Optical Defect Research Articles

Wavelength optimization of fine optical surface defect detection based on FDTD

Wavelength optimization of fine optical surface defect detection based on FDTD

Identification of a Novel Frameshift variant of the ATRX gene: a Case Report and Review of the genotype–phenotype relationship

BackgroundX-linked intellectual disability-hypotonic facies syndrome-1 (MRXHF1) and Alpha-thalassemia X-linked intellectual disability (ATR-X) syndrome are caused by pathogenic variant in the ATRX gene, a member of the switch/sucrose non-fermentable (SWI-SNF) protein family that exhibits chromatin remodeling activity. These syndromes show a wide spectrum of clinical manifestations, such as distinctive dysmorphic features, mild-to-profound intellectual disability, motor development delay, seizures, urogenital abnormalities, and gastrointestinal disorders.Case presentation and literature reviewA 3-year-old boy from a Chinese non-consanguineous family was diagnosed with MRXHF1 by whole-exome sequencing. Comprehensive family history information was obtained. The Medline database was searched until 1st Aug 2023 for articles related to ATRX pathogenic variant. Data on gene/protein mutations and clinical symptoms were extracted. The proband showed intellectual disability, motor development delay, typical facial abnormalities, urogenital defect, behavior problems, and optical nerve dysplasia. A novel frameshift mutation c.399_400dup, (p.Leu134Cysfs*2) in the ATRX gene was the primary cause, which occurs right before the ATRXDNMT3-DNMT3L (ADD) domain of ATRX protein. Missense mutation is the most common variation type. The ADD and helicase-like domains are the most frequently affected domains. Epilepsy, congenital heart disease, urogenital defect, acoustic defect, and optical defect are more prevalent in patients with frameshift mutations compared to those with missense mutations. There are more urogenital defects with C-terminal frameshift mutations than with N-terminal frameshift mutations.ConclusionWe described a novel frameshift mutation in the ATRX gene in a patient with MRXHF1 syndrome and summarized the genotype–phenotype relationship of ATRX pathogenic variant by variation type and affected protein domain. The regulatory mechanism underlying ATRX variant requires comprehensive analysis in future studies.

Galileo’s microscopic and telescopic observations and their impact on how bodies are conceived

Abstract Four hundred years ago Galileo Galilei published a work that was immensely successful directly after its publication but is relatively unknown today. The Assayer (Il Saggiatore) started as a polemic reply to Orazio Grassi’s interpretation of the first telescopic observation of comets in history. The Jesuit defended the idea that comets were bodies moving in the superlunary region. However, Galileo never explicitly stated that comets are an illusion or an optical defect. Rather he aimed at undermining Grassi’s argumentation. Consequently, what announced itself initially as a controversy about the nature of comets turned out to become a controversy about the nature of scientific methodology. This paper focuses on two elements that Galileo elaborates on in this pioneering work of scientific method: his views on the qualities of bodies and the fact that “the book of nature” is written in the language of mathematics. It demonstrates how these two elements are not only connected in The Assayer (1623) but also in his earlier work. In addition, it shows how they both played a role in Galileo’s defence of mathematical demonstration and his rejection of the tools of scholastic philosophy.

Visible-light induced effective and sustainable remediation of nitro organics pollutants using Pd-doped ZnO nanocatalyst

Nitroaromatic compounds represent a class of highly toxic pollutants discharged into aquatic environments by various industrial activities, posing significant threats to ecological integrity and human health due to their persistent and hazardous nature. In this study, Pd-doped ZnO nanoparticles were investigated as a potential solution for the degradation of nitro organics, offering heightened photocatalytic efficacy and prolonged stability. The synthesis of Pd-doped ZnO NPs was achieved via the hydrothermal method, with subsequent analysis through XRD spectra and XPS confirming successful Pd doping within the ZnO matrix. Characterization through FESEM and HRTEM unveiled the heterogeneous morphologies of both undoped and Pd-doped ZnO nanoparticles. Additionally, UV–vis and PL spectroscopy provided insights into the optical properties, chemical bonding, and defect structures of the synthesized Pd-doped ZnO NPs. Pd doping induces a redshift in ZnO’s absorption spectra, reducing the bandgap from 3.12 to 2.94 eV as Pd concentration rises from 0 to 0.2 wt.%. The photocatalytic degradation, following pseudo-first-order kinetics, achieved 90% nitrobenzene abatement (200 µg/L, pH 7) under visible light within 320 min with a catalyst loading of 16 µg/mL. The photocatalytic efficacy of 0.08 wt% Pd-doped ZnO (k = 0.058 min⁻1) exhibited a 25-fold enhancement compared to bare ZnO (k = 3.1 × 10–4 min-1). Subsequent quenching and ESR experiments identified hydroxyl radicals (OH•) as the predominant active species in the degradation mechanism. Mass spectrometry analysis unveiled potential breakdown intermediates, illuminating a plausible degradation pathway. The investigated Pd-doped ZnO nanoparticles demonstrated reusability for up to five successive treatment cycles, offering a sustainable solution to nitro organics contamination challenges.

A chart-based test of contrast sensitivity in noise: reference ranges, effects of age and optical abnormality

ABSTRACT Clinical relevance Contrast sensitivity plays an important role in the comprehensive assessment of visual function; however, measurement with standard eye charts can be affected by age and optical abnormality. Background This study describes a novel chart-based test of letter contrast sensitivity (CS) in luminance noise (the Illinois Eye and Ear Noise CS test), defines normal reference ranges, estimates test-retest repeatability, and assesses the effects of age and simulated optical abnormalities. Methods Seventy-five individuals with normal visual function (age 18–85 years) participated. Subjects identified letter optotypes that spanned a broad contrast range (0.9% to 59.6%) printed in a book-based test. Letters were presented against a grey background (no-noise condition) and in luminance noise that consisted of light and dark checks (noise condition). A subset of 10 subjects repeated the test to define short-term variability and performed the test under three additional conditions: simulated cataract, +2.00D defocus, and low room illuminance. Results In the no-noise condition, CS was independent of age (mean log CS of 1.74) until approximately 54 years, and declined for older subjects (CS loss of 0.1 log unit/decade). CS measured in noise was independent of age across the range of ages tested (mean log CS of 0.91). The 95% limits of agreement for test-retest repeatability was 0.19 log units. Simulated cataract, +2.00D defocus, and reduced illumination significantly reduced CS in the no-noise condition (F = 102.6, p < 0.001), whereas these optical manipulations did not significantly affect CS in noise (F = 2.58, p = 0.074). Conclusions Measurements of CS in luminance noise may be valuable, as these measures are largely independent of age and certain forms of optical degradation. CS measurements in noise may provide useful insight into visual function in patients who have combined neural and optical abnormality, as noise minimises CS loss from optical defects.

Comprehensive characterization of nitrogen-related defect states in β-Ga2O3 using quantitative optical and thermal defect spectroscopy methods

This study provides a comprehensive analysis of the dominant deep acceptor level in nitrogen-doped beta-phase gallium oxide (β-Ga2O3), elucidating and reconciling the hole emission features observed in deep-level optical spectroscopy (DLOS). The unique behavior of this defect, coupled with its small optical cross section, complicates trap concentration analysis using DLOS, which is essential for defect characterization in β-Ga2O3. A complex feature arises in DLOS results due to simultaneous electron emission to the conduction band and hole emission to the valence band from the same defect state, indicating the formation of two distinct atomic configurations and suggesting metastable defect characteristics. This study discusses the implications of this behavior on DLOS analysis and employs advanced spectroscopy techniques such as double-beam DLOS and optical isothermal measurements to address these complications. The double-beam DLOS method reveals a distinct hole emission process at EV+1.3 eV previously obscured in conventional DLOS. Optical isothermal measurements further characterize this energy level, appearing only in N-doped β-Ga2O3. This enables an estimate of the β-Ga2O3 hole effective mass by analyzing temperature-dependent carrier emission rates. This work highlights the impact of partial trap-filling behavior on DLOS analysis and identifies the presence of hole trapping and emission in β-Ga2O3. Although N-doping is ideal for creating semi-insulating material through the efficient compensation of free electrons, this study also reveals a significant hole emission and migration process within the weak electric fields of the Schottky diode depletion region.

Vitreopapillary Findings in Nonarteritic Ischemic Optic Neuropathy versus Healthy Eyes: A Clinical and OCT Comparison

PurposeTo study the vitreopapillary interface in non‐arteritic ischemic optic neuropathy (NAION) for features that may predispose to optic nerve perfusion defects. DesignCase-control study. Participants and ControlsPatients with NAION (Study group) were compared with healthy non‐NAION patients with crowded discs (Control group I) and non-crowded optic discs (Control group II). MethodsThe vitreopapillary interface was studied in 32 eyes with NAION using high-resolution OCT scans. Results were compared with two control groups consisting of age, sex, and refraction‐matched non‐NAION individuals with crowded optic discs (Control Group I: 31 eyes) and non-crowded optic discs (Control Group II: 32 eyes). Main Outcome MeasuresThe incidence of total posterior vitreous detachment (PVD), vitreopapillary and vitreovascular attachments, and epipapillary membranes. ResultsThe rate of PVD over the macula was similar among groups (NAION: 62.5%, Control I: 61.3%, and Control II: 65.6%, p=0.93) while the posterior hyaloid remained attached to the crowded discs at a significantly higher rate (NAION: 81.2%, Control I: 83.9% and Control II: 43.7%, p=0.0005). A higher rate of focal vitreopapillary attachments on crowded discs than on non-crowded discs was noted (NAION: 72.2%, crowded control I: 58.7%, and non-crowded control II: 19.1%, p=0.007). Vitreovascular attachments (NAION: 69%, crowded control I: 3% vs non-crowded control II: 6%, p=0.00001) and dense epipapillary membranes were observed in NAION eyes. ConclusionsCrowded discs may have stronger vitreopapillary attachments. A close relationship of these attachments with optic nerve vessels may lead to the transmission of strong tractional forces by a syneretic vitreous gel, especially after macular PVD. This transduced mechanical force may contort the vessel wall and disrupt the blood flow in NAION.

Practical Improvement of Noncontact Production Monitoring of Doping in SiC Wafers with Extended Epilayer Defects

We discuss two defect related practical improvements in the corona noncontact CV metrology, (CnCV) for SiC. The improvements are introduced in response to requests from industrial tool users. The first improvement quantifies mapping of electrically active defects with the QUAD technique (Quality, Uniformity, and Defects). It provides the capability of user selectable die grids directly comparable with Near UV-PL and optical defect mapping. This shall enhance understanding of the device killer defects and help to correlate epilayer defects and device yield. The second improvement introduces auto-remeasurement of outliers appearing in doping measurements on defective sites. This procedure is analogous to that used in the Hg probe technique and it provides a means for correcting defect related distortions in SPC doping monitoring charts.

Electrical and electrochemical properties of A-site non-stoichiometry Ca0.67La0.22□0.11Ti(1−x)CrxO3−δ electrolyte materials for solid oxide fuel cells

Due to increasing global energy demands and environmental concerns, the search for alternative and environmentally friendly energy sources is of paramount importance. Solid oxide fuel cells (SOFCs) have emerged as a promising solution thanks to their high efficiency and minimal environmental impact. In this regard, perovskite oxides, with their unique properties, have attracted significant attention. This study investigates the dielectric dispersion, electrical features, scaling behavior, and optical defects of Ca0.67La0.22Ti0.85Cr0.15O3 with x = 0.15, CLT0.85Cr0.15. The presence of a vacancy in the A-site is denoted by the square in the formula. Relaxation phenomena were analysed using dielectric and modulus formalism, while the conductivity mechanism was explored through electrical conductivity measurements. The optical defects of CLT0.85Cr0.15 were analysed using electron paramagnetic resonance (EPR) spectroscopy. The findings revealed the formation of Cr3+–VO center defects. These defects serve as sources of in-gap electron traps, thereby enhancing the optical properties of CLT0.85Cr0.15, making it as a compelling material for various optical applications. The power density increased with temperature, reaching 0.73 W/cm2 at 850 °C, suggesting that CLT0.85Cr0.15 could be a promising electrolyte for IT-SOFCs. The peak in power density correlated with temperature due to thermal effects on ion motion. However, the open circuit voltage decreased with temperature increase, due to increased oxygen vacancies and electron/hole conduction in CLT0.85Cr0.15. The findings suggest that perovskite materials could revolutionize SOFCs technology, paving the way for more efficient and environmentally friendly energy solutions.

Automatic identification and classification of surface defects in small-sized optics

Abstract Precision optics are widely used in lighting systems, imaging systems, and high-precision inspection equipment. The presence of surface defects in optics can seriously affect the design performance of the equipment, so the optics must be rigorously inspected to eliminate defective optics. Currently, engineering products are moving toward smaller sizes, resulting in smaller optics in them also moving towards smaller sizes. However, realizing the surface defect detection of small-sized optics is a great challenge because it requires micrometer-scale high-resolution image acquisition and automatic detection of defects on their surfaces. A machine learning-based automatic surface defect detection method is proposed for surface defects with many types and small sizes. A dark-field micro-scattering imaging system is used to acquire dark-field images. Then the image segmentation and feature analysis are performed on each image to extract the original feature data, and the original feature data are compressed by reliefF algorithm. Based on the compressed feature data, a classification model is built using a support vector machine. The detection method can classify three kinds of defects, namely, dig, scratch, and scuff mark. The accuracy of the method is up to 98%. The experimental results of this study show that the method can automatically and accurately detect a wide range of micro defects occurring in small-sized optics, thus providing valuable insights into the realization of mass production of small-sized optics. In addition, our proposed method provides some ideas for further research in the field of defect detection in small-sized optics.

Investigation of impact of kesterites as hole transport layer on (FA)2BiCuI6 based ecofriendly double perovskite solar cell to obtain optimized PCE above 25%

This paper presents a detailed study of double perovskite (FA)2BiCuI6 based perovskite solar cells(PSC) using different kesterites as hole transport layers (HTL) and titanium-based electron transport layers (ETL). The designed double perovskite PSC utilized TiO2 as an ETL, different kesterite materials (CZTSe, CFTS, CBTS, CMTS, CNTS and CZTS) as the HTL, double perovskite material (FA)2BiCuI6 as the perovskite absorption layer (PAL), Indium tin oxide (ITO) as top electrode and Au as an anode. The different parameters of architecture (ITO/TiO2/(FA)2BiCuI6/HTL/Au) is improved via the SCAPS-1D simulator by first optimizing thickness and then the defect density of PAL. Energy band matching of the different layers with (FA)2BiCuI6 is thoroughly investigated in order to understand its operation. AM 1.5G illumination is used as input light source. To obtain optimum performance of (FA)2BiCuI6 based PSC the effects of optical thickness, defect density, temperature, series resistance, and shunt resistance are monitored. Among all the kesterites, CNTS based PSC performed extraordinarily well with PCE of 26.09 %. JSC 22.64 mA/cm2, VOC 1.38 V, FF 83.33 %, and the variables influencing solar cell performance are clarified by simulations. The findings presented in this work will aid researchers in the production of ecofriendly solar cells with great efficiency.

Probing Correlation of Optical Emission and Defect Sites in Hexagonal Boron Nitride by High-Resolution STEM-EELS.

Optically bright emitters in hexagonal boron nitride (hBN) often acting as a source of a single-photon are mostly attributed to point-defect centers, featuring localized intra-bandgap electronic states. Although vacancies, anti-sites, and impurities have been proposed as candidates, the exact physical and chemical nature of most hBN single-photon emitters (SPEs) within the visible region are still up for debate. Combining site-specific high-angle annular dark-field imaging (HAADF) with electron energy loss spectroscopy (EELS), we resolve and identify a few carbon substitutions among neighboring hBN hexagons, all within the same sample region, from which typical defect emission is observed. Our experimental results are further supported by first-principles calculations, through which the stability and possible optical transitions of the proposed carbon-defect complex are assessed. The presented correlation between optical emission and defects provides valuable information toward the controlled creation of emitters in hBN, highlighting carbon complexes as another probable cause of its visible SPEs.

A Portable Technology for Measuring Haze Levels in Thick Laminated Glass Panels

Increasing security concerns and a trend towards larger glass panels are driving the adoption of thicker laminate glass panels in prominent architectural works worldwide. However, the polymeric materials used in these laminates can lead to haze, a detrimental optical defect that impairs transparency perception, particularly when used in thick, multi-layer laminates. This work presents a novel technology capable of accurately and robustly measuring haze in glass laminates of arbitrary thickness, based on using computer-vision to measure changes in contrast when viewing a standard mask through the material under controlled diffuse lighting conditions. Unlike previous approaches, this technology can be employed on installed glasses without requiring exposed edges for double-sided measurements, making it suitable for on-site work. The experimental evidence provided indicates that its precision and robustness are adequate for quality control.

Remyelination-oriented clemastine treatment attenuates neuropathies of optic nerve and retina in glaucoma.

As one of the top causes of blindness worldwide, glaucoma leads to diverse optic neuropathies such as degeneration of retinal ganglion cells (RGCs). It is widely accepted that the level of intraocular pressure (IOP) is a major risk factor in human glaucoma, and reduction of IOP level is the principally most well-known method to prevent cell death of RGCs. However, clinical studies show that lowering IOP fails to prevent RGC degeneration in the progression of glaucoma. Thus, a comprehensive understanding of glaucoma pathological process is required for developing new therapeutic strategies. In this study, we provide functional and histological evidence showing that optic nerve defects occurred before retina damage in an ocular hypertension glaucoma mouse model, in which oligodendroglial lineage cells were responsible for the subsequent neuropathology. By treatment with clemastine, an Food and Drug Administration (FDA)-approved first-generation antihistamine medicine, we demonstrate that the optic nerve and retina damages were attenuated via promoting oligodendrocyte precursor cell (OPC) differentiation and enhancing remyelination. Taken together, our results reveal the timeline of the optic neuropathies in glaucoma and highlight the potential role of oligodendroglial lineage cells playing in its treatment. Clemastine may be used in future clinical applications for demyelination-associated glaucoma.

59‐2: Invited Paper: Deep Learning‐enhanced Self‐interference Incoherent Digital Holography

We propose deep learning‐enhanced self‐interference incoherent digital holography. Self‐interference incoherent digital holography is a hologram acquisition technique under the incoherent light condition, which can capture the real‐world complex hologram. To overcome unwanted optical defects of the self‐interference, we suggest a data‐driven approach for reducing the additional noise and enhancing the image quality.

Local disorder of multi-site of Eu dopant and its effect on spectroscopy properties in NaCaPO4 host

Optical spectroscopy and defect disorder of multi-site of Eu dopant in NaCaPO4 structure was studied by computational and experimental methods. The prediction of intrinsic disorder and the symmetry and detailed geometry of multi-site of Eu dopant was made by atomistic modeling. The crystal field parameters are then calculated and used to obtain the 7F1 sublevels of the Eu3+ ion, which we used to discuss the local symmetry of the multi-site of Eu3+. The calculations suggest that the most energetically feasible configurations involve the substitution of Eu3+ and Eu2+ ions at the Ca2 site. For Eu3+ substitution, charge charge compensation by NaCa2′ defect is the most provable. The solution energies for the other configuration, for the two Eu3+ dopant ions, are very similar. This means that the Eu3+ dopant can be found in all Ca sites in the NaCaPO4. The theoretical spectroscopic study showed that the symmetry of the Eu3+ ions, based on the amount of non-null crystal field parameters, is a C4 symmetry for all multi-site of Eu3+. A set of phenomenological charge factors and the 7F1 manifold split were satisfactorily reproduced in agreement with the experimental data.

Cascadic degradation of selected polyolefin grades in a simulated closed-loop recycling process

Reintroducing recycled plastics into production processes can lead to irreversible degradation and changes in their properties, thereby limiting their recycling potential to a finite number of loops. This study investigates the impact of process-induced degradation resulting from multiple reprocessing cycles on specific material properties and aims to establish structure–property relationships. Four different polyolefins, including two polypropylenes, high-density polyethylene, and low-density polyethylene, were selected for the study. The materials underwent extrusion, pelletizing, injection molding, and milling before being reintroduced into the reprocessing cycle. This sequence of processing steps was repeated six times on each material. Various characterization techniques, including high-temperature gel permeation chromatography, melt mass flow rate, parallel-plate rheology, differential scanning calorimetry, gas chromatography–mass spectrometry, and optical defect control system, were performed to evaluate the molecular structure, rheological behavior, thermal stability, and the resulting contaminants and defects after each reprocessing step. The reprocessing of polypropylene resulted in a gradual decrease in the average molecular weights accompanied by a shift to lower viscosities and higher melt mass flow rates, whereas the polyethylene grades showed the opposite trend with a less pronounced effect in high-density polyethylene. The volatile organic compounds rose in polypropylene and sank in polyethylene after reprocessing. Additionally, all four materials exhibited an increase in degradation-related defects based on optical defect analysis.Graphical abstract

2 in. Bulk β-Ga2O3 Single Crystals Grown by EFG Method with High Wafer-Scale Quality.

2 in. bulk β-Ga2O3 single crystals are successfully grown by the edge-defined film-fed growth method with a homemade furnace system. By considering the significance of wafer quality in future mass manufacture, a nine-point characterization method is developed to evaluate the full-scale quality of the processed 2 in. (100)-orientated β-Ga2O3 single-crystal wafers. Crystalline and structural characteristics were evaluated using X-ray diffraction and Raman spectroscopy, revealing decent crystalline quality with a mean full width at half-maximum value of 60.8 arcsec and homogeneous bonding structures. The statistical root-mean-square surface roughness, determined from nine scanning areas, was found to be only 0.196 nm, indicating superior surface quality. Linear optical properties and defect levels were further investigated using UV-visible spectrophotometry and photoluminescence spectroscopy. The high wafer-scale quality of the processed β-Ga2O3 wafers meets the requirements for homoepitaxial growth substrates in electronic and photonic devices with vertical configurations.

Effect of Zr4+ concentration on optical properties and defect structure of Zr:Ho:LiNbO3 crystals

Effect of Zr4+ concentration on optical properties and defect structure of Zr:Ho:LiNbO3 crystals

Atypical Form of Unilateral Optic Neuropathy Caused by Ocular Toxocariasis

Purpose: To report an atypical form of ocular toxocariasis presenting as unilateral optic neuropathy.Case summary: A 75-year-old man was referred to our clinic owing to the recently developed visual difficulty in his right eye. The visual acuity of the right eye was 0.4, a relative afferent pupillary defect was positive in the right eye. On slit lamp biomicroscopy, anterior chamber inflammation and vitreous cells and haze were detected in the right eye. On fundus examination, optic disc swelling and focal retinitis around the optic disc were found in the right eye. Fluorescein angiography revealed focal retinitis along with leakage near the optic disc in the right eye. Serology was positive for Toxocara IgG. Under the suspicion of an atypical form of ocular toxocariasis, the patient was treated with local and oral steroids and albendazole. Subsequently, optic disc swelling and vitreous inflammation improved, but the final visual acuity was 0.125 with pale optic disc and central visual field defects in the right eye.Conclusions: In patients suspected of optic neuritis, when the anterior chamber and vitreous inflammation and uveitis are accompanied, ocular toxocariasis can present atypically and requires attention because may have a bad prognosis owing to irreversible optic nerve damage.