Search Results (5,477)

The development of phase change materials (PCMs) for window applications with both high optical transparency and effective temperature regulation is crucial for passive energy saving. However, liquid leakage during phase transition and enhanced interfacial light scattering often cause fluctuations in optical transmittance and deterioration of image clarity. To address these challenges, a highly transparent phase change composite was constructed via a microencapsulation strategy. Submicron core–shell microcapsules were fabricated using n-octadecane as the core and silica as the shell, enabling effective encapsulation of the liquid PCM component. The resulting microcapsules exhibited a high melting enthalpy of 155.3 J g⁻¹. They were subsequently homogeneously dispersed within a refractive-index-matched polymer matrix, mitigating light scattering during phase transition by reducing interfacial refractive index mismatch. The composite exhibited favorable thermal energy storage capability and transmittance performance, with a visible light transmittance of 83.75% and a transmittance fluctuation of only ~5% before and after phase transition. After 100 thermal cycles, the optical attenuation remained as low as 0.35%, demonstrating excellent cycling stability. This work provides a new strategy for balancing optical transparency and phase change function, with potential applications in smart windows and flexible electronics. Full article

In the field of industrial robotic vision, accurate recognition and localization of transparent objects pose significant challenges. Unlike opaque objects, transparent objects are difficult to distinguish in RGB images, and due to refraction and reflection, their depth information often suffers from large-area missing or erroneous values, leading to failed grasp pose prediction. Therefore, depth completion is crucial for transparent object grasping tasks. However, existing depth completion methods still exhibit obvious limitations. Multi-stage optimization methods, while achieving high accuracy, involve complex pipelines and high computational costs. Single-stage end-to-end networks, when processing sparse edge features of transparent objects that are also contaminated by background interference, are constrained by the receptive field and smoothing effect of conventional convolutions, often resulting in contour blurring and loss of geometric details. Moreover, existing methods still lack sufficient capability in modeling multi-directional gradient variations of transparent objects under complex backgrounds. To address these issues, this paper proposes ADDFNet for transparent object depth completion, achieving synergistic improvement in accuracy and robustness through two key designs: MDAM and CMFR. To tackle the problem of sparse edge features of transparent objects that are easily disturbed by noise, we design the Multi-directional Differential Attention Module (MDAM), which explicitly extracts multi-directional gradient information through multi-branch differential convolution. Within MDAM, we introduce the Detail Enhancement Differential sub-Module (DEDM) and the Dynamic Convolution with Symmetry-enhanced Geometry Attention sub-module (DSCA) to enhance the network’s perception of fine contours and improve global–local synergistic modeling capability. To address insufficient cross-modal information interaction, we introduce the Cross-Modal Feature Refinement (CMFR) module, which utilizes RGB context to guide and enhance depth features layer by layer during the encoding stage, improving the accuracy and robustness of depth completion while mitigating feature degradation caused by traditional simple fusion approaches. Experimental results on the ClearPose and TransCG datasets demonstrate that ADDFNet outperforms comparison methods in terms of RMSE, REL, MAE, and threshold accuracy metrics, exhibiting more stable performance in edge recovery and internal detail reconstruction of transparent objects. Full article

Background/Objectives: To assess the accuracy of several intraocular lens power calculation formulas in phacotrabeculectomy for open angle glaucoma. Methods: Patients who underwent phacotrabeculectomy for open angle glaucoma were included. Refraction and biometry measurements were repeated at 3, 6 and ≥12 months. Prediction error (PE) and absolute error (AE) were calculated using the SRK/T, Holladay 1, Hoffer Q, Haigis, Kane, Emmetropia Verifying Optical (EVO) and Barrett Universal II formulas at ≥12 months, and their accuracy was compared using linear mixed-effects models accounting for repeated measurements within the same eye and inter-eye correlation. Results: Sixty eyes from 40 patients were included. The linear mixed-effects model showed a significant overall effect of formula on PE (χ²(6) = 119.14, p < 0.001). Most formulas showed a tendency toward a hyperopic refractive shift, whereas Haigis showed a negative PE. Based on estimated marginal mean AE, the formulas were ranked as follows: EVO (0.548 D), Barrett Universal II (0.551 D), Holladay and SRK/T (0.561 D), Haigis (0.572 D), Kane (0.577 D) and Hoffer Q (0.617 D). However, the AE did not significantly differ among the formulas (χ²(6) = 3.75, p = 0.711). The percentage of eyes within ± 1.00D of PE ranged from 81.7% to 90% across the formulas (p > 0.05). Significant axial length shortening, anterior chamber deepening and mean keratometry reduction were detected postoperatively at ≥12 months (p < 0.05). Conclusions: Despite postoperative ocular anatomic changes, all formulas showed acceptable refractive accuracy after phacotrabeculectomy. Although no significant difference in the AE was detected among the formulas, the PE differed significantly, with most formulas showing a tendency toward a hyperopic shift and Haigis showing a myopic shift. This inter-formula difference should be considered when selecting the refractive target, particularly when using formulas that tend toward hyperopic PE. Full article

We present a Fourier-transform (FT)-based framework for quantitative analysis of whispering gallery mode (WGM) spectra in soft photonic microcavities. By treating the WGM spectrum as a quasi-periodic signal, the method enables robust extraction of the optical path length $L_{\mathrm{opt}}={\lambda }_c^2/\Delta \lambda$ directly in the frequency domain, avoiding explicit peak identification and reducing sensitivity to background and spectral overlap. This quantity is used as a primary measurand within a unified metrological formulation: when the cavity radius R is known, it yields the effective refractive index $n_{\mathrm{eff}}=L_{\mathrm{opt}}/\left(2\pi R\right)$; when the refractive index n is known, it provides an inferred geometric path length $l_{\mathrm{geo}}=L_{\mathrm{opt}}/n$. Following the Guide to the Expression of Uncertainty in Measurement (GUM), we establish the measurement models and evaluate the uncertainty budget, identifying the FSR determination as the dominant contribution (relative uncertainty $7.7\%$), with secondary contributions from radius measurement ($1.5\%$) and negligible influence from wavelength calibration. The framework is applied to two representative soft photonic systems as complementary test and consistency cases. For Rhodamine B-doped mesoporous silica microcapsules ($R=44 \mu \mathrm{m}$), we obtain $n_{\mathrm{eff}}=1.164\pm 0.09$, corresponding to a porosity of $63.3\%$ via Bruggeman effective medium theory, in close agreement with independent BET measurements ($62.8\%$). For surfactant-stabilized Rhodamine 640-doped benzyl alcohol microdroplets, the method identifies dominant Fourier-domain periodicities and yields inferred geometric path lengths consistent with near-equatorial mode propagation. An additional $N=14$ droplet analysis gives an FT-inferred radius of $60.78\pm 1.91 \mu \mathrm{m}$, in close agreement with the microscopy-estimated radius of approximately $60 \mu \mathrm{m}$. By combining Fourier-domain analysis with explicit measurement modeling and uncertainty quantification, this work establishes FT-WGM spectroscopy as a reproducible and generalizable tool for single-particle metrology in complex soft-matter microcavities. Full article

We developed a reference look-up table (RLUT) of particles of spheroidal shape. This RLUT will be used in our lidar-data inversion algorithm we have developed in the past 25 years for the retrieval of microphysical parameters of non-spherical particles from 3β + 2α + 3δ optical datasets measured with Raman/HSRL lidar. The optical datasets are described by particle backscatter coefficients (β) at three wavelengths λ = 355, 532, and 1064 nm, particle extinction coefficients (α) at two wavelengths λ = 355 and 532 nm, and particle linear depolarization ratios (PLDRs, δ) at three wavelengths λ = 355, 532, and 1064 nm. The RLUT contains 64,032 synthetic 3β + 2α + 3δ—datasets calculated on the basis of a light-scattering model of randomly oriented spheroids and spheroid particle size distributions described by different particle complex refractive indices (CRIs) and lognormal functions with different Gauss parameters such as mean radius (μ) and standard deviation (σ). We investigate major features of the RLUT such as information content encoded in the 3β + 2α + 3δ datasets, conditionality, determinacy and the sensitivity of the retrievals to the underlying measurement errors. We find that major features of the sphere and spheroid RLUTs are similar; however, extra information is encoded in the PLDRs. The PLDR spectrum on the domain λ ∈ [355; 1064] μm contains significant information about the size of spheroid particles. The analysis of the information content is more productive if we use the cross-polarized backscatter-related Ångström exponent (CrPBAE) at the wavelength pairs 355 and 532 nm [${\dot{\beta }}^{\perp }$(355/532)] and the wavelength pairs 532 and 1064 nm [${\dot{\beta }}^{\perp }$(532/1064)]. In particular, the cycloid-like behavior of the interdependency ${\dot{\beta }}^{\perp }$(355/532) versus ${\dot{\beta }}^{\perp }$(532/1064), i.e., hysteresis, means that non-spherical particle size changes. Full article

Background: Children and teenagers use electronic devices daily, especially smartphones. The use of these devices exposes children and adolescents to excess blue light, which can alter the structures of the eye, especially the retina. As a protective mechanism, the macular region contains pigments represented by lutein, zeaxanthin, and meso-zeaxanthin. In this study, we aimed to analyze the relationship between the Macular Pigment Optical Density (MPOD) levels in the macula and the time spent on smartphones in children and adolescents. Methods: Fifty-seven children and teenagers aged between 8 and 18 were evaluated, with a total of 114 eyes. The patients included in the study were divided into two groups: those who spent less than two hours a day on the device and those who exceeded this period. To determine the amount of macular pigment, the Heterochromatic Flicker Photometry technique was used. Results: We found a statistically significant difference in screen time between weekdays and weekends in favor of the latter. We compared the different refractive categories with respect to pigment levels and screen time and found no significant differences between groups. When comparing the patients with respect to environment, we found a slight difference in macular pigmentation in the favor of rural areas and also in the screen time which was shorter in rural areas. We found a strong association at all levels between longer screen time (both weekdays and weekend) and lower macular pigment quantities for both eyes. When comparing the groups with more/less than 2 h of screen time, the MPOD was lower for both eyes in the group with over 2 h screen time. Conclusions: In this study we demonstrated that smartphone use is a risk factor leading to a decrease in MPOD in children and adolescents. The amount of lutein in the retina, brain and serum are correlated, therefore MPOD can be considered a natural biomarker of lutein and zeaxanthin levels in the body. Full article

A semi-distributed interferometer is a low-reflectivity device with refractive index sensing capability, exploiting the random reflectivity of a nanoparticle-doped fiber to form a weak distributed cavity. In this work, we extend this concept to an extrinsic semi-distributed interferometer (ESDI), using an overlay made of polydimethylsiloxane (PDMS) around the fiber tip; this structure can then be surface-modified using a thin metallic film or a nanoparticle coating. We report gold-sputtered and gold-nanoparticle-coated ESDI structures for refractive index sensing capability, with the latter achieving superior performances with an average sensitivity of 62.8 dB/RIU (refractive index units) with resolution of 3.9 × 10⁻⁵ RIU over the range of 1.34790–1.35981. We also report a possible biological application using a biofunctionalized version of this probe for the detection of VEGF (vascular endothelial growth factor); the gold-sputtered probe achieves the highest sensitivity, 0.0565 dB for each 10× concentration increase, with 355 fM detection limit. Full article

A novel transition-metal-free alkyne–thiol click polymerization with 100% atom economy is reported. Using ^tBuOLi as a catalyst at 80 °C, the polymerization efficiently yields poly(vinyl sulfide)s (PVSs) with molecular weights up to 11,800 g/mol and yields up to 91%. These sulfur-rich polymers exhibit high thermal stability (T_d up to 293 °C) and high refractive indices (1.8375–1.6383) across the visible range. By integrating abundant sulfur coordination sites with aggregation-induced emission (AIE) properties, the PVS aggregates serve as high-performance fluorescent chemosensors. The sensor enables exclusive, sensitive trace detection of Pd²⁺ and Au³⁺ with remarkable anti-interference capability and pH robustness (pH 1–7). Notably, an ultrafast response (1–2 min) for Pd²⁺ is achieved, with limits of detection (LOD) reaching 7.11 × 10⁻⁷ M for Pd²⁺ and 1.06 × 10⁻⁶ M for Au³⁺, and corresponding limits of quantification (LOQ) reaching 2.37 × 10⁻⁶ M and 3.53 × 10⁻⁶ M, respectively. This methodology offers a sustainable route to heteroatom-rich macromolecules for next-generation optical engineering and environmental monitoring. Full article

Tantalum pentoxide (Ta₂O₅) has emerged as a versatile material at the intersection of optical coatings and integrated photonics because it combines a high refractive index, a wide bandgap, low optical loss, and compatibility with multiple thin-film deposition routes. Over the past decade, the literature has expanded from conventional dielectric coating studies to low-loss waveguides, micro-ring resonators, wavelength conversion, and broadband supercontinuum generation, while more recent work has increasingly emphasized defect engineering, nonlinear absorption, and laser damage reliability under strong optical fields. The objective of this review is to establish a process–structure–composition–property–function–reliability framework for understanding Ta₂O₅ and non-stoichiometric Ta₂O_5−x optical coatings in high-power photonics. Unlike previous reviews that mainly emphasized dielectric properties, deposition methods, or general thin-film applications, this review highlights how deposition-induced composition changes, oxygen vacancy-related defects, nonlinear optical response, and laser damage reliability jointly determine the operational limits of tantalum oxide photonic materials. Particular attention is given to ion-assisted and ion gun-assisted processes, which have repeatedly been associated with higher film density, smoother morphology, reduced oxygen vacancy-related loss, and more stable high-field behavior. By linking coating-level process control to device-level functions such as four-wave mixing, self-phase modulation, wavelength conversion, and supercontinuum generation, this review highlights how thin-film engineering governs both optical performance and operational limits. It also identifies several persistent gaps, including the need for standardized reporting of nonlinear absorption, unified damage metrics across film and device geometries, and stronger correlations among microstructure, composition, defects, and long-term optical stability. Overall, this review provides a composition-aware and coating-informed framework for interpreting Ta₂O₅ photonics and a practical roadmap for developing durable high-power photonic components. Full article

Biophysical sensing technologies have become central to modern drug discovery because they enable direct, quantitative characterization of ligand–target interactions. In contrast to conventional biochemical and cellular assays that infer binding from downstream functional responses, biophysical methods detect interaction events through measurable physical changes such as refractive index, heat, fluorescence, mass, or protein stability. This review surveys the major classes of biophysical sensors used in drug discovery, including surface-based optical methods, calorimetry, solution-state spectroscopic techniques, mass spectrometry-based approaches, and cellular target engagement assays. For each modality, we outline the measurement principle, the key parameters obtained, and its value across hit identification, hit validation, lead optimization, and mechanism-of-action studies. We also emphasize the growing importance of combining orthogonal methods to improve confidence in binding data, resolve assay artifacts, and strengthen early decision-making. Finally, we discuss how biophysical measurements are increasingly integrated with structural biology and computational analysis to support more predictive and mechanism-driven discovery workflows. Collectively, these technologies provide a richer and more reliable understanding of molecular recognition and thereby improve the progression of drug candidates. Full article

Bilirubin is an important biomarker, where a small unbound fraction dissociated from albumin can cross the blood–brain barrier and induce neurotoxicity, such as kernicterus, at low nanomolar levels. Accurate detection of this low-level fraction remains challenging. Surface-enhanced Raman spectroscopy (SERS) enables label-free molecular detection; however, variations in the local refractive index (RI) at plasmonic hotspots can detune the resonance from the excitation wavelength, leading to signal fluctuations and limited quantitative reliability. Here, we present a multi-resonant nanolaminate SERS substrate designed to achieve RI-insensitive and robust signal enhancement. The vertically stacked metal–insulator–metal architecture provides broadband spectral overlap with both excitation and Raman scattering under dielectric loading, maintaining consistent enhancement across varying RI conditions. We demonstrate label-free bilirubin detection with a highly linear response over 10⁻⁹ to 10⁻⁴ M, achieving an R² value of 0.99. Compared with previously reported bilirubin SERS substrates relying mainly on single-resonant plasmonic enhancement, this RI-insensitive design offers improved quantitative reliability under dielectric environmental changes. These results highlight the importance of RI-insensitive SERS design for reliable quantification and provide a general strategy for robust SERS-based biosensing. Full article

To propose which tests may be used for diagnosing convergence excess. A prospective study of a consecutive clinical sample was performed. Patients (18–35 years) attending optometric care underwent subjective refraction, cover test, and Symptom Questionnaire for Visual Dysfunctions (SQVD). Based on cover test and SQVD scores, two groups were recruited: 64 symptomatic subjects with near esophoria and 64 asymptomatic with normal binocular vision. Accommodative and binocular tests were assessed, identifying those with significant statistical differences between groups. Diagnostic validity was analysed using ROC curves, sensitivity, specificity, and likelihood ratios. A serial testing strategy combining tests was also evaluated. ROC analysis showed best diagnostic accuracy for binocular accommodative facility (BAF) failing with −2.00 D (area under the curve, AUC = 0.865) and vergence facility (VF) failing with base-in prisms (AUC = 0.864). Using cutoffs from ROC analysis (BAF: ≤8.25 cpm and VF ≤ 12.75 cpm), their combination showed best validity (S = 0.625, Sp = 0.938, LR+ = 10, LR− = 0.4). The combined AUC was 0.932. The proposal for diagnosing convergence excess is to use, in addition to near esophoria with normal distance heterophoria, the combination of failing BAF with negative lenses and failing vergence facility with base-in prisms. Full article

The aim of this work is to develop high-precision time-of-flight (TOF) devices based on high-refractive-index solid Cherenkov radiators read out by silicon photomultipliers (SiPMs). Cherenkov light is prompt and, therefore, ideal for reaching the intrinsic timing limits of TOF systems. By utilizing a thin, high-refractive-index radiator, a nearly instantaneous signal is generated by particles exceeding the Cherenkov threshold. In order to achieve the ultimate time resolution, we carried out a rigorous optimization of the radiator material and geometry, alongside the efficiency of the optical coupling to the SiPM sensors. The key factors limiting the time resolution were characterized by comprehensive Monte Carlo simulations, subsequently validated against experimental beam test data. We assembled small-scale prototypes instrumented with various Hamamatsu SiPM array sensors with active areas ranging from 1.3 to 3 mm, coupled with various window materials, such as fused silica and MgF₂, featuring various thickness values. The prototypes were successfully tested in beam test campaigns at the CERN-PS T10 beamline. The data were collected with a complete chain of front-end and readout electronics based on either the Petiroc 2A or the Radioroc 2 interfaced to a picoTDC to measure charges and times. By comparing the time measurements from two SiPM arrays, we were able to measure a time resolution better than 33.2 ps at the full system level, with a charged-particle detection efficiency of 100%. Our results demonstrate the expected performance benchmarks for the charged-particle detection efficiency and time resolution, and they highlight the potential of the developed Cherenkov-based TOF detectors for next-generation particle identification systems. Full article

We present the development of an infrared sensor based on a meta surface utilizing Dolmen plasmonic nanostructures. This meta surface is engineered to enhance the absorption of infrared light at a specific wavelength. The sensor is optimized for high sensitivity and selectivity in the infrared spectrum. This straightforward meta surface sensor shows promise for various applications, including gas sensing, biosensing, and security. The design is compact and easy to fabricate with studied fabrication tolerance ensuring reliable performance. The sensor was tested for water-based sensing applications, and we tested its performance by using different materials such as ZrN, TiN, Cr, and Au on silicon dioxide. In a separate configuration, a gold nanostructure was fabricated on a silicon layer over a silicon dioxide base to examine the resulting plasmonic response. The results surpass those of other water quality sensors, underscoring the potential of this design for high-performance sensing. The sensor’s high sensitivity and low fabrication costs make it a promising technology for future sensing and monitoring applications. Full article

An approximate analytical model for the variation of A-weighted broadband sound levels with distance over flat acoustically soft ground from a source of known sound power depends on the reduction in low frequency content in noise spectra due to A-weighting. Also, it assumes a weak linear sound speed gradient and a frequency independent attenuation coefficient for air absorption. The model introduces adjustable frequency independent parameters for ground effect, turbulence and atmospheric refraction. An additional parameter allows for the source being located over acoustically hard ground. Predictions of the model are compared with measurements over several ground surfaces. The approximate model predicts a more rapid reduction in sound attenuation due to ground effect with increasing mean propagation path height than the simplified method in a widely used international standard. Moreover, predictions of A-weighted sound levels from onshore wind turbines using the approximate analytical method compare with data and numerical simulations better than the simplified and octave band methods in the international standard and the Swedish standard method. Full article