Incoming Light Research Articles

Direct Laser Interference Patterning of Fluorine‐Doped Tin Oxide as a Pathway to Higher Efficiency in Perovskite Solar Cells

AbstractImproving light‐trapping capabilities through surface microstructuring of transparent conductive oxides is a promising approach to enhance solar cell efficiency. This study focuses on treating fluorine‐doped tin oxide (FTO) thin films using four‐beam direct laser interference patterning (DLIP) to create dot‐like periodic surface microstructures. The surface analysis using scanning electron microscopy and confocal microscopy reveals the presence of a periodic square grid of microcraters with a spatial period of ≈700 nm and an average depth ranging between 4 and 18 nm. These structures enhance the dispersion of incoming light up to 1000% in the visible and NIR spectra. When integrated into metal halide perovskite solar cells, FTO films patterned using low fluence conditions lead to a notable increase in the power conversion efficiencies (PCEs) compared to those made using untreated FTO. Importantly, preliminary stability tests on devices based on patterned FTO substrates show significantly improved stability compared to those fabricated using reference unpatterned substrates. These findings demonstrate that a DLIP treatment of FTO substrates is a promising technique that can substantially enhance the efficiency and stability of perovskite photovoltaic devices.

Erbium-Doped Tunable Fiber Laser Based on a Vernier Effect Filter

A novel vernier effect filter is designed utilizing two cascaded Mach–Zehnder interferometers (MZIs). Integrating the filter into an erbium-doped fiber laser (EDFL), the tunability of laser wavelength is achieved. Each MZI comprises two sequentially interconnected 3 dB optical couplers (OCs), where the incoming light is initially split into two arms at the first OC and subsequently recombined at the second OC. Interference occurs due to the optical path difference between these two beams. Notably, the two MZIs exhibit closely matched free spectral ranges (FSRs), leading to the formation of a broadened envelope in the superimposed spectrum. By delicately adjusting the optical path difference between the two arms of one MZI, a little drift of the interference spectrum is induced. This small amount of drift, in turn, triggers a significant movement of the envelope, giving rise to the so-called vernier effect. Integrating the vernier effect filter into an EDFL, the wavelength of the fiber laser can be tuned from 1542.56 nm to 1556.62 nm, with a tuning range of 14.06 nm. Furthermore, by employing a high-precision stepper motor, a remarkable tuning accuracy of 0.01 nm is attainable. The side mode suppression ratio of all wavelengths is above 55 dB. In comparison to reported tunable fiber lasers utilizing MZI filters, the proposed fiber laser in this study offers enhanced precision and a more user-friendly tuning process.

Binary amplitude holograms for shaping complex light fields with digital micromirror devices

Abstract Digital micromirror devices are a popular type of spatial light modulators for wavefront shaping applications. While they offer several advantages when compared to liquid crystal modulators, such as polarization insensitivity and rapid-switching, they only provide a binary amplitude modulation. Despite this restriction, it is possible to use binary holograms to modulate both the amplitude and phase of the incoming light, thus allowing the creation of complex light fields. Here, a didactic exploration of various types of binary holograms is presented. A particular emphasis is placed on the fact that the finite number of pixels coupled with the binary modulation limits the number of complex values that can be encoded into the holograms. This entails an inevitable trade-off between the number of complex values that can be modulated with the hologram and the number of independent degrees of freedom available to shape light, both of which impact the quality of the shaped field. Nonetheless, it is shown that by appropriately choosing the type of hologram and its parameters, it is possible to find a suitable compromise that allows shaping a wide range of complex fields with high accuracy. In particular, it is shown that choosing the appropriate alignment between the hologram and the micromirror array allows for maximizing the number of complex values. Likewise, the implications of the type of hologram and its parameters on the diffraction efficiency are also considered.

Visible diffuse reflectance smartphone spectrometer with high spectral accuracy

A smartphone-based spectrometer employing principle of diffuse reflection is reported for the surface analysis of solid samples. The instrument utilizes a thin-film grating to diffract incoming light, while a diffuse reflecting surface projects the image of this diffracted light onto the detector plane. The CMOS camera of smartphone camera directly captures the diffusely reflected photons within its limited field-of-view thus eliminating the need for collection, conditioning and converging optics. The optical setup of the instrument provides facility to calibrate the spectral response considering the nonlinear distribution of the wavelength across the diffraction direction. Additional correction in the detector response at different light intensity results a reduced spectral error with a maximum wavelength resolution of δλ=0.08 nm/pixel in the camera within the spectral range Δλ = (400 – 700) nm. As a proof of the concept, the instrument demonstrates successful detection of color pigments in food samples by absorption measurement of the samples at an average spectral error < 6 %. The distinct absorption peak associated with standard food colors are compared against the absorption profile of unknown food colors used in pastry cake. This field-functional smart analysis with internet connectivity opens opportunity of identifying food adulteration by using toxic chemical colors at the point-of-test and immediate reporting to others. The overall instrument is fabricated by utilizing low-cost and light weight plastic wood to make compact (110 mm × 105 mm × 125 mm), robust, inexpensive (∼$ 50) and suitable for field-portable (∼145 gm) hand-held operation.

Community gross primary production and respiration in epilithic macroalgae and Posidonia oceanica macrophytodetritus accumulation in the Bay of Revellata (Corsica)

We report estimates of community gross primary production (GPP), community respiration (CR), and net community production (NCP) based on the change of dissolved O2 during incubations over epilithic turf-forming macroalgae (Halopteris scoparia, Padina pavonica, and Dictyota dichotoma) on 7 occasions and in accumulations of Posidonia oceanica macrophytodetritus (i.e. litter) on 8 occasions in the Bay of Revellata (Corsica) from March 2009 to May 2011. In the epilithic macroalgae community, GPP ranged between 7.8 and 82.2 mmol O2 m−2 d−1, CR ranged between −108.5 and −13.6 mmol O2 m−2 d−1, and NCP ranged between −53.2 and −5.7 mmol O2 m−2 d−1. In the P. oceanica macrophytodetritus accumulation, GPP ranged between 5.7 and 91.6 mmol O2 m−2 d−1, CR ranged between −112.8 and −27.2 mmol O2 m−2 d−1, and NCP ranged between −46.8 and −9.9 mmol O2 m−2 d−1. GPP in both the epilithic macroalgae community and the P. oceanica macrophytodetritus accumulation peaked in summer and was lowest in fall, following the seasonal variation of incoming light. GPP correlated to macroalgal biomass but was unrelated to the biomass of living macroscopic plant material in the P. oceanica macrophytodetritus accumulation. The annual average of GPP was equivalent in the epilithic macroalgae and P. oceanica macrophytodetritus accumulation communities (17.6 and 19.4mol O2 m−2 yr−1). Both the epilithic macroalgae community and the P. oceanica macrophytodetritus accumulation were net heterotrophic with an annual average NCP of −6.1 and −8.8mol O2 m−2 yr−1, respectively. The NCP of the adjacent P. oceanica meadow at 10 m depth based on simultaneous measurements based on the open water O2 mass balance from moored O2 probes (optodes) was 28.9mol O2 m−2 yr−1. The potential export of dissolved organic carbon from the P. oceanica meadow could quantitatively meet the carbon demand to sustain the net heterotrophy of the adjacent epilithic macroalgae community in the Bay of Revellata. We also show the limitation and possibly over-estimation of extrapolating decay rates based on litter bag experiments with small quantities of material to “real” macrophytodetritus biomass densities.

Metalens Topology Optimization

Photonic metasurfaces are thin optical elements comprised of structures arranged strategically upon a surface to manipulate electromagnetic waves. To produce metasurfaces at a large scale, it is beneficial to obtain not just an optimal design, but also an understanding of which areas of the metasurface are most influential on the overall performance of the device and require greater manufacturing accuracy. My work consisted of implementing and testing a new physics-based method for identifying the relative importance of different regions of a proposed metasurface design. This method built on an existing topology optimization code, where the designable region of the metasurface was discretized, and the material density of each point in the design was optimized such that incoming light was maximally focussed to a target location. The existing optimization algorithm was then coupled to a molecular dynamics model called a Nosé-Hoover thermostat, by modelling the discrete locations on the design region as particles and their corresponding material densities as their positions. By numerically integrating the equations of motion of the thermostat model, I was able to generate metasurface designs at different thermostat temperatures, and observe how the designs changed with increasing temperature. To determine the most important areas of the metasurface design, I calculated the entropy of each of the "particles" for all temperature samples, and looked for design regions that had low entropy even at high temperatures, indicating strong convergence on an optimal material density value amidst high thermal noise. Once I implemented this design analysis framework, I tested it on both a metalens and a reflector design at multiple wavelengths of incoming light. My results demonstrated that this physics-based method provides easily interpretable information about the relative importance of different elements of a metasurface design.

Dynamic responses of chlorophyll fluorescence parameters to drought across diverse plant families.

Chlorophyll fluorescence measurement is a quick and efficient tool for plant stress-level detection. The use of Pulse amplitude modulation (PAM), allows the detection of the plant stress level under field conditions. Over the years, several parameters estimating different parts of the chlorophyll and photosystem response were developed to describe the plant stress level. Despite all fluorescence parameters being based on the same measurements, their relationship remains unclear, and their response to drought stress is significantly influenced by the incoming light intensity. In this study, we use six different annual plants from different families, both C3 and C4 photosynthesis types, to describe the plant response to drought through the fluorescence parameters response (NPQ, Y(NPQ), and qN). To describe the dynamic response to drought, we employed light-response curves, adapting and fitting an equation for each curve to compare the drought response for each fluorescence parameter. The results demonstrated that the non-photochemical quenching (NPQ) and the quantum yield of non-photochemical quenching [Y(NPQ)] maximal values decrease when the PSII functionality (Fv/Fm) is lower than ~0.7. The basal fluorescence level ( and remained unaffected by the stress level and stayed stable across the various plants and stress levels. Our results indicate that the response of different stress parameters follows a distinct order under continuous drought. Consequently, monitoring just one parameter during long-term stress assessments may result in biased analysis outcomes. Incorporating multiple chlorophyll fluorescence parameters offers a more accurate reflection of the plant's stress level.

The Fundamental of Fiber Bragg Grating (FBG) Sensor

An optical sensor known as an FBG is produced by laterally exposing a single mode fiber core to a strong UV laser light pattern on a regular basis. The exposure causes a sustained increase in the refractive index (ncore) of the fiber's core, resulting in fixed index modulation called grating (λ). The grating inside the fiber optic core must reflect a certain wavelength of incoming light while transmitting all other wavelengths. This wavelength is referred to as the Bragg wavelength or Bragg linked to grating period. FBG functions as intended when a Bragg reflector is built on an optical fiber by taking use of the regular fluctuations in the refractive index of the single mode fiber core. When light travels through the FBG, certain wavelengths will be transmitted and others will be reflected. When the strain or temperature around the grating varies, a shift in the wavelength of the light reflected is observed.

ChromaFlash: Snapshot Hyperspectral Imaging Using Rolling Shutter Cameras

Hyperspectral imaging captures scene information across narrow, contiguous bands of the electromagnetic spectrum. Despite its proven utility in industrial and biomedical applications, its ubiquity has been limited by bulky form factors, slow capture times, and prohibitive costs. In this work, we propose a generalized approach to snapshot hyperspectral imaging that only requires a standard rolling shutter camera and wavelength-adjustable lighting. The crux of this approach entails using the rolling shutter as a spatiotemporal mask, varying incoming light quicker than the camera's frame rate in order for the captured image to contain rows of pixels illuminated at different wavelengths. An image reconstruction pipeline then converts this coded image into a complete hyperspectral image using sparse optimization. We demonstrate the feasibility of this approach by deploying a low-cost system called ChromaFlash, which uses a smartphone's camera for image acquisition and a series of LEDs to change the scene's illumination. We evaluated ChromaFlash through simulations on two public hyperspectral datasets and assessed its spatial and spectral accuracy across various system parameters. We also tested the real-world performance of our prototype by capturing diverse scenes under varied ambient lighting conditions. In both experiments, ChromaFlash outperformed state-of-the-art techniques that use deep learning to convert RGB images into hyperspectral ones, achieving snapshot performance not demonstrated by prior attempts at accessible hyperspectral imaging.

Multiband polarimetric imaging of HD 34700 with SCExAO/CHARIS

Abstract We present Subaru/SCExAO + CHARIS broadband (JHK) integral field spectroscopy of HD 34700 A in polarized light. CHARIS has the unique ability to obtain polarized integral field images at 22 wavelength channels in broadband, as the incoming light is first split into different polarization states before passing though the lenslet array. We recover the transition disk around HD 34700 A in multiband polarized light in our data. We combine our polarized intensity data with previous total intensity data to examine the scattering profiles, scattering phase functions and polarized fraction of the disk at multiple wavelengths. We also carry out 3D Monte Carlo radiative transfer simulations of the disk using MCFOST, and make qualitative comparisons between our models and data to constrain dust grain properties. We find that in addition to micron-sized dust grains, a population of sub-micron grains is needed to match the surface brightness in polarized light and polarized fraction. This could indicate the existence of a population of small grains in the disk, or it could be caused by Mie theory simulations using additional small grains to compensate for sub-micron structures of real dust aggregates. We find models that match the polarized fraction of the data but the models do not apply strong constraints on the dust grain type or compositions. We find no models that can match all observed properties of the disk. More detailed modeling using realistic dust aggregates with irregular surfaces and complex structures is required to further constrain the dust properties.

(Invited) Mie Resonant Silicon Nanosphere Nanoantenna for Fluorescence Enhancement

A nanoantenna is a device that manipulates light propagation and enhances light-matter interaction at the nanoscale. Integration of an emitter into a nanoantenna capable of increasing local density of photonic states at the emission wavelength results in the enhancement of the spontaneous emission rate (Purcell effect) and modifies the emission spectrum. A nanoantenna can also control the directionality and radiation pattern of an emitter. Traditionally, plasmonic nanoantennas made from gold or silver nanostructures supporting localized surface plasmon resonances had been the main stream of the nanoantenna research. Recently, high refractive index nanoparticles having low-order Mie resonances have been attracting attention as a new type of dielectric nanoantennas. Advantages of a dielectric nanoantenna compared to a plasmonic one are the smaller loss and the possession of magnetic type Mie resonances arising from light-induced displacement current. By properly controlling the overlap of the magnetic and electric multipole resonances, radiation patters of an emitter placed nearby can be tailored with high degree of freedom. Furthermore, magnetic-type Mie resonances can couple with higher-order optical transitions of an emitter such as a magnetic-dipole transition, and thus can enhance and control radiation from otherwise weak forbidden transitions.Recently, we have succeeded in producing perfectly spherical nanoparticles of crystalline silicon (Si) in 100-300 nm in diameters. These Si nanospheres exhibit the electric and magnetic multipole resonances at the optical frequency [1]. In this presentation, we first show scattering and absorption properties of the Mie resonant Si nanospheres. Especially, we show that solutions of size-purified Si nanospheres exhibit vivid structural color and the solutions can be used as structural color inks. We then show that the solutions can preserve helicity of incoming circularly-polarized light and can enhance local chiral fields around nanospheres [2, 3]. This property can be used to improve the sensitivity of enantiomer-selective chiral molecular sensing. We then show some examples of enhanced light-matter interaction by Si nanoparticles. These include enhancement of magnetic dipole transitions of an emitter by magnetic-type Mie resonances of Si nanospheres (magnetic Purcell effect) [4, 5], enhancement of excitation and emission processes of in-plane dipoles of monolayer transition metal dichalcogenides (TMDC) [6], and enhancement of a spin forbidden singlet-to-triplet absorption transition of a molecule by Si nanodisks [7, 8].

Correcting Fabry-Pérot etalon effects in solar observations

Context. Data processing pipelines of Fabry–Pérot interferometers (FPI) must take into account the side effects these devices introduce in the observations. Interpretation of these observations without proper correction can lead to inaccurate or false results, with consequent impact on their physical interpretation. Corrections typically require prior knowledge of the properties of the etalon and the way they affect the incoming light in order to calibrate the data successfully. Aims. We have developed an algorithm to derive etalon properties from flat-field observations and tested its applicability and accuracy using simulated observations and real measurements. Methods. We employed analytical expressions of the transmission profiles for FPIs in collimated and telecentric configurations to derive their expected impact on the observations. These analytical expressions allowed us to develop a customized optimization algorithm capable of inferring the properties of the etalon from the observations. The algorithm’s performance has been tested on simulated observations with an etalon in collimated and telecentric setups employing various noise levels and spectral samplings. Additionally, we explored how tilting the etalon in a telecentric configuration influences the algorithm’s effectiveness. Lastly, we also applied the algorithm to a set of real flat-field observations taken with the high-resolution telescope of the Polarimetric and Helioseismic Imager on board the Solar Orbiter mission (HRT-SO/PHI). Results. The algorithm is able to retrieve the gain and etalon induced transmission velocity shifts (cavity map), with an average accuracy ranging between 0.4% and 0.1% for the former and between 120 m s−1 and 30 m s−1 for the latter. Both reducing the noise level and increasing the spectral sampling of the observations proved to greatly increase the algorithm’s performance, as expected. Results also suggest that determination of the observed object from the data is possible but an additional error between 40 m s−1 and 10 m s−1 is to be expected in the inferred cavity map. Furthermore, we show that neglecting the asymmetries arising from either tilts of the etalon or imperfections in the telecentrism can lead to large errors when determining the gain. Tests with HRT-SO/PHI data have verified the applicability of the algorithm in real cases. Conclusions. Our presented method enabled us to derive the transmission profile of FPIs from observations of collimated and telecentric configurations. It has proven to be robust against the presence of noise and limited spectral line sampling. The results reported here also show the importance of accounting for the asymmetries arising in real telecentric mounts when interpreting the results of real instruments.

Spin noise spectroscopy of an alignment-based atomic magnetometer

Optically pumped magnetometers (OPMs) are revolutionizing the task of magnetic-field sensing due to their extremely high sensitivity combined with technological improvements in miniaturization which have led to compact and portable devices. OPMs can be based on spin-oriented or spin-aligned atomic ensembles which are spin polarized through optical pumping with circular or linear polarized light, respectively. Characterization of OPMs and the dynamical properties of their noise is important for applications in real-time sensing tasks. In our work, we experimentally perform spin noise spectroscopy of an alignment-based magnetometer. Moreover, we propose a stochastic model that predicts the noise power spectra exhibited by the device when, apart from the strong magnetic field responsible for the Larmor precession of the spin, white noise is applied in the perpendicular direction aligned with the pumping-probing beam. By varying the strength of the noise applied as well as the linear-polarization angle of incoming light, we verify the model to accurately predict the heights of the Larmor-induced spectral peaks and their corresponding linewidths. Our work paves the way for alignment-based magnetometers to become operational in real-time sensing tasks. Published by the American Physical Society 2024

Temperature mapping methods for thermoelastic analyses of the ARIEL spacecraft payload module

The ARIEL mission is a European space project that aims to detect exoplanets with a spacecraft orbiting around the L2 point of the Sun-Earth system. The main payload consists of a Cassegrain telescope composed of mirrors that reflect and concentrate the incoming light from the deep space observations to finally guide it to the detectors. As in many other space missions, a dedicated complex assessment is established during the design phase to evaluate the impact on the optical performance caused by thermoelastic effects, which involves the coordinated work of the thermal, structural, and optical engineers. Despite that well-known and standardized processes and tools are established separately in each involved area, there is a lack of standardization about the way of exchanging the data between them, where additional calculations are required in some cases. This work focuses on the temperature mapping, which is the intermediate step between thermal and structural analyses, where temperatures are transferred to the structural model. The main difficulty of this process is related to the differences in modelling methods and approaches between both models, being necessary the development of an adequate algorithm to find the most accurate transfer of temperatures. This paper shows two different options for temperature mapping, detailing the proposed flowcharts. One of these methods requires the performance of an additional thermal conductive analysis, where a new improved procedure has been implemented in this work to solve some computational issues that made its application for large models difficult or even unfeasible. Both temperature mapping methods have been applied to the payload module of the ARIEL spacecraft, comparing the output results in terms of temperatures, stresses, forces, and displacements to evaluate their differences.

Photochemical reactivity of dissolved organic carbon in subarctic lakes along a color gradient

ABSTRACT Lake–atmosphere carbon exchanges can be significantly affected by photochemical dissolved organic matter (DOM) mineralization. However, our understanding of how increasing allochthonous organic carbon input affects the photoreactivity of DOM per unit of absorbed incoming light is incomplete. Here, we measured the absorption of ultraviolet (UV) light and subsequent photochemical DOM decay in 148 lakes within the subarctic region of Abisko, Sweden. These lakes range from brown-water lakes with allochthonous input from mires to tundra clear-water lakes with relatively more autochthonous input. We used fluorescence excitation–emission matrix analysis to assess the DOM chemical composition to determine how increasing colored DOM (CDOM) affects photomineralization. We found that the photo decay rates in absolute values were positively correlated to CDOM. However, the photo decay per unit of absorbed light energy did not increase with increasing CDOM; rather, it showed a weak decreasing trend. Fluorescence analyses helped explain these patterns; humic-like fluorescent DOM, presumably of terrestrial origin, was associated with high absolute photo decay rates, but not generally with higher photoreactivity per unit of absorbed light energy than other types of DOM. The results suggest that even though increasing inputs of terrestrial substances lead to a higher abundance of photodegradable materials, CO2 emissions do not necessarily increase in lakes where browning limits the ability of light to penetrate deeper water.

Urolithin A promotes p62-dependent lysophagy to prevent acute retinal neurodegeneration

BackgroundAge-related macular degeneration (AMD) is the leading cause of blindness in elderly people in the developed world, and the number of people affected is expected to almost double by 2040. The retina presents one of the highest metabolic demands in our bodies that is partially or fully fulfilled by mitochondria in the neuroretina and retinal pigment epithelium (RPE), respectively. Together with its post-mitotic status and constant photooxidative damage from incoming light, the retina requires a tightly-regulated housekeeping system that involves autophagy. The natural polyphenol Urolithin A (UA) has shown neuroprotective benefits in several models of aging and age-associated disorders, mostly attributed to its ability to induce mitophagy and mitochondrial biogenesis. Sodium iodate (SI) administration recapitulates the late stages of AMD, including geographic atrophy and photoreceptor cell death.MethodsA combination of in vitro, ex vivo and in vivo models were used to test the neuroprotective potential of UA in the SI model. Functional assays (OCT, ERGs), cellular analysis (flow cytometry, qPCR) and fine confocal microscopy (immunohistochemistry, tandem selective autophagy reporters) helped address this question.ResultsUA alleviated neurodegeneration and preserved visual function in SI-treated mice. Simultaneously, we observed severe proteostasis defects upon SI damage induction, including autophagosome accumulation, that were resolved in animals that received UA. Treatment with UA restored autophagic flux and triggered PINK1/Parkin-dependent mitophagy, as previously reported in the literature. Autophagy blockage caused by SI was caused by severe lysosomal membrane permeabilization. While UA did not induce lysosomal biogenesis, it did restore upcycling of permeabilized lysosomes through lysophagy. Knockdown of the lysophagy adaptor SQSTM1/p62 abrogated viability rescue by UA in SI-treated cells, exacerbated lysosomal defects and inhibited lysophagy.ConclusionsCollectively, these data highlight a novel putative application of UA in the treatment of AMD whereby it bypasses lysosomal defects by promoting p62-dependent lysophagy to sustain proteostasis.Graphical

Hierarchical Phased-Array Antennas Coupled to Al KIDs: A Scalable Architecture for Multi-band Millimeter/Submillimeter Focal Planes

We present the optical characterization of two-scale hierarchical phased-array antenna kinetic inductance detectors (KIDs) for millimeter/submillimeter wavelengths. Our KIDs have a lumped-element architecture with parallel plate capacitors and aluminum inductors. The incoming light is received with a hierarchical phased array of slot dipole antennas, split into 4 frequency bands (between 125 GHz and 365 GHz) with on-chip lumped-element band-pass filters, and routed to different KIDs using microstriplines. Individual pixels detect light for the 3 higher-frequency bands (190–365 GHz), and the signals from four individual pixels are coherently summed to create a larger pixel detecting light for the lowest frequency band (125–175 GHz). The spectral response of the band-pass filters was measured using Fourier transform spectroscopy (FTS), the far-field beam pattern of the phased-array antennas was obtained using an infrared source mounted on a 2-axis translating stage, and the optical efficiency of the KIDs was characterized by observing loads at 294 K and 77 K. We report on the results of these three measurements.

Daylighting Through Electrochromic Glazing Under Overcast Skies: Impacts on Visual Task Performance and Perception

ABSTRACT Electrochromic (EC) glazing allows modulating the intensity of visual and solar transmission by dynamically switching between bleached (clear) and tinted (colored) states, leading to changes in spectral power distribution (SPD), correlated color temperature (CCT), and illuminance of the incoming daylight. In this experimental study, we investigated the impact of spectral composition of daylight filtered through a 6-pane EC façade on visual task performance and visual perception. In a semi-controlled test room, 19 subjects were exposed to five setting scenarios of the EC façade (fully bleached, mixed setting after fully bleached, fully tinted, mixed setting after fully tinted, and user-controlled). Test subjects performed a series of visual tasks, and their assessments of the indoor environment and of the outside view were collected along with luminous and spectral measurements under each condition. The analysis provided statistical evidence that the changes in spectral composition of daylight do not have a practically relevant effect on visual task performance in terms of visual acuity and color naming accuracy. However, the daylight filtered through the fully tinted glazing had a substantive impact on visual perception, evoking negative responses to the color rendering of the indoor environment and of the outside view. A mixed settings of the EC façade could improve a natural assessment of the incoming light compared to the fully tinted state, achieving better ratings in terms of perception of the indoor and outdoor environments. When given control of the EC glazing, subjects expressed higher acceptance and satisfaction compared to the tinted and mixed scenarios.

An innovative method of the vertical coupling effect improvement to the tandem Cu(In, Ga)Se2/perovskite solar cells using Ag cluster nanostructures

The efficiency of double-junction CIGS/Perovskite-based solar cells has significantly improved through recent research. This study presents a new plasmonic structure for these optical devices, utilizing cluster nanostructures to increase photon absorption between 650 and 1137 nm wavelength ranges. The proposed nanostructure includes two vertically coupled silver nanoparticles embedded at the center of the bottom active layer (CIGS) that absorb most of the incoming light to CIGS within the active layer. The electric field produced by the coupling of the nanoparticles has a superior performance. To analyze the effect of nanoparticle coupling on CIGS/Perovskite solar cell performance, evaluated the short-circuit current density and power conversion efficiency for single and cluster nanostructures with a single nanoparticle in the middle of CIGS. The structures with a single nanoparticle displayed Jsc = 16.89 mA cm−2 and PCE = 31.76%, while the cluster nanostructure represents Jsc = 19 mA cm−2 and PCE = 35.81%. Not only did the use of the cluster nanostructure significantly improve absorption and performance compared to the bare case, but it also exhibited a suitable improvement compared to the single nanoparticle.

Scars from human-tree interactions: pollarding, pathogens, body reserves, and long-term response by Salix fragilis L. (Salicaceae) in Scodovacca, Italy

ABSTRACT Arboriculture provides opportunities for assessing long-term tree-environment interactions. We assessed the surrounding context, scars, re-sprouts, and absolute width-growth of twenty-four Salix fragilis trees pollarded by the grandfather, father, and son of one family covering 120 years, quantifying the effects of cut, microorganism-infection, and body-accumulated photosynthate on the pollards’ resprout-and-growth. We determined pollard diameter, age, scars-number (C) and basal area (CAB), median times pruned (Cmn), putrid holes number (H), cumulative length (HL), and length-average (HAV), and two indicators of remaining photosynthate (Q, and QAV). Response variables were number of re-sprouts (RN), re-sprout-basal area (RAB), and trunk’s Absolute Growth (AG; Classic (MLR), and Bayesian Multiple Linear Regressions (BMLR)). The pollards experienced similar incoming light, water, CO2, nutrients, and temperatures. Higher C-values for 40-year-old pollards produced higher H-values (Linear Regression, R2 = 0.54, p = 0.02; Bayesian Linear Regression: BF10 = 3.79, n = 8) suggesting more infection when cutting. RN slightly changed in response to life-long accumulated CAB, Cmn, H, and HAV (BMLR, BF10 from 1.10 to 2.82, n = 24). RAB slightly changed responding to C, H, HAV, Q, and QAV (BMLR, BF10 = 1.11; MLR: p < 0.05, n = 24). AG declined in response to Cmn (MLR, R2 = 0.38, p < 0.001, n = 24). Thus, under favourable conditions severely wounded-and-infected trees keep re-sprouting and growing, even if growth is reduced.