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Optical skyrmions are topologically stable quasiparticles that can be constructed with electric field, spin angular momentum, polarization Stokes vector, pseudospin, etc. In this letter, both theoretical and experimental studies are carried out to reveal the role of Gouy phase in the topology transformation during the tight focusing of Stokes skyrmions. The Stokes skyrmionic beam can be constructed by superposing two orthogonally polarized components with orthogonal spatial modes. The Gouy phase produced in the focused field depends on the orbital angular momentum carried by the high order mode component of the incident Stokes skyrmionic beam. While the beam size of the focused field is diffraction limited, the variation of the Stokes vectors in the skyrmion topology is in the sub‐diffraction limited scale. The presented results shed light on the understanding of the topology transformation between the incident and the tightly focused fields, paving the way for engineering the optical skyrmions in micro‐nano scale and their applications in information processing, quantum technology, metrology, etc. [ABSTRACT FROM AUTHOR]

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Two-dimensional (2D) transition metal dichalcogenides (TMDs) have garnered considerable attention for their promising applications in sensors and optoelectronic devices, owing to their exceptional optical, electronic, and optoelectronic properties. However, the inherent high symmetry of TMD lattices imposes limitations on their functional versatility. Here, we present a strategy to disrupt the C3 rotational symmetry of monolayer WSe2 by fabricating a heterostructure incorporating WSe2 and SiP flakes. Through comprehensive experimental investigations and first-principle calculations, we elucidate that in the WSe2/SiP heterostructure, excitons—both neutral and charged—emanating from WSe2 exhibit pronounced anisotropy, which remains robust against temperature variations. Notably, we observe an anisotropic ratio reaching up to 1.5, indicating a substantial degree of anisotropy. Furthermore, we demonstrate the tunability of exciton anisotropy through the application of a magnetic field, resulting in a significant reduction in the anisotropic ratio with increasing field strength, from 1.57 to 1.18. Remarkably, the change in heterojunction anisotropy ratio reaches 24.8% as the magnetic field increases. Our findings elucidate that the perturbation of the C3 rotational symmetry of the WSe2 monolayer arises from a non-uniform charge density distribution within the layer, exhibiting mirror symmetry. These results underscore the potential of heterostructure engineering in tailoring the properties of isotropic materials and provide a promising avenue for advancing the application of anisotropic devices across various fields. [ABSTRACT FROM AUTHOR]

Photonic technologies have made enormous impacts on modern medicine, advancing disease diagnostics and treatments as well as health monitoring. A long‐standing challenge in the use of light and its widespread effects in photomedicine is the finite penetration of light in tissues. However, judiciously engineered optical fibers helped overcome this challenge and advance light delivery to deep tissues with spatial precision and desired accessibility. In recent years, the development of photonic technologies including optical biomaterials, fiber functionalization, and biomedical device innovations has greatly expanded the scope of light‐based healthcare. Here, the fundamentals and materials of fiber optics to endow themselves with biocompatibility, flexibility, and diverse functionalities required for long‐term implantation are overviewed. The design strategies of lab‐on‐fiber techniques, operation requirements to construct fiber optic sensors, and their health monitoring applications as wearable and implantable devices are presented. The use of fiber optics in major light‐based therapeutic modalities including optogenetics, photodynamic therapy, photobiomodulation, photochemical cross–linking, and photothermal therapy is illustrated to enhance their effectiveness, specificity, and feasibility. In short, a comprehensive review is provided on the fiber optic techniques and the latest photonic devices, which are envisioned to evolve photomedicine in clinical and point‐of‐care practices. [ABSTRACT FROM AUTHOR]

Coherent Rayleigh scattering‐based distributed fibre optic sensing technology enables real‐time acquisition of vibration and acoustic information along the optical fibres. However, the complexity of monitoring environments often leads to false alarms and missed detections during the process of information source identification with distributed acoustic sensing (DAS). Therefore, it becomes crucial to effectively extract meaningful signal features and perform accurate pattern recognition in the presence of external noise disturbance. The authors provide a comprehensive review of signal feature extraction and pattern recognition techniques applied in DAS technology. After introducing the fundamentals of DAS, specific applications are considered, and the following techniques have been analysed and compared: feature extraction algorithms based on wavelet decomposition, feature extraction schemes utilising other decomposition models, traditional recognition classifiers, and neural network‐based recognition classifiers using deep learning. The advantages and limitations of each scheme are discussed, along with their potential applications in various scenarios. The aim is to provide insights into the latest technologies in signal processing and pattern recognition for DAS, fostering further advancements in this field. [ABSTRACT FROM AUTHOR]

Herein, we report the metal ion sensing property of two 2,2'‐bis (pyridylmethyl) amine‐based chromogenic probes at physiological pH in buffered media. The binding of metal ions to the bispicolyl site alters its electronic property, which subsequently influences the optical property of the covalently‐linked signaling unit. The compound experienced a change in the solution color from red to deep and light yellow respectively upon the addition of Cu2+ and Ni2+ ions. Further, it is observed that by modifying the signaling unit, one can tune the mode of metal ion binding and sensitivity. The compound with an electron‐deficient quinolinium unit as the signaling moiety, showed 2 : 1 stoichiometry of binding with metal ions, while the compound functionalized with a pyrene unit formed complexes with 1 : 1 stoichiometry. It was conferred that changes in the signaling moiety not only alter the basicity/nucleophilicity of the pyridine nitrogen ends but also influence their aggregation properties. Such kind of studies will be beneficial for engineering new optical probes with tuneable sensitivity. [ABSTRACT FROM AUTHOR]

In this study, we examine the dynamic behavior of optical solitons in the nonlinear conformable Gross–Pitaevskii equation (GPE) within Bose–Einstein condensates, which refer to the phenomenon of many ultra-cold bosonic particles occupying a single quantum state. The GPE is a cornerstone of advanced statistical physics, has application in various engineering disciplines, particularly in the realm of quantum mechanics and optical engineering. By precisely encoding the GPE’s steady-state solutions, we make it possible to compute nonlinear models pertinent to engineering systems and clarify solutions within particular parameter regimes that are essential for engineering applications. Our study encompasses repulsive and attractive nonlinearities in GPE, including quadratic and double-well potentials. We focus on discovering solutions, employing the generalized Riccati equation mapping method and modified extended tanh-function method to extract soliton solutions. The study yields a variety of soliton including combined dark–bright, singular, combo dark-singular, periodic-singular, and rational solutions with physical perspectives. Through 2D and 3D representations, the internal structure of these phenomena is effectively illustrated, offering insights into their behavior and dynamics, which is significant for optimization process and engineering design. [ABSTRACT FROM AUTHOR]

Doped semiconductors are more advantageous than pure semiconductors, because doping of a semiconductor can tune electrical conductivity and optical bandgap engineering that allows flexible designs of microelectronic and optoelectronic devices, respectively. In the present work, pure and Mn-doped SnO2 nanocrystallites have been prepared using single-step wet chemical method calcined at 500 °C and 650 °C to investigate structural, optical, impedance, and ferromagnetic properties. X-ray diffraction confirmed single-phase Mn-doped SnO2, and NEXAFS spectra further revealed + 2 oxidation state of Mn ions in SnO2. The surface morphology depicted densely packed grains and optical spectra showed Mn and temperature-dependent variation of bandgaps. While dielectric and impedance study disclosed frequency response and dominance of grains resistance. Further, conduction mechanism and room temperature ferromagnetism were improved with doping and sintering temperature. Hence, prepared compounds are attractive for frequency-related devices and data storage applications. [ABSTRACT FROM AUTHOR]

Endoscopy, enabling high-resolution imaging of deep tissues and internal organs, plays an important role in basic research and clinical practice. Recent advances in photoacoustic microscopy (PAM), demonstrating excellent capabilities in high-resolution functional imaging, have sparked significant interest in its integration into the field of endoscopy. However, there are challenges in achieving functional PAM in the endoscopic setting. This Perspective article discusses current progress in the development of endoscopic PAM and the challenges related to functional measurements. Then, it points out potential directions to advance endoscopic PAM for functional imaging by leveraging fiber optics, microfabrication, optical engineering, and computational approaches. Finally, it highlights emerging opportunities for functional endoscopic PAM in basic and translational biomedicine. [ABSTRACT FROM AUTHOR]

In this research work, the nonlinear Landau–Ginzburg–Higgs model under investigation on the base of auxiliary equation method. The nonlinear Landau–Ginzburg–Higgs equation mainly describe nonlinear wave propagation, categorizes wave velocity, and materializes several phenomena through the dispersive system. The secured optical soliton solutions are interested, more general and some novel in kink solitons, bright solitons, periodic singular solitons, anti-kink solitons and dark solitons. The physical structure of some explored solitons solutions are represented graphically as contour, 2D and 3D plots by utilizing the symbolic computational tool Mathematica. The secured soliton will be play important role to the investigation of nonlinear phenomena in the various domains of nonlinear sciences and engineering such as optical fibers, nonlinear dynamics, communication system, solitons wave theory, nonlinear optics, transmission system, electronic engineering and ocean engineering. The auxiliary equation method is a basic analytical, powerful, efficient approach for the investigation of optical soliton inside the nonlinear Landau–Ginzburg–Higgs equation and also other nonlinear equations. [ABSTRACT FROM AUTHOR]

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. • Structural, Thermal and Optical Performance (STOP) analysis on the ARIEL spacecraft. • Development of two procedures for temperature transfer between thermal and structural models. • Definition of a process to overcome computational issues found in thermal analysis in NASTRAN. • Validation of the proposed procedures for the temperature mapping of a large and complex model. • Comparison of results between two temperature mapping methods (PWT and PAT) on ARIEL. [ABSTRACT FROM AUTHOR]

In recent years, the concept of hyperbolic phonon polaritons (HPPs) has revolutionized the field of nanophotonic, enabling unprecedented control over light-matter interactions at the nanoscale. Here, we theoretically propose and study the lateral optical forces in twisted mixed-dimensional MoO3 homostructures. Assisted with the low-symmetry HPPs, we realize a lateral optical force exerted on the Au nanoparticles near the surface of mixed-dimensional MoO3 homostructures with a linear polarized incident light. By controlling the polarization state, incident angle of light and the twisted angle of MoO3, the amplitude and direction of the lateral optical forces can be tailored in the mid-infrared range. Our findings provide a new platform for engineering lateral optical forces to manipulate diverse objects in a flexible and efficient manner. [ABSTRACT FROM AUTHOR]

Two-dimensional WSi2X4 (X = N, P, As) has stimulated extensive studies due to its structural diversity and intriguing properties. Here, a systematic study on the strain engineering of electronic and optical properties in monolayer WSi2X4 is presented. Our results demonstrate that the monolayer WSi2X4 can withstand biaxial tensile strains of 13.1%, 16.3%, and 12.2% for X = N, P, and As, respectively, while the corresponding critical stresses are 27.90 GPa, 14.58 GPa,and 13.56 GPa, respectively. Furthermore, the bandgap of monolayer WSi2X4 can undergo a direct-to-indirect transition and even achieve a semiconductor-to-metal transition under appropriate biaxial strains. In addition, the light absorption of monolayer WSi2X4 in the visible region can be effectively improved by tensile strain, and the red (blue) shift of the absorption peak can be observed by tensile (compression) strain. The results show that monolayer WSi2X4 exhibits outstanding mechanical strength and physical properties, which is promising for future optoelectronic devices. [ABSTRACT FROM AUTHOR]

The construction of active materials with controllable optical response facilitates the development of advanced photonic devices. However, the achievement of robust active materials with wide wavelength tunable and broadband emission remains a great challenge, mainly due to the fixed energy levels of conventional active dopants and limited inhomogeneous broadening in common hosts. Here, the study proposes that the cluster in the mesoscopic scale of ≈1 nm may break this bottleneck issue and demonstrate a strategy for the management of photon emission by engineering the cluster evolution. The amorphous glass as the host to tailor the characteristic configuration of Te clusters from 1 to 2 nm by control of the topological structures in glass is employed. Impressively, it presents a distinct optical response totally different from the conventional active centers and this enables to construct of active photonic glass with continuously tunable emission from 888 to 1064 nm. More importantly, Te cluster‐activated photonic glass fibers are fabricated and the broadband on‐off gain is successfully achieved. Furthermore, benefiting from the unique tunable emission, novel near‐infrared devices are constructed and their application in imaging is demonstrated. The approach of cluster engineering mediated tunable optical response is believed to bring new opportunities for developing advanced photonic devices. [ABSTRACT FROM AUTHOR]

High-throughput microscopy is vital for screening applications, where three-dimensional (3D) cellular models play a key role. However, due to defocus susceptibility, current 3D high-throughput microscopes require axial scanning, which lowers throughput and increases photobleaching and photodamage. Point spread function (PSF) engineering is an optical method that enables various 3D imaging capabilities, yet it has not been implemented in high-throughput microscopy due to the cumbersome optical extension it typically requires. Here we demonstrate compact PSF engineering in the objective lens, which allows us to enhance the imaging depth of field and, combined with deep learning, recover 3D information using single snapshots. Beyond the applications shown here, this work showcases the usefulness of high-throughput microscopy in obtaining training data for deep learning-based algorithms, applicable to a variety of microscopy modalities. Implementing point spread function (PSF) engineering in high-throughput microscopy has proved challenging. Here, the authors propose a compact PSF engineering approach, which allows for enhanced depth of field and for the recovery of 3D information using single snapshots. [ABSTRACT FROM AUTHOR]

The realization of Janus monolayers presents an exciting opportunity to disrupt structural symmetry, opening up novel avenues in the realm of layered materials. While several ternary systems, comprising the group-III monochalcogenides, has been proposed for this purpose, the impact of oxygen interaction on the electronic, thermoelectric and optical characteristics of gallium and indium monochalcogenides has been observed. Interestingly, the concept of incorporating oxygen as a third element in ternary systems has not yet been explored extensively. Here we embark on the design and exploration of 2D A2OX (A = Ga, In and X = S, Se) monolayer through first-principles calculations. Our investigation includes the analysis of electronic band structure, optical and thermoelectric properties, revealing that Ga2OS, Ga2OSe and In2OS exhibit direct band nature. However, In2OSe is found to be metallic in unstrained condition. Moreover, the band gap in these materials can be fine-tuned through the application of tensile or compressive strain. Additionally, our analysis suggests strong optical absorption within the visible, and/or ultraviolet regions, depending on the specific system under consideration. Our findings reveal that Ga2OS and In2OS monolayers elevated power factors with application of tensile strain, rendering them as compelling candidates for applications in thermoelectric devices. [ABSTRACT FROM AUTHOR]

Nonlinear partial integro-differential equations (PIDEs) are applied to present the various practical phenomena in a multitude of sectors of modern science and engineering, especially in optic fiber, quantum electronics, modern physics, and the special field of nonlinear wave motion. Basically, our research demonstrates a way to generate a significant quantity of solutions to these types of two PIDEs. In this research, we have used an efficient mathematical tool namely the generalized G ′ / G -expansion method to acquire the closed form soliton solutions for the (2 + 1)-dimensional first integro-differential Kadomtsev–Petviashivili (KP) hierarchy equation and the (2 + 1)-dimensional second integro-differential KP hierarchy equation utilizing a code likely Mathematica. The explicit closed form soliton solutions of these two PIDEs are found in the pattern of trigonometric, hyperbolic, and rational functions which are compared to all the well-known results that are yielded in the paper. We attain solutions that are graphically displayed in addition to physically described in 3D structure, contour, and 2D, such as a bell-shaped soliton, a singular bell-shaped soliton, and some kink-shaped solitons. As far as the authors' wisdom, the outcomes of these problems gained by the offered expansion method are renewed closed form solitary wave and investigated here for the first time. The analysis of obtained results will be able to provide a constructive explanation of the physical phenomena in optical physics and engineering. [ABSTRACT FROM AUTHOR]

Auxetic materials have a negative Poisson's ratio and are of significant interest in applications that include impact mitigation, membrane separations and biomedical engineering. While there are numerous examples of structured materials that exhibit auxetic behavior, the examples of engineered auxetic structures is largely limited to periodic lattice structures that are limited to directional or anisotropic auxetic response. Structures that exhibit a three-dimensionally isotropic auxetic response have been, unfortunately, slow to evolve. Here we introduce an inverse design algorithm based on global node optimization to design three-dimensional auxetic metamaterial structures from disordered networks. After specifying the target Poisson's ratio for a structure, an inverse design algorithm is used to adjust the positions of all nodes in a disordered network structure until the desired mechanical response is achieved. The proposed algorithm allows independent control of shear and bulk moduli, while preserving the density and connectivity of the networks. When the angle bending stiffness in the network is kept low, it is possible to realize optimized structures with a Poisson's ratios as low as −0.6. During the optimization, the bulk modulus of these networks decreases by almost two orders of magnitude, but the shear modulus remains largely unaltered. The materials designed in this manner are fabricated by dual-material 3D-printing, and are found to exhibit the mechanical responses that were originally encoded in the computational design engine. The approach proposed here provides a materials-by-design platform that could be extended for engineering of optical, acoustic, and electrical properties, beyond the design of auxetic metamaterials. [ABSTRACT FROM AUTHOR]

This article is an interview with optical scientist and engineer Joseph Braat, who discusses his career and contributions to the field of optics. He talks about his experiences at the Institut d'Optique in Paris and his work on holography using spatially incoherent light. Braat also discusses his role in designing the light path for recording and reading optical discs, including CD, DVD, and Blu-ray technology. The article explores the development of optical data storage and lithography technology, noting the challenges faced and advancements made. It concludes with Braat's reflections on his career and advice for students and researchers in the field of optics and photonics. [Extracted from the article]

Energy sustainability and interconnectivity are the two main pillars on which cutting‐edge architecture is based and require the realization of energy and intelligent devices that can be fully integrated into buildings, capable of meeting stringent regulatory requirements and operating in real‐world conditions. Luminescent solar concentrators, particularly those based on near‐infrared emitting reabsorption‐free quantum dots, are considered good candidates for the realization of semi‐transparent photovoltaic glazing, but despite important advances in optical property engineering strategies, studies of finished devices suitable for real‐world operation are still lacking. In this paper, the first example of a fully assembled quantum dot luminescent solar concentrator‐based photovoltaic glazing is demonstrated that meets all international standards for photovoltaic and building elements. It is also shown that these devices are capable of functioning as efficient Visible Light Communication (VLC) receivers even under full sunlight, thus combining energy and wireless connectivity functions in a realistic solution for smart, sustainable buildings. [ABSTRACT FROM AUTHOR]

It is hard to overstate the utility of lasers in modern technology. Optical-fiber-based lasers are of particular value thanks to their combination of small form factors, afforded by the coilability of the thin strands of fiber, and high beam-quality output. The optical fiber geometry also possesses a relatively high surface-area-to-volume ratio, rendering thermal management somewhat more straightforward than in other bulk laser types. Regardless, the generation of heat during the lasing process can still be problematic for a myriad of reasons, and conventional methods of thermal management do not comport with the potential compactness and elegance of fiber lasers as technological solutions. This Perspective summarizes recent advances in glass science and optical fiber engineering to support the provocative premise that heat generation in future laser systems can be entirely managed by a combination of fiber materials and novel laser physics. Letting the fiber manage heat itself would have significant impacts on enhancing system performance while greatly reducing size, weight, power-consumption, and cost. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) MXenes, having comparable transport properties like graphene and a wide spectrum application, are often limited to being used in optoelectronics due to metallic bandgap. Here, by employing density functional theory we report the bandgap engineering and tuning optoelectronic properties through modulating the anions of novel 2D spinel Hf3X2O2 (X = N, P and As) MXenes structures and show that the material class can be among the few semiconducting MXenes. Phonon spectra and cohesive energies confirm that these structures are dynamically stable and chemically exothermic. Modulating anions X = N, P, and As in Hf3X2O2, the electronic bandgaps are found ∼0.46 eV for N, metallic for P, and ∼48 meV for As atoms, suggesting the semiconducting, metallic, and semi-metallic MXenes. The biaxial strains are incorporated to tune the features: In the Hf3N2O2 structure, the bandgap is increased with both compressive and tensile strains, while for the Hf3As2O2 structure, the gap decreased at the GGA-PBE level. For Hf3P2O2 structures, the bandgaps are all metallic irrespective of pristine or biaxial strain. Spin–orbit coupling SOC+GGA reveals that Hf3N2O2 is highly spin responsive while Hf3As2O2 shows semi-metal-to-metallic bandgap transition for pristine as well as biaxial strained conditions. From optical properties analysis, optical absorptions are found located in the visible spectral regions that are also highly receptive to biaxial strains. These properties we have unleashed for the novel Hf3X2O2 (X = N, P, As) semiconducting MXene, thus, show the potentiality of the utilization of the material class in nanoelectronics and optoelectronics applications. [ABSTRACT FROM AUTHOR]

Holographic techniques are indispensable tools for modern optical engineering. Over the past two decades, research about incoherent digital holography has continued to attract attention. Optical scanning holography (OSH) can obtain incoherent holograms using single-pixel detection and structured illumination with Fresnel zone patterns (FZPs). Particularly by changing the size of a detector, OSH can also obtain holograms under coherently illuminated conditions. Since 1979, OSH has continuously evolved. According to the evolution of semiconductor technology, spatial light modulators (SLMs) come to be useful for various imaging fields. By using SLM techniques for OSH, the practicality of OSH is improved. These SLM-based OSH methods are termed computational OSH (COSH). In this review, the configurations, recording and reconstruction methods, and proposed applications of COSH are reviewed. [ABSTRACT FROM AUTHOR]

We present the design and the experimental characterization of a miniature “portable” mini-endoscope with a large field-of-view (≈360rmmum) that operates with two spectral bands adapted for mCherry (peak emission at 610 nm) and GCaMP6s (peak emission at 513 nm) fluorophores. The diameter of the implant is very small (0.5 mm), the total weight is 1.8 g, the size is 10×12×21mm3, and the lateral resolution of the device is ≈4.5μm. This compact and lightweight system allows investigation of the neural activity of two different neuronal populations.

Defects introduced to synthetic type Ib diamond micrometer-size particles by electron-beam irradiation were studied by electron paramagnetic resonance and photoluminescence (PL) spectroscopy as a function of e-beam fluence and post-irradiation thermal annealing. Increasing electron-beam fluence causes a substantial reduction of the substitutional nitrogen (P1) content, accompanied by progressively higher concentrations of paramagnetic negatively charged vacancies (V−) and triplet interstitials (R1/R2). Annealing results in a drastic decrease in the V− and R1/R2 content and an increase in the negatively charged nitrogen-vacancies (NV− or W15). Analysis of PL spectra allows for identification of color centers in the irradiated diamond samples and following their evolution after annealing. These data facilitate understanding of different factors contributing to the formation of color centers in diamond and promote efforts toward controlled engineering of optical centers in fluorescent diamond particles. [ABSTRACT FROM AUTHOR]

A regional aerosol model can complement globally averaged models and improve the accuracy of atmospheric numerical models in local applications. This study established a seasonal aerosol model based on data from the Aerosol Robotic Network (AERONET) of the sea area around eastern China, and its performance in calculating the aerosol optical depth (AOD) was evaluated. The seasonal columnar volume particle size distributions (VPSDs) illustrated a bimodal structure consisting of fine and coarse modes. The VPSDs of spring, autumn, and winter roughly agreed with each other, with their amplitudes of fine and coarse modes being almost equal; however, the fine mode of the summer VPSD was approximately twice as high as that of the coarse mode. Lognormal mode decomposition analysis revealed that fine and coarse modes comprised two sub-modes. Fitting the seasonal VPSDs to the four-mode lognormal distribution yielded a parameterized aerosol size distribution model. Furthermore, seasonal variations in complex refractive indices (CRIs) indicated unignorable changes in aerosol compositions. Overall, error analysis validated that the proposed model could meet accuracy requirements for optical engineering applications, with median AOD calculation errors of less than 0.01. [ABSTRACT FROM AUTHOR]

The recently developed concept of optical skyrmions has introduced an exciting dimension to the emerging field of Poincaré engineering in optical lattices. There remains an unexplored territory in investigating system geometries to enhance the versatility of manipulating the topological landscape within optical lattices. Here, we present both experimental and theoretical evidence showcasing the periodic vectorial characteristics of field- and spin-based skyrmion lattices, generated by plasmonic vortices with varying topological charges. Our findings reveal that the geometric symmetry of the system plays a pivotal role in governing the periodic arrangement of these vortex patterns. Building upon this arrangement, the orbital–orbital coupling of plasmonic vortices gives rise to densely packed energy flow distributions, intricately bonded to topological charges. Consequently, this results in the formation of sublattices within the momentum space, each characterized by distinct k-vectors. Skyrmion and meron topologies, driven by the intrinsic spin–orbital coupling, are presented in these lattices. This proposed framework illuminates how symmetry serves as a fundamental tool in the manipulation of optical lattice topologies, opening up new avenues in fields ranging from optical trapping, laser writing, quantum gas microscopy, to electron quantum state control, each of which is poised to benefit from these nontrivial advances. [ABSTRACT FROM AUTHOR]

This work investigates the potential to rely on the complex refractive index to correlate the chemical composition of polymers with their optical properties, including transmittance, reflectance and absorbance. The optical properties of polycarbonate slabs with various controlled concentrations of two dyes were initially measured and analyzed. The reflection and transmission measurements obtained were used to determine the corresponding complex refractive index over a wide range of wavelengths. Comparing it with that of a clear material provided the spectral deviation of the complex refractive index induced by the dye concentrations and resulted in assigning a spectral efficiency to both of them. A modification function of the complex refractive index was established based on this spectral efficiency, which acts as a spectral fingerprint related to each dye. Finally, two samples doped with the two dyes mixed were studied to assess the model's capabilities. On the one hand, based on the measured transmittance, the dye concentrations were determined within a deviation below 8% in comparison with the values provided by the manufacturer. On the other hand, when the dye concentrations were known, the model reproduced the optical properties with good accuracy beyond the limitations of the experimental setup. The model's effectiveness in correlating the chemical composition of polymer with its optical properties through the complex refractive index makes it a valuable asset in analyzing and formulating plastics with intended optical properties. [ABSTRACT FROM AUTHOR]

We propose a method for creating parallel Bessel-like vortical optical needles with an arbitrary axial intensity distribution via the superposition of different cone-angle Bessel vortices. We analyzed the interplay between the separation of individual optical vortical needles and their respective lengths and introduce a super-Gaussian function as their axial profile. We also analyzed the physical limitations to observe well-separated optical needles, as they are influenced by the mutual interference of the individual beams. To verify our theoretical and numerical results, we generated controllable spatial arrays of individual Bessel beams with various numbers and spatial separations by altering the spectrum of the incoming laser beam via the spatial light modulator. We demonstrate experimentally how to implement such beams using a diffractive mask. The presented method facilitates the creation of diverse spatial intensity distributions in three dimensions, potentially finding applications in specific microfabrication tasks or other contexts. These beams may have benefits in laser material processing applications such as nanochannel machining, glass via production, modification of glass refractive indices, and glass dicing. [ABSTRACT FROM AUTHOR]

Calcium phosphate (CaP) glass has recently gained popularity as a promising material for a wide range of biomedical applications. Recent developments have seen CaP glasses moving from a passive implant material to an active degradable material, particularly as a major constituent of bioresorbable photonic devices. This holds great promise in advanced biomedical applications, since the main constituents of CaP glasses are present in the human body. In this review, the progressive advancements in the biomedical applications of calcium phosphate glass-based devices over the past 50 years are discussed. An overview of their role as reinforcing agents and the studies on doping their matrices for ion releasing and drug and gene delivery are reviewed. Recent applications of CaP glass and fibers in soft-tissue engineering and their potential for optical quality bioresorbable devices are then discussed along with the current challenges and potential future directions, emphasizing the promising role of CaP glass in the next generation of biomaterials. Considering their progress and potential in performing several biomedical functionalities over time, CaP glass-based devices hold promise for becoming enabling tools as an implantable, bioresorbable, multifunctional class of devices in future biomedicine. [ABSTRACT FROM AUTHOR]

Characterization of the atomic level processes that determine optical transitions in emerging materials is critical to the development of new platforms for classical and quantum networking. Such understanding often emerges from studies of the temperature dependence of the transitions. We report measurements of the temperature dependent Er3+ photoluminescence in single crystal Er2O3 thin films epitaxially grown on Si(111) focused on transitions that involve the closely spaced Stark-split levels. Radiative intensities are compared to a model that includes relevant Stark-split states, single phonon-assisted excitations, and the well-established level population redistribution due to thermalization. This approach, applied to the individual Stark-split states and employing Er2O3 specific single-phonon-assisted excitations, gives good agreement with experiment. This model allows us to demonstrate the difference in the electron-phonon coupling of the 4S3/2 and 2H11/2 states of Er3+ in E2O3 and suggests that the temperature dependence of Er3+ emission intensity may vary significantly with small shifts in the wavelength (~0.1 nm) of the excitation source. Rare-earth elements are effective for engineering the optical properties of materials for a range of applications from lasers to quantum information technologies. Here, the authors investigate the temperature-dependent properties of Er3+ photoluminescence in Er2O3 thin films, focusing on the Stark-Stark transitions and how their temperature-dependent behaviour results from electron-phonon interactions. [ABSTRACT FROM AUTHOR]

Characterization of the atomic level processes that determine optical transitions in emerging materials is critical to the development of new platforms for classical and quantum networking. Such understanding often emerges from studies of the temperature dependence of the transitions. We report measurements of the temperature dependent Er3+ photoluminescence in single crystal Er2O3 thin films epitaxially grown on Si(111) focused on transitions that involve the closely spaced Stark-split levels. Radiative intensities are compared to a model that includes relevant Stark-split states, single phonon-assisted excitations, and the well-established level population redistribution due to thermalization. This approach, applied to the individual Stark-split states and employing Er2O3 specific single-phonon-assisted excitations, gives good agreement with experiment. This model allows us to demonstrate the difference in the electron-phonon coupling of the 4S3/2 and 2H11/2 states of Er3+ in E2O3 and suggests that the temperature dependence of Er3+ emission intensity may vary significantly with small shifts in the wavelength (~0.1 nm) of the excitation source. Rare-earth elements are effective for engineering the optical properties of materials for a range of applications from lasers to quantum information technologies. Here, the authors investigate the temperature-dependent properties of Er3+ photoluminescence in Er2O3 thin films, focusing on the Stark-Stark transitions and how their temperature-dependent behaviour results from electron-phonon interactions. [ABSTRACT FROM AUTHOR]

The pursuit for enhanced light‐matter interactions using ever more suitable plasmonic materials has led to the development of novel bulk materials, such as ϵ‐near‐zero (ENZ) media. The ability to control the free carrier density gives semiconductors a significant advantage over traditionally used noble metals and phonon‐based materials as ENZ media for infrared applications. A metal‐ENZ‐metal structure is designed of epitaxially‐grown III‐V semiconductors and patterned into nanoantennas by electron‐beam lithography (from 200 up to 1800 nm) and demonstrates plasmonic resonances tuned from the terahertz up to the near‐infrared, according to the ENZ doping level (1 × 1016, 1 × 1019, and 2 × 1019 cm‐3). Experimental results, corroborated by numerical simulations, show that the designed metal‐ENZ‐metal structure is a promising vehicle to provide additional insights regarding ENZ‐based phenomena including the resonance pinning, the near‐constant phase, and the dispersive nature of ENZ materials. It is believed that III‐V semiconductors within a metal‐ENZ‐metal structure address the problem of weak light‐matter interactions and shall greatly benefit infrared applications, e.g., sensing and communication, as they can be engineered to take advantage of both plasmon and ENZ effects and integrated onto modern photonics devices. [ABSTRACT FROM AUTHOR]

We extensively survey applications of Clifford Geometric algebra in recent years (mainly 2019–2022). This includes engineering; electric engineering; optical fibers; geographic information systems; geometry; molecular geometry; protein structure; neural networks; artificial intelligence; encryption; physics; signal, image, and video processing; and software. [ABSTRACT FROM AUTHOR]

This work is devoted to optimizing the optical and dielectric parameters of polyvinyl alcohol (PVA): polyvinyl pyrrolidone (PVP) (1:1) polymer nanocomposites by controlling barium stannate contents (BaSnO3) aspiring to engage it into flexible optoelectronics and thermally stable capacitors. Herein, high purity BaSnO3 was synthesized by solid‐state route and loaded with different ratios (5–20 wt%) into PVA/PVP blend to form films by solution casting method. Further, the degree of crystallinity (Xc) was highly increased upon increasing the filler contents (BaSnO3), as confirmed by X‐ray diffractometer measurement. The surface morphology pictured by a field emission scanning electron microscope revealed the variation of the surface from smooth to rough surface upon insertion of BaSnO3. The thermodynamic parameters including enthalpy (ΔH), entropy (ΔS), and Gibb's free energy (ΔG) were extracted from TGA measurements and studied in detail. The optical characteristics of plain PVA/PVP and polymer nanocomposite films are explored by UV–Vis–NIR spectrophotometer. The presence of charge‐transfer complexes within the polymer nanocomposites was certified via shifting of band gap energy from 5.02 to 4.33 eV and variation of band tailing energy (Eu) from 0.22 to 0.44 eV. The real and imaginary part of optical conductivity (σp1, σp2) was confirmed to be enhanced with the insertion of BaSnO3. It is also found that the dielectric constant and DC current increased with the insertion of BaSnO3 content, while the dielectric loss decreases. The findings recommend these polymer nanocomposites as a good candidate for green energy applications and high‐performance capacitors. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) materials as tungsten disulphide (WS2) are rising as the ideal platform for the next generation of nanoscale devices due to the excellent electric‐transport and optical properties. However, the presence of defects in the as grown samples represents one of the main limiting factors for commercial applications. At the same time, WS2 properties are frequently tailored by introducing impurities at specific sites. Aim of this review paper is to present a complete description and discussion of the effects of both intentional and unintentional defects in WS2, by an in depth analysis of the recent experimental and theoretical investigations reported in the literature. First, the most frequent intrinsic defects in WS2 are presented and their effects in the readily synthetized material are discussed. Possible solutions to remove and heal unintentional defects are also analyzed. Following, different doping schemes are reported, including the traditional substitution approach and innovative techniques based on the surface charge transfer with adsorbed atoms or molecules. The plethora of WS2 monolayer modifications presented in this review and the systematic analysis of the corresponding optical and electronic properties, represent strategic degrees of freedom the researchers may exploit to tailor WS2 optical and electronic properties for specific device applications. [ABSTRACT FROM AUTHOR]

We herein describe the synthesis of a new class of axially chiral aza/boracyclophanes (BDN1, BXN1, BDB1 and BXB1) using binaphthyls as chiral building blocks and the main‐group (B/N) chemistry with tunable electronic effects. All macrocycles substituted with triarylamine donors or triarylborane acceptors are strongly luminescent. These macrocycles showed two distinct meta and para π‐conjugation pathways, leading to the formation of quasi figure‐of‐eight and square‐shaped conformations. Interestingly, comparison of such structural models revealed that the former type of macrocycles BXN1 and BXB1 gave higher racemization barriers relative to the other ones. The results reported here may provide a new approach to engineer the optical stability of π‐conjugated chiral macrocycles by controlling π‐substitution patterns. The ring constraints induced by macrocyclization were also demonstrated to contribute to the configurational persistence as compared with the open‐chain analogues p‐BTT and m‐BTT. [ABSTRACT FROM AUTHOR]

Perfect vortex beams (PVBs) take advantage of conventional vortex beams regarding their property of constant diameter of the annular intensity distribution on different topological charges (TCs), facilitating spatially coupling multiple beams with different TCs simultaneously. However, there are demands for PVBs with larger TCs that can be integrated with CMOS-fabrication processes in applications since conditional PVBs are composed of bulky optical components. In this work, we demonstrate metasurface-based PVBs (MPVBs) with TCs as high as −32 and 16 in the visible, manifesting annular intensity distributions capable of broadband operation. The optical eraser concept by integrating MPVBs has been conducted, and the flower-like interference performs a helicity switch to facilitate the uniformization of ring-shaped intensity profiles for the MPVBs with different TCs. The optical eraser experiments demonstrate the potential of MPVBs in advancing both quantum optics and optical device engineering and pave the way for probing quantum behaviors in optics. In this work, metasurface-based perfect vortex beams (MPVBs) featuring topological charges (TCs) of −32 and 16 have been successfully manufactured. As one of the tremendous phenomena in quantum mechanics, the fancy optical eraser experiment by integrating these MPVBs has also been successfully demonstrated in this study. [ABSTRACT FROM AUTHOR]

Micron-level flaws on component surface can seriously affect the optical and mechanical properties of optics, so it is significant to accurately classify and repair surface flaws. However, the small scale, multiple categories, and complex characteristics of surface flaws make the accurate classification a great challenge in the field of precision optical engineering. In this work, a novel automated classification approach is proposed for multi-classification of flaws. Images of flaws illuminated by multi-light sources are automatically acquired by classification equipment to enrich the characteristics of flaws, and a series of automated workflows are set up to accomplish flaw detection, classification, and mitigation. SingleCNN-MergeRGB, a feature extraction structure based on a single convolutional neural network (CNN) and multi-light source fusion, is constructed to extract the integrated features of flaws under different illumination. The experimental results show that SingleCNN-MergeRGB has stronger capability of feature description compared with single light source and other feature extraction networks. The integrated deep learning architecture SingleCNN-MergeRGB + SVM and prediction probability threshold adjustment strategy are proposed to improve the accuracy of flaw classification and correct failure cases. Validation results on the test set show that the proposed flaw classification method obtains an accuracy of 96.34% and a recall rate of 100%. The experiments demonstrate the effectiveness of the automatic classification equipment and methods in this work in the classification of surface flaws in large-aperture optical components. [ABSTRACT FROM AUTHOR]

In this study, we introduce a novel approach for dynamic micro-vibration measurement, employing an Orbital Angular Momentum (OAM) interferometer, where the reference beam is Gaussian (GS) and the measurement beam is OAM. The OAM light reflected back from the target carries information about the target's vibrations. The interference of the OAM light with Gaussian light generates petal-shaped patterns, and the target's vibration information can be measured by detecting the rotation angle of these petals. Our proposed method demonstrates enhanced tolerance to misalignment and superior precision. The effects of vibration frequency, CCD frame rates, and Topological Charges (TCs) on measurement accuracy are analyzed thoroughly. Experimental results reveal that the proposed method offers a higher accuracy (up to 22.34 nm) and an extended measurement range of (0–800 cm). These capabilities render our technique highly suitable for applications demanding nanometer-scale resolution in various fields, including precision engineering and advanced optical systems. [ABSTRACT FROM AUTHOR]

We theoretically study the nonlinear optical phenomena including optical stability state and four-wave mixing (FWM) process in a hybrid opto-electromechanical system with the cross-Kerr (CK) effect. The hybrid system consists of an optomechanical cavity in which the cross-Kerr (CK) effect and Coulomb interaction are simultaneously introduced by the CK medium and the mechanical resonator capacitively coupling to an external circuit, respectively. The CK interaction induces a tristability behavior of the mean intracavity photon number, which can be modulated by the strength of the CK effect and electrically controlled by the voltage on the capacitor. In addition, we give the effects of the optomechanical, CK, and Coulomb coupling strengths on the FWM of the output field. The results show that the voltage can be employed to electrically engineer the optical nonlinear phenomena. [ABSTRACT FROM AUTHOR]

See‐through near‐eye displays, such as head‐mounted displays and augmented reality glasses, integrate physical environment with virtual digital contents to form a cohesive world that combines both realities. Field‐of‐view (FOV) is a critical parameter determines the optical performance of these displays. Here we evaluate the see‐through FOV of an optical see‐through near eye display. The evaluation is based on the standardized Michelson contrast method, which provides a unified metric for the measurement of see‐through FOV in near‐eye displays. [ABSTRACT FROM AUTHOR]

A recent article in Advanced Photonics discusses the development of iso-propagation vortices (IPVs), which are vortex beams designed to maintain a constant size and divergence during propagation. These IPVs have significant implications for optical communication systems, as they offer improved transmission dynamics, obstacle recovery ability, and reduced mode scattering in atmospheric turbulence. The IPVs can increase the subchannel availability by up to 14 times compared to conventional orbital angular momentum (OAM) multiplexing, leading to faster data rates and improved signal quality. The integration of metasurfaces and IPVs further enhances beam control and enables advanced multiplexing techniques, adaptive optics, high-resolution imaging, and quantum communications. Overall, IPVs show promise for the future of high-capacity optical communication networks. [Extracted from the article]

Optical dispersion, the variation of the speed of light with frequency in a material, presents significant challenges in modern optical systems, including chromatic aberration and pulse signal distortion. Traditional approaches to dispersion engineering of an optical lens system require the use of a set of sub-lenses of opposite dispersion properties, largely increasing the overall lens thickness. Ultrathin metasurfaces offer unprecedented control over optical wavefronts with advanced functionalities. Developing achromatic metalenses has thereby emerged as a timely research topic for metasurface research. This Perspective article provides a comprehensive overview of dispersion engineering methods in metalenses, including the use of 2D and 3D meta-atoms fabricated from planar lithography and 3D laser lithography methods, respectively. We compare key figures of merit of achromatic metalenses developed for different wavelength ranges and discuss recent inverse design of large-scale achromatic metalenses. We believe advanced machine learning methods as well as hybrid nanofabrication of diffractive metalenses, refractive lenses, and metamaterials-like spaceplates could offer promising avenues for overcoming current challenges and eventually push ultrathin achromatic optics to practical applications in optics-related fields. [ABSTRACT FROM AUTHOR]

This paper reports simple but accurate analytical expressions of group delay and modal dispersion parameters for single-mode graded index fibers over a wide range of V numbers. The formulation employs power series expression for the fundamental modal field of graded index fiber derived by Chebyshev formalism. Choosing some typical step, parabolic and triangular index fibers as examples in our present study, we use the prescribed formulations to estimate group delay and modal dispersion parameters of those fibers both in presence and absence of Kerr nonlinearity. Iterative technique is applied for prediction of concerned propagation parameters in presence of Kerr nonlinearity. Our results show excellent agreement with the numerical exact ones both in absence and presence of Kerr nonlinearity. The exact results in case of Kerr nonlinearity are obtained using cumbersome finite element method. The execution of our accurate formalism involves little computation and is thus user friendly for technologists and researchers working in the field of nonlinear optical engineering. [ABSTRACT FROM AUTHOR]