designs that offer industrial advantages such as fewer layers and lower fabrication cost—remain insufficiently investigated. In this work, non-quarter-wave HfO₂/SiO₂ multilayer antireflection films were fabricated by ion beam-assisted electron beam evaporation, and the effects of thermal annealing on their laser-induced damage characteristics were systematically investigated. Experimental results show that the effect of thermal annealing between 300 and 700 °C on the laser damage resistance of the antireflection coating is not monotonic: the laser-induced damage threshold rises from 27.6 J/cm² in the as-deposited state to 36.7 J/cm² at 500 °C, an improvement of approximately 33.1%, and then falls at 600 °C and 700 °C, while remaining above the as-deposited value throughout. This non-monotonic behavior originates from a competition between two contributions. On the one hand, the repair of oxygen vacancies, the densification of the film, and the growth of the crystallites continuously reduce the population of initiating absorbers and improve heat dissipation. On the other hand, the penalties arising from the exhaustion of the free volume and from the accumulation of tensile stress accelerate in the upper part of the temperature range, and their influence on the threshold progressively outweighs the gain produced by the former. Annealing at 500 °C is therefore the optimum state determined by this competition. Full article

A seven-layer broadband antireflection coating consisting of Al₂O₃, TiO₂, SiO₂, and MgF₂ was designed and deposited on both sides of K9 glass for the 400–1100 nm range. The deposition parameters for TiO₂ and SiO₂ single layers were optimized, and the measured optical constants were used in TFCalc to refine the multilayer design. Layer-specific thickness-tolerance analysis was performed to identify the layers requiring strict process control. The initially characterized double-sided coating showed an average transmittance of 98.72% over 400–1100 nm. Four samples prepared in one additional deposition batch exhibited closely matching transmittance spectra, indicating low sample-to-sample variation within that batch. Five-position profilometry indicated consistent total-thickness control. Cross-sectional scanning electron microscopy (SEM) revealed well-defined multilayer contrast without obvious cracking, and regional energy-dispersive X-ray spectroscopy (EDS) analysis detected the constituent elements of the coating. These results demonstrate a practical design-to-fabrication approach that combines process-specific optical constants with tolerance analysis, with potential applications in imaging systems, optical windows, and lidar. Full article

Despite recent advances in computer vision and optical imaging, the image-based recognition of ophthalmic lens categories characterized by different refractive indices and anti-reflective coating types remains largely unexplored. In this work, we formulate this problem as a non-destructive optical inspection task, where lens-induced visual changes are treated as subtle micro-texture signatures produced by the interaction between the lens and a controlled visual target. Although these signatures are often imperceptible to the human eye, they can be quantified using local texture analysis. To establish the first systematic benchmark for this emerging application, we present a comprehensive evaluation of state-of-the-art local texture descriptors, with particular emphasis on Local Binary Pattern (LBP)-like methods, under unified evaluation protocols. The evaluation is conducted on two dedicated ophthalmic lens image datasets acquired under controlled conditions, using consistent visual targets designed to reveal lens-induced texture and color variations. This setting enables a rigorous assessment of whether handcrafted micro-texture descriptors can capture discriminative image signatures associated with different refractive indices and anti-reflective coating types. The experimental results demonstrate that several modern LBP variants provide excellent recognition performance, confirming the relevance of local micro-texture analysis for image-based ophthalmic lens category recognition. Comparisons with pretrained deep feature extractors further show that although deep representations generally achieve the highest recognition rates, several handcrafted descriptors offer comparable performance while requiring neither network training nor fine-tuning. Beyond recognition accuracy, the benchmark investigates performance stability across datasets, robustness under limited training samples, classifier influence, and the statistical significance of the observed performance differences. Overall, this work establishes the first reproducible image-based benchmark for non-destructive ophthalmic lens inspection and provides practical guidelines for selecting local texture descriptors in ophthalmic lens recognition systems. Full article

We demonstrate a novel method for fabricating densely packed, high-aspect-ratio cavities (depth to diameter ratio > 1) in silicon wafers coated with diamond-like carbon (DLC). The process combines femtosecond laser irradiation with subsequent wet etch (potassium hydroxide-based) or plasma etch (chlorine- and oxygen-based). The femtosecond laser is used to pattern precise openings in the DLC layer, exposing the underlying silicon, which is then rapidly etched to form well-defined cavities. This combined laser ablation and etching approach enables high-throughput fabrication of densely packed micrometer cavities and offers scalability toward industrial production. The resulting hybrid DLC-coated silicon structure, featuring densely packed cavities, may exhibit antireflective properties in the far-infrared spectrum range. Full article

Background: The optical losses in the form of reflections, parasitic absorption, and scattering limit photovoltaic efficiency. This review examines plasma-assisted surface engineering as an effective tool for improving light management in solar cells. Plasma-based methods, including etching, oxidation, deposition, and texturing, enable precise control of surface morphology and chemistry, lowering reflectance, enhancing light trapping, and passivating defects. Methods: In contrast to wet-chemical or high-temperature processes, plasma processes are dry, low-temperature, scalable, and can be used with silicon, perovskite, thin-film, and organic solar cells, as well as tandem structures. The fundamentals of optical losses are described, along with the principles of radio-frequency (RF), inductively coupled plasma (ICP), microwave, and atmospheric plasma systems and their distinctive advantages for controlling ion and reactive-species generation. Key applications reviewed include black-silicon texturing by ICP reactive-ion etching (ICP-RIE), anti-reflective/passivation coatings by plasma-enhanced chemical vapor deposition (PECVD), and interface activation by atmospheric plasma. Results: Among performance improvements are a reflectance of less than 2%, a photocurrent increase of 10–20%, and longer carrier lifetime. Conclusions: The advantages of plasma compared to lithography and sol–gel processes are in the precision and affordability of the method. The difficulties include damage caused by the processing, uniformity over extensive areas, and environmental stress resistance. Future directions rely on low-temperature plasmas for flexible PV, machine-learning-guided process optimization, and hybrid plasma–laser systems. This synthesis of otherwise fragmented studies is intended to support the implementation of plasma-based methods in next-generation, high-efficiency, and sustainable solar production. Full article

Slippery liquid-infused porous surfaces (SLIPS) can reduce ice adhesion, but their durability depends on coupled wetting, rheological, and phase-transition effects. Here, seven imidazolium ionic liquids (ILs) with varied alkyl and disiloxane substituents were evaluated as lubricants for laser-textured superhydrophobic aluminum. Surface tension, viscosity, thermal behavior, lubricant retention, wetting, and ice adhesion at −10 °C were correlated over 30 icing-deicing cycles. All freshly prepared coatings were water-wettable but exhibited weak droplet pinning, with sliding angles of 1.4–7.5°, despite apparent water contact angles below 90°. This combination reflects the lubricant-mediated interface, for which droplet mobility is not determined by the static contact angle alone. The behavior of SLIPS with different lubricants diverged under centrifugal loading: low-viscosity ILs were depleted, whereas ILs that solidified under the applied cooling protocol were retained more effectively within the texture. Counterintuitively, greater lubricant retention produced higher ice adhesion because solidified ILs stabilized ice bridges within the surface relief. The lowest adhesion after cycling was obtained for the coating infused with [C₉C₃Si₂Oim][NTf₂], which after lubricant depletion restored a superhydrophobic state with a water static contact angle of 171.6 ± 1.6°. These results identify lubricant phase state and interfacial redistribution as key design parameters for durable anti-icing SLIPS. Full article

In the Western Anti-Atlas, the stratiform copper mineralisations of the Tabia Member are distinctly hosted within sedimentary rocks, forming deposits comparable to the sediment-hosted stratabound copper (SSC) type. In Tizert, Ouarmdaz, and Talat n’Ouamane, the sandstones and clays host primary sulphides as disseminations and copper carbonates occurring as small continuous or lenticular beds, small geodes, and coatings on clay laminations. In Tiferki, the conglomerates are more mineralised; sulphides are represented by chalcopyrite and bornite, locally altered into chalcocite. Copper carbonates appear as malachite and azurite coating pebbles and deeply impregnate the granular matrix. From a sedimentological and sequence-stratigraphic perspective, the conglomeratic level at Tiferki represents a low-sea-level prism (LST) formed during a stage of maximum platform exposure allowing erosion products to accumulate at the base of the slope. By contrast, the silty–sandy complex known as the “Talat n’ Ouamane level” corresponds to a prograding sedimentary sequence (Highstand Systems Tract, HST) that developed after a relative regression where the platform was only partially exposed. In both cases, relative sea-level fall promoted the emergence of the hinterland and active erosion, supplying the depositional environment with coarse detrital during the maximum drops in sea level and sandy-to-micro-conglomeratic deposits during less pronounced regressions. This detrital supply probably brought copper in the form of grains and especially dissolved copper, which is largely deposited at the bottom of slopes and in marine environments where microbial communities contribute to the precipitation of copper. The selective distribution of sulphides within the Tabia Member shows that only the low-sea-level and high-sea-level prisms are enriched in stratiform copper, while the transgressive and maximum flooding systems tracts lack significant mineralisation. This suggests that sea-level variations played a controlling role in copper deposition. The regressive trend of the high sea-level suite continued until emergence, reflected by the invasion of the environment by red or ochre siltstones from the alluvial plain. The emergence at the transition from sandstones to dolomites, and the “Red Beds”-type mineralisation embedded in these subaerial facies, support the syngenetic origin of the sulphides in the Tabia Member. After this main emplacement of stratiform copper, the sulphides would have undergone remobilisation and alteration during a significant episode of vertical water escape that deformed the host facies and enhanced mineral concentration within permeable sandstones. Even the clays were delaminated and coated with a thin films of copper carbonates on their surfaces. In the Tamjout dolomites, carbonates are percolated by acidic solutions, contributing to the brecciation and silicification of the stromatolitic layers. Copper mineralisation accompanies this silicification and fills the karstification pockets. Full article

In the present paper, we studied the interaction of microwave radiation with conductive indium tin oxide (ITO) coatings deposited on a borosilicate glass. The experiments were carried out with the ITO films, the thickness of which varied in the range from 85 to 607 nm. The transmittance and reflectivity of the ITO film/K108 glass structures were measured in the frequency region from 3 to 23 GHz. Theoretical modeling of the spectra was performed by means of the transfer matrix method. It was shown that for a given thickness of the glass substrate, the transmission and reflection spectra of the ITO film/K108 glass structures were fully determined by only one parameter of the ITO film, namely, its DC sheet resistivity. The considered model predicts an increase in maximum microwave shielding effectiveness up to 45.6 dB with a decrease in DC sheet resistivity to 1 Ohm/sq. ITO coatings with DC sheet resistivities down to 2.3 Ohm/sq have been experimentally investigated. The model microwave transmittance and reflectivity spectra were in good agreement with the experimental ones. In particular, the coefficient of determination for the transmittance spectra was rather high: R² > 0.93. It was experimentally demonstrated that applying antireflective coatings on both sides of the ITO film/K108 glass microwave shielding filter significantly improved its transparency in the operating optical range. A filter has been created that provides microwave shielding effectiveness of 38.7 dB with an average transmission coefficient of 0.81 in the visible range. Full article

Background/Objectives: Vesicular Stomatitis Virus (VSV)-vectored vaccines represent a versatile platform for the development of vaccines against infectious diseases. Replication-competent recombinant VSV vectors in which the native glycoprotein (G) is replaced with a heterologous antigen (rVSVΔG) are widely used and have demonstrated clinical success. In addition to antigen-specific responses, these vaccines induce humoral immunity directed against vector components, which primarily reflects vector exposure and contributes to the overall characterization of vaccine-induced immunity. Standardized assays for quantifying such vector-directed responses are therefore of increasing importance. Methods: We developed and qualified a quantitative enzyme-linked immunosorbent assay (ELISA) for the detection of human IgG antibodies against VSV-Nucleoprotein (N). Assay development included optimization of antigen coating, blocking conditions, and detection reagents. A 10-point standard curve was established using pooled human serum, and assay performance was evaluated by assessing dynamic range, sensitivity, cut point, dilutional linearity, precision, robustness, and sample stability. Results: The optimized assay utilized a coating concentration of 2 μg/mL VSV-N antigen (100 ng/well) and 1% casein as the blocking buffer. The assay demonstrated a dynamic range of 0.33–41.66 arbitrary units per milliliter (AU/mL) with excellent curve fit (R² > 0.996). The cut point was established at an OD₄₅₀ of 0.286. Precision across intra-assay, inter-assay, and inter-operator evaluations met predefined acceptance criteria (≤25% CV). The assay was robust across different plate washers and readers and maintained performance following up to three freeze–thaw cycles. Conclusions: This study describes a robust and reproducible ELISA for quantifying anti-VSV-N IgG responses. The assay provides a fit-for-purpose tool for assessing vector-directed humoral immunity and supports standardized immunogenicity evaluations across VSV-vectored vaccine studies. Full article

The amniotic membrane is widely recognized in regenerative medicine due to its rich content of extracellular matrix proteins and growth factors that confer anti-inflammatory and pro-regenerative properties. However, its rapid degradation restricts its standalone clinical use. To overcome these limitations, we developed biofilms by incorporating decellularized human amniotic membrane matrix (dHAM) into polycaprolactone (PCL) and polyvinylpyrrolidone (PVP) matrices using spin-coating. Bone marrow-derived mesenchymal stem cells (BM-MSCs) were used to evaluate film biocompatibility through cell viability, proliferation, and wound healing migration assays. Surface characterization was performed using contact angle measurements, Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, and scanning electron microscopy. Soluble dHAM extracts (4–6 mg/mL) significantly enhanced BM-MSC proliferation at 48 h compared to controls (p ≤ 0.01 and p ≤ 0.0001). Both PCL-dHAM and PVP-dHAM biofilms exhibited high cell viability (>90%) and improved initial adhesion. Notably, dHAM incorporation significantly increased wound closure rates at 24 h, reaching 98.47% for PCL-dHAM and 93.13% for PVP-dHAM, compared to 76.56% and 64.20% for pure polymers (p = 0.0001). All scaffolds maintained hydrophilic surfaces (<90°), favorable for cell interaction. The integration of dHAM into PCL and PVP by spin-coating produces biofilms biocompatible with enhanced regenerative potential, representing promising candidates for wound healing applications. In conclusion, these coatings support BM-MSC adhesion, proliferation, and migration, while significantly accelerating wound closure, underscoring their value as advanced bioactive coatings for regenerative medicine. Full article

The evolution of 193 nm deep-ultraviolet (DUV) lithography toward high numerical aperture (NA > 1.35) presents challenges approaching physical limits for antireflective (AR) coatings on strongly curved lens elements. In this study, a full-stack multi-objective optimization framework is developed by coupling the Non-dominated Sorting Genetic Algorithm II (NSGA-II) with the Transfer Matrix Method (TMM) to optimize a 7-layer LaF₃/MgF₂ system on strongly curved substrates ($R=150$ mm). The model integrates material dispersion, thermo-optic effects, deposition flux deviations, and manufacturing thickness constraints. Following 1500 generations of optimization and TOPSIS-based decision-making, the selected Pareto optimal solution achieves a full-aperture average reflectance of 1.3633% and a radial uniformity of 9.5037%. The design further exhibits high environmental robustness with a thermal drift of 0.0019% and a residual stress of 39.23 MPa. These results demonstrate that the proposed method overcomes the critical process bottleneck of achieving full-aperture uniformity below 10% on strongly curved optics. This framework provides a general paradigm for the robust design of next-generation ultra-precision DUV optical systems, effectively balancing theoretical depth with engineering feasibility. Full article

Photovoltaic modules require efficient sunlight modulation, including enhanced visible transmittance and conversion of unused ultraviolet light. This study develops a synthetic optical coating that achieves both functions by integrating down-conversion BAM (BaMgAl₁₀O₁₇:Eu²⁺, Mn²⁺) nanophosphors into a silica anti-reflection sol. The key novelty lies in a synergistic surface engineering strategy that decouples dispersion stabilization from luminescence protection. Five dispersants are systematically compared under combined ball and sand milling. The polyester-modified acrylic long-chain dispersant (DK062) yields a stable nanodispersion with an average particle size of 228 nm and a Zeta potential of −7.61 mV, effectively suppressing re-agglomeration while retaining high photoluminescence. Subsequent surface modification with KH570 grafts a dense silane passivation layer via Si–O–M covalent bonds, further increasing the photoluminescence intensity by 1.39-fold. The optimized nanophosphors are incorporated into a commercial anti-reflection sol and dip-coated onto photovoltaic glass. At a doping concentration of 2‰ and a withdrawal speed of 8 mm/s, the resulting DCSAR coating exhibits an average transmittance of 91.16%—slightly higher than that of the pure anti-reflection coating (90.96%)—while showing strong green emission at 515 nm. Industrial on-site testing further demonstrates an average transmittance of 94.20%–94.31% with uniform green emission. This work provides a scalable route to fabricate highly transparent, light-converting anti-reflection coatings by combining dispersant-assisted milling and silane passivation. Full article

Laser-induced damage of sol–gel SiO₂ antireflection coatings remains a key reliability issue in high-power laser systems because porous networks, residual hydroxyl groups, and defect-related absorption centers can trigger localized heating and stress concentration under nanosecond irradiation. In this work, continuous-wave CO₂ laser conditioning was used as a localized post-treatment method to regulate the microstructure of sol–gel SiO₂ coatings on fused silica substrates. The revised manuscript clarifies the processing window, scanning parameters, laser damage testing protocol, and the sample-specific nature of the reported LIDT values. Laser conditioning induces partial densification of the porous coating, dehydration of Si-OH groups, relaxation of the Si-O-Si network, and enhancement of mechanical properties. Under the optimized conditioning condition, the surface roughness decreases from 14.08 nm to 9.76 nm, and the LIDT at 1064 nm increases from 4.8 J/cm² to 7.0 J/cm². The LIDT values are discussed as a relative microstructure–property comparison for the present coating system rather than as the upper technological limit of sol–gel silica coatings. Combined FTIR analysis, thermal simulation, morphology observation, and damage probability analysis indicate that the improvement originates from the combined effects of reduced defect absorption, moderated porosity, improved heat dissipation, and enhanced resistance to thermally induced cracking. The results provide a mechanism-guided strategy for using CO₂ laser conditioning to tune sol–gel silica coatings while also identifying the need for further validation on higher-LIDT coatings and at application-relevant wavelengths. Full article

Cyclophosphamide (CTX)-induced premature ovarian failure (POF) is characterized by disruption of the follicular microenvironment, granulosa-cell loss, endocrine imbalance, and oxidative-inflammatory injury. Here, we evaluated two multi-bioactive formulations developed to enhance ovarian stress resilience: a base formulation containing coenzyme Q10, calcium L-5-methyltetrahydrofolate, and Vitex agnus-castus extract (Base), and a urolithin A-enriched formulation (Base + U). Using a CTX-induced female C57BL/6 mouse model, we integrated phenotypic, histological, endocrine, oxidative-inflammatory, and transcriptional readouts to assess efficacy and mechanistic consistency. CTX markedly reduced ovarian index, disrupted estrous cyclicity, shifted follicle development toward atresia, increased granulosa-cell apoptosis, and caused endocrine dysregulation, including decreased anti-Müllerian hormone and estradiol and increased GnRH, FSH, and LH. CoQ10, Base, and Base + U each partially alleviated these abnormalities, improving ovarian index and coat condition, showing a trend toward improved follicular distribution, and normalizing hormone profiles. CTX also induced an ovarian oxidative-inflammatory shift, as reflected by decreased GSH-Px, increased MDA, and elevated IL-1β, IL-6, and TNF-α, all of which were attenuated by the interventions. Notably, Base + U more effectively reduced lipid peroxidation and TNF-α than Base alone. Consistently, ovarian transcripts related to follicle responsiveness and steroid regulation, including Fshr, Esr1, and Hsd17b2, were restored, whereas hypothalamic qRT-PCR analysis did not reveal robust transcriptional alterations within the intervention window. These findings suggest that the urolithin A-enhanced formulation partially alleviates CTX-induced ovarian dysfunction by suppressing oxidative-inflammatory stress and preserving granulosa-cell and follicle fate. Full article