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We investigated how long-term visual experience with habitual spherical aberration (SA) influences subjective depth of focus (DoF). Nine healthy cycloplegic eyes with habitual SAs of different signs and magnitudes were enrolled. An adaptive optics (AO) visual simulator was used to measure through-focus high-contrast visual acuity after correcting all monochromatic aberrations and imposing + 0.5 μm and − 0.5 μm SAs for a 6-mm pupil. The positive (n = 6) and negative (n = 3) habitual SA groups ranged from 0.17 to 0.8 μm and from − 1.2 to – 0.12 μm for a 6-mm pupil, respectively. Although all optical conditions were identical, and the subjective DoFs were expected to be the same for all participants, the DoFs of individuals differed between the positive and negative habitual SA groups. For the positive habitual SA group, the mean DoF with positive AO-induced SA (2.14 D) was larger than that with negative AO-induced SA (1.88 D); for the negative habitual SA group, a smaller DoF was measured with positive AO-induced SA (1.94 D) than that with negative AO-induced SA (2.14 D). Subjective DoF tended to be larger when the induced SA in terms of sign and magnitude was closer to the participant's habitual SA. Our findings suggest that neural adaptation to habitual SA compensated for optical blur at multiple object distances, perceptually expanding DoF. As a result, the outcomes of optical treatments for presbyopia may differ due to the neural compensation mechanism influenced by an individual's visual experience with their habitual optics. [ABSTRACT FROM AUTHOR]

Conic sections are commonly used in reflective X‐ray optics. Hyperbolic mirrors can focus a converging light source and are frequently paired with elliptical or parabolic mirrors in Wolter type configurations. This paper derives the closed‐form expression for a mirror‐centered hyperbolic shape, with zero‐slope at the origin. Combined with the slope and curvature, such an expression facilitates metrology, manufacturing and mirror‐bending calculations. Previous works consider ellipses, parabolas, magnifying hyperbolas or employ lengthy approximations. Here, the exact shape function is given in terms of the mirror incidence angle and the source and image distances. [ABSTRACT FROM AUTHOR]

Hard X‐ray microscopes with 20–30 nm spatial resolution ranges are an advanced tool for the inspection of materials at the nanoscale. However, the limited efficiency of the focusing optics, for example, a Fresnel zone plate (ZP) lens, can significantly reduce the power of a nanoprobe. Despite several reports on ZP lenses that focus hard X‐rays with 20 nm resolution – mainly constructed by zone‐doubling techniques – a systematic investigation into the limiting factors has not been reported. We report the structural effects on the focusing and imaging efficiency of 20–30 nm‐resolution ZPs, employing a modified beam‐propagation method. The zone width and the duty cycle (zone width/ring pitch) were optimized to achieve maximum efficiency, and a comparative analysis of the zone materials was conducted. The optimized zone structures were used in the fabrication of Pt‐hydrogen silsesquioxane (HSQ) ZPs. The highest focusing efficiency of the Pt‐HSQ‐ZP with a resolution of 30 nm was 10% at 7 keV and >5% in the range 6–10 keV, whereas the highest efficiency of the Pt‐HSQ‐ZP with a resolution of 20 nm was realized at 7 keV with an efficiency of 7.6%. Optical characterization conducted at X‐ray beamlines demonstrated significant enhancement of the focusing and imaging efficiency in a broader range of hard X‐rays from 5 keV to 10 keV, demonstrating the potential application in hard X‐ray focusing and imaging. [ABSTRACT FROM AUTHOR]

X‐ray multilayer optics play a vital role in synchrotron optics due to their ability to generate constructive interference. These devices typically consist of several tens to hundreds of periods of alternating layers coated on a substrate. In contrast to single‐layer mirrors that reflect X‐rays within a specific energy range, multilayer optics can be tailored to achieve a high reflection over a broad energy spectrum. This is a sought‐after property for many beamlines and has led to the development of numerous new X‐ray applications and capabilities. This review highlights advances in multilayer optics, including fabrication techniques, layer structure design, material choice, and strategies to enhance performance. This is placed in the context of recent applications of such multilayers as monochromator and gratings, focusing devices, and polarizers. Current challenges and the future outlook within this field are also proposed. This comprehensive summary of a rapidly advancing field highlights recent achievements and is intended to promote practical applications in terms of the use of multilayer synchrotron optics. [ABSTRACT FROM AUTHOR]

Significance: Esophageal cancer is becoming increasingly prevalent in Western countries. Early detection is crucial for effective treatment. Multimodal imaging combining optical coherence tomography (OCT) with complementary optical imaging techniques may provide enhanced diagnostic capabilities by simultaneously assessing tissue morphology and biochemical content. Aim: We aim to develop a tethered capsule endoscope (TCE) that can accommodate a variety of point-scanning techniques in addition to OCT without requiring design iterations on the optical or mechanical design. Approach: We propose a TCE utilizing exclusively reflective optics to focus and steer light from and to a double-clad fiber. Specifically, we use an ellipsoidal mirror to achieve finite conjugation between the fiber tip and the imaging plane. Results: We demonstrate a functional all-reflective TCE. We first detail the design, fabrication, and assembly steps required to obtain such a device. We then characterize its performance and demonstrate combined OCT at 1300 nm and visible spectroscopic imaging in the 500- to 700-nm range. Finally, we discuss the advantages and limitations of the proposed design. Conclusions: An all-reflective TCE is feasible and allows for achromatic highquality imaging. Such a device could be utilized as a platform for testing various combinations of modalities to identify the optimal candidates without requiring design iterations. [ABSTRACT FROM AUTHOR]

Quantum random number generation (QRNG) leveraging intrinsic quantum uncertainty has attracted significant interest in the field of integrated photonic architecture, with applications in quantum cryptography, tests of quantum nonlocality, and beyond. The demand for compact, low-energy consumption, robust, fast, and cost-effective QRNGs integrated into photonic chips is highlighted, whereas most previous works focused on bulk optics. Here, based on the metalens array entangled source, we experimentally realized a miniaturized, high-dimensional quantum random number generator via a meta-device without post-randomness extraction. Specifically, the device has a high-density output with 100 channels per square millimeter. This chip-scale quantum randomness source can obtain random number arrays without post-randomness extraction and enable compact integration for quantum applications needing secure keys or randomness. Our approach demonstrates potential in secure key generation and randomness for quantum applications. [ABSTRACT FROM AUTHOR]

Full‐field transmission X‐ray microscopy has been recently implemented at the hard X‐ray ROCK–SOLEIL quick‐EXAFS beamline, adding micrometre spatial resolution to the second time resolution characterizing the beamline. Benefiting from a beam size versatility due to the beamline focusing optics, full‐field hyperspectral XANES imaging has been successfully used at the Fe K‐edge for monitoring the pressure‐induced spin transition of a 150 µm × 150 µm Fe(o‐phen)2(NCS)2 single crystal and the charge of millimetre‐sized LiFePO4 battery electrodes. Hyperspectral imaging over 2000 eV has been reported for the simultaneous monitoring of Fe and Cu speciation changes during activation of a FeCu bimetallic catalyst along a millimetre‐sized catalyst bed. Strategies of data acquisition and post‐data analysis using Jupyter notebooks and multivariate data analysis are presented, and the gain obtained using full‐field hyperspectral quick‐EXAFS imaging for studies of functional materials under process conditions in comparison with macroscopic information obtained by non‐spatially resolved quick‐EXAFS techniques is discussed. [ABSTRACT FROM AUTHOR]

Physics instructors have faced challenges in providing relevant and interesting content to students in distant courses during the COVID-19 pandemic. To address this, a study used the manual focusing feature of smartphone cameras to demonstrate the relative positions of images in mirror and lens setups. Videos of manual focus practices were recorded and shown to students during distant optics lessons. The videos were found to be effective in helping students understand the concepts of image formation and light ray propagation. The use of smartphones with manual focus features can be a valuable tool for optics labs and can also be utilized by students for extracurricular learning. [Extracted from the article]

In this work, we studied the x‐ray energy dependence of x‐ray beam diameter focused by polycapillary optics. A quantitative beam diameter–energy relation enables more accurate estimation of the element‐specific interrogation area of a sample using the compositional maps produced by a micro‐XRF system. This improves upon our ability to visualize individual beam‐diameter sized mineral grains and in turn directly benefits Planetary Instrument for X‐ray Lithochemistry (PIXL) analyses of martian soil in addition to benefitting other micro‐focused x‐ray fluorescence (XRF) systems. The spatial distribution of an array of characteristic XRF emission lines was measured by sampling via a knife‐edge approach with small motor stepping of the beam across target edges. Data taken as part of this effort, from the Planetary Flight Model (PFM), were limited to only seven beam energies corresponding to the elements Ni, Cu, Se, Ta, Au, Ti and Ba. Hence, we conducted additional analysis using JPL's lab‐based breadboard (LBB) micro‐XRF system, a system that emulates PIXL's functionality where we measured beam diameter corresponding to 18 elements: Na, Mg, Al, Si, Cl, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, Se, Sr and Mo. The experimental results were also compared with Monte Carlo simulations. The beam diameter (y)–energy (x) relation that we obtained for LBB was y = 185.79 exp(−0.078x) whose exponential component was then used to get a more accurate relation for the PFM even with the limited data set: y = 227.53 exp(−0.078x). The difference in the two coefficients for the PFM and LBB stems mainly from the difference in the polycapillary optic design, and this work establishes x‐ray beam diameter versus energy relation quantitatively for both the systems. [ABSTRACT FROM AUTHOR]

A preparatory study is underway to investigate the feasibility study of high-energetic, non-thermal electron distribution function measurements using a vertical-viewing electron cyclotron emission (ECE) diagnostic on JT-60SA. The system is designed to detect broad ECE spectra (70–260 GHz) due to the second, third, and fourth harmonics using a focusing optics system with four quasi-optical mirrors in the upper port of JT-60SA. A Gaussian beam optics design is performed in vacuum, and ray tracing calculations are performed in plasma using the TRAVIS code to investigate density characteristics. A ceramic viewing dump is also designed to reduce the effects of multiple reflections from the opposing vacuum vessel surface. [ABSTRACT FROM AUTHOR]

In the scope of the latest upgrade of the Swiss Light Source, five hard X‐ray beamlines will be constructed or rebuilt. To use synergies between these beamline projects, a concept is developed here for hard X‐ray beamlines that is tailored to the new storage ring. Herein, this concept is described from the source, via the front end, to the beamline optics. The latter will be outlined in detail, including a new and modular concept for hard X‐ray monochromators, focusing optics and heat‐load management. With a simple, easy‐to‐operate and robust beamline design, the new beamlines will greatly profit from the increased brilliance of the new storage ring. The performance increase is up to four orders of magnitude, while the beamline concept allows for the broad application of experimental techniques, from propagation‐based methods, such as phase‐contrast tomography, to imaging techniques with nanometre resolution. At the same time, spectroscopy experiments are possible as well as high‐performance serial X‐ray crystallography. [ABSTRACT FROM AUTHOR]

POLARBEAR-2b (PB-2b) is the second receiver in the Simons Array, a cosmic microwave background (CMB) polarization experiment. The Simons Array uses dichroic polarization sensitive lenslet-coupled sinuous antennas and transition-edge sensor (TES) bolometers made of superconducting films. These bolometers are read out with frequency multiplexing electronics. PB-2b contains ∼ 7500 detectors in two bands at 90 and 150 GHz with arcminute resolution. The polarization of these detectors is modulated by a cryogenic continuously rotating half-wave plate. PB-2b was installed on its telescope in 2022 in the Atacama Desert at an altitude of 5.2 km. This paper will detail initial readout commissioning, test of a new loopgain monitoring method, and focusing the optics. Work is ongoing to commission the remaining ambient temperature readout electronics, measure detector time constants, and observe with the cryogenic half-wave plate spinning [ABSTRACT FROM AUTHOR]

The Lunar Environment heliospheric X-ray Imager (LEXI) is a wide field-of-view soft X-ray telescope developed to study solar wind-magnetosphere coupling. LEXI is part of the Blue Ghost 1 mission comprised of 10 payloads to be deployed on the lunar surface. LEXI monitors the dayside magnetopause position and shape as a function of time by observing soft X-rays (0.1–2 keV) emitted from solar wind charge-exchange between exospheric neutrals and high charge-state solar wind plasma in the dayside magnetosheath. Measurements of the shape and position of the magnetopause are used to test temporal models of meso- and macro-scale magnetic reconnection. To image the boundary, LEXI employs lobster-eye optics to focus X-rays to a microchannel plate detector with a 9.1 × ∘ 9.1 ∘ field of view. [ABSTRACT FROM AUTHOR]

Knife-edge imaging is a successful method for determining the wavefront distortion of focusing optics such as Kirkpatrick-Baez mirrors or compound refractive lenses. In this study, the wavefront error of an imperfect elliptical mirror is predicted by developing a knife-edge program using the SHADOW/OASYS platform. It is shown that the focusing optics can be aligned perfectly by minimizing the parabolic and cubic coefficients of the wavefront error. The residual wavefront error provides precise information about the figure/height errors of the focusing optics suggesting it as an accurate method for in situ optical metrology. A Python program is developed to design a customized wavefront refractive corrector to minimize the residual wavefront error. Uniform beam at and out of focus and higher peak intensity are achieved by the wavefront correction in comparison with ideal focusing. The developed code provides a quick way for wavefront error analysis and corrector design for non-ideal optics especially for the new-generation diffraction-limited sources, and saves considerable experimental time and effort. [ABSTRACT FROM AUTHOR]

Angle-resolved photoemission spectroscopy (ARPES) is a technique used to map the occupied electronic structure of solids. Recent progress in x-ray focusing optics has led to the development of ARPES into a microscopic tool, permitting the electronic structure to be spatially mapped across the surface of a sample. This comes at the expense of a time-consuming scanning process to cover not only a three-dimensional energy-momentum (E, kx, ky) space but also the two-dimensional surface area. Here, we implement a protocol to autonomously search both k- and real-space in order to find positions of particular interest, either because of their high photoemission intensity or because of sharp spectral features. The search is based on the use of Gaussian process regression and can easily be expanded to include additional parameters or optimization criteria. This autonomous experimental control is implemented on the SGM4 micro-focus beamline of the synchrotron radiation source ASTRID2. [ABSTRACT FROM AUTHOR]

A new compact micro‐x‐ray fluorescence (μ‐XRF) spectrometer covering wide range of elements was developed and fabricated. The working capabilities of this new compact custom‐made μ‐XRF spectrometer are presented. The spectrometer uses a low power Rh target x‐ray tube for sample excitation. Polycapillary optics focuses the polychromatic beam down to 40 μm. The emitted radiation is measured by a peltier cooled silicon drift detector of 30 mm2 crystal size. It was observed that the polychromatic excitation provides sufficient photons for an efficient excitation of the sample to achieve good detection limit and area resolution. The detection limits are comparable with that one obtained by TXRF for a thin film sample. The advantage of the present setup, is the fact that it is suitable for specific applications for example, for radioactive and toxic samples requiring instrument adoption in glove boxes or fume hoods because of its good analytical features accompanied by simple and compact instrumentation. [ABSTRACT FROM AUTHOR]

The generation of optical beam arrays with prospective uses within the realms of microscopy, photonics, non-linear optics, and material processing often requires Dammann gratings. Here, we report the direct fabrication of one- and two-dimensional Dammann grating-like structures on soda lime glass using a nanosecond pulsed laser beam with a 1064 nm wavelength. Using the fabricated grating, an axicon lens, and an optical magnification system, we propose a scheme of generation of a diverging array of zero-order Bessel beams with a sub-micron-size central core, extending longitudinally over several hundred microns. Two different grating fabrication strategies are also proposed to control the number of Bessel beams in an array. It was demonstrated that Bessel beams of 12 degrees conical half-angle in an array of up to [5 × 5] dimensions can be generated using a suitable combination of Dammann grating, axicon lens and focusing optics. [ABSTRACT FROM AUTHOR]

Extreme Ultraviolet (EUV) radiation is a short-wavelength light source that has important applications in many fields, such as optical communication, particle manipulation, and ultrahigh resolution imaging. However, the highly absorptive nature of EUV light makes it challenging to design suitable focusing optics, such as focal splitters, to properly manipulate the energetic light. Here, we propose modified spiral photon sieves to transform EUV laser light into azimuthally splitting focusing. A genetic algorithm was used to design and optimize the azimuthally focal splitters. A capillary discharge EUV laser at 46.9 nm was used to verify the effectiveness of our proposed method, and PMMA targets were used to record the focused laser spot. The profile of the recorded patterns measured by atomic force microscopy shows that the focal spots in the experiment are diffraction-limited and agreed with the theoretical analysis. The proposed technique provides a new way for manipulating EUV light and further extends the applications ranging from EUV to soft x rays. [ABSTRACT FROM AUTHOR]

In one and a half years, the Imaging X-ray Polarimetry Explorer has demonstrated the role and the potentiality of Polarimetry in X-ray Astronomy. The next steps include extension to higher energies. There is margin for an extension of the photoelectric approach up to 20–25 keV, but above that energy the only technique is Compton Scattering. Grazing incidence optics can focus photons up to 80 keV, not excluding a marginal extension to 150–200 keV. Given the physical constraints involved, the passage from photoelectric to scattering approach can make less effective the use of optics because of the high background. I discuss the choices in terms of detector design to mitigate the problem and the guidelines for future technological developments. [ABSTRACT FROM AUTHOR]

X-ray fluorescence (XRF) is a successful technique often used for the elemental analysis of cultural heritage artefacts. It is non-invasive, the equipment can be miniaturized and made portable and it allows addressing crucial issues such as the fabrication technology, authenticity and provenance of the artefacts. Depending on the components' selection (e.g., the primary source, the detector and the focusing optics, if present), the analytical performance and the consequent suitability to investigate a given class of materials may vary significantly. The present paper discusses the analytical performance—with special regard to the limits of detection and the quantification uncertainty—of two portable XRF spectrometers developed within a collaboration between INFN-LNF-FISMEL and CNR-ISPC. The devices are expressly designed for heritage materials. In particular, one is equipped with focusing optics and it is intended to analyze small details on glasses and pigmented surfaces, whereas the other has a 70 kV X-ray tube, which greatly improves sensitivity for medium-Z elements, which is important in copper-based artefacts. Finally, this paper discusses two case studies to highlight the features of the instruments: one concerns Etruscan vitreous material beads and the other pre- and proto-historic copper-based artefacts from Tyrrhenian Central Italy. Thanks to the small size of the equipment, both investigations could easily be carried out in situ, namely, at the Museo Nazionale Etrusco in Rome and the Museo della Preistoria della Tuscia e della Rocca Farnese at Valentano. [ABSTRACT FROM AUTHOR]

The sub-nanometer amplitudes of the samples vibrated with high frequencies were measured by 57Fe Mössbauer spectroscopy using a nuclear Bragg monochromator and focusing optics. The Mössbauer spectra of the vibrated single-line absorber showed comb-like absorption peaks, and the amplitudes of the absorbers were determined by the sideband intensities. We used the stainless-steel foil glued on the quartz crystal or the polyvinylidene fluoride (PVDF) film as samples. The mean value and the variance of the amplitude in sub-nanometer order were obtained for the irradiated area of 100 μm diameter in the sample. We could obtain the sub-nanometer amplitude with almost zero variance, using the 57Fe synchrotron Mössbauer source and focusing optics for the PVDF film. The resonant absorber vibrated with high frequency and amplitude without variance is useful for the control of gamma rays. This work will advance X-ray quantum optics and quantum technology applications using a single gamma photon. [ABSTRACT FROM AUTHOR]

This study presents an approach for fabricating Wolter type-I mirrors for x-ray telescopes using a nickel electroforming replication process with quartz glass mandrels. The proposed method addresses the challenges encountered in conventional fabrication techniques, which involve using electroless nickel-coated aluminum mandrels that are susceptible to corrosion and thermal deformation. Quartz glass mandrels offer excellent chemical, thermal, and mechanical stability, enabling the efficient production of high-performance mirrors. Wolter type-I mirrors for telescopes possess a large aperture that collects x-ray photons from the universe. However, previous nickel electroforming replication processes using quartz glass mandrels have challenges in fabricating large mirrors, particularly due to bubble pit formation during nickel shell development. In this study, we introduced an efficient pitting inhibition technique via vacuum degassing. This technique facilitates the precise replication of pit-free Wolter type-I mirrors for telescopes using quartz glass mandrels. We demonstrated the fabrication process on a Wolter type-I mirror proposed for FOXSI-4 [(FOXSI) Focusing Optics X-ray Solar Imager], resulting in three mirrors obtained from the same mandrel without repolishing or repairing. The figure error of the mirror was within 1 µm over most areas in both longitudinal and circumferential directions. The ray-tracing simulation indicated that the performance of the mirror was ∼12 arcsec in half-power diameter, comparable to the performance achieved by previous high-resolution x-ray missions. [ABSTRACT FROM AUTHOR]

Micro X‐ray fluorescence spectrometry (micro‐XRF) is conducted for elemental imaging and analysis of small regions, by focusing on primary X‐rays. An appropriate beam diameter evaluation is essential as is directly related to the spatial resolution of micro‐XRF imaging. The X‐ray beam size was experimentally determined from the XRF intensity with respect to the scanning distance (thin‐wire scanning method) or its differentiated curve (knife‐edge scanning method). However, a beam diameter is not currently evaluated in a mathematically appropriate method and is known to differ significantly from the actual value under certain conditions. A formula to correct this difference has been proposed; however, to the best of our knowledge, no study has discussed the performance of the correction formula and conditions under which they can be applied. By mathematically analyzing the overlapping volume between the X‐ray beam and the scanning material, we succeeded in deriving an appropriate fitting function that replaces the Gaussian function taking into account the effect of absorption. The fitting function is effective for each method. This technique was applied to evaluate the micro X‐ray beam created using polycapillary X‐ray focusing optics. Both thin‐wire and knife‐edge scanning methods were used with wires of different sizes to determine the X‐ray beam size. The beam size obtained by the conventional fitting function can be accurately corrected using the newly derived correction formula. Simulations were performed using the derived fitting function, and the applicability of the correction formulas was demonstrated. [ABSTRACT FROM AUTHOR]

The review is devoted to the principles, state of the art and problems of diffractive optics used to focus X-ray and γ-radiation in telescopes at orbital stations. Various multilayer structures for normal incidence telescopes, supermirrors for Wolter optics, Laue lens as a soft γ-radiation concentrator, as well as modified Fresnel zone plates for focusing radiation in a wide energy range with an unprecedented high angular resolution (10–1–10–3″). [ABSTRACT FROM AUTHOR]

Confocal micro X-ray fluorescence (CMXRF) spectroscopy is a non-destructive, depth-resolved, and element-specific technique that is used to analyze the elemental composition of a sample. For this, a focused beam of mono- or polychromatic X-rays is applied to excite the atoms in the sample, causing them to emit fluorescence radiation which is detected with focusing capillary optics. The confocal design of the instrument allows for depth-resolved analysis, in most cases with a resolution in the lower micrometer dimension after collecting X-rays from a predefined volume within the sample. The element-specific nature of the technique allows information to be obtained about the presence and concentration of specific elements in this volume. This makes CMXRF spectroscopy a valuable tool for a wide range of applications, especially when samples with an inhomogeneous distribution of elements and a relatively light matrix have to be analyzed, which are typical examples in materials science, geology, and biology. The technique is also commonly used in the art and archaeology fields to analyze the elemental composition of historical artifacts and works of art, helping to provide valuable insights into their provenance, composition, and making. Recent technical developments to increase sensitivity and efforts to improve quantification in three-dimensional samples will encourage wider use of this method across a multitude of fields of application in the near future. Confocal micro X-ray fluorescence (CMXRF) is based on the confocal overlap of two polycapillary lens foci, creating a depth-sensitive and non-destructive probing volume. Three-dimensional resolved element distribution images can be obtained by measuring the fluorescence intensity as function of the three-dimensional position. [ABSTRACT FROM AUTHOR]

Transmitting a vortex beam (VB) with orbital angular momentum encounters significant aberrations due to atmospheric turbulence (AT) in free-space optical communication systems. Historically, research has focused on adaptive optics (AO) to correct distorted VB intensity distributions by generating phase compensation screens. In this paper, we introduce an image-translation-based machine learning (ML) framework using generative networks to directly produce corrected VB intensity profiles, thus mitigating AT-induced aberrations. Our network was trained with numerical simulation datasets to learn the mapping relationship between distorted and pristine intensity distributions. Subsequently, we evaluated its generalization capabilities using datasets with varied AT conditions and propagation distances. The trained network consistently generated corrected intensity profiles closely matching the desired outcomes, significantly reducing the required training data. Our methodology effectively compensates for distorted VB intensity, achieving a remarkable 40 dB enhancement compared to the distorted profiles. [ABSTRACT FROM AUTHOR]

The paper examines how the scarcely discussed problem of force obstruction contributed to shaping Kepler's concept of force, that is, the question whether corporeal forces are blocked when an intermediate body is interposed between the force source and the target body. We explore the role played by this problem in Kepler's works, focusing on his Optics, Foundations of Astrology, Astronomia Nova and Epitome. While the problem is instrumental in abandoning an initially physicalistic framework for astrology, Kepler attempts at different solutions when discussing the forces responsible for planetary motion. These forces are first modelled upon light, and then magnetism (and gravity). However, after considering several ways to get rid of the problem, he is eventually unable to decide why observable effects of obstruction are usually absent. So he accepts this absence at face value, similarly to Newton in his most relevant passages, allowing for a new ontological category that is physical on the one hand, but non-material on the other. [ABSTRACT FROM AUTHOR]

Digital maskless lithography is gaining popularity due to its unique ability to quickly fabricate high-resolution parts without the use of physical masks. By implementing controlled grayscaling and exposure control, it has the potential to replace conventional lithography altogether. However, despite the existence of a theoretical foundation for photopolymerization, observing the voxel growth process in situ is a significant challenge. This difficulty can be attributed to several factors, including the microscopic size of the parts, the low refractive index difference between cured and uncured resin, and the rapid rate of photopolymerization once it crosses a certain threshold. As such, there is a pressing need for a system that can address these issues. To tackle these challenges, the paper proposes a modified Schlieren-based observation system that utilizes confocal magnifying optics to create a virtual screen at the camera's focal plane. This system allows for the visualization of the minute changes in refractive indices made visible by the use of Schlieren optics, specifically the deflection of light by the changing density-induced refractive index gradient. The use of focusing optics provides the system with the flexibility needed to position the virtual screen and implement optical magnification. The researchers employed single-shot binary images with different pixel numbers to fabricate voxels and examine the various factors affecting voxel shape, including chemical composition and energy input. The observed results were then compared against simulations based on Beer-Lambert's law, photopolymerization curve, and Gaussian beam propagation theory. The physical experimental results validated the effectiveness of the proposed observation system. The paper also briefly discusses the application of this system in fabricating microlenses and its advantages over theoretical model-based profile predictions. [ABSTRACT FROM AUTHOR]

Visible light optical elements such as lenses and mirrors have counterparts for X-rays. In the visible regime, a variable focusing power can be achieved by an Alvarez lens which consists of a pair of inline planar refractors with a cubic thickness profile. When the two refractors are laterally displaced in opposite directions, the parabolic component of the wavefront is changed resulting in a longitudinal displacement of the focus. This paper reports an implementation of this concept for X-rays using two planar microfabricated refractive elements. The Alvarez X-ray lens can vary the focal distance of an elliptical X-ray mirror or a planar compound X-ray lens over several millimetres. The study presents the first demonstration of an Alvarez X-ray lens which adaptively corrects defocus and astigmatism aberrations of X-ray optics. In addition, the Alvarez X-ray lens eliminates coma aberration in an elliptical mirror, to the lowest order, when combining the lens with an adjustment of the pitch angle of the mirror. Development of synchroton facilities increases the demand of optics for focusing X-ray beam to achieve diffraction-limited focusing onto samples. Here, the authors demonstrated an X-ray optical element based on visible light Alvarez varifocal lens providing precise performance focusing elements. [ABSTRACT FROM AUTHOR]

Picosecond laser ablation has recently emerged as a minimally invasive alternative to conventional surgical resection of early tumors, offering high precision and limited thermal damage to surrounding tissue. Potential clinical application routes include deployment through the working channels of endoscopes or needle bores, which require the delivery of ultrashort high energy pulses through flexible optical fibers with focusing optics at the distal end. The manufacture of distal end optical systems for fiber ablation is challenging, inhibiting translation toward clinical applications. Here, we present a miniature fiber-coupled ablation probe developed using ultrafast laser inscription and chemical etching, employing a hollow-core fiber for pulse delivery. Its design, fabrication, and characterization are detailed, along with a feasibility demonstration for the ablation of stainless steel and chicken tissue. [ABSTRACT FROM AUTHOR]

X-ray optics with good focusing ability and high spectral resolution are required in X-ray spectroscopy for the diagnosis of high temperature and density plasmas. In our study, a novel X-ray spectrometer is developed to provide the ability to record spectra with excellent focusing performance and high energy resolution. It is accomplished by using a continuously conical crystal (CCC) that is formed by circles with different curvatures. In this paper, we present the foundational work of the design and development of continuously conical crystal spectrometer (CCCS) along with initial results obtained with a titanium (Ti) target as the object source. First, the spectrometer based on such a continuously conical crystal is used to measure X-ray spectra on Ti target X-ray Tube device. The spectral resolution (λ/Δλ) is around 615 with the source size of 1 mm. Then, we test the capability of the spectrometer on Xingguang-III Laser Facility with Ti target. He-like and Li-like Ti lines are recorded based on which the spectrometer performance is evaluated. The experiment result shows that the spectrometer provides a high spectral resolving power up to 1000, while acquiring a one-dimensional image of the source. [ABSTRACT FROM AUTHOR]

This study investigated pre-service science teachers' conceptual understanding and confidence in geometrical optics with respect to gender and their previous achievement in geometrical optics course. A total of 189 (60% female and 40% male) pre-service science teachers who had completed geometrical optics course in state universities in Turkey participated in this study. The conceptual test instrument consisted of 20 items taken from the first tier of the Four-Tier Geometrical Optics Test (FTGOT) developed by the researcher, followed by a self-reported measure of teachers' confidence in the accuracy of their responses. The interest and experience scores were obtained through scales previously developed by the researcher, and these two variables were used as covariates in the analysis. The two-way between-groups ANCOVA tests were conducted to answer the research questions. The results showed that male pre-service teachers tend to have slightly higher conceptual understanding and confidence scores in geometrical optics than females with medium effect sizes while controlling for geometrical optics experience and interest scores. The findings were discussed, and implications for research in geometrical optics were provided. [ABSTRACT FROM AUTHOR]

We present the first survey of quiet Sun features observed in hard X-rays (HXRs), using the Nuclear Spectroscopic Telescope ARray (NuSTAR), a HXR focusing optics telescope. The recent solar minimum, combined with NuSTAR's high sensitivity, has presented a unique opportunity to perform the first HXR imaging spectroscopy on a range of features in the quiet Sun. By studying the HXR emission of these features, we can detect or constrain the presence of high temperature (> 5 MK) or non-thermal sources, to help understand how they relate to larger, more energetic solar phenomena, and determine their contribution to heating the solar atmosphere. We report on several features observed in the 28 September 2018 NuSTAR full-disk quiet Sun mosaics, the first of the NuSTAR quiet Sun observing campaigns, which mostly include steady features of X-ray bright points and an emerging flux region, which later evolved into an active region, as well as a short-lived jet. We find that the features' HXR spectra are well fitted with isothermal models with temperatures ranging between 2.0 – 3.2 MK. Combining the NuSTAR data with softer X-ray emission from Hinode/XRT and EUV from SDO/AIA, we recover the differential emission measures, confirming little significant emission above 4 MK. The NuSTAR HXR spectra allow us to constrain the possible non-thermal emission that would still be consistent with a null HXR detection. We found that for only one of the features (the jet) was there a potential non-thermal upper limit capable of powering the heating observed. However, even here, the non-thermal electron distribution had to be very steep (effectively mono-energetic) with a low energy cut-off between 3 – 4 keV. [ABSTRACT FROM AUTHOR]

In this paper, Cu-Au nanospherical structures were formed on glass surfaces by nanosecond UV laser irradiation. ArF laser pulses (193 nm wavelength, 15 ns time duration) were used for the experiments. Cu-Au bimetallic thin-film sample surfaces are structured under ArF excimer laser irradiation during the ablation process. Laser irradiation experiments were carried out using different laser fluences, the number of pulses, and focusing optics. Morphology of the irradiated surfaces and images of the nanostructures were obtained by the scanning electron microscopy method. Also, the optical and plasmonic behaviors of the nanostructures were collected by UV-Vis spectroscopy. Elemental composition and its spatial distribution were obtained using energy-dispersive x-ray spectroscopy (EDS) and mapping. EDS mapping shows that bimetallic nanospheres have a core-shell structure. Our results show that different laser irradiation parameters change the nanostructures' composition, size, distribution, morphology, and optical properties. Cu-Au nanospherical structures can be used for nano-biosensing, catalysis, and enhanced spectroscopy applications. [ABSTRACT FROM AUTHOR]

Demonstration tests of the alignment of Fresnel zone plate focusing optics using a full-field x-ray microscope and microbeam x-ray diffraction measurements combined with the full-field x-ray microscope were performed. It was confirmed that the full-field x-ray microscope enables direct two-dimensional observation of a microbeam with sub-micrometer spatial resolution. This allowed visualization of the misalignment of the focusing optics, resulting in accurate alignment of the optics within a short time. In addition, the microscope could be used to observe the sample as well as the microbeam, which enabled clarification of the position and two-dimensional shape of the microbeam on the sample. This realized a measurement procedure that a 100-μm-size sample was imaged with sub-micrometer spatial resolution, and then, microbeam-use measurements were performed for only the region of interest determined by the microscope, which has been difficult with conventional microbeam applications. The combination of observations by a full-field x-ray microscope and measurements using a microbeam is expected to open a new style of measurement. [ABSTRACT FROM AUTHOR]

The proposed facility explores materials under ultra-high magnetic fields. By combining the power of high fields to tune materials and of neutron scattering to probe the resulting changes down to the atomic scale, this facility will enable transformative progress in the study of quantum materials and is named for the "TITAN" subset of Greek gods to reflect this transformation. TITAN will offer DC magnetic fields up to at least 20 T. Exploiting the record brightness and bandwidth of the Second Target Station at the Spallation Neutron Source, TITAN will probe atomic-scale responses through high efficiency neutron spectroscopy up to 80 meV energy transfer, high resolution diffraction, and small angle neutron scattering. Focusing neutron optics will maximize flux on accurately positioned samples, while radial collimation and optimized shielding and detection strategies will minimize backgrounds. [ABSTRACT FROM AUTHOR]

X-ray diffraction microscopy (XDM) is an established lens-less imaging method extensively practiced at synchrotrons and X-ray free-electron lasers (XFELs). XDM is broadly operated in two different modes: scanning and non-scanning. The non-scanning mode of operation in XDM is commonly called coherent diffraction imaging (CDI) and has been the key research direction of many XFEL facilities. This method typically images objects smaller than the size of the illumination, which precludes the imaging of a large group of samples physically larger than the illumination. Furthermore, satisfying this requirement at X-ray free-electron lasers tremendously reduces the volume of practically useful data, leading the experimental scheme to be less efficient. Such a limitation can be circumvented by using a uniform illumination probe rather than the traditional Gaussian-focused probe from the X-ray focusing optics. Here in this article, we report a numerical study on the design of an optical element to generate uniform X-ray illumination and its application to the CDI. We demonstrate the benefits of such illumination in imaging objects that are larger than the illumination size and in improving the efficiency of the experimental scheme overall. [ABSTRACT FROM AUTHOR]

The Ring-Imaging Cherenkov (RICH) detectors at LHCb have an excellent intrinsic time resolution due to the prompt Cherenkov radiation and focusing mirror optics. Novel RICH readout electronics, to be installed during the third Long Shutdown period (LS3) of the LHC, will introduce fast-timing information in the LHCb experiment. Central to the readout chain is a new application-specific integrated circuit (ASIC), called the FastRICH, with a unique set of features targeting operation in high-energy physics experiments and in particular the LHCb RICH detector. [ABSTRACT FROM AUTHOR]

We demonstrated a single-mode yellow fiber laser using a Dy3+-doped single-mode double-clad structured weatherproof fluoro-aluminate glass fiber (Dy3+:SM-DC-WPFGF) and a 450-nm GaN laser diode (LD) as the excitation light. The power of 445 mW and the slope efficiency of 51.2% were achieved for the single-mode yellow fiber laser. The power level was approximately 20 times higher than our previous result due to improved efficiency of the focusing optics and increased Dy3+ doping concentration (10,000 ppm) in the fiber core. This yellow fiber laser shows particular promise for use in the medical field, e.g., for the treatment of melasma and telangiectasia. • We demonstrated a single-mode yellow laser with the power of 445 mW and a slope efficiency of 51.2% in Dy3+:SM-DC-WPFGF. • To our knowledge, this is the first time a highly efficient half-watt single-mode yellow fiber laser has been achieved. • This achievements thank to an improved focusing optics and an increased Dy3+ concentration (10,000 ppm) in the fiber core. • This yellow fiber laser shows particular promise for use in the medical field, e.g., for the treatment of melasma. [ABSTRACT FROM AUTHOR]

Nonisothermal glass molding (NGM) is developed aiming to satisfy the fabrication of complex and precision optical elements at high production volumes. The technology, however, was encountered by the high form deviation of manufactured glass optics. During the nonisothermal compression molding, glass undergoes a rapid temperature change making it a transition from equilibrium to nonequilibrium nature of matter. Owing to this characteristic, viscoelastic material behaviors of glass depend on not only temperature but also thermal history. Understanding the nature of nonequilibrium thermoviscoelasticity, the central importance to control the final shape and optical characteristics of the manufactured glass optics is the focus of this research. First, this study presents preliminary experimental investigations indicating the difference in viscoelastic deformation responses under the equilibrated and nonequilibrated glass specimens. In the following, modeling the temperature‐dependent viscoelasticity over a wide temperature range in glass transition region is described, where temperature is directly coupled in each parameter of a rheological constitutive model. This concept allows us to bypass the thermorheologically simple assumption used to tolerate the description of thermoviscoelastic responses in most of the earlier works. Finally, we propose a modeling method that incorporates temperature and thermal history into the rheological model parameters, each of which is described by employing the Mauro–Allan–Potuzak viscosity equation. Viscoelastic experiments were carried out to validate the model. The results show that the time‐dependent responses varying with temperature are well predicted in both equilibrium and nonequilibrium regimes of glass‐forming systems. The benefit of this research is that a unique material model is entirely applicable for numerical studies of various hot forming processes such as annealing when glass undergoes pure thermal loads, as well as precision glass molding and NGM when glass is deformed by fully coupled thermal–mechanical loads under either its equilibrium or nonequilibrium state of materials, respectively. [ABSTRACT FROM AUTHOR]

Space and time coherent mapping (STCM) is a technology developed in our laboratory for improved matrix-assisted laser desorption ionization (MALDI) time of flight (TOF) imaging mass spectrometry (IMS). STCM excels in high spatial resolutions, which probe-based scanning methods cannot attain in conventional MALDI IMS. By replacing a scanning probe with a large field laser beam, focusing ion optics, and position-sensitive detectors, STCM tracks the entire flight trajectories of individual ions throughout the ionization process and visualizes the ionization site on the sample surface with a subcellular scale of precision and a substantially short acquisition time. Results obtained in thinly sectioned leech segmental ganglia and epididymis demonstrate that STCM IMS is highly suited for (1) imaging bioactive lipid messengers such as endocannabinoids and the mediators of neuronal activities in situ with spatial resolution sufficient to detail subcellular localization, (2) integrating resultant images in mass spectrometry to optically defined cell anatomy, and (3) assembling a stack of ion maps derived from mass spectra for cluster analysis. We propose that STCM IMS is the choice over a probe-based scanning mass spectrometer for high-resolution single-cell molecular imaging. [ABSTRACT FROM AUTHOR]