Light Spread Research Articles

Optimizing the spatial resolution and gamma discrimination of SiPM-based Anger cameras

SiPM Anger cameras have been designed for use as 2-dimensional thermal neutron detectors for scientific applications such as at single crystal diffraction instruments. These cameras utilize a neutron sensitive scintillator and an array of SiPM photosensors, separated by a light spreading glass. While this optics package is very effective at detecting and positioning neutrons, it is also sensitive to gamma rays, which are a source of unwanted noise. In this work, we underwent a search of scintillator and spreader glass thicknesses to determine the optimal combination for maximizing spatial resolution. Both experimental results and GEANT4 simulations are presented. To address the issue of gamma ray detection, we have also designed and presented a multi-layer scintillator that reduces the amount of scintillation light produced via gamma-ray energy deposition, allowing for easier pulse-height discrimination. A sample of this geometry has been produced that results in a factor of 2 improvement over an equivalent thickness monolithic scintillator.

Illumination matters part I: comparative analysis of light sources and illumination in flexible ureteroscopy-fundamental findings from a PEARLS analysis

PurposeIllumination characteristics of flexible ureteroscopes have been evaluated in air, but not in saline, the native operative medium for endourology. The aim was to evaluate light properties of contemporary ureteroscopes in air versus saline, light distribution analysis, and color temperature.MethodsWe evaluated the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, and OTU WiScope using a 3D printed black target board in-vitro model submerged in saline. A spectrometer was used for lux and color temperature measurements at different opening locations.ResultsIlluminance was higher in saline compared to air (5679 vs. 5205 lx with Flex-Xc, p = 0.02). Illuminance in saline differed between ureteroscopes (ANOVA p < 0.001), with highest for the Flex-Xc at 100% brightness setting (5679 lx), followed by Pusen 9.2F (5280 lx), Flex-X2s (4613 lx), P7 (4371 lx), V3 (2374 lx), WiScope (582 lx) and finally Pusen 7.5F (255 lx). The same ranking was found at 50% brightness setting, with the highest ureteroscope illuminance value 34 times that of the scope with lowest illuminance.Most scopes had maximum illuminance off center, with skewness. Three scopes had two light sources, with one light source for all other scopes. Inter-scope comparisons revealed significant differences of color temperature (ANOVA p < 0.001).ConclusionThe study demonstrates the presence of inhomogeneous light spread as well as large differences in illumination properties of ureteroscopes, possibly impacting on the performance of individual scopes in vivo. Additionally, the study suggests that future studies on illumination characteristics of flexible ureteroscopes should ideally be done in saline, and no longer in air.

Expansion-flow-modulated 3D printing of vertically aligned graphene photofuel cell

Channel-aligned regulation of photoelectrode within the bulk structure to generate eminent light absorbance and high-level pollutant adsorption is pivotal but challenging for realizing high-performance photofuel cell (PFC) system. Herein, we demonstrated an effective and scalable expansion-flow-modulated direct ink writing (DIW) 3D printing strategy for controllably constructing microlattice photoelectrode, with multiscale well-interconnected oriented channels built by layer-by-layer highly-regular assembly of filaments and vertical alignment of graphene nanosheets within filaments as well as uniform coupling of abundant photoactive nanoparticles to highly ordered channel walls. The unique architectural features enabled high-speed and effective diffusion/trapping of wastewater pollutants throughout the entire photoelectrode, and meanwhile facilitated ready spreading of incident light into the photoelectrode interior to yield high light absorption. As a result, an integrated 3D-printed vertically-aligned PFC (3DP VAPFC) assembled with as-fabricated photoelectrode exhibited its powerful capability for efficiently converting wastewater pollutants into electric energy under sunlight, with remarkable cycling stability and maximum power density of 0.11 mW cm−2. This work opens a promising route for architecting advanced photoelectrode toward PFC devices with highly efficient degradation and electricity generation of pollutants.

Influence of the addition of carbon nanotube on the physical behavior of a lateritic soil from the southwest Amazon

In this work we evaluate the physical-mechanical behavior of lateritic soil with addition of carbon nanotubes. The soil was collected in a commercial deposit located in Rio Branco – AC and later characterized through particle size tests, X-Ray Diffraction, X-Ray Dispersion Spectroscopy and Tropical Compressed Miniature essay. The dispersion of nanotubes in solution was carried out and the size of the nanoparticles was verified using Dynamic Light Spreading - DLS, Zeta Potential and PDI. Three percentages of additions (0.05%, 0.1% and 0.2%) of carbon nanotubes were evaluated and compared with the control group according to the parameters of Atterberg limits, real density, dry density maximum and optimum humidity. The results indicate that the soil has a clayey behavior with a medium texture, with the presence of clay mineral kaolinite in its composition and silicon and iron oxides. The dispersion of carbon nanotubes reached particles with an average hydrodynamic diameter of 68.9 nm and Zeta Potential of -24.87 mV and PDI of 0.231, characterizing a solution as moderately dispersed and kinetically stable. The results of the liquidity limit and plasticity tests showed a reduction of 10 and 13%, respectively, with the addition of carbon nanotubes, while for the parameters of plasticity index, real specific mass, maximum dry density and optimal moisture, they did not show significant variation. Carbon nanotubes interact with soils with lateritic behavior, and further studies are essential to better understand the mechanisms behind this interaction.

Peak Broadening in Photoelectron Spectroscopy of Amorphous Polymers: The Leading Role of the Electrostatic Landscape.

The broadening in photoelectron spectra of polymers can be attributed to several factors, such as light source spread, spectrometer resolution, the finite lifetime of the hole state, and solid-state effects. Here, for the first time, we set up a computational protocol to assess the peak broadening induced for both core and valence levels by solid-state effects in four amorphous polymers by using a combination of density functional theory, many-body perturbation theory, and classical polarizable embedding. We show that intrinsic local inhomogeneities in the electrostatic environment induce a Gaussian broadening of 0.2-0.7 eV in the binding energies of both core and semivalence electrons, corresponding to a full width at half-maximum (FWHM) of 0.5-1.7 eV for the investigated systems. The induced broadening is larger in acrylate-based than in styrene-based polymers, revealing the crucial role of polar groups in controlling the roughness of the electrostatic landscape in the solid matrix.

Challenges in Ungoverned Spaces and the Crisis of Insecurity Across the Sahel

The paper tries to underscore the challenges associated with ungoverned spaces and the crisis of insecurity in the Sahel. It tries to look into the dominant narratives and perspectives on the immediate and remote causes of the crisis and how it has destabilized the region. It also looks at the various conterminous and contentions interpretation of the terms, ‘space’, and ‘ungoverned’ in a bid to ascertain the range, scope and borders of governance. The paper relied on existing materials as sources of data. It finds amongst other things that some domestic and external triggers have given rise to the prolonged and contracted crisis in the region, some of which include; political representation, marginalization, unequal allocation of resources and the gap in wealth distribution. It highlights the impact of the proliferation and spread of light and small weapons in the region and how this has further intensified and balkanized the crisis and instability. It concludes by demystifying claims that the conflict seeks to serve the interest of spreading the so-called concept of ‘Islamic Jihad’.

Quantum quenches in driven-dissipative quadratic fermionic systems with parity-time symmetry

We study the quench dynamics of noninteracting fermionic quantum many-body systems that are subjected to Markovian drive and dissipation and are described by a quadratic Liouvillian which has parity-time (PT) symmetry. In recent work, we have shown that such systems relax locally to a maximum entropy ensemble that we have dubbed the PT-symmetric generalized Gibbs ensemble (PTGGE), in analogy to the generalized Gibbs ensemble that describes the steady state of isolated integrable quantum many-body systems after a quench. Here, using driven-dissipative versions of the Su-Schrieffer-Heeger (SSH) model and the Kitaev chain as paradigmatic model systems, we corroborate and substantially expand upon our previous results. In particular, we confirm the validity of a dissipative quasiparticle picture at finite dissipation by demonstrating light cone spreading of correlations and the linear growth and saturation to the PTGGE prediction of the quasiparticle-pair contribution to the subsystem entropy in the PT-symmetric phase. Further, we introduce the concept of directional pumping phases, which is related to the non-Hermitian topology of the Liouvillian and based upon qualitatively different dynamics of the dual string order parameter and the subsystem fermion parity in the SSH model and the Kitaev chain, respectively: depending on the postquench parameters, there can be pumping of string order and fermion parity through both ends of a subsystem corresponding to a finite segment of the one-dimensional lattice, through only one end, or there can be no pumping at all. We show that transitions between dynamical pumping phases give rise to a new and independent type of dynamical critical behavior of the rates of directional pumping, which are determined by the soft modes of the PTGGE. Published by the American Physical Society 2024

Electromagnetic Waves, Light and Information

In this paper electromagnetic waves and visible light were examined. Information and communication technology were studied. Electromagnetic radiation, quantum energy, photon and electromagnetic waves were considered. The methodology of macroscopic and microscopic approach were used. Discrete energy quantity, photon, and information were employed. In this paper the light spread law was derived, first time in literature. The sun light changeable velocity was defined. Also, equation for information transfer functionalities were developed. These results can be applied in communication.

Optical-Quality Analysis and Defocus-Curve Simulations of a Novel Hydrophobic Trifocal Intraocular Lens.

The optical function of a novel refractive-diffractive trifocal intraocular lens (IOL) was tested in vitro to provide preclinical metrics that predict postoperative performance and may guide patient selection. Fundamental optical characteristics of a trifocal hydrophobic-acrylic IOL with a C-loop haptic configuration (AT ELANA 841P, Carl Zeiss Meditec) were assessed using a fully automated optical test device under both monochromatic and polychromatic conditions combined with increased or compensated spherical aberration (SA). The area under the modulation transfer function (MTFa) was calculated across a defocus range from +1D to -3.5D and used to simulate visual acuity (VA). A polychromatic point spread function (PSF) was employed to assess the light distribution and identify photic phenomena. The highest MTFa values were obtained under monochromatic conditions using an SA-neutral corneal model. Nevertheless, after introducing SA and polychromatic light, the IOL performance remained good. Simulated VA values were 0.00 logMAR for distance, 0.1 logMAR at 100 cm, and progressively improving to 0.05 logMAR at 40 cm from the intermediate point. The light-spread analysis confirmed halos around the PSF center, which is a characteristic of trifocal technology. AT ELANA 841P demonstrated good optical performance across various distances, independently of spectral and SA conditions, resulting in good simulated VA. Although light spread resembles standard trifocal IOLs, clinical studies are essential to confirm these laboratory results.

Timing estimation of the exponentiated energy-weighted average for crosshair light sharing TOF-DOI PET detector

In TOF-PET, the method of timestamp calculation is an important factor that affects coincidence resolving time (CRT). In independent readout detectors, for one-to-one coupled detectors, the first hit (FH) timestamp is the optimal one, while in light-sharing detectors, the optimal timestamp must be calculated from multiple timestamps. The method for the latter performs energy-weighted averaging (EWA) using several photosensors with earlier timestamps, but the light distribution varies depending on the detector structure. Here, we developed an exponentiated energy-weighted averaging (EEWA) method for our previously developed light-sharing detector that limits light spreading. The crosshair light-sharing (CLS) PET detector was developed as a TOF-DOI PET detector. It uses fast LGSO crystals with dimensions of 1.45 × 1.45 × 15 mm3 arranged in a 2D crystal array with three layers of enhanced specular reflectors (ESRs) forming a loop structure within a pair of crystals. The 2D crystal array is optically connected to an 8 × 8 MPPC array. The signals of the MPPC array are individually read out and processed by using TOFPET2 ASICs. To effectively utilize multiple timestamps, the EEWA method introduces a power term to the energy, giving priority to timestamps with higher energy. Additionally, we use Lumirror to increase the light collection efficiency and we compared its performance with the ESRs. In the FH method, the CRTs of the ESR and Lumirror arrays were 250 and 232 ps, respectively. In the EWA method, the CRT deteriorated as the number of MPPCs used was increased compared to the FH method. In the EEWA method, by optimizing the number of MPPCs used and the power factor, the CRT was improved to 226 and 221 ps, respectively. In summary, we developed the EEWA method for timestamp estimation and achieved an improvement of up to 24 ps in CRT.

Computational simulation of the optical performance of an EDOF intraocular lens in post-LASIK eyes.

To evaluate computationally the optical performance of AcrySof IQ Vivity extended depth-of-focus (EDOF) intraocular lenses (IOLs) in post-laser in situ keratomileusis (LASIK) eyes. Visual Optics and Biophotonics Laboratory, Madrid, Spain. Experimental study. Computer pseudophakic eye models were implemented using reported post-LASIK corneal aberrations (refractive corrections from -7.5 to +4.5 diopters [D]) and virtually implanted with monofocal (AcrySof IQ) or EDOF (AcrySof IQ Vivity) IOLs. Retinal image quality was quantified through visual Strehl (VS). The depth of focus (DOF) was calculated from the through-focus VS curves. Halos were estimated from the light spread in the image of a pinhole. Those quantitative parameters were obtained for 5.0 and 3.0 mm pupil diameters. Simulated virgin eyes showed VS of 0.89/0.99 with monofocal IOLs and 0.74/0.52 with EDOF IOLs for 5.0/3.0 mm pupils at best focus. VS decreased with induced spherical aberration (SA) by 25% and with induced SA + coma by 61% on average (3.0 mm pupils). The DOF was 2.50 D in virgin eyes with EDOF IOLs, 1.66 ± 0.30 and 2.54 ± 0.31 D ( P < .05) on average in post-LASIK eyes for 3.0 mm pupils, monofocal and EDOF IOLs, respectively. Halos were more sensitive to SA induction for 5.0 mm pupils, and induction of positive SA (myopic LASIK) resulted in reduced halos with the EDOF when compared with the monofocal IOLs, by 1.62 (SA) and 1.86 arc min (SA + coma), on average. Computer post-LASIK pseudophakic eye models showed that the DOF was less dependent on the presence of SA and coma with EDOF IOLs and that halos were reduced with EDOF IOLs compared with the monofocal IOL for a range of SA.

42‐3: Impact of resolution of image condensation and of matrix BLU on power saving, contrast enhancement and local dimming processor complexity dedicated to automotive applications

This paper treats for automotive application the trade‐off between power saving and visual quality enhancement at one side and logic complexity as well as processing speed of local dimming processor at the other side. A key parameter is the resolution of an image condensed which is effectively the input image for the LED optimization. A higher number of condensation cells allows a more detailed consideration of the image given and the shape of the light spread function (LSF) of an LED. On the other hand, more memories are needed, and the processing steps are increased. The number of condensations cells are varied for 3 backlight units (BLU) with 133, 240 and 384 LEDs for a standard automotive display size of 12.3 inches. Power saving rate for a set of automotive HMIs as well as contrast enhancement are calculated. A recommendation for the resolution of image condensation in dependence of the LED resolution of the BLU will be given.

ENGINEERING PORTABLE UNDERWATER LAMP AS AN AUXILIARY GEAR FOR PURSE SEINE

Lights are common supporting tool in purse seine fishing in Indonesia. Currently, lamps on purse seines use mercury and metal halide (MH) which require very high electrical power. Therefore, there is a need for an effective underwater light technology alternative with low electric power. The aim of this research is to design a portable underwater lamp (PUL) which can be controlled remotely to support fishing operations. The design engineering process in creating the PUL includes light and buoy construction, temperature testing, light distribution, waterproofing, and motion testing. The results show that the PUL design enables the tools to be controlled remotely. The average temperature of the lamp on the PUL is 40 ⁰C, this temperature is lower than the MH lamp which reaches 250 ⁰C. The light spreads evenly at an angle of 360⁰ to the horizontal and 180° to the vertical. Meanwhile, the results of the lamp motion test showed that the lamp was watertight and highly stable.&#x0D; Keywords: Light emitting diode, Remote control, Waterproof, Electric Power.

Image Enhancement in Lens-Coupled Detectors for industrial CT systems

These days, lens-coupled detectors have been taken into consideration due to their cost effectiveness, but they have some disadvantages relative to other detectors such as flat panel detectors. Meanwhile, white spot noise and light spreading due to optical distance, will result in reduction of the quality of the reconstructed object in computed tomography applications. In this paper, due to limited power of classical methods, to fix these dysfunctions, we have learned a Neural network for improvement of the images.

Enhanced Imaging Using Inverse Design of Nanophotonic Scintillators

AbstractConverting ionizing radiation into visible light is essential in a wide range of fundamental and industrial applications, such as electromagnetic calorimeters in high‐energy particle detectors, electron detectors, image intensifiers, and X‐ray imaging. These different areas of technology all rely on scintillators or phosphors, i.e., materials that emit light upon bombardment by high‐energy particles. In all cases, the emission is throughspontaneous emission. The fundamental nature of spontaneous emission poses limitations on all these technologies, imposing an intrinsictrade‐offbetween efficiency and resolution in all imaging applications: thicker phosphors are more efficient due to their greater stopping power, which however comes at the expense of image blurring due to light spread inside the thicker phosphors. Here, the concept of inverse‐designed nanophotonic scintillators is proposed, which can overcome the trade‐off between resolution and efficiency by reshaping the intrinsic spontaneous emission. To exemplify the concept, multilayer phosphor nanostructures are designed and these nanostructures are compared to state‐of‐the‐art phosphor screens in image intensifiers, showing a threefold resolution enhancement simultaneous with a threefold efficiency enhancement. The enabling concept is applying the ubiquitous Purcell effect for the first time in a new context—for improving image resolution. Looking forward, this approach directly applies to a wide range of technologies, including X‐ray imaging applications.

Determination of intensity and spread of light to the surrounding in conventional phototherapy and comparison with novel converging photo unit — an observational study

BackgroundBlue light phototherapy used extensively in the management of hyperbilirubinemia has many side effects like dry eyes, blurring, headache, and altered circadian rhythm. Healthcare providers working around the phototherapy are unduly exposed to these side effects. Altered circadian rhythm results in disruption in the sleep-wake cycle affecting healthcare providers particularly working during the night shift. The constant glare of the blue light interrupts in clinical observation of the baby on phototherapy. With the intent of providing effective phototherapy with minimal exposure of blue light to healthcare providers, a light source called the photo unit was designed and developed.The objective of this study was to estimate the intensity and spread of blue light to the surrounding in conventional phototherapy and to compare the same with newly developed converging photo unit.ResultsThe therapeutic range of irradiance was noted up to 22 inch in diameter with conventional phototherapy compared to only 7 inch with our photo unit. The light spread with a conventional phototherapy unit was seen beyond 50 inch in all directions whereas was confined to 19-inch diameter with photo unit.ConclusionPhoto unit developed by the authors has minimal divergence of light to the surrounding, thereby mitigating the side effects of blue light exposure to the people working in the vicinity. Multiple of these photo units can be used to make a phototherapy device.

Purification and scrambling in a chaotic Hamiltonian dynamics with measurements

Chaotic transverse-field Ising model with measurements exhibits interesting purification dynamics. Ensemble of non-unitary dynamics of a chaotic many-body system with measurements exhibits a purification phase transition. We numerically find that the law of the increase dynamics of the purity changes by projective measurements in the model. In order to study this behavior in detail, we construct the formalism of the tripartite mutual information (TMI) for non-unitary time evolution operator by using the state-channel map. The numerical result of the saturation value of the TMI indicates the existence of a measurement-induced phase transition. This implies the existence of two distinct phases, mixed phase and purified phase. Furthermore, the real-space spread of the TMI is investigated to explore spatial patterns of information spreading. Even in the purified phase, the spatial pattern of the light cone spread of quantum information is not deformed, but its density of information propagation is reduced on average by the projective measurements. We also find that this spatial pattern of the TMI distinguishes the chaotic and integrable regimes of the system.

Visualization of Ray Propagation through Extended Depth-of-Focus Intraocular Lenses.

Extended depth-of-focus (EDoF) presbyopia-correcting intraocular lens (IOL) models differ in their optical design and performance. In the laboratory, we compared the ray propagation and light intensity profiles of four IOLs: the non-diffractive AcrySof IQ Vivity (Alcon Inc., Fort Worth, TX, USA) and two diffractive models, Symfony ZXR00 (Johnson & Johnson Vision, Jacksonville, FL, USA) and AT Lara 829 MP (Carl Zeiss Meditec, Berlin, Germany). A fourth lens, the monofocal AcrySof IQ SN60WF (Alcon Inc.) acted as the control. We projected a 520 nm laser light through each submerged lens in a bath of fluorescein solution. A camera mounted on a microscope captured the light that emerged from the IOL. We recorded the IOLs' point spread function (PSF) to determine the presence of unwanted visual effects. The ray propagation visualization and light intensity profile of the monofocal control showed one distinct focus, while the AcrySof IQ Vivity demonstrated an extended focus area. We observed two distinct foci with each diffractive IOL. We found a lower level of light spread beyond the PSF center for the AcrySof IQ Vivity compared to the diffractive IOLs. In conclusion, we could confirm the extended range of focus for all the EDoF IOL models. However, the non-diffractive AcrySof IQ Vivity appears to have a smoother transition from a far to an intermediate range. We discuss whether, in clinical use, the higher level of spurious light we found in the diffractive designs may translate into increased dysphotopsia.

Lighting System Design Based on SNI 6197-2011 and Software-Based Design DIALux Evo 9.2 (Case Study: Pekanbaru High School of Technology)

Lighting is one of the important factors in a room design. The intensity of lighting that does not meet the standards can affect eye health and work activities. In this study, measurements of the lighting intensity were carried out at Pekanbaru College of Technology (STTP) i.e., in classroom 01A and library. Lumen method is one of the calculation methods to determine the number of luminaires required to improve the lighting quality in the room. For the lighting in classroom 01A, the mathematical calculations result in 363.23 lux while the DIALux evo 9.2 software obtained 375 lux. There is 3.1% difference in these results This might occur because the condition of the room, supporting equipment, and color has an influence on the results of calculations and the spread of light, while the effect of color is not considered. However, in calculations using DIALux evo 9.2 software, surface color has an influence on the results obtained.by changing the specifications of the lamp using the type of LED lamp. The lighting standard to improve the lighting system refers to SNI 6197:2011.

Design Optimization and Characterization of Cold Neutron Imaging Detector Based on Novel Gadolinium Scintillation Glass Fiber Arrays and Infinity Corrected Optics

The use of scintillation glass fiber array in the reported cold neutron imaging detector can suppress lateral spreading of the scintillation light effectively and achieve a high spatial resolution while maintaining high detection efficiency. Theoretical analysis and experiments were combined to investigate influencing factors on the spatial resolution, the imaging contrast, the signal-to-noise ratio (SNR), and the detection efficiency with a cold neutron imaging detector made of new gadolinium scintillation glass fiber array and an infinity corrected optical readout system. The experiments were carried out on the Cold Neutron Radiography Facility at China Academy of Engineering Physics (CAEP). The cold neutron imaging detector made of 0.3-mm-thick Tb3+/Ce3+ co-doped Gd2O3 scintillation glass fiber array with a fiber diameter of 6 mm achieved a spatial resolution of 28.8 lp/mm (17.4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> ), an SNR of 28.6:1, and a cold neutron detection efficiency of 31.6%, i.e., a cold neutron absorption efficiency of 81.0%.