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The ability to spatially resolve the carrier mobility profile along the cross section of micrometer-thin solar cells is vital, both for fundamental studies in photovoltaics and as quality control for reproducibly obtaining high conversion efficiencies in commercial solar cell modules. Presently, no technique capable of such an endeavor is available to the best of our knowledge. Here, we introduce a novel method capable of profiling the carrier mobility along the z axis in thin-film photovoltaics. Our setup is based on the integration of photogenerated charge extraction by linearly increasing voltage (p-CELIV) with a scanning confocal optical microscope (SCOM) toward a confocal and cross-sectional p-CELIV (cs-p-CELIV) system. As monomolecular recombination of excess carriers is the most frequent radiative pathway for electrons and holes in solar cells at low power density of illumination, while multimolecular recombination dominates at high power, enhanced multimolecular recombination occurs at the SCOM focal plane. Thus, the cs-p-CELIV signal provides enhanced information on the mobility of all of the cross-sectional layers except the focal plane. By scanning the focal plane along the z axis, the mobility profile can be derived. To demonstrate our technique, we use it to investigate the carrier mobility in three hydrogenated amorphous silicon (a-Si:H) solar cells. The mobility profiles obtained by cs-p-CELIV correlate well with well-known depletion layer effects and the H content profile in a-Si:H, which is measured independently. Our findings are in excellent agreement with models suggesting a critical role of Si–H bonding in locally determining the carrier mobility in a-Si:H. [ABSTRACT FROM AUTHOR]

The MIllimeter Sardinia radio Telescope Receiver based on Array of Lumped elements KIDs, MISTRAL, is a cryogenic LEKID camera, operating in the W band ( 77 - 103 GHz ) from the Gregorian focus of the 64-m aperture Sardinia Radio Telescope (SRT), in Italy. This instrument features a high angular resolution ( ∼ 12 arcsec ) and a wide instantaneous field of view ( ∼ 4 arcmin ), allowing continuum surveys of the mm-wave sky with many scientific targets, including observations of galaxy clusters via the Sunyaev–Zel'dovich effect. In May 2023, MISTRAL has been installed at SRT for the technical commissioning. In this contribution, we will describe the MISTRAL instrument focusing on the laboratory characterization of its focal plane: a ∼ 400 -pixel LEKID array. We will show the optical performance of the detectors highlighting the procedure for the identification of the pixels on the focal plane, the measurements of the optical responsivity and NEP, and the estimation of the optical efficiency. [ABSTRACT FROM AUTHOR]

STUDY QUESTION What are the implications of the presence cytoplasmic strings (Cyt-S) and their quantity and dynamics for the pre-implantation development of human blastocysts? SUMMARY ANSWER Cyt-S are common in human embryos and are associated with faster blastocyst development, larger expansion, and better morphological quality. WHAT IS KNOWN ALREADY Cyt-S are dynamic cellular projections connecting inner cell mass and trophectoderm (TE) cells, that can be observed during blastocyst expansion. Their prevalence in human embryos has been estimated to be between 44% and 93%. Data relevant to their clinical implications and role in development are lacking, limited, or controversial. STUDY DESIGN, SIZE, DURATION Retrospective study conducted at a single IVF center between May 2013 and November 2014 and involving 124 pre-implantation genetic testing for aneuploidy cycles in a time-lapse incubator with ≥1 blastocyst biopsied and vitrified (N = 370 embryos assessed). These cycles resulted in 87 vitrified-warmed single-euploid blastocyst transfers. PARTICIPANTS/MATERIALS, SETTING, METHODS ICSI, continuous blastocyst culture (Days 5–7), TE biopsy of fully expanded blastocysts without Day 3 zona pellucida drilling, qPCR to assess uniform full-chromosome aneuploidies, and vitrification were all performed. Only vitrified-warmed euploid single-embryo-transfers were conducted. Blastocyst morphological quality was defined according to Gardner's criteria. The AI-based software CHLOE™ (Fairtility) automatically registered timings from time of starting blastulation (tSB) to biopsy (t-biopsy, i.e. blastocyst full-expansion) as hours-post-insemination (hpi), embryo area (including zona pellucida in µm2), and spontaneous blastocyst collapses. One senior embryologist manually annotated Cyt-S presence, quantity, timings, and type (thick cell-to-cell connections and/or threads). All significant associations were confirmed through regression analyses. All couples', cycles', and embryos' main features were also tested for associations with Cyt-S presence, quantity, and dynamics. MAIN RESULTS AND THE ROLE OF CHANCE About 94.3% of the patients (N = 117/124) had ≥1 embryo with Cyt-S. Out of a total of 370 blastocysts, 55 degenerated between blastulation and full-expansion (N = 55/370, 14.9%). The degeneration rate among embryos with ≥1 Cyt-S was 10.8% (N = 33/304), significantly lower than that of embryos without Cyt-S (33.3%, N = 22/66, P  < 0.01). Of the remaining 315 viable blastocysts analyzed, 86% (N = 271/315; P  < 0.01) had ≥1 Cyt-S, on average 3.5 ± 2.1 per embryo ranging 1–13. The first Cyt-S per viable embryo appeared at 115.3 ± 12.5 hpi (85.7–157.7), corresponding to 10.5 ± 5.8 h (0.5–31) after tSB. Overall, we analyzed 937 Cyt-S showing a mean duration of 3.8 ± 2.7 h (0.3–20.9). Cyt-S were mostly threads (N = 508/937, 54.2%) or thick cell-to-cell connections becoming threads (N = 382/937, 40.8%) than thick bridges (N = 47/937, 5.0%). The presence and quantity of Cyt-S were significantly associated with developmentally faster (on average 6–12 h faster) and more expanded (on average 2700 µm2-larger blastocyst's area at t-biopsy) embryos. Also, the presence and duration of Cyt-S were associated with better morphology. Lastly, while euploidy rates were comparable between blastocysts with and without Cyt-S, all euploid blastocysts transferred from the latter group failed to implant (N = 10). LIMITATIONS, REASONS FOR CAUTION Cyt-S presence and dynamics were assessed manually on seven focal planes from video frames recorded every 15 min. The patients included were mostly of advanced maternal age. Only associations could be reported, but no causations/consequences. Lastly, larger datasets are required to better assess Cyt-S associations with clinical outcomes. WIDER IMPLICATIONS OF THE FINDINGS Cyt-S are common during human blastocyst expansion, suggesting their physiological implication in this process. Their presence, quantity and dynamics mirror embryo viability, and morphological quality, yet their role is still unknown. Future basic science studies are encouraged to finally describe Cyt-S molecular nature and biophysical properties, and Artificial Intelligence tools should aid these studies by incorporating Cyt-S assessment. STUDY FUNDING/COMPETING INTEREST(S) None. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Purpose: To introduce a method to calculate retinal irradiance caused by ophthalmoscopy. This may be used to verify the compliance of an instrument with the radiation limits set by light hazard standards. The proposed method is simpler to use and less prone to error than the methods currently found in the light hazard standards. Methods: The optical properties of the standardised human eye, specified by current light hazard standards, are used to calculate the magnification of an aerial image of the retinal surface by the combination of the optics of eye and the auxiliary lens used for ophthalmoscopy. The magnification of the aerial image is used to transform the spectral irradiance of the instrument illumination source to retinal irradiation values. The spectral irradiance of the instrument illumination source can be measured directly as the aerial image is located in the focal plane of the viewing optics of the ophthalmoscope. These spectral irradiation values are then processed using weightings specified by current light hazard standards to give a weighted irradiance which is converted directly to a retinal irradiance value. Results: A single formula is provided to calculate the retinal irradiance using the processed, measured spectral irradiance values of the illumination source. Conclusion: The new method introduced here is simpler to use, requires fewer physical measurements and is less likely to introduce measurement error than that currently found in light hazard standards. The only physical measurement that needs to be taken is the illumination source spectral irradiance measured in the viewing focal plane of the instrument. These values are weighted using given in the light hazard standards. The combined irradiance value is then converted to retinal irradiance using the formula given in this paper. [ABSTRACT FROM AUTHOR]

Background: Pilomatrixoma is an uncommon benign skin neoplasm originating from the hair follicle. Here, we report a rare case of giant and atypical proliferating pilomatrixoma affecting the eyelid. Case presentation: A 47-year-old male presented with a solitary, giant mass on his left upper eyelid, which had recently shown progressive enlargement. The lesion appeared well-circumscribed with a firm consistency, and measuring 7 × 10 cm. Orbital computed tomography scan revealed no intraorbital extension. The lesion was surgically excised. Histopathological examination identified the mass as an atypical proliferating pilomatrixoma, characterized by a minimal infiltrating margin of the deep plane and focal cytological atypia of the basaloid cells. No recurrence was observed up to one year postoperatively. Conclusions: Pilomatrixoma is a rare periocular tumor with potential for malignant transformation, often mimicking other lesions in this region. Therefore, any enlarging masses in this area should be excised for histopathological evaluation to rule out malignancy. [ABSTRACT FROM AUTHOR]

A common problem in confocal microscopy is the decrease in intensity of excitation light and emission signal from fluorophores as they travel through 3D specimens, resulting in decreased signal detected as a function of depth. Here, we report a visualization program compatible with widely used fluorophores in cell biology to facilitate image interpretation of differential protein disposition in 3D specimens. Glioblastoma cell clusters were fluorescently labeled for mitochondrial complex I (COXI), P2X7 receptor (P2X7R), β-Actin, Ki-67, and DAPI. Each cell cluster was imaged using a laser scanning confocal microscope. We observed up to ~70% loss in fluorescence signal across the depth in Z-stacks. This progressive underrepresentation of fluorescence intensity as the focal plane deepens hinders an accurate representation of signal location within a 3D structure. To address these challenges, we developed ProDiVis: a program that adjusts apparent fluorescent signals by normalizing one fluorescent signal to a reference signal at each focal plane. ProDiVis serves as a free and accessible, unbiased visualization tool to use in conjunction with fluorescence microscopy images and imaging software. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs) are an emerging class of materials, leveraging maximum atom utilization and distinctive structural and electronic properties to bridge heterogeneous and homogeneous catalysis. Direct imaging methods, such as aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy, are commonly applied to confirm the atomic dispersion of active sites. However, interpretations of data from these techniques can be challenging due to simultaneous contributions to intensity from impurities introduced during synthesis processes, as well as any variation in position relative to the focal plane of the electron beam. To address this matter, this paper presents a comprehensive study on two representative SACs containing isolated nickel or copper atoms. Spectroscopic techniques, including X‐ray absorption spectroscopy, were employed to prove the high metal dispersion of the catalytic atoms. Employing scanning transmission electron microscopy imaging combined with single‐atom‐sensitive electron energy loss spectroscopy, we scrutinized thin specimens of the catalysts to provide an unambiguous chemical identification of the observed single‐atom species and thereby distinguish impurities from active sites at the single‐atom level. Overall, the study underscores the complexity of SACs characterization and establishes the importance of the use of spectroscopy in tandem with imaging at atomic resolution to fully and reliably characterize single‐atom catalysts. [ABSTRACT FROM AUTHOR]

Infrared polarization detection has attracted wide applications in military and civilian fields by demonstrating more accurate target detection and identification capabilities due to more dimensional target information. A multifocal metalens for simultaneous detection of the polarization state of incident light at dual wavelengths is proposed based on the independent control of orthogonally polarized light. When light is incident at different wavelengths, the metalens array splits and focuses the light on three different polarization bases to form six focal points with various positions. When the incident light with varying states of polarization of dual wavelengths to be detected passes through the substrate and reaches the metalens array, the incident light detected in each wavelength forms six focal points at different positions of the focal plane of the metalens. The Stokes parameters are calculated based on the intensities of the six polarization components in the same focal plane to determine the polarization data of the azimuthal and elliptic angles of the incident light detected in each wavelength. In addition, the theoretical Stokes parameters of incident light with different polarization states at two wavelengths are compared with the reconstructed Stokes parameters, proving our method's validity. The device can directly examine the polarization state of the incident light in mid-wave infrared and long-wave infrared, significantly simplifying the polarization detection system. [ABSTRACT FROM AUTHOR]

Underwater target information is submerged in background scattered light due to the scattering effect of suspended particles in turbid water. In order to improve the quality of target imaging in turbid water, this paper proposes a method for achieving clear underwater target imaging using the second Lorentz depolarization index based on a dual division of focal plane Mueller matrix imaging system. This method can directly quantify the attenuation of light in water, and then solve a clear image of the target. Experimental results on underwater targets of different materials (plastic, paper, metal) show that the method proposed can effectively remove background scattering light while enhancing image contrast, ultimately improving the imaging quality of targets in turbid water. [ABSTRACT FROM AUTHOR]

Skyrmions, topologically stable quasiparticles with complex vector textures, have been extensively studied across various fields. Their presence in optics has only recently been observed. Optical skyrmions can be generated using various 3D vector fields, including electric fields, spin angular momentum, and Stokes vectors. In this study, a method is proposed for creating customized arrangements of tightly focused optical Stokes skyrmions on the focal plane. Both simulations and experiments confirm that distinct focused fields can be achieved by adjusting the phase of the incident vector beam, resulting in formations of arbitrary arrays of Stokes skyrmions. These tailored fields, characterized by multiple Stokes skyrmions and their topological stability, offer promising potential for applications in information processing, transfer, and storage. [ABSTRACT FROM AUTHOR]

The White Blood Cell (WBC) differential test ranks as the second most frequently performed diagnostic assay. It requires manual confirmation of the peripheral blood smear by experts to identify signs of abnormalities. Automated digital microscopy has emerged as a solution to reduce this labor-intensive process and improve efficiency. Several publicly available datasets provide various WBC subtypes of differing quality and resolution. These datasets have contributed to advancing WBC classification using machine learning techniques. However, digital microscopy of blood cells with high magnification often requires a wider depth of field, posing challenges for automatic digital microscopy that necessitates capturing multiple stacks of focal planes to obtain complete images of specific blood cells. Our dataset provides 25,773 image stacks from 72 patients. The image labels consist of 18 classes encompassing normal and abnormal cells, with two experts reviewing each label. Each image includes 10 z-stacks of cropped 200 by 200 pixel images, captured using a 50X microscope with 400 nm intervals. This study presents a comprehensive multi-focus dataset for WBC classification. [ABSTRACT FROM AUTHOR]

A magnetic proton recoil (MPR) neutron spectrometer is being designed for SPARC, a high magnetic field (BT = 12 T), compact (R0 = 1.85 m, a = 0.57 m) tokamak currently under construction in Devens, MA, USA. MPR neutron spectrometers are versatile tools for making high fidelity ab initio calibrated measurements of fusion neutron flux spectra and have been used to infer fusion power, ion temperature, fuel ion ratio, and suprathermal fuel populations at several high performance fusion experiments. The performance of an MPR neutron spectrometer is in large part determined by the design of the magnetic field, which disperses and focuses recoil protons. This article details the ion optical design of a high-resolution MPR neutron spectrometer, including the amelioration of image aberrations due to nonlinear effects. An optimized design is presented that achieves ion optical energy resolution δE/E < 1% and focal plane properties that enable straightforward integration with the hodoscope detector array. [ABSTRACT FROM AUTHOR]

We propose a workflow for the recognition of the hierarchical segmentation of faults through earthquake hypocenter clustering without prior information. Our approach combines density‐based clustering algorithms (DBSCAN and OPTICS), and principal component analysis (PCA). Given a spatial distribution of earthquake hypocenters, DBSCAN identifies first‐order clusters, representing regions with the highest density of connected seismic events. Within each first‐order cluster, OPTICS further identifies nested higher‐order clusters, providing information on their number and size. PCA analysis is applied to first‐ and higher‐order clusters to evaluate eigenvalues, allowing discrimination between seismicity associated with planar features and distributed seismicity that remains uncategorized. The identified planes are then geometrically characterized in terms of their location and orientation in the space, length, and height. This automated procedure operates within two spatial scales: the largest scale corresponds to the longest pattern of approximately equally dense earthquake clouds, while the smallest scale relates to earthquake location errors. By applying PCA analysis, a planar feature outputted from a first‐order cluster can be interpreted as a fault surface while planes outputted after OPTICS can be interpreted as fault segments comprised within the fault surface. The evenness between the orientation of illuminated fault surfaces and fault segments, and that of the nodal planes of earthquake focal mechanisms calculated along the same faults, corroborates this interpretation. Our workflow has been successfully applied to earthquake hypocenter distributions from various seismically active areas (Italy, Taiwan, and California) associated with faults exhibiting diverse kinematics. Plain Language Summary: Active faults are associated with ongoing movement and seismic activity. Recognizing them within large clouds of earthquake hypocenters is at the same time challenging and crucial for seismic hazard estimates. Here, we present a new procedure that can illuminate fault surfaces and its constituting segments by exclusively using hypocenter locations and their spatial density. We apply our approach to hypocenter distributions from various seismically active areas (Italy, Taiwan, and California). The evenness between the orientation of illuminated fault surfaces and fault segments, and that derived from other data sources, corroborates our workflow. This workflow is showed to be an effective tool to derive unbiased fault geometries. It also offers new perspectives for the study of the relationships between seismic activity patterns and fault segment interactions, as well as seismic forecasting. Key Points: We present a workflow to reveal segmented fault surfaces within hypocenter distributions through unsupervised learning algorithmsComparison with earthquake focal mechanisms corroborates the procedureWe derive a hierarchical order of planar fault segments associated with different types of faulting [ABSTRACT FROM AUTHOR]

Infrared hyperspectral instrument is a complex optical instrument. The requirement for the application of the infrared hyperspectral interferometer is fine calibration accuracy. The accuracy of the spectral frequency of the infrared hyperspectral interferometer is a key influencing factor of the radiometric calibration accuracy. In order to meet the quantitative application, the spectral calibration accuracy is generally within 10ppm. For infrared hyperspectral instruments in geostationary orbit, the focal plane has the characteristics of large array and small detector size. When the detector size of an infrared hyperspectral interferometer is in the geostationary orbit whether the detector as a point detector will affect the spectral calibration accuracy. In this paper, we simulate and analyze the influence of the shape of the detector (square and point detector) on the spectral calibration accuracy. This paper first builds an infrared hyperspectral observation and calibration simulation model. The brightness temperature deviation between the calibration spectrum and the input spectrum is close to 0 K, which shows the rationality of building the simulation model. Then, in the process of spectral calibration, two methods, square detectors and point detectors, are adopted, respectively. The spectral calibration of the square detector needs to calculate the line shape function of the instrument according to the detector position. Regarding point detector spectral calibration, this paper proposes a spectral calibration parameter optimization algorithm based on the optimization algorithm, which does not depend on the physical parameters of the instrument, but only uses the observed simulated spectrum and the reference spectrum. The results show that the spectral calibration accuracy of the point detector based on the optimization method can be close to 0ppm, which is consistent with the spectral calibration accuracy of the square detector. [ABSTRACT FROM AUTHOR]

Lensless microscopy provides a wide field of view (FOV) determined by the image sensor size, allowing visualization of large sample areas. Coupled with advanced and even pixel super‐resolution phase retrieval algorithms, it can achieve resolutions up to the sub‐micron level, enabling both large‐FOV and high‐resolution imaging. However, high‐throughput lensless imaging encounters challenges in rapid data acquisition and large‐scale phase retrieval. Furthermore, when examining biological samples over a large FOV, focal plane inconsistencies often emerge among distinct regions. This study introduces a fast acquisition and efficient reconstruction method for coherent lensless imaging. Multiple measurements are manually modulated using an axial translation stage and sequentially captured by an image sensor, requiring no hardware synchronization. Optical parameter calibration, region‐wise auto‐focusing, and region‐wise phase retrieval algorithms are integrated to establish a general parallel computing framework for rapid, efficient, and high‐throughput lensless imaging. Experimental results demonstrate a 7.4 mm × 5.5 mm FOV and 1.38 µm half‐pitch resolution imaging of human skin and lung tumor sections with region‐wise focusing, requiring ≈0.5‐s acquisition time and 17‐s reconstruction time. By incorporating pixel super‐resolution, a 0.98 µm half‐pitch resolution is achieved in full‐FOV peripheral blood smears without additional data required, advantageous for discerning hollow shapes and segmenting blood cells. [ABSTRACT FROM AUTHOR]

The distribution of diffuse spot energy can be used to sensitively evaluate the aberrations and defects of optical systems. Therefore, the objective and quantitative measurement of diffuse spot parameters is an important means to control the detection quality of space debris detection systems. At present, the existing optical system dispersion measurement method can only judge whether the energy distribution meets the index. However, these methods ca not provide an objective quantitative basis to guide the installation process. To solve this problem, a mathematical simulation model of 3D multi-phase sub-pixel PSF distribution is proposed. According to the relation between the CCD target plane and the theoretical image plane (focal plane, defocus, and deflection), the diffuse spot distribution of the optical system is simulated with different phase combinations. Then, Pearson Correlation Coefficient (PCC) is used to evaluate the matching similarity of the diffuse spot image. The simulation results show that when the PCC is greater than 0.96, the distribution of the two diffuse spots can be identified as matching. This also confirms the accuracy of the proposed PSF model. Then, the focusing deviation of the system being tested can be analyzed according to the phase size of the diffuse spot simulation image. This method can quickly and accurately guide the focal surface installation and testing of the system. Therefore, the purpose of improving the detection accuracy of space debris is achieved. It also provides a quantitative basis for the engineering application of optical detection systems in the future. [ABSTRACT FROM AUTHOR]

The application of CdZnTe(CZT) crystals in infrared focal plane detectors and x-ray imaging detectors is hindered by the low infrared transmittance (IRT) and the presence of Cd/Te inclusions/precipitation. Over the preceding decades, strategies involving Cd vapor control during the growth process and substrate post-annealing have been posited to address these challenges. Presently, the prioritized approach is the utilization of substrate post-annealing, owing to the limited precision in comprehending the Cd-Te equilibrium and the intricacies associated with Cd vapor control technology. This study delves into the effect of the removed surface layer depth of a CZT and the selection of the (111) A-face or (111) B-face on IRT during Cd atmosphere annealing. It is recommended that a minimum of 60 μm of the surface layer be eliminated using chemical mechanical polishing technology before annealing. Experimental findings further reveal that Cd atom diffusion from the (111) A-face results in an IRT enhancement of up to 60%, in stark contrast to the slight improvement observed with the (111) B-face after annealing. The mechanism of Cd atom diffusions affecting the IRT in the annealing process is discussed. [ABSTRACT FROM AUTHOR]

Quantum‐confined CsPbI3 perovskite nanoplatelets (NPLs) are highly desirable for optoelectronic applications owing to their anisotropic electronic properties that substantially boost the light outcoupling efficiency in light‐emitting diodes (LEDs). However, the structural instability of the emissive CsPbI3 phases makes it degrade rapidly to the non‐emissive δ‐phase under ambient conditions. Here, the study presents a synthetic approach to produce spectrally stable CsPbI3 nanoplatelets (NPLs) through solid‐phase crude reactions with metal iodide powders, MI2 (M2+ = Mn2+ or Zn2+). The synthesized NPLs exhibit narrow and color‐pure red emission with high photoluminescence (PL) quantum yields (QYs, ηPL) of up to 85%. Systematic investigations into the surface chemistry of NPLs reveal that metal iodide treatment stabilizes anisotropic CsPbI3 NPLs via surface passivation with metal and halide ions, substantially hindering from the formation of non‐emissive yellow phase. The anisotropic NPLs display signatures of spontaneous self‐assembly in spin‐casted films, which yield strong emission anisotropy, with up to 82% of the transition dipoles being horizontally oriented with respect to the substrate, as revealed by the back focal plane (BFP) imaging. The results presented here shed light on solid‐phase approaches for the preparation of quantum‐confined nanocrystals (NCs) with desirable geometry, which boost the light outcoupling efficiency in LEDs. [ABSTRACT FROM AUTHOR]

Macroautophagy is often quantified by live imaging of autophagosomes labeled with fluorescently tagged ATG8 protein (FP–ATG8) in Arabidopsis thaliana. The labeled particles are then counted in single focal planes. This approach may lead to inaccurate results as the actual 3D distribution of autophagosomes is not taken into account and appropriate sampling in the Z -direction is not performed. To overcome this issue, we developed a workflow consisting of immunolabeling of autophagosomes with an anti-ATG8 antibody followed by stereological image analysis using the optical disector and the Cavalieri principle. Our protocol specifically recognized autophagosomes in epidermal cells of Arabidopsis root. Since the anti-ATG8 antibody recognizes multiple At ATG8 isoforms, we were able to detect a higher number of immunolabeled autophagosomes than with the FP– At ATG8e marker, that most probably does not recognize all autophagosomes in a cell. The number of autophagosomes per tissue volume positively correlated with the intensity of autophagy induction. Compared with the quantification of autophagosomes in maximum intensity projections, stereological methods were able to detect the autophagosomes present in a given volume with higher accuracy. Our novel workflow provides a powerful toolkit for unbiased and reproducible quantification of autophagosomes and offers a convenient alternative to the standard of live imaging with FP–ATG8 markers. [ABSTRACT FROM AUTHOR]

Spectroscopic multiplex bioassay allows the rapid and simultaneous detection of various biomarkers in biomedical applications. The high cost and bulky configuration of conventional spectrometers hinder the decentralization of biomedical instruments for point‐of‐care diagnostics. Here a flat‐field lens grating‐based microspectrometer (FLG‐µSPEC) is reported for continuous detection of multi‐target nucleic acid amplification. FLG‐µSPEC features the vertical integration of microslit, integrated flat‐field lens and transmission grating (FLG), concave mirror, and CMOS line sensor. FLG effectively corrects the field curvature by flattening the focal plane of dispersed wavelengths and also facilitates compact module packaging. FLG‐µSPEC module is precisely assembled into a dimension of 10 mm × 16 mm × 10 mm. The average spectral resolution exhibits 3.4 ± 0.9 nm over an operating range of 500 to 950 nm. A spectral detection system utilizing FLG‐µSPEC demonstrates the amplification of lambda DNA (휆‐DNA) for each target, exhibiting a high correlation with the obtained result from a conventional real‐time PCR (qPCR) machine. Furthermore, multiplex qPCR analysis using FLG‐µSPEC and spectral deconvolution successfully demonstrates simultaneous and accurate quantification of three different targets. The FLG‐µSPEC module offers diverse on‐demand analytical applications, including not only multiplex bioassay but also environmental monitoring. [ABSTRACT FROM AUTHOR]

Steganography technology which conceals a message in a carrier to make it invisible is critical for information security. Conventional optical image steganography using diffractive optical components or spatial light modulators suffers from less encoding channel and bulky volume. The emergence of multifunctional metasurface that can manipulate abundant physical dimensions of optical fields allows the multi‐channel image steganography in a compact volume. Here, the image hiding in a metasurface is demonstrated by modulating the amplitude, phase, and polarization states of terahertz (THz) waves completely. Especially, the phase channel can decouple from the amplitude channel based on a Fresnel‐diffraction‐based algorithm. By directly measuring the phase distribution using the homemade THz focal plane imaging system, the number of transmission channels can expand from N to 2N. As a proof of concept, it is shown that the secret images can encode in the phase channel and subsequently extract by using different keys, such as polarization states, detection distances, and its combinations. Moreover, different hiding strategies with different attacker behaviors are also demonstrated. The decoupling of the phase and amplitude channels with a single metasurface may open an avenue toward innovative optoelectronic devices for optical image steganography, data storage, and terahertz communication. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Can the density of the inner cell mass (ICM) be a new indicator of the quality of the human blastocyst? SUMMARY ANSWER The densification index (DI) developed in this study can quantify ICM density and provide positive guidance for ploidy, pregnancy, and live birth. WHAT IS KNOWN ALREADY In evaluating the quality of ICM, reproductive care clinics still use size indicators without further evaluation. The main disadvantage of this current method is that the evaluation of blastocyst ICM is relatively rough and cannot meet the needs of clinical embryologists, especially when multiple blastocysts have the same ICM score, which makes them difficult to evaluate further. STUDY DESIGN, SIZE, DURATION This observational study included data from 2272 blastocysts in 1991 frozen–thawed embryo transfer (FET) cycles between January 2018 to November 2021 and 1105 blastocysts in 430 preimplantation genetic testing cycles between January 2019 and February 2023. PARTICIPANTS/MATERIALS, SETTING, METHODS FET, ICSI, blastocyst culture, trophectoderm biopsy, time-lapse (TL) monitoring, and next-generation sequencing were performed. After preliminary sample size selection, the 11 focal plane images captured by the TL system were normalized and the spatial frequency was used to construct the DI of the ICM. MAIN RESULTS AND THE ROLE OF CHANCE This study successfully constructed a quantitative indicator DI that can reflect the degree of ICM density in terms of fusion and texture features. The higher the DI value, the better the density of the blastocyst ICM, and the higher the chances that the blastocyst was euploid (P  < 0.001) and that pregnancy (P  < 0.001) and live birth (P  = 0.005) were reached. In blastocysts with ICM graded B and blastocysts graded 4BB, DI was also positively associated with ploidy, pregnancy, and live birth (P  < 0.05). ROC analysis showed that combining the Gardner scoring system with DI can more effectively predict pregnancy and live births, when compared to using the Gardner scoring system alone. LIMITATIONS, REASONS FOR CAUTION Accurate calculation of the DI value places high demands on image quality, requiring manual selection of the clearest focal plane and exposure control. Images with the ICM not completely within the field of view cannot be used. The association between the density of ICM and chromosomal mosaicism was not evaluated. The associations between the density of ICM and different assisted reproductive technologies and different culture conditions in embryo laboratories were also not evaluated. Prospective studies are needed to further investigate the impact of ICM density on clinical outcomes. WIDER IMPLICATIONS OF THE FINDINGS ICM density assessment is a new direction in blastocyst assessment. This study explores new ways of assessing blastocyst ICM density and develops quantitative indicators and a corresponding qualitative evaluation scheme for ICM density. The DI of the blastocyst ICM developed in this study is easy to calculate and requires only TL equipment and image processing, providing positive guidance for clinical outcomes. The qualitative evaluation scheme of ICM density can assist embryologists without TL equipment to manually evaluate ICM density. ICM density is a simple indicator that can be used in practice and is a good complement to the blastocyst scoring systems currently used in most centers. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the National Key Research & Development Program of China (2021YFC2700603). The authors report no financial or commercial conflicts of interest. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

• Combining multistage thermoelectric cooler with infrared detectors for analysis. • Finite rate heat transfer irreversibility is considered and a finite time thermodynamic model of a heat-pipe-type four-stage thermoelectric cooler is developed. • New evaluation indexes are proposed: module utilization coefficient and coordination performance coefficient. • Heat pipe is used to enhance heat transfer and improve the performance of the thermoelectric cooler. • Large temperature difference cooling to meet the requirements of detectors is achieved. A cooler provides a low-temperature working environment for refrigerated infrared detection chips and is an indispensable component in infrared detectors that ensures their smooth operation. In this paper, a thermodynamic model of a heat-pipe-type four-stage thermoelectric cooler with a large temperature difference applied to a focal plane infrared detector is constructed. The heat leakage of the detector is calculated using the model. The performance indexes of the coordination performance coefficient and module utilization coefficient are used to unify the cooling capacity and economic performance of the device. The impression of the working current, heat pipe parameters, and cross-sectional area of the thermoelectric leg on the performance of cooler are analyzed. A Pareto optimal solution is obtained using an NSGA-II algorithm and TOPSIS decision. A low cooling temperature is obtained using a multistage thermoelectric cooler to achieve a large cooling temperature difference. When the working current is 5.65 A and the cross-sectional area is 4.5 mm2, the maximum cooling temperature difference reaches 110.6 °C, and the lowest cooling temperature reaches -83.6 °C. When the working temperature of the detector is -60 °C, the current and cross-sectional area corresponding to the optimal solution of cooling capacity-COP-power consumption are 1.51 A and 2.74 mm2, respectively. [ABSTRACT FROM AUTHOR]

Keyhole laser-based processes have been adopted widely due to the high-quality welds and cuts that they produce and the accurately controlled dimensions of the end part. Fast-running simulation tools are required in order to estimate the dependence of process outputs, efficiency, and stability on the process variables. This work presents a fast-running simulation tool for keyhole laser-based processes with inert or no assisting gas that takes into account the effect of laser beam defocusing and the alteration of the effective reflectivity of the material due to the keyhole cavity. The model is built upgrading a successful model for the thermal phenomena based on finite differences and the enthalpy method. The presented model is compared to experimental results for the laser cutting process with both CO 2 and fiber laser sources and inert assisting gas. The model accurately predicts cutting depth and kerf, heat-affected zone width, and the dependence of the cutting depth on the position of the focal plane. The model manages to achieve reduced computational time enabling its utilization in process digital twins. [ABSTRACT FROM AUTHOR]

In this paper, a comparative analysis and numerical simulation of operation of two types of amplitude binary gratings (conventional and fork), both in the focal plane and near-field diffraction under illumination by mode beams with different polarization states, were performed. The simulation of the field formation in the focal plane was performed using the Richards–Wolf formalism. The diffraction calculation in the near-field diffraction was performed based on the FDTD method, considering the 3D structure of optical elements. The possibility of multiplying the incident beam in different diffraction orders of binary gratings and the polarization transformation associated with spin–orbit interaction at tight focusing were shown. In this case, various polarization transformations were formed in ±1 diffraction orders of the fork grating due to different signs of the introduced vortex-like phase singularity. The obtained results can be useful for the laser processing of materials and surface structuring. [ABSTRACT FROM AUTHOR]

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We report on a method of measuring the stiffness in photophoretic force tweezers in air by using an experimental configuration with two counter-propagating hollow beams. By setting the optical traps of both beams in the same focal plane of the camera, we are able to record the flight procedure of a trapped particle into the other trap after the initial trapping beam is switched off. Then, the stiffness of optical trap can be obtained by fitting the relationship of particle position vs time during the flight procedure. It is found that the measurement is tolerant to the distance between the traps and laser power variation. In addition, the measured stiffness is demonstrated applicable in determining the size of aerosol particles. The reliable method provided in this work is not only useful in studying the physical behavior of signal particle under atmosphere condition but also meaningful in the applications of aerosol studies, such as in situ aerosol characterization and the local surrounding environment sensing. [ABSTRACT FROM AUTHOR]

Technologies associated with using concentrated energy flows are increasingly used in industry due to the need to manufacture products made of hard alloys and other difficult-to-process materials. This work is devoted to expanding knowledge about the processes accompanying the impact of laser pulses on material surfaces. The features of these processes are reflected in the acoustic emission signals, the parameters of which were used as a tool for understanding the accompanying phenomena. The influence of plasma formations above the material surface on self-oscillatory phenomena and the self-regulation process that affects pulse productivity were examined. The stability of plasma formation over time, its influence on the pulse performance, and changes in the heat flux power density were considered. Experimental data show the change in the power density transmitted by laser pulses to the surface when the focal plane is shifted. Experiments on the impact of laser pulses of different powers and durations on the surface of a hard alloy showed a relationship between the amplitude of acoustic emission and the pulse performance. This work shows the data content of acoustic emission signals and the possibility of expanding the research of concentrated energy flow technologies. [ABSTRACT FROM AUTHOR]

Camera arrays can enhance the signal-to-noise ratio (SNR) between dim targets and backgrounds through multi-view synthesis. This is crucial for the detection of dim targets. To this end, we design and develop an infrared camera array system with a large baseline. The multi-view synthesis of camera arrays relies heavily on the calibration accuracy of relative poses in the sub-cameras. However, the sub-cameras within a camera array lack strict geometric constraints. Therefore, most current calibration methods still consider the camera array as multiple pinhole cameras for calibration. Moreover, when detecting distant targets, the camera array usually needs to adjust the focal length to maintain a larger depth of field (DoF), so that the distant targets are located on the camera's focal plane. This means that the calibration scene should be selected within this DoF range to obtain clear images. Nevertheless, the small parallax between the distant sub-aperture views limits the calibration. To address these issues, we propose a calibration model for camera arrays in distant scenes. In this model, we first extend the parallax by employing dual-array frames (i.e., recording a scene at two spatial locations). Secondly, we investigate the linear constraints between the dual-array frames, to maintain the minimum degrees of freedom of the model. We develop a real-world light field dataset called NUDT-Dual-Array using an infrared camera array to evaluate our method. Experimental results on our self-developed datasets demonstrate the effectiveness of our method. Using the calibrated model, we improve the SNR of distant dim targets, which ultimately enhances the detection and perception of dim targets. [ABSTRACT FROM AUTHOR]

Due to the high carrier mobility and direct bandgap character, indium selenide (InSe) exhibits great advantages for advanced optoelectronic applications. However, the unique optical section rule in InSe weakens the light‐matter interaction when the electric field of illuminated light is perpendicular to the c‐axis of planar InSe flake. To overcome this constraint, ultramicrotome technique is introduced to achieve vertically aligned InSe ribbons, aiming to reconfigure the optical paths for improved optical absorption and device performance. The well‐designed InSe ribbons are acquired with uniform morphology, showing an integrated structure free of cracks or fragments. First, the structural symmetry, crystal orientation, and optical anisotropy of InSe ribbon are carefully revealed by polarization‐dependent Raman spectrum, second harmonic generation (SHG), and photoluminescence measurements. Then, the back focal plane (BFP) imaging of photoluminescence distinguishes the in‐plane and out‐of‐plane dipole emission of InSe ribbons and planar InSe flakes, respectively. Notably, the ribbon exhibits new PL peaks with energy lower than the exciton peak of InSe at low temperature, which is attributed to Se vacancies. The work by introducing vertically aligned InSe nanoribbons provides a new strategy to manipulate the light‐matter interactions and defect engineering for novel optoelectronics, which can be also extended to other 2D semiconductors. [ABSTRACT FROM AUTHOR]

Nonlinear optical methods based on second harmonic generation have been widely used to observe ferroelectric domain structures. However, most previous methods have some flaws, such as limitations in structure patterns and time-consuming scanning processes. We have developed a technique called nonlinear spiral interferometry to observe domain walls, which avoids these problems. By placing a spiral phase plate on the rear focal plane of the imaging system, the intensity of the second harmonic wave can be concentrated at 180° domain walls, while regions with homogeneous polarization appear as a dark field. This phenomenon originates from the interference of point spread functions with spiral phase, and the principle is applicable to samples with any polarized pattern. Using this method, disturbing miscellaneous peaks can be suppressed, and imaging contrast is improved due to the redistribution of energy. This technique is verified through theoretical calculations and experiments, providing an effective and convenient way to observe domain structures. [ABSTRACT FROM AUTHOR]

We observe concurrent precessional and partial orbital motion of highly birefringent liquid crystal (LC) particles trapped in a spherically aberrated optical trap, which is built employing a tilted refractive index stratified medium. For input circularly polarized light, the breaking of azimuthal symmetry induced by the tilt leads to an asymmetric intensity distribution in the radial direction near the trap focal plane, which—in combination with the spin–orbit conversion effects for input circularly polarized light—results in nonuniform canonical and spin momentum densities in those regions. In addition, while the canonical momentum remains always oriented toward the axial direction, the spin momentum reverses direction along spatial loops in the radial direction. As a consequence, the total momentum precesses around the canonical momentum vector along elliptical spatial loops—akin to a Larmor-like precession of magnetic moment (total momentum in our case) around a magnetic field (canonical momentum). We probe this precession experimentally using the single trapped LC particles—with the direction of precession and orbital motion determined by the helicity of the input light, with the precession frequency varying linearly with the laser power. Our experimental results are validated by numerical simulations of the system where we employ the Debye–Wolf theory for tight focusing in the presence of a tilted stratified media. [ABSTRACT FROM AUTHOR]

The utilization of digital statistical processes in images and videos can effectively tackle numerous challenges encountered in optical sensors. This research endeavors to overcome the limitations inherent in traditional focus models, particularly their inadequate accuracy. It aims to bolster the precision of real-time perception and dynamic control by employing enhanced data fusion methodologies. The ultimate objective is to facilitate information services that enable seamless interaction and profound integration between computational and physical processes within an open environment. To achieve this, an enhanced sum-modulus difference (SMD) evaluation function has been proposed. This innovation is founded on the concept of threshold value evaluation, aimed at rectifying the accuracy shortcomings of traditional focusing models. Through the computation of each gray value after threshold segmentation, the method identifies the most suitable threshold for image segmentation. This identified threshold is then applied to the focus search strategy employing the radial basis function (RBF) algorithm. Furthermore, an intelligent focusing system has been developed on the Zynq development platform, encompassing both hardware design and software program development. The test results affirm that the focusing model based on the improved SMD evaluation function rapidly identifies the peak point of the gray variance curve, ascertains the optimal focal plane position, and notably enhances the sensitivity of the focusing model. [ABSTRACT FROM AUTHOR]

The next-generation magnetic recoil spectrometer (MRSnext) is being designed to replace the current MRS at the National Ignition Facility and OMEGA for measurements of the neutron spectrum from an inertial confinement fusion implosion. The MRSnext will provide a far-superior performance and faster data turnaround than the current MRS systems, i.e., a 2× and 6× improvement in energy resolution at the NIF and OMEGA, respectively, and 20× improvement in data turnaround time. The substantially improved performance of the MRSnext is enabled by using electromagnets that provide a short focal plane (12–16 cm) and unprecedented flexibility for a wide range of applications. In addition to being able to measure neutron yield, apparent ion temperature, areal density, and plasma-flow velocity over a wide range of yields, the NIF MRSnext will be able to directly, uniquely assess the alpha heating of the fuel ions through measurements of the alpha knock-on tail in the neutron spectrum. The goal is to implement a radiation-hard electronic detection system capable of providing rapid data acquisition and analysis. The development of the MRSnext will also set the foundation for the more advanced, time-resolving MRSt and serve as a testbed for its implementation on the NIF. [ABSTRACT FROM AUTHOR]

The mission of the JT-60SA project is to complement ITER's capabilities by addressing the fundamental physics and engineering challenges necessary to develop a practical and reliable fusion power plant. Diagnostics play a pivotal role in achieving this mission, especially the Thomson Scattering (TS) diagnostic systems developed by a collaborative Japan–EU team. The edge Thomson scattering of JT-60SA is tailored to measure the low field side outer region of the plasma, in particular, to resolve the electron temperature Te and density ne. The collection optics of the edge TS system have a critical role in meeting the required field of view and spatial resolution despite the limited space. This work presents a comprehensive optomechanical design of the optics assembly, whose main features are telecentricity and compactness, highlighting its capabilities. The tests undertaken to verify its performance: focal plane identification, thermal cycle, and magnification, are described. [ABSTRACT FROM AUTHOR]

Optical real-time data processing is advancing fields like tensor algebra acceleration, cryptography, and digital holography. This technology offers advantages such as reduced complexity through optical fast Fourier transform and passive dot-product multiplication. In this study, the proposed Reconfigurable Complex Convolution Module (RCCM) is capable of independently modulating both phase and amplitude over two million pixels. This research is relevant for applications in optical computing, hardware acceleration, encryption, and machine learning, where precise signal modulation is crucial. We demonstrate simultaneous amplitude and phase modulation of an optical two-dimensional signal in a thin lens's Fourier plane. Utilizing two spatial light modulators (SLMs) in a Michelson interferometer placed in the focal plane of two Fourier lenses, our system enables full modulation in a 4F system's Fourier domain. This setup addresses challenges like SLMs' non-linear inter-pixel crosstalk and variable modulation efficiency. The integration of these technologies in the RCCM contributes to the advancement of optical computing and related fields. [ABSTRACT FROM AUTHOR]

Nanophotonic structures have shown promising routes to controlling and enhancing nonlinear optical processes at the nanoscale. However, most nonlinear nanostructures require a handling substrate, reducing their application scope. Due to the underwhelming heat dissipation, it has been a challenge to evaluate the nonlinear optical properties of free-standing nanostructures. Here, we overcome this challenge by performing shot-controlled fifth harmonic generation (FHG) measurements on a SiC meta-membrane – a free-standing transmission metasurface with pronounced optical resonances in the mid-infrared (λres ≈ 4,000 nm). Back focal plane imaging of the FHG diffraction orders and rigorous finite-difference time-domain simulations reveal at least two orders of magnitude enhancement of the FHG from the meta-membrane, compared to the unstructured SiC film of the same thickness. Single-shot measurements of the meta-membrane with varying resonance positions reveal an unusual spectral behavior that we explain with Kerr-driven intensity-dependent resonance dynamics. This work paves the way for novel substrate-less nanophotonic architectures. [ABSTRACT FROM AUTHOR]

Xinjiang Qitai is constructing a 110-m fully steerable radio telescope (QiTai radio Telescope [QTT]) equipped with a phased array feeds (PAF) receiver, which will install the focal plane operating from 0.7 to 1.8 GHz. In this article, we introduce a PAF receiver model for beamforming, and the numerical model of the internal and external noise for this PAF receiver is provided using electromagnetic field simulation software. The linear constraint minimum variance (LCMV) algorithm is used to simulate the interference mitigation. The interference mitigation rate is from 0.581 to 0.921, and the signal restoration rate is from 0.998 to 1.512 within the error range of an interference arrival angle of 10°. This conclusion can be used in the signal correction of the PAF receiver for interference mitigation. [ABSTRACT FROM AUTHOR]

Wide-angle metalenses in the longwave infrared have shown great advantages over the traditional refractive doublets or triplets, due to light weight, CMOS compatibility, and low cost. However, previous endeavors have been plagued by challenges including a narrow waveband, large F-number, distortion, and spherical aberration. To address these problems, this study introduces two dispersive metasurfaces, placed near the front focal plane and upon the rear plane of a plano-convex lens, to correct optical aberrations. Utilizing this methodology, we propose and experimentally demonstrate an aberration-corrected hybrid metalens for thermal imaging in the 8–12 μm waveband, featuring an FOV of 24°, F-number of 1.2, and diameter of 12.2 mm. The developed hybrid metalens rigorously evaluated, exhibits Modulation Transfer Function (MTF) values exceeding 0.2 at 20 Lp/mm across the full FOV, and features an average transmission of 48.7 %, a relative focusing efficiencies of up to 42.1 %, polarization insensitivity and broadband imaging capacity. These results emphasize the potential applications of our system in diverse fields, such as camera lenses, autonomous driving, healthcare, and environmental monitoring. [ABSTRACT FROM AUTHOR]

Context. The spatial coherence wavefront outer scale (ℒ0) characterizes the size of the largest turbulence eddies in Earth's atmosphere, determining low spatial frequency perturbations in the wavefront of the light captured by ground-based telescopes. Advances in adaptive optics (AO) techniques designed to compensate for atmospheric turbulence emphasize the crucial role of this parameter for the next generation of large telescopes. Aims. The motivation of this work is to introduce a novel technique for estimating ℒ0 from seeing-limited integral field spectroscopic (IFS) data. This approach is based on the impact of a finite ℒ0 on the light collected by the pupil entrance of a ground-based telescope. Methods. We take advantage of the homogeneity of IFS observations to generate band filter images spanning a wide wavelength range, enabling the assessment of image quality (IQ) at the telescope's focal plane. Comparing the measured wavelength-dependent IQ variation with predictions derived from a first-order analytical approach based on turbulence statistics simplifications using the von Kármán model provides valuable insights into the prevailing ℒ0 parameter during the observations. We applied the proposed technique to observations from the Multi-Unit Spectroscopic Explorer (MUSE) in the wide-field mode obtained at the Paranal Observatory. Results. Our analysis successfully validates the first-order analytical expression, which combines the seeing (ε0) and the ℒ0 parameters, to predict the IQ variations with the wavelength in ground-based astronomical data. However, we observed some discrepancies between the measured and predictions of the IQ that are analyzed in terms of uncertainties in the estimated ε0 and dome-induced turbulence contributions. Conclusions. This work constitutes the empirical validation of the analytical expression for estimating IQ at the focal plane of ground-based telescopes under specific ε0 and finite ℒ0 conditions. Additionally, we provide a simple methodology to characterize the ℒ0 and dome-seeing (εdome) as by-products of IFS observations routinely conducted at major ground-based astronomical observatories. [ABSTRACT FROM AUTHOR]

Fourier ptychographic microscopy (FPM) is a computational imaging technology that can acquire high-resolution large-area images for applications ranging from biology to microelectronics. In this study, we utilize multifocal plane imaging to enhance the existing FPM technology. Using an RGB light emitting diode (LED) array to illuminate the sample, raw images are captured using a color camera. Then, exploiting the basic optical principle of wavelength-dependent focal length variation, three focal plane images are extracted from the raw image through simple R, G, and B channel separation. Herein, a single aspherical lens with a numerical aperture (NA) of 0.15 was used as the objective lens, and the illumination NA used for FPM image reconstruction was 0.08. Therefore, simultaneous multifocal plane FPM with a synthetic NA of 0.23 was achieved. The multifocal imaging performance of the enhanced FPM system was then evaluated by inspecting a transparent organic light-emitting diode (OLED) sample. The FPM system was able to simultaneously inspect the individual OLED pixels as well as the surface of the encapsulating glass substrate by separating R, G, and B channel images from the raw image, which was taken in one shot. [ABSTRACT FROM AUTHOR]

The bioinspired camera, comprising a single lens and a curved image sensor—a photodiode array on a curved surface—, was born of flexible electronics. Its economical build lends itself well to space-constrained machine vision applications. The curved sensor, much akin to the retina, helps image focusing, but the curvature also creates a problem of image distortion, which can undermine machine vision tasks such as object recognition. Here we report an anti-distortion single-lens camera, where 4096 silicon photodiodes arrayed on a curved surface in a nonuniform pattern assimilated to the distorting optics are the key to anti-distortion engineering. That is, the photo-pixel distribution pattern itself is warped in the same manner as images are warped, which correctively reverses distortion. Acquired images feature no appreciable distortion across a 120° horizontal view, as confirmed by their neural-network recognition accuracies. This distortion correction via photo-pixel array reconfiguration is a form of in-sensor computing. Curvature of image sensors that match the focal plane of the lens facilitate focussing but can cause image distortion. Here, an anti-distortion single-lens camera was developed using a curved image sensor with a photo-pixel distribution pattern warped like image warping to correctively reverse distortion. [ABSTRACT FROM AUTHOR]

It is shown in this work that, with strong focusing of a beam with optical vortex and circular polarization, three energy flows take place in the focal plane: direct longitudinal, reverse longitudinal and azimuthal transverse flows. Calculations are made analytically using the Richards–Wolf formalism and by numerical simulation. Moreover, the energy rotation at different lengths from the optical axis occurs in different directions. Therefore, the focal plane intersects along the optical axis only part of the initial beam energy per unit time. The same energy part (other things being equal) intersects the focal plane along the positive direction of the optical axis when an optical vortex with cylindrical polarization is focused. The difference is that, if an optical vortex is present, then the transverse energy flux at the focus rotates around the optical axis. If an optical vortex is not present (a beam with only cylindrical polarization), then the average transverse flow in the focal plane is zero, though, in some regions in the focal plane, the flow is directed towards the optical axis and, in other regions, away from it. This behavior of the transverse energy flow at the focus (flow direction towards the optical axis and away from the optical axis) of a cylindrical vector beam can be deemed another kind of Hall effect. [ABSTRACT FROM AUTHOR]

We report on the effects of cosmic ray interactions with the kinetic inductance detector (KID)-based focal plane array for the terahertz intensity mapper (TIM). TIM is a NASA-funded balloon-borne experiment designed to probe the peak of the star formation in the Universe. It employs two spectroscopic bands, each equipped with a focal plane of four ∼ 900-pixel, KID-based array chips. Measurements of an 864-pixel TIM array show 791 resonators in a 0.5 GHz bandwidth. We discuss challenges with resonator calibration caused by this high multiplexing density. We robustly identify the physical positions of 788 (99.6 %) detectors using a custom LED-based identification scheme. Using this information, we show that cosmic ray events occur at a rate of 2.1 events / min / cm 2 in our array. 66 % of the events affect a single pixel, and other 33 % affect < 5 KIDs per event spread over a 0.66 cm 2 region (2 pixel pitches in radius). We observe a total cosmic ray dead fraction of 0.0011 % and predict that the maximum possible in-flight dead fraction is ∼ 0.124 %, which demonstrates our design will be robust against these high-energy events. [ABSTRACT FROM AUTHOR]