Interaction Of Light Research Articles

Investigating the fractional Caudrey-Dodd-Gibbon-Sawada-Kotera equation: an iterative framework for nonlinear wave dynamics

Abstract This paper addresses the solution of the fractional Caudrey-Dodd-Gibbon-Sawada-Kotera (CDGSK) equation using the Conformable Laplace Decomposition Method (CLDM). The CDGSK equation, a fundamental model in wave dynamics and fluid mechanics, is explored for its applications in quantum mechanics and nonlinear optics. By employing fractional calculus, we demonstrate how fractional derivatives influence the physical characteristics of wave propagation in both optical and quantum systems. The exact solutions obtained provide insight into soliton behavior, essential for understanding wave-particle interactions in quantum fields and light–matter interactions in optics. The fractional nature of the equation allows for more accurate modeling of non-integer order dynamics commonly found in optical fibers and quantum waveguides. The CLDM method proves to be highly effective, providing approximate solutions with minimal computational effort. These findings offer significant contributions to the fields of quantum mechanics and nonlinear optics, where the fractional CDGSK equation can be applied to solve complex wave equations with great accuracy.

A Polarization‐Insensitive and Adaptively‐Blazed Meta‐Grating Based on Dispersive Metasurfaces

AbstractThe diffraction efficiency of blaze gratings is optimized only at a specific frequency due to a fixed blaze angle, resulting in reduced and variable diffraction efficiencies over the working frequency band. Additionally, blazed gratings demonstrate polarization dependence due to their groove structures and the interaction of light with their surfaces. Consequently, designing gratings with constant diffraction efficiencies across a wide frequency bandwidth while maintaining polarization independence remains a challenge. Here, a design paradigm of dispersion engineerable meta‐grating inspired by orthogonal harmonic oscillations (OHO) is presented. Utilizing the OHO model, the phase dispersion of a metasurface can be precisely controlled, which applies to any unit cell featuring two orthogonal electromagnetic resonances. As a proof of concept, a polarization‐insensitive meta‐grating is showcased, where the blazed angle adapts with the incident frequency, ensuring broadband performance. In the experiment, the adaptively‐blazed grating measured an optimized and constant diffraction efficiency of ≈80% over the working wavelength range, i.e., 8.7–12.2 µm. The difference in diffraction efficiency between the two perpendicular linear polarization states remains within 4.6%. The proposed paradigm paves the way for meta‐device design based on precise dispersion engineering, which has potential applications in spectrometers, broadband beam forming and steering, hyperspectral imaging, etc.

Chirality-induced phonon spin selectivity by elastic spin–orbit interaction

Spin and orbital degrees of freedom are crucial in not only fundamental particles but also classical waves such as optical systems, wherein the spin-orbit interaction (SOI) of light provides new perspectives for manipulating electromagnetic waves. Elastic waves possess similar spin angular momentum (SAM) and orbital angular momentum (OAM). However, the elastic counterpart of SOI remains unexplored, even for ubiquitous elastic waveguides (WG). Here, we demonstrate the existence of elastic SOI in helical WG. We prove that the torsion and curvature of helical WG induces synthetic gauge potentials in describing the elastic vibrations. Through analytical theory and simulations, we unveil the interplay among elastic SAM, intrinsic OAM, and extrinsic OAM, impacted by the elastic SOI. Importantly, results show that elastic SOI can introduce the Chirality-Induced Phonon Spin Selectivity. These findings advance our understanding of angular momentum physics in elastic waves and enable practical strategies for wave manipulation.

IoT real-time monitoring system implemented to observe sunlight-influenced methylene blue degradation by AC/HAp.

Activated carbon (AC) and hydroxyapatite (HAp) composite were successfully prepared via mechanical mixing and exhibited a crushed snack-like morphology compared to the well-defined pore structure of pure AC. The purpose of this research was to explore the potential of AC/HAp for the degradation of methylene blue (MB) dye and hydrogen production. Despite the morphological changes, AC and AC/HAp achieved a high MB degradation rate (92.75 and 82.05) % under sunlight, at a temperature of 26.24°C and pH of 4.18, and showed optimum hydrogen production (3579mol/g.h). These performances are suspected from the decrease in crystallite size and narrowed and confirmed by image processing results with RBG enhancement showing more light transmitted by the solution. Increasing in indicates the potential for improved light interaction. IoT-enabled real-time monitoring system demonstrates its efficacy in facilitating wastewater treatment and hydrogen production, offering a promising solution for aquatic ecosystem restoration.

A Surface‐based Appearance Model for Pennaceous Feathers

AbstractThe appearance of a real‐world feather results from the complex interaction of light with its multi‐scale biological structure, including the central shaft, branching barbs, and interlocking barbules on those barbs. In this work, we propose a practical surface‐based appearance model for feathers. We represent the far‐field appearance of feathers using a BSDF that implicitly represents the light scattering from the main biological structures of a feather, such as the shaft, barb and barbules. Our model accounts for the particular characteristics of feather barbs such as the non‐cylindrical cross‐sections and the scattering media via a numerically‐based BCSDF. To model the relative visibility between barbs and barbules, we derive a masking term for the differential projected areas of the different components of the feather's microgeometry, which allows us to analytically compute the masking between barbs and barbules. As opposed to previous works, our model uses a lightweight representation of the geometry based on a 2D texture, and does not require explicitly representing the barbs as curves. We show the flexibility and potential of our appearance model approach to represent the most important visual features of several pennaceous feathers.

Blue light reflectance imaging in non-perfusion areas detection: insights from multimodal analysis

DesignA retrospective, cross-sectional image analysis using a convenience sample.SubjectsFive cases selected based on the availability of comprehensive imaging data.MethodsThis study involved a retrospective review of images from five cases, focusing on the use of retinal monochromatic blue light reflectance (BLR) imaging to detect non-perfusion areas. Two cases of sickle-cell retinopathy demonstrated peripheral retinal non-perfusion identified through widefield fluorescein angiography. Three other cases—one with branch retinal vein occlusion, one with branch retinal artery occlusion, and one presenting paracentral acute middle maculopathy showed focal macular non-perfusion detected by structural OCT and OCTA. The areas of nonperfused retinal tissue, confirmed by fluorescein angiography, OCT, and OCTA, were then correlated with findings from the BLR image. This correlation aimed to identify any potential associations between these imaging modalities.Main outcome measuresEnhance understanding of the utilization of retinal monochromatic BLR images as a non-perfusion biomarker.ResultsThe perfusion defects identified through fluorescein angiography were qualitatively correlated with hypo-reflective regions observed in the BLR images. A notable correlation was also observed between the OCTA deep capillary plexus findings and the BLR images. Additionally, areas of retinal thinning identified on structural OCT thickness maps corresponded with the hypo-reflective regions in the BLR images. This indicates the potential of BLR in identifying non-perfused retinal areas.ConclusionsThis study reinforces the evidence, through OCT, OCTA, and angiographic correlation, that the BLR can effectively identify areas of retinal non-perfusion in a non-invasive manner. Further research is warranted to assess the method’s sensitivity, specificity, and limitations. While the interaction of blue light with the retina, leading to specular reflections and scattering, is established, this research represents a pioneering effort in suggesting which specific retinal structures may be implicated in this phenomenon. This novel insight opens avenues for deeper exploration into the underlying mechanisms and potential clinical applications of utilizing the BLR imaging technique for assessing retinal vascular abnormalities.

Light and Color: Art and Science Using an Interdisciplinary Approach in Primary Education Teacher Training

Light and color present complex interactions whose understanding is not always intuitive. Over the past forty years, numerous studies have aimed to identify preconceived notions and the various models employed in schools. Numerous teaching and learning strategies, along with didactic analyses, often fail to consider the multidimensional and interdisciplinary nature of these phenomena. This article presents a teaching experience aimed at training future primary education teachers. The theoretical context of this proposal, designed within the domains of physical and chemical didactics and plastic and visual expression, will be discussed. Instruments consistent with qualitative action research were used. Some results from the analysis of students’ narratives, both in laboratory notebooks and in sessions recorded audiovisually, will be presented.

The mechanistic origin of amber pigmentation of Perithemis tenera (Say, 1840) wings (Odonata: Libellulidae) and its function in conspecific signalling

Animal coloration serves various signaling and non-signaling functions. In damselflies and dragonflies (Odonata), such colors may not only play photoprotective and/or thermoregulatory roles but also serve as visual signals during courtship and/or agonistic interactions. Here, we analyzed the coloration of Perithemis tenera wings, a potential secondary sexual ornament, applying spectrophotometry and visual modeling to gain a deeper understanding of their color mechanisms and functions. The amber coloration of the P. tenera wings results from the interaction of light with both the melanized chitin matrix and possibly ommochrome pigments. Additionally, by fitting the absorbance curve of P. tenera wings to the extinction coefficient of different melanins, we deduced that pheomelanin is likely the pigment embedded in the wing’s chitinous matrix. The amber coloration of P. tenera wings stands out against their natural habitat, making it detectable by conspecifics. Finding multiple pigments in the P. tenera wings not only enhances our understanding of the functional roles of pigmentation in Odonata but also offer broader insights into how structural and pigment-based colorations evolve as multifunctional traits.

Improving essential oil production and antioxidant properties of Carum copticum L. by titanium dioxide nanoparticles and light spectrum interaction under hydroponic conditions

Improving essential oil production and antioxidant properties of Carum copticum L. by titanium dioxide nanoparticles and light spectrum interaction under hydroponic conditions

Enhanced Photocatalysis via Inverse Opal Structures: Synthesis and Characterization of TiO2/ZnO and ZnO/TiO2 Composites Using Plasma-Enhanced ALD

Inverse opals (IO) based functional materials show potential in photocatalysis due to their unique light interaction properties. This study presents a low-temperature plasma-enhanced atomic layer deposition (PEALD) method for synthesizing TiO2, ZnO, and composite IOs using a polystyrene nanoparticle-based opal template. We comprehensively characterized the obtained materials using SEM-EDX, TSEM, TG, FTIR, XRD, Raman, ellipsometry, photoluminescence (PL), and UV-Visible spectroscopy. SEM analysis confirmed the successful formation of PEALD IOs with a periodically ordered structure, enabling conformal coating while preserving their original architecture. XRD and Raman analysis also confirmed that the IOs consisted of anatase for TiO2 and hexagonal wurtzite for ZnO. UV-Vis reflectance spectroscopy revealed strong UV absorption and modified photonic bandgaps (PBGs) for all materials. The bare and composite IOs exhibited PBGs in the visible region, suggesting that the arising "slow photon" effect might enhance photocatalysis. This study explored the photocatalytic degradation of 4-Nitrophenol (4-NP) and Rhodamine 6G (Rh6G) using pristine and composite IO photocatalysts under UV and visible light irradiation. Pristine TiO2 and ZnO IOs demonstrated superior performance for 4-NP degradation under UV light. This can be attributed to two key factors: their highly ordered macroporous structure (with a large surface area for efficient dye adsorption, and their band gaps (3.0 eV for TiO2 and 3.2 eV for ZnO) that enable strong absorption of UV light photons for effective pollutant degradation. Conversely, composite IOs (TiO2/ZnO and ZnO/TiO2) displayed higher activity for both test molecules under visible light due to a synergistic effect between bandgap harmonization and the PBG effect.

Large-scale high purity and brightness structural color generation in layered thin film structures via coupled cavity resonance

Abstract Structural colors, resulting from the interaction of light with nanostructured materials rather than pigments, present a promising avenue for diverse applications ranging from ink-free printing to optical anti-counterfeiting. Achieving structural colors with high purity and brightness over large areas and at low costs is beneficial for many practical applications, but still remains a challenge for current designs. Here, we introduce a novel approach to realizing large-scale structural colors in layered thin film structures that are characterized by both high brightness and purity. Unlike conventional designs relying on single Fabry–Pérot cavity resonance, our method leverages coupled resonance between adjacent cavities to achieve sharp and intense transmission peaks with significantly suppressed sideband intensity. We demonstrate this approach by designing and experimentally validating transmission-type red, green, and blue colors using an Ag/SiO2/Ag/SiO2/Ag configuration on fused silica substrate. The measured spectra exhibit narrow resonant linewidths (full width at half maximum ∼60 nm), high peak efficiencies (>40 %), and well-suppressed sideband intensities (∼0 %). In addition, the generated color can be easily tuned by adjusting the thickness of SiO2 layer, and the associated color gamut coverage shows a wider range than many existing standards. Moreover, the proposed design method is versatile and compatible with various choices of dielectric and metallic layers. For instance, we demonstrate the production of angle-robust structural colors by utilizing high-index Ta2O5 as the dielectric layer. Finally, we showcase a series of printed color images based on the proposed structures. The coupled-cavity-resonance architecture presented here successfully mitigates the trade-off between color brightness and purity in conventional layered thin film structures and provides a novel and cost-effective route towards the realization of large-scale and high-performance structural colors.

Computational Modeling of Light Scattering in Polymer Nanoparticles for Optical Characterization

The scattering of light by polymeric nanoparticles is a crucial phenomenon in various applications, ranging from nanomedicine to nanophononics. This study introduces a theoretical framework for differentiating between absorption and scattering spectra in light interactions with these nanoparticles. Characteristic spectral data of nanoparticles synthesized via the reprecipitationmethod and suspended in an aqueous medium analyzed under electromagnetic radiation. These nanoparticles exhibit two primary optical phenomena: absorption and scattering. To fully understand their optical response, it is essential to separate these phenomena. This study established a relationship between wavelength variation, nanoparticle size, and radiation loss due to scatteringin an aqueous medium. Additionally, we calculated extinction efficiency and extinction factors as functions of wavelength, taking into account variations in nanoparticle radii and refractive indices.

Multimodal In-Sensor Computing System Using Integrated Silicon Photonic Convolutional Processor.

Photonic integrated circuits offer miniaturized solutions for multimodal spectroscopic sensory systems by leveraging the simultaneous interaction of light with temperature, chemicals, and biomolecules, among others. The multimodal spectroscopic sensory data is complex and has huge data volume with high redundancy, thus requiring high communication bandwidth associated with high communication power consumption to transfer the sensory data. To circumvent this high communication cost, the photonic sensor and processor are brought into intimacy and propose a photonic multimodal in-sensor computing system using an integrated silicon photonic convolutional processor. A microring resonator crossbar array is used as the photonic processor to implement convolutional operation with 5-bit accuracy, validated through image edge detection tasks. Further integrating the processor with a photonic spectroscopic sensor, the in situ processing of multimodal spectroscopic sensory data is demonstrated, achieving the classification of protein species of different types and concentrations at various temperatures. A classification accuracy of 97.58% across 45 different classes is achieved. The multimodal in-sensor computing system demonstrates the feasibility of integrating photonic processors and photonic sensors to enhance the data processing capability of photonic devices at the edge.

Bacterial Responses and Material-Cell Interplays With Novel MoAlB@MBene.

Developing efficient antibacterial nanomaterials has potential across diverse fields, but it requires a deeper understanding of material-bacteria interactions. In this study, a novel 2D core-shell MoAlB@MBene structure is synthesized using a mild wet-chemical etching approach. The growth of E. coli, S. aureus, and B. subtilis bacteria in the presence of MoAlB@MBene decreased in a concentration-dependent manner, with a prolonged lag phase in the initial 6h of incubation. Even under dark conditions, MoAlB@MBene triggered the formation of intercellular reactive oxygen species (ROS) and singlet oxygen (1O2) in bacteria, while the bacteria protected themselves by forming biofilm and altering cell morphology. The MoAlB@MBene shows consistent light absorption across the visible range, along with a distinctive UV absorption edge. Two types of band gaps are identified: direct (1.67eV) and indirect (0.74eV), which facilitate complex light interactions with MoAlB@MBene. Exposure to simulated white light led to decreased viability rates of E. coli (20.6%), S. aureus (22.9%), and B. subtilis (21.4%). Altogether, the presented study enhances the understanding of bacteria responses in the presence of light-activated 2D nanomaterials.

Tunable MXene/WO3 Fabry−Pérot Microcavity Architecture for Bioinspired Soft Electrochromic Actuators with Vivid Colors

AbstractInspired by stimuli‐responsive creatures in nature, developing devices with synergistic color change and deformation will be of great value for realizing the adaptive variants. Yet, integrating adaptive color variation and deformation into a single device remains elusive. Herein, an intriguing electrochromic actuator based on MXene/WO3 bilayer film is developed with Fabry−Pérot (F–P) microcavity, which successfully integrates both functions of reversible deformation and vivid color variations into the same device. Upon applying a small electric field, the ion intercalation/de‐intercalation can synchronously alter the stress distribution and optical absorption of MXene/WO3, resulting in the dual response of electrochromic phenomenon and ultra‐fast deformation with a maximum angle of 95° within 10 s. Moreover, the F–P microcavity architecture with the physical light interaction additionally endows the bilayer film with a bright color gamut and high color tunability (yellow–green, purple, pink, blue, etc.). Furthermore, an asymmetric soft actuator based on MXene/WO3 bilayer film is assembled, which displays robust grasping ability and excellent cycling stability up to 1000 cycles. These findings may open new opportunities for somatosensory soft robots and next‐generation intelligent robots.

Light Exposure on Alertness after Wake-Up in Healthy Men: Comparing Dim, Bright, Red, and Blue Light

Introduction: Light is a key factor in moderating human alertness, both subjective and objective. However, the methodology applies in research on the effects of exposure to light of different wavelengths and intensities on objective and subjective alertness varies greatly and evidence on objective alertness in particular is still inconclusive. Thus, the present, highly standardized within-subject laboratory study on N = 44 healthy males explored how LED light of different intensities (dim vs. bright light) and wavelengths (red vs. blue) affected objective (reaction time/RT) as well as subjective (sleepiness) alertness in the morning after wake-up. Methods: Participants spent two separate nights in the laboratory and were exposed to either one of the two light intensities or colors for 60 min after wake-up. Additionally, they indicated their sleepiness on the Karolinska Sleepiness Scale and participated in an auditory RT task before and after light intervention. It was hypothesized that both bright and blue light would lead to greater subjective and objective alertness when compared to dim and red light, respectively. Results: Results indicated that average RTs were longer for participants in the bright light condition (p = 0.004, f2 = 0.07) and that RTs decreased post-light exposure irrespective of light being dim or bright (p = 0.026, f2 = 0.07). However, dim versus bright light and RT did not interact (p = 0.758, f2 = 0.07). Chronotype was a significant covariate in the interaction of dim versus bright light and subjective sleepiness (p = 0.008, f2 = 0.22). There was no difference in RTs when comparing exposure to red or blue light (p = 0.488, f2 = 0.01). Findings on subjective sleepiness and light of different wavelengths revealed that sleepiness was reduced after light exposure (p = 0.007, f2 = 0.06), although the wavelength of light did not appear to play a role in this effect (p = 0.817, f2 = 0.06). Conclusion: Hence, neither of the hypotheses could be confirmed. However, they indicated that evening types might benefit from exposure to bright light regarding sleepiness, but not morning types.

Modulation transfer protocol for Rydberg RF receivers

We propose and demonstrate a modulation transfer protocol to increase the detection sensitivity of a Rydberg RF receiver to fields out of resonance from the transition between Rydberg levels. This protocol is based on a phase modulation of the control field used to create the Electromagnetically Induced Transparency signal. The nonlinear wave mixing of the multi-component coupling laser and the probe laser transfers the modulation to the probe laser, which is used for the RF-field detection. The measurements compare well with semi-classical simulations of atom–light interaction and show an improvement in the RF bandwidth of the sensor and an improved sensitivity of the response to weak fields.

Extreme Electron-Photon Interaction in Disordered Perovskites.

The interaction of light with solids can be dramatically enhanced owing to electron-photon momentum matching. This mechanism manifests when light scattering from nanometer-sized clusters including a specific case of self-assembled nanostructures that form a long-range translational order but local disorder (crystal-liquid duality). In this paper, a new strategy based on both cases for the light-matter-interaction enhancement in a direct bandgap semiconductor - lead halide perovskite CsPbBr3 - by using electric pulse-driven structural disorder, is addressed. The disordered state allows the generation of confined photons, and the formation of an electronic continuum of static/dynamic defect states across the forbidden gap (Urbach bridge). Both mechanisms underlie photon-momentum-enabled electronic Raman scattering (ERS) and single-photon anti-Stokes photoluminescence (PL) under sub-band pump. PL/ERS blinking is discussed to be associated with thermal fluctuations of cross-linked [PbBr6]4- octahedra. Time-delayed synchronization of PL/ERS blinking causes enhanced spontaneous emission at room temperature. These findings indicate the role of photon momentum in enhanced light-matter interactions in disordered and nanostructured solids.

Hexagonal Enhanced Porous GaN with Delayed Integrated Pulse Electrochemical (iPEC) Etching

This present study investigates the effect of time delay (Td) on the formation of porous GaN (P-GaN) using integrated pulse electrochemical (iPEC) etching. Porous GaN (P-GaN) was formed by etching an N-type GaN wafer with a 4% KOH electrolyte for 60 minutes under an ultraviolet (UV) lamp at a current density of 80 mA/cm2. A Td of 120 minutes was applied before electrochemically etching the P-GaN sample. The top view image of the field emission scanning electron microscopy (FESEM) revealed a significant difference when a Td was applied. A dense and uniform hexagonal P-GaN was obtained from the Td iPEC sample, while the non-Td sample exhibited a multi-layered hexagonal porous structure with unfinished pore-etched areas. Higher porosity and deeper pores were observed in the Td sample. Intense high-resolution X-ray diffraction (HR-XRD) peak intensity was observed in the Td iPEC sample with a lower full width half maximum (FWHM), indicating that the sample had better crystallinity. The Raman spectra of the sample anodized with a Td exhibited higher Raman peak intensity and a slight shift to a higher frequency concerning as-grown GaN, indicating better crystallinity and a tensile stress relaxation of 0.24 GPa. Post etching, a blue shift of the photoluminescence (PL) peak, from 364 nm (as-grown GaN) to 363 nm (P-GaN), was observed, and a small PL peak started to form around 385 nm compared to the as-grown GaN due to the relaxation of the tensile stress, which modified the bandgap. The PL peak intensity of the Td sample was higher than the non-Td sample, indicating that the porosity and uniformity allowed more light interaction with the material, resulting in more efficient photon absorption and emission. The results indicated that potentially efficient optoelectronics devices can be fabricated on a P-GaN using a combination of electroless and electrochemical etching of the GaN epitaxial layer.

Rheological modelling of apple puree based on machine learning combined Monte Carlo simulation: Insight into the fundamental light- particle structure interaction processes

In this work, apple purees from different particle concentration and verifying in size were reconstituted to investigate their impacts on rheological behaviors, optical properties and light interaction at 900–1650 nm. The optical scattering of different puree particle concentration varied more intensively than particle size. Based on Monte Carol simulation (MCX), the highest proportion of diffuse reflection energy and absorption were observed in 1050 nm and 1480 nm, respectively. The averaged light propagation of all the photons in purees varied from 259.29 mm to 199.17 mm with the particle concentration from 25 % to 45 %. Finally, support vector machine regression based on optical scattering properties fused with MCX parameters at 1050 nm effectively evaluated puree apparent viscosity parameters (RPD > 2.39), viscous and elastic modulus (RPD > 2.47). These extended our knowledge of the fundamental light - particle structure interaction processes and provided a new solution for rheological modelling in pureed food.