Short-wave Light Research Articles

Synthesis, characterization, and double shielding performance for ultraviolet and short-wave blue light of ceria-based materials

In order to extend the photo-shielding range of ceria from the ultraviolet (UV) region (≤400 nm) to the high-energy short-wave blue light (BL) region (400–450 nm), three groups of ceria-based materials, including ceria nanoparticles (nano-CeO2), cerium-oxygen-sulfur (Ce-O-S) composites and samarium-cerium-oxygen-sulfur (Sm-Ce-O-S) composites, were prepared from the perspectives of improving the preparation method, non-metal doping and metal/non-metal co-doping. Although the three groups of as-prepared samples have similar phase composition, morphology and pore structure, the Sm-Ce-O-S composites show remarkable double shielding performance for UV light and short-wave BL. Compared with nano-CeO2 and Ce-O-S composites, Sm-Ce-O-S composites that retains the characteristics of n-type semiconductor exhibits a greater degree of lattice distortion, higher concentrations of Ce3+ (41.17 %) and oxygen vacancy (77.29 %), and narrower band gap (2.71 eV). Through the comparison of the three groups of samples, the order of modification degree from high to low is as follows: metal/non-metal co-doping > non-metal doping > improving the preparation method. This paper provides experimental and theoretical support for breaking through the bottleneck of ceria in the fields of UV shielding agents and catalysts.

Properties of Multistranded Twisted Graphene Fibers and Their Application in Flexible Light-Emitting Devices.

As a typical carbon-based material electrode, graphene fiber exhibits many advantages, such as good electrical conductivity, lightweight, and strong structural designability. Its demand is increasing in the wearable display field. With the help of fine denier fiber spinning combined with multistranded graphene fibers prepared via twisting and drafting, their petal-like twisted structure endows the fibers with a high specific surface area, enabling them to complete dye adsorption within 30 min. Simultaneously, compared with that of a single fiber with the same thickness, the volume specific resistance of a multistranded twisted graphene fiber is reduced by 2.4 times. During force sensing, the twisted structure of multistranded fibers exhibits varying simultaneity of fiber fracture with excellent resistance sensitivity reaching up to 55%. The multistranded twisted flexible graphene fibers demonstrate excellent robustness. Electroluminescent flexible devices prepared with graphene fibers and fiber braided fabrics with different organizational structures as electrodes emit highly saturated short-wave blue light during long-term multiple use. Therefore, multistranded twisted graphene fibers exhibit considerable potential for future applications in wearable multicolor smart displays and flexible optical signal electronics.

Assessing the attraction of narrow-spectrum and broad-spectrum artificial light to nocturnal insects: patterns and predictive models

The significant ecological risks posed by artificial light at night (ALAN) are rapidly increasing globally. The rapid development of narrow-spectrum light-emitting diodes (LEDs) presents various challenges for reducing fatal attraction to ALAN and associated ecological risks. However, the potential risks and variations in the fatal attraction have not been precisely measured and assessed. Insects are ecological indicator species and photosensitive animals that are often fatally attracted to ALAN. In this paper, we conduct phototaxis experiments in Tianjin, China. We explored insect phototactic behavior and rhythms by comparing the effects of different time periods and spectra on the number of phototactic insects using UV light as a baseline. The spectra include seven narrow-spectrum lights with different peak wavelengths and two broad-spectrum lights with different color temperatures. In general, shorter wavelength light was more attractive: short-wave blue light (447 nm and 478 nm) was the most attractive, followed by medium-wave green light (500 nm and 519 nm) and long-wave red light (627 nm, 660 nm, and 740 nm). Insects were more attracted to 4,500 K LEDs than 3,000 K LEDs, but the difference in attraction between 4,500 K and 3,000 K LEDs was not significant. For eco-risk periods, that is, the peak hours of the fatal attraction of insects to ALAN in the field, LEDs attract insects at the fastest rate from 20:00 to 21:30 (from 1.5 hours to 3 hours after sunset). The phototactic rate curves of insect orders differed among different spectral LEDs. We proposed a method to predict the relative attractiveness of LEDs to insects and orders by calculating the relative attraction coefficient (Pi) of each narrow-spectrum LED and assigning Pi as a coefficient to the spectral irradiance percentage of the corresponding band of the LEDs to be predicted. The model-calculated relative attraction was highly significantly correlated with both the experimentally obtained attraction and the spectral response of insect vision. The results demonstrate that the attractiveness of broad-spectrum LEDs to insects can be altered, evaluated, and predicted through narrow-spectrum LEDs. Our findings will aid the development of ecological light sources, ecological conservation, and improvements in urban light ecology.

Preventative Effects of Cordyceps cicadae Mycelial Extracts on the Early-Stage Development of Cataracts in UVB-Induced Mice Cataract Model.

Cataracts, a prevalent age-related eye condition, pose a significant global health concern, with rising rates due to an aging population and increased digital device usage. In Taiwan, cataract prevalence is particularly high, reaching up to 90% among individuals aged 70 and above. The lens of the eye absorbs short-wave light, which can lead to oxidative stress in lens epithelial cells and contribute to cataract formation. Exposure to ultraviolet (UV) light further exacerbates the risk of cataracts by generating reactive oxygen species. Heat-shock proteins (HSPs), involved in protein maintenance and repair, have been linked to cataract development. Cordyceps cicadae (C. cicadae), a traditional Chinese medicine, has a long history of use and is known for its pharmacological effects. N6-(2-hydroxyethyl) adenosine (HEA), a bioactive compound found in C. cicadae, exhibits anti-inflammatory, immunomodulatory, and neuroprotective properties. Previous studies have shown that C. cicadae mycelial extracts improve dry eye disease and reduce intraocular pressure in animal models. Additionally, C. cicadae possesses antioxidant properties, which are beneficial for combating cataract formation. In this study, we aim to evaluate the preventive efficacy of C. cicadae mycelial extracts in UV-induced cataract development. By investigating the ameliorative effects of C. cicadae on eye diseases and its potential role in ocular health improvement, we hope to uncover new options for cataract prevention and provide insights into the mechanisms of action. The findings of this research could provide a novel approach for nutritional supplements targeting cataract prevention, offering potential benefits in the field of ocular health.

A Dietary Strategy for Optimizing the Visual Range of Athletes.

Visual range is quantified by assessing how far one can see clearly (an ability crucial to many athletes). This ability tends to vary significantly across individuals despite similar personal characteristics. We hypothesize that the primary driver of these differences is the individual response to scattered short-wave light in the environment moderated by the dietarily derived retinal pigments lutein and zeaxanthin.

The Effects of Blue-Light Filtering Intraocular Implants on Glare Geometry

Purpose One common complaint with natural opacified lenses is the deleterious effects of higher-order ocular aberrations and intraocular scatter, such as halos and starbursts, which are not always remedied with surgery and intraocular lens (IOL) implantation. Blue-light filtering (BLF) IOL filter scatter-prone short-wave light. Here, we determine whether BLF IOL reduce halo and starburst size. Methods This study was a case-control design, between- and within-subjects (contralateral implantation). Sixty-nine participants with either the BLF IOL (n = 25; AlconSN60AT), clear IOL (n = 24; AlconSA60AT or WF), or both (n = 20) IOL participated. Participants were exposed to a point source of broadband simulated sunlight, which created the appearance of halos/starbursts. Dysphotopsia was measured as the diameter of broadband light-induced halos and starbursts. Results A case-control analysis. Halo size was significantly larger (t[35.05] = 2.98, p = 0.005) in participants with the clear control lens (M = 3°55′ ± 2°48′), compared to the BLF IOL (M = 1°84′ ± 1°34′). Starburst size was not significantly different between groups. Contralateral analysis. Halo size was significantly smaller (t = −3.89, p = .001) in test eyes with the BLF (M = 3°16′ ± 2°35′) compared to the fellow control eyes (M = 5°42′ ± 3°17′). Starburst size was also significantly smaller (t = −2.60, p < 0.018) in BLF test eyes (M = 9°57′ ± 4°25′) than the fellow eye with the clear IOL (M = 12°33′ ± 5°25′). Conclusions BLF IOL filter short-wave light and mimic retinal screening by the young, natural crystalline lens. Such filtering can reduce some deleterious effects of bright light by decreasing ocular diffusion/halos and starbursts.

Welding Arc Maculopathy Caused by Malfunction of a High-tech Electronic Protection Shield

Welderʼs arc maculopathy is a rarely described outer retinal photic damage mainly caused by radiation in the short-wave visual light spectrum [1], [2]. Contemporary shielding devices convey effective protection by electronically controlled adaptive filter systems installed in welding helmets. In this report, the observation of welding arc retinopathy is described in a case after use of a malfunctioning high-tech welding helmet.

Centimeter-size single crystals of 2D hybrid perovskites for shortwave light photodetection with a low detection limit

Weak shortwave light photodetection with a low detection limit was achieved via centimeter-size single crystals of 2D perovskite (PA)2PbBr4. Under an extremely low illumination of 20 nW cm−2, the detector still exhibits a remarkable photoresponse.

Robust and Enhanced Short-Wave Near-Infrared Light Emission in Phosphorene through Photon-Activated Oxidation

Robust and Enhanced Short-Wave Near-Infrared Light Emission in Phosphorene through Photon-Activated Oxidation

Calculation of high-order harmonic generation of atoms and molecules by combining time series prediction and neural networks.

High-order harmonic generation (HHG) from the interaction of ultra-intense laser pulses with atoms is an important tabletop short-wave coherent light source. Accurate quantum simulations of it present large computational difficulties due to multi-electron multidimensional effects. In this paper, the time-dependent response of hydrogen atoms is calculated using a time-series prediction scheme, the HHG spectrum is reconstructed very accurately. The accuracy of the forecasting is further improved by using a neural network scheme. This scheme is also applied to the simulation of the harmonic emission on multi-electron systems, and the applicability of the scheme is confirmed by the harmonic calculation of complex systems. This method is expected to simulate the nonlinear dynamic process of multi-electron atoms and molecules irradiated by intense laser pulses quickly and accurately.

High-energy short-wave blue light conversion films via carbon quantum dots for preventing retinal photochemical damage

It is urgent to develop anti-high-energy short-wave blue light films for preventing retinal damage. Carbon quantum dots (CQDs) with robust optical tuning properties are potential candidates for addressing the issue. Here, bright yellow CQDs (Y-CQDs) with quantum yields up to 71% are synthesized via the alkali-catalyzed molecular fusion strategy, which demonstrates excellent anti-short-wave blue light performance. To construct anti-short-wave blue light WLEDs, the flexible transparent Y-CQD/PVA films are manufactured by mixing Y-CQDs and PVA, whose short-wave blue light conversion performance is further verified by being applied on R-, G-, B-LEDs, and WLED. Furthermore, a series of biological experiments regarding retinal protection from photochemical damage is further conducted, verifying that the Y-CQD/PVA films (≥20 wt%) have a significant protective effect on the retina. Our discoveries endow CQDs with a permit into the field of light conversion and will propel the progress of carbon-based optical materials for manufacturing forward-looking anti-short-wave blue light films and devices.

Pupillary response to chromatic light stimuli as a possible biomarker at the early stage of glaucoma: a review.

Glaucoma is a multifactorial neurodegenerative disease of the optic nerve currently considered a severe health problem because of its high prevalence, being the primary cause of irreversible blindness worldwide. The most common type corresponds to Primary Open-Angle Glaucoma. Glaucoma produces, among other alterations, a progressive loss of retinal ganglion cells (RGC) and its axons which are the key contributors to generate action potentials that reach the visual cortex to create the visual image. Glaucoma is characterized by Visual Field loss whose main feature is to be painless and therefore makes early detection difficult, causing a late diagnosis and a delayed treatment indication that slows down its progression. Intrinsically photosensitive retinal ganglion cells, which represent a subgroup of RGCs are characterized by their response to short-wave light stimulation close to 480nm, their non-visual function, and their role in the generation of the pupillary reflex. Currently, the sensitivity of clinical examinations correlates to RGC damage; however, the need for an early damage biomarker is still relevant. It is an urgent task to create new diagnostic approaches to detect an early stage of glaucoma in a prompt, quick, and economical manner. We summarize the pathology of glaucoma and its current clinical detection methods, and we suggest evaluating the pupillary response to chromatic light as a potential biomarker of disease, due to its diagnostic benefit and its cost-effectiveness in clinical practice in order to reduce irreversible damage caused by glaucoma.

Ecology drives patterns of spectral transmission in the ocular lenses of frogs and salamanders

Abstract The spectral characteristics of vertebrate ocular lenses affect the image of the world that is projected onto the retina, and thus help shape diverse visual capabilities. Here, we tested whether amphibian lens transmission is driven by adaptation to diurnal activity (bright light) and/or scansorial habits (complex visual environments). Spectral transmission through the lenses of 79 species of frogs and six species of salamanders was measured, and data for 29 additional frog species compiled from published literature. Phylogenetic comparative methods were used to test ecological explanations of variation in lens transmission and to test for selection across traits. Lenses of diurnal (day‐active) and scansorial (climbing) frogs transmitted significantly less shortwave light than those of non‐diurnal or non‐scansorial amphibians, and evolutionary modelling suggested that these differences have resulted from differential selection. The presence of shortwave‐transparent lenses was common among the sampled amphibians, which implies that many are sensitive to shortwave light to some degree even in the absence of visual pigments maximally sensitive in the UV. This suggests that shortwave light, including UV, could play an important role in amphibian behaviour and ecology. Shortwave‐absorbing lens pigments likely provide higher visual acuity to diurnally active frogs of multiple ecologies and to nocturnally active scansorial frogs. This new mechanistic understanding of amphibian visual systems suggests that shortwave‐filtering lenses are adaptive not only in daylight conditions but also in those scotopic conditions where high acuity is advantageous. Read the free Plain Language Summary for this article on the Journal blog.

High Tg and excellent ultraviolet-shielding efficiency modified PMMA derived from protocatechuic acid

The precise synthesis of acrylate derived from protocatechuic acid was reported for the first time via a simple two-step reaction route. Copolymerizing the monomer with methyl methacrylate in the presence of radical initiator gave the copolymers. The copolymer exhibited high glass transition temperature (Tg) and thermostability, excellent ultraviolet-shielding efficiency and good dimensional stability. Moreover, the modified polymethyl methacrylate (PMMA) also showed good mechanical properties while the transparency lightly decreased in visible light. The best results were obtained when the weight ratio of methyl methacrylate and protocatechuic acid -based acrylate was 1:1. In that case, the cured polymer showed Tg of 159.6 °C and a coefficient of thermal expansion (CTE) of 69.54 ppm/°C. The shielding rate of copolymer reached 99.38% in ultraviolet light (320–400 nm) and 82.56% in short-wave blue light (400–450 nm). These indicated that it may be applied to lenses, and this contribution would provide a new way for the conversion of bio-based glucose to the high-performance polymers.

Improvement of the far-infrared optical property for glasses by plasma-assisted dispersion of fluorocarbon species into the shallow surface.

Owing to global warming together with the demands for thermal energy storage in diverse fields, there is demand for transparent glasses achieving reflection of the short-wave far-infrared (IR) light from solar radiation while also absorbing the longer wavelength part. Here, we performed the plasma-assisted ion implantation using a desktop-type low-pressure fluorocarbon plasma generator system to improve the optical properties of transparent soda-lime glasses. Investigations using positron annihilation techniques for the plasma-treated glass demonstrated that the fluorocarbon species occupy the sub-nanoscale interstitial sites available in the glass network of the soda-lime glass as the intrinsic open spaces, forming an implantation layer in the shallow-surface region around a depth of 50nm. As revealed by optical spectroscopy, the subsurface layer, due to the implanted fluorocarbon species, significantly cuts off the short-wave far-IR light around a wavelength of ∼3 µm and also acts as the absorber of the longer wavelength region from 7 to 12 µm. Plasma treatment could be a promising tool to improve the optical properties in the IR light region for various materials.

Molecular Engineering toward an Enlarged Optical Band Gap in a Bismuth Sulfate via Homovalent Cation Substitution.

Materials capable of generating coherent short-wave (<300 nm) light have attracted extensive scientific and technical interest due to their wide utilization in laser research. In this study, a the rare-earth-metal sulfate NaCe(SO4)2(H2O) (NCSO) was synthesized through a hydrothermal method, while NaBi(SO4)2(H2O) (NBSO) was successfully obtained via a homovalent cation substitution of the parent compound NCSO under hydrothermal conditions. The space groups of crystalline NCSO and NBSO are P3121 and P3221, respectively. Both compounds have similar connectivities which feature a three-dimensional channel structure formed by asymmetric [CeO9]15-/[BiO9]15- tricapped trigonal prisms and distorted [SO4]2- tetrahedra. The introduction of Bi3+ with larger ionic radii and stereochemically active lone-pair electrons simultaneously enhanced the SHG effect and band gap of NBSO in comparison to its parent compound NCSO. In contrast to NCSO, which possesses a narrow energy band gap (2.46 eV), NBSO displays the largest energy band gap (4.54 eV) among the reported bismuth sulfate NLO materials. Powder frequency-doubling-effect measurements exhibit that NCSO and NBSO possess phase-matchable SHG responses of 0.2 × KDP and 0.38 × KDP at 1064 nm, respectively. Theoretical studies have been implemented to further elucidate the structure-performance relationships of the two compounds. Experimental and theoretical studies both demonstrate that NBSO may be a promising nonlinear material applied in the short-wavelength region.

Electrostatic and Dynamic Analysis of P+PNP Double Junction Type and P+PNPN Triple Junction Type Pinned Photodiodes

This paper explains the device structure and operation of image sensors and solar cells. Both are semiconductor devices operating with the same physical principle of detecting photons. A high efficiency of the photon to electron energy conversion is very much desired in both devices. Image sensors now use a very advanced and scaled down CMOS fabrication process technology to achieve high performance features such as the excellent short wave blue light sensitivity for good color reproduction, the low noise and the no image lag picture quality for filmless and mechanical free action cameras. On the other hand, solar cells are still now built with the primitive floating N+P single junction type photodiode to minimize the fabrication process cost but with very low energy conversion efficiency of about 20%. It is explained in details that the depletion region of the PN junction is not the only place where we can achieve photo electron and hole pair separations effectively. The short-wave blue light has only 1000 Å silicon crystal penetration depth. The pinned surface P+P Gaussian doping profile has a very important role to achieve a better photon to energy conversion efficiency, especially for the short-wave blue light. Electrostatic and dynamic behaviors of Pinned Surface P+PNP Double Junction type Dynamic Photo Transistor and Pinned Surface P+PNPN Triple Junction type Dynamic Photo Thyristor are analyzed in details. Both of them are shown to be expected to have much excellent photon-to-electron energy conversion efficiency.

Blue-light-blocking CdS-PMMA nanocomposite films with tunable cut-off wavelength and narrow absorbing transitional band

The widespread application of white light-emitting diodes makes us surrounding by plenty of blue-rich light, promoting the development of blue-light-blocking filters because blue light between 415 and 455 nm wavelength can cause light damage to the retina cells. While longer wavelength blue light is also essential to trigger physiological responses, which puts forward higher requirements for the precise blue-light-blocking ability of the filters. In this paper, CdS quantum dot (QD) with strong absorption in the blue region was synthesized and its size was regulated by extended reaction time. Polymerizable molecule was chemically grafted on CdS surface and then copolymerized with methyl methacrylate (MMA) monomer for transparent films with a narrow absorption transition band (wavelength span from 0.05 to 0.8 Tmax) about 20 nm and tunable cut-off wavelength at 0.05 Tmax from 436.9 to 447.8 nm due to quantum size effect of CdS QD. This provides a possibility for more accurate adjustment of the blue-light-blocking performance, minimizing the harmful visual damage of short-wave blue light and preserving the beneficial physiological effects of long-wave blue light.

Theoretical study on the improvement of optoelectronic properties of Al_xGa_(1-x) As nanowires with variable Al content adsorbed by metal nanoparticles

GaAs nanowire arrays with variable Al content can effectively improve the photoelectric emission of nanowires due to the existence of internal electric field. Metal particles adsorb nanowires, which can excite local plasmons and enhance the optical absorption of nanowires. In this paper, the Al content change of Al_xGa_ (1-x) As material and metal particle adsorption are combined to study the light absorption and quantum efficiency of the Al_xGa_ (1-x) As nanowire array with metal particles adsorbed on the surface. Based on the finite element method and COMSOL multiphysics software, the effects of the number of metal nanoparticles, the distribution of particles, array period and particle size on the optical properties of the array are analyzed. The results show that metal particle adsorption can enhance the light capture ability of Al_xGa_(1-x) As nanowires arrays, the absorption of short wave light can be improved by adding adsorption particles layer by layer. Higher quantum efficiency can be obtained by appropriately increasing the array period and the diameter of metal particles of the structure.

Influence of Light and Water Activity on Growth and Mycotoxin Formation of Selected Isolates of Aspergillus flavus and Aspergillus parasiticus.

Aspergillus flavus and A. parasiticus are the main causes of aflatoxin contamination in various foods, particularly grains, as they can thrive in environments with lower water activity and higher temperatures. The growth of Aspergillus and the formation of the mycotoxins aflatoxin and cyclopiazonic acid are strongly influenced by environmental stimuli and can be reduced by modulating parameters such as water activity, pH, temperature and light during the storage. This study has two objectives—on the one hand, to assess how global warming and an increase in exposure to sunlight affect growth and mycotoxin formation, and on the other hand, how the findings from these experiments can be used to reduce fungal growth and mycotoxin formation in stored foods. Using growth substrates with two different water activities (aw 0.95, aw 0.98), together with a light incubation device consisting of different chambers equipped with diodes emitting visible light of five different wavelengths (455 nm, 470 nm, 530 nm, 590 nm, 627 nm) plus white light, we analyzed the growth and mycotoxin formation of selected Aspergillus flavus and A. parasiticus isolates. It was shown that light with a wavelength of 455/470 nm alone, but especially in combination with a lower water activity of aw 0.95, leads to a significant reduction in growth and mycotoxin formation, which was accompanied by reduced transcriptional activity of the responsible mycotoxin biosynthetic genes. Therefore, these results can be used to significantly reduce the growth and the mycotoxin formation of the analyzed fungi during storage and to estimate the trend of fungal infestation by Aspergillus flavus and A. parasiticus in water activity- and light exposure-equivalent climate change scenarios. Mycotoxin-producing aspergilli can be effective and sustainably inhibited using a combination of short-wave light and lowered water activity in the substrate. A higher annual mean temperature accompanying climate change may lead to an increased spread of aflatoxin-producing fungi in areas that were previously too cold for them. On the other hand, there will be regions in the world where contamination with aflatoxin-producing fungi will be reduced due to increased drought and sun exposure.