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Two-dimensional electronic spectroscopy (2D-ES) has become an important technique for studying energy transfer, electronic coupling, and electronic–vibrational coherence in the past ten years. However, since 2D-ES is not interface specific, the electronic information at surfaces and interfaces could not be demonstrated clearly. Two-dimensional electronic sum-frequency generation (2D-ESFG) is an emerging spectroscopic technique that explores the correlations between different interfacial electronic transitions and is the extension of 2D-ES to surface and interfacial specificity. In this work, we present the detailed development and implementation of phase-cycling 2D-ESFG spectroscopy using an acousto-optic pulse shaper in a pump–probe geometry. With the pulse pair generated by a pulse shaper rather than optical devices based on birefringence or interference, this 2D-ESFG setup enables rapid scanning, phase cycling, and the separation of rephasing and nonrephasing signals. In addition, by collecting data in a rotating frame, we greatly improve experimental efficiency. We demonstrate the method for azo-derivative molecules at the air/water interface. This method could be readily extended to different interfaces and surfaces. The unique phase-cycling 2D-ESFG technique enables one to quantify the energy transfer, charge transfer, electronic coupling, and many other electronic properties and dynamics at surfaces and interfaces with precision and relative ease of use. Our goal in this article is to present the fine details of the fourth-order nonlinear optical technique in a manner that is comprehensive, succinct, and approachable such that other researchers can implement, improve, and adapt it to probe unique and innovative problems to advance the field. [ABSTRACT FROM AUTHOR]

Polarization is one of the fundamental properties of light and has an important application value, involving multiple fields, such as imaging, display, quantum computing, and biosensing. The artificial metasurface can achieve comprehensive control of electromagnetic waves, such as amplitudes, phases, and polarization states. Compared to traditional optical devices, the metasurfaces have advantages, such as small size and diverse functions, meeting the needs of modern optical systems for ultra-lightweight, ultra-compact, and multifunctional optical components. Chiral media are widely presented in various macroscopic and microscopic systems in nature. Circular dichroism (CD) is commonly used to describe the difference in absorption rates of left-handed circularly polarized light and right-handed circularly polarized light in chiral media. However, the optical response of chiral media in nature is usually weak and mainly located in the ultraviolet band, which limits their detection sensitivity and practical application range. In this work, we proposed a chiral metasurface model with four rectangular holes with proper rotation. By rotating the rectangular or elliptical holes at a certain angle, the symmetry of the structure is disrupted, making it chiral. The proposed metasurface devices were fabricated, and the optical measurements were performed, which were in good agreement with the designs. The normalized CD values are around 0.01 at the near-infrared region. This work provides a complete procedure of the metasurface device and initials chiral-tunable flat meta-devices. It also has broad application prospects in fields, such as polarization imaging, life sciences, and drug chiral detection. [ABSTRACT FROM AUTHOR]

The emergence of many efficient optical field modulation methods and planar optical devices is attributed to the continuous research of geometric phase. Nevertheless, conjugate symmetry of the geometric phase limits the multiplexing of metasurfaces. To overcome this limitation, integrating the propagation phase and the geometric phase to achieve self-decouped metasurfaces can effectively double channel capacity. Herein, a more in-depth derivation of Jones matrices is conducted, leveraging two degrees of freedom offered by the propagation phase and the geometric phase. This approach enables complete modulation in circular polarization channels. By designing the phase difference between a fast axis and a slow axis, energy allocation between different channels can be controlled. It means independent complex amplitude modulation is achieved. On this basis, the geometric phase is introduced to realize tri-channel multiplexing metasurfaces. To verify the feasibility of this method, two metasurfaces are designed, including a bifocal metasurface with adjustable energy allocation and a tri-channel multiplexing metasurface. The proposed multifunctional metasurface offers new insights into wavefront multiplexing for communication systems. [ABSTRACT FROM AUTHOR]

The study of light-emitting defects in silicon created by ion implantation has gained renewed interest with the development of quantum optical devices. Improving techniques for creating and optimizing these defects remains a major focus. This work presents a comprehensive analysis of a photoluminescence line at a wavelength of 1240 nm (1 eV) caused by defects arising from the ion irradiation of the SiO2/Si system and subsequent thermal annealing. It is assumed that this emission is due to the formation of defect complexes WM with trigonal symmetry similar to the well-known W-centers. A distinctive feature of these defects is their thermal resistance up to temperatures of 800 °C and less pronounced temperature quenching compared to the W-line. The difference in the properties of these defect centers and W-centers can be explained by their different defect environments, resulting from the larger spatial separation between vacancies and interstitial atoms diffusing from the irradiated layer. This, in turn, is associated with the difference in the distribution of primary radiation defects during irradiation of the SiO2/Si system and silicon not covered with a SiO2 film. The patterns of changes in the WM line depending on various factors, such as the thickness of the SiO2 film, type of conductivity and impurity concentration in the original silicon, irradiation parameters, and annealing regimes, is studied and explained in detail. These findings demonstrate the benefits of this new approach when compared to previous methods. [ABSTRACT FROM AUTHOR]

In this research, we propose a simple and novel graphene-black phosphorus composite structure. Through the coupling mechanism of bright–bright mode, four layers of graphene and one layer of black phosphorus produce a quadruple plasmon-induced transparency (PIT) effect. The response of the proposed structure to the angle of polarized light is investigated, and it is found that the sensitivities of graphene and black phosphorus to the polarization angle of light are different. In addition, the dynamic regulation of PIT by the Fermi level of graphene and the carrier concentration of black phosphorus are discussed. The modulation depths of the fivefold optical switching are 96%, 99%, 87%, 93%, and 80%, respectively. The quadruple PIT can also be converted into triple PIT, in which single, dual, or triple optical switching are realized, respectively. Finally, with the change in the refractive index of the environment medium, the sensitivity response of the proposed structure is as high as 4.790 THz⋅RIU−1. We believe that this research will contribute to the development of optical switches, modulators, and sensors. [ABSTRACT FROM AUTHOR]

High tilt angle (45 °) ferroelectric liquid crystal (F L C) in surface stabilized geometry, having no chiral smectic A (S m A ∗) phase, has been studied for the reorientation of the smectic layers near the transition temperature (T c). The electro-optical studies have shown the stripe domain formation in which the liquid crystal molecules are aligned along the rubbing direction, but the smectic layers are tilted away from the rubbing direction at room temperature. In such high tilt angle F L C s , the molecular alignment and smectic layer formation start from bottom and top rubbed grooves at T c. The domain formation of the FLC takes place in the middle of the top and bottom surfaces due to the frustration of the dipolar interaction. The smectic layer switching is observed by optical microscopy and confirmed by the dielectric spectroscopy method near T c of S m C ∗ and chiral nematic phases. Domain switching has shown a larger switching angle than the molecular tilt angle within the smectic layer. These studies are expected to be significant for understanding the smectic layer structure and the domain switching process, which may pave the way for large optical switching devices. [ABSTRACT FROM AUTHOR]

Optical eigenstates with a high quality (Q) factor provide substantial advantages for a broad spectrum of optical devices, particularly those demanding strong light–matter interactions. Recently, it has been demonstrated that ultrahigh- Q resonances can be realized in planar photonic structures by merging multiple bound states in the continuum (BICs) in the momentum space. Photonic lattices with thin-film geometry are known to support abundant TE-polarized and TM-polarized BICs. While prior research has explored the merging of TE-polarized BICs, this paper presents analytical and numerical results concerning the merging of TM-polarized BICs in laterally periodic one-dimensional photonic lattices. As the thickness of photonic lattices increases, TM-polarized accidental BICs descend along the dispersion curves and eventually merge at the upper edge of the second stop band. Employing coupled-mode analysis, we calculate the analytical merging thickness at which multiple TM-polarized BICs come together at the second-order Γ point. We confirm the merging of TM-polarized BICs through finite-element method simulations. Our results can be beneficial for achieving ultrahigh- Q resonances through the merging of BICs. [ABSTRACT FROM AUTHOR]

Polymer-based ternary nanocomposites with tunable optical properties are the key components for optoelectronics applications. Here, we demonstrate the linear and nonlinear optical properties of polypyrrole (PPy) and its ternary composites with different concentrations of the MoS2–ZnO core–shell (ZnO@MoS2) heterostructure. The interesting observation of multiple excitons and their transportation through the interface of PPy and ZnO@MoS2 by using photoluminescence and fluorescence lifetime spectroscopy was studied. Furthermore, the third-order nonlinear optical properties of all samples were also measured by employing the z-scan technique at an excitation wavelength of 532 nm. The reverse saturable absorption of pure PPy was switched to saturable absorption after the addition of ZnO@MoS2 at the uniform linear transmittance. These ternary composites with good nonlinear responses provide an option for the development of high-performance nonlinear optical devices and open a new path for the future development of ternary systems in the optical fields. [ABSTRACT FROM AUTHOR]

This review concentrates on the microstructure of InxGa1−xN layers and quantum wells (QWs) in relation to their optical properties. The microstructure of InxGa1−xN, with a constant In(x) concentration, shifts with layer thickness. Only layers below 100 nm for x = 0.1 are nearly defect-free. A photoluminescence peak is observed at 405 nm, in line with ∼10% In, suggesting band-edge luminescence. Layers with greater thickness and In content present a corrugated surface with numerous structural defects, including V-defects, causing redshifts and multi-peaks in photoluminescence up to 490 nm. These defects, resembling those in GaN, lead to a corrugated sample surface. Atomic force microscopy shows a 3.7-fold larger corrugation in samples with 20 QWs compared to those with 5 QWs measured on 2 × 2 μm2 areas. Like in GaN, dual growth on different crystallographic planes results in varied QW thicknesses, influencing optical traits of devices made from InxGa1−xN layers. The purpose of this review and the chosen subject is to highlight the significant contribution of Wladek Walukiewicz and his group to the current research on the properties of InxGa1−xN, which are crucial alloys in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal chalcogenides (2D TMCs) like MoS2, WS2 etc., have established significant dominance in the field of nanoscience and nanotechnology, owing to their unique properties like strong light–matter interaction, high carrier mobility, large photo-responsivity etc. Despite the widespread utilization of these binary TMCs, their potential in the advancement of the optoelectronic research is limited due to the constraints in band tuning and charge carrier lifetime. To overcome these limitations, ternary transition metal chalcogenides have emerged as promising alternatives. Although, the optical properties of these materials have never been explored properly. Herein, we have investigated one such promising member of this group, Cu2MoS4 (CMS) using both steady state and time-resolved spectroscopic techniques. The material exhibits a broad range of visible light absorption, peaking at 576 nm. Photoluminescence spectroscopy confirmed the presence of both band gap emission and trap state-mediated emissions. Transient absorption spectroscopy unraveled the excited state charge carrier dynamics of CMS in sub-ps timescale, upon irradiation of visible light. We found significant influence of the trap mediated recombination, while Auger process being dominant at high charge density. We extended our study in a wide temperature range (5–300 K), which reveals the impact of electron-phonon coupling strength on the band gap and charge carrier dynamics of this material. This detailed study would draw more attention toward the unexplored optical properties of ternary 2D chalcogenides and will open new avenues for the construction of 2D material-based optical devices. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: How to obtain organic electro‐optic materials with large electro‐optic coefficients, high glass transition temperature, and good optical transparency remains a challenge in this field. To solve this problem, we introduce groups that can undergo Huisgen cycloaddition reactions into the donor and electron bridge of chromophores with large hyperpolarizability using tetrahydroquinoline as the donor. Binary cross‐linkable chromophores TLD1‐2 with CF3‐TCF as the acceptor and chromophores TLD3‐4 with 5Fph‐TCF as the acceptor were synthesized. After poling and crosslinking, the Tg of TLD1/TLD2 and TLD3/TLD4 were raised to 152 and 174 °C, respectively. The electro‐optical coefficients of chromophores TLD1/TLD2 and TLD3/TLD4 were as high as 312 pm/V and 287 pm/V, respectively. The long‐term alignment stability test showed that after being left at 85 °C for 500 h, the cross‐linked film TLD3/TLD4 can still maintain more than 98% of the original electro‐optical coefficient value, which is higher than that of TLD1/TLD2 (93%). The chromophore TLD3‐4 exhibited much blue‐shifted maximum absorption wavelengths (~40 nm) compared to TLD1‐2 which was beneficial for reducing optical loss in the device. The combination of high electro‐optic coefficient, strong stability, and excellent optical transparency makes the TLD series of binary cross‐linked materials very promising for practical high‐performance electro‐optic devices. [ABSTRACT FROM AUTHOR]

The practical usage of natural enzymes is limited due to their sensitivity and need for special conditions. On the other hand, nanozymes provide robust catalytic performance, high stability in challenging conditions, economical production, and versatile surface modification. With these benefits, nanozymes surpass the constraints of natural enzymes and are a better option for a range of applications. Iron oxide-based nanomaterials have attracted significant attention due to their distinctive properties, such as catalase-like function under pH seven and peroxidase enzyme activity at acrid pH values as well as higher enzyme-like activities. This study has explored how synthesis procedures have advanced recently, presenting creative approaches with increased stability, regulated particle sizes, and catalytic activities. The potential of iron oxide nanozymes in a range of domains, such as healthcare, hyperthermia, MRI, optical devices, and anticancer activity, has also been investigated. This critical study provides a comprehensive overview of the synthesis, characterization, and potential uses of iron oxide-based nanozymes, identifies the areas where research is currently lacking, and makes options for future directions to maximize its potential in medicine. Overall, this review expands our understanding of iron oxide nanozymes and is a helpful resource for scientists creating novel medicinal and diagnostic tools. [ABSTRACT FROM AUTHOR]

Recently, there has been growing interest in materials that combine the advantages of glass and polymer materials. Such a combination results in a kind of hybrid glass-polymer optics that meets the requirements for high-quality imaging in various environmental conditions. So far, the literature on these materials is quite scarce. This article is an attempt to review the most important reports on the topic of available polymers with optical properties, dividing them into groups, i.e. synthetic optical polymers (including polymethylmethacrylate, polyethylene terephthalate, polypropylene, cyclic olefin copolymers and polyolefin elastomers) and biopolymers (including polylactide and gelatin). A separate place and chapter is given to transparent CR-39 plastic and the issue of individual dosimetry for radon detection. Moreover, testing methods for measuring the most important optical properties of polymers and their major applications are briefly discussed. [ABSTRACT FROM AUTHOR]

Introduction: The recently developed platelet aggregation technique based on low-angle light scattering (LaSca) in diluted platelet-rich plasma (PRP) requires only a small sample volume and provides information about platelet aggregation and shape change. This study aimed to investigate the influence of preanalytical and analytical variables and to validate the method in a real-life pediatric hematology hospital setting. Methods: Platelet aggregation was induced by ADP in diluted PRP in the presence of 2 mM calcium at 23 °C. The study included healthy adults (n = 30), healthy children (n = 20), and pediatric patients with suspected or diagnosed platelet function abnormalities (n = 25). Results: The assay parameters were stable for at least 3 h after isolation of PRP and were sensitive to plasma dilution in the range of 2–8%. The initial aggregation velocity was significantly reduced in pediatric patients compared with healthy children (p < 0.05). ADP-induced light transmission amplitude was moderately correlated with LaSca amplitude of aggregation in healthy children (p = 0.52, p < 0.05) but not in pediatric patients. Conclusions: We standardized the protocol for platelet aggregation assessment by LaSca and characterized the influence of preanalytical and analytical variables on it. [ABSTRACT FROM AUTHOR]

Lead sulfide (PbS) has substantial potential for applications in many fields, such as optical devices and solar cells. Although PbS can be obtained from complex lead-antimony sulfide ores by vacuum distillation, the evaporation mechanism of PbS under vacuum is still unclear. Herein, the evaporation kinetics of PbS at 973 K to 1173 K and 5 to 1000 Pa were investigated using a vacuum thermogravimetric furnace. The practical evaporation rate of PbS was obtained through linear and nonlinear fitting of the experimental data compared with the original theoretical evaporation rate and corrected for the Langmuir maximum evaporation coefficient. The evaporation coefficients and critical pressures of PbS at 973 K, 1023 K, 1073 K, 1123 K, and 1173 K were 0.5225, 0.4056, 0.2080, 0.1995, and 0.1007 as well as 12.49, 16.67, 20.83, 24.19, and 30.15 Pa, respectively. Experimental results indicate that the evaporation rate conforms to the logistic nonlinear model, and the critical pressure is positively correlated with temperature. This paper provides a kinetic data base for PbS vacuum evaporation and also provides a reference for improving the process conditions and production equipment parameters of PbS vacuum distillation. Meanwhile, it improves and develops the theory and practice of vacuum distillation for the preparation of high-purity sulfides and fills the gap of basic kinetic data of nonferrous sulfides. [ABSTRACT FROM AUTHOR]

In this paper, we propose an N -bit optical digital-to-analog converter (DAC) by integrating N pairs of 2 × 2 phase change based on-chip photonic switches and 2 × 2 multimode interference (MMI) splitters. An on-chip photonic switch is constructed by integrating a wavelength-selectable racetrack micro-ring resonator with the phase change chalcogenide Ge2Sb2Se4Te (GSST). The GSST-integrated switch utilizes a racetrack resonator configuration for performing the accurate modulation of the resonant wavelength to prevent intercoupling between adjacent units. In order for electrothermal heating of the GSST film to trigger its phase transition for switchable control, an indium tin oxide heater with a bowtie-shaped structure is integrated into the racetrack resonator. Using numerical calculations, we demonstrate that an 8 V voltage pulse at a duration of 300 ns, with an energy consumption of 18.45 nJ, could change the optical state from an OFF state to an ON state. Another 6 V voltage pulse of 250 ns duration, followed by a 4 V pulse of varying duration, with a total energy consumption of 34.78 nJ, can switch the optical state from an ON state to an OFF state. The asymmetric structure of the 2 × 2 MMI shows ultra-high transmittance approaching 50% in the through port (connected to the next order of MMI), enabling the creation of multistage cascaded MMI splitters with an output light power ratio close to 50%. Our results show that this configuration potentially offers a feasible solution for applications of optical DACs. [ABSTRACT FROM AUTHOR]

Controlling light‐matter interactions via cavity systems manifested by Rabi splitting is paramount important for nanophotonics. However, achieving conveniently accessible and active tuning of light‐matter interactions remains a formidable challenge. Traditional approaches often necessitate either sophisticated design or meticulous nanofabrication to address this issue. Here, a handy strategy is experimentally demonstrated to build an adjustable coupling system featuring reversibly modulated responses based on dielectric‐hydrogel‐metal resonators. By controlling the top tungsten disulfide layer thickness, the flexible manipulation of weak‐intermediate‐strong transitions in exciton‐cavity interactions is revealed on a large‐scale hydrogel membrane without nanopositioning or lithography. Crucially, by leveraging the inflation sensitivity of the hydrogel, the coupling strength can be reversibly tailored with excellent reproducibility by modulating the resonator's dry/immersed states. The combined merits of captivating design and daily stimulus render the novel hydrogel‐based nanocavities as a groundbreaking step toward the development of active and practical integrated optical devices, such as polariton lasing, switches, and sensors. [ABSTRACT FROM AUTHOR]

The investigation reveals that the crystal field environment induces photoluminescence in Eu3+. These synthesized materials hold promise for a wide array of commercial applications, particularly in the light emitting diode industry, representing a significant advancement for the current generation of technology. The lead‐free electroceramics 0.94NB1−xEuxTiO3‐0.06SrTiO3 (x = 0 and x = 0.1) are fabricated using the conventional solid‐state reaction technique. Within these ceramics, both rhombohedral (R3c) and tetragonal (P4mm) structural phases coexist. The structural conformation and fluctuations in average grain size indicate the successful substitution of Eu3+ in 0.94NB1−xTiO3‐0.06SrTiO3 (x = 0). The incorporation of Eu3+ ions into the host matrix induces a long‐range ferroelectric state, marked by a rhombohedral (R3c) distortion, alongside enhanced tetragonal (P4mm) features. This structural modification results from the interaction between the Eu3+ ions and the host lattice, which fosters the emergence of a ferroelectric polarization. The coexistence of rhombohedral and tetragonal symmetries suggests a complex interplay of phases that collectively enhance the material's ferroelectric properties, potentially offering new avenues for applications in electronic and optical devices. Notably, compared to 0.94NB1−xEuxTiO3‐0.06SrTiO3 with (x = 0), the coercive field (Ec) significantly improves, while remanent polarization decreases in the presence of Eu3+. The domain orientation, particularly in Stage‐C, demonstrates a pronounced scaling behavior, which can be attributed to the crystal field surrounding the Eu3+ ions. This interaction influences the material's domain dynamics, enhancing its electromechanical properties. As a result, both of these lead‐free ceramics exhibit considerable potential for future electroceramic applications, offering a promising alternative in environmentally sustainable technologies. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van der Waals (vdW) semiconductors play a key role in developing nanoscale nonlinear optical devices. 2D Ruddlesden-Popper lead halide perovskites (RPPs) expand the potential of using 2D vdW semiconductors in nonlinear optical applications because they exhibit electrically switchable and chiral second-order optical nonlinearity originating from the emergence of ferroelectricity and chirality. However, electrically switchable chiral nonlinear optics has not yet been realized because of the difficulty in electrically manipulating chiral structures. Here, we demonstrate that chiral second-harmonic generation (SHG) can be electrically induced and switched in an achiral biaxial ferroelectric 2D RPP. We observe reversible and continuous electrical switching of SHG circular dichroism and large nonlinear chiroptical activity. Polarization-resolved SHG imaging reveals that electrical poling induces the ferroelectric multidomain structure arising from the biaxial nature of the material, and the planar chirality appears. Our findings show a simple electrical control of the nonlinear chiroptical responses and establish chiral nonlinear optics based on ferroelectric 2D RPPs. [ABSTRACT FROM AUTHOR]

To achieve dye-sensitized solar cells (DSSCs) with high transparency, multi-color capability, and long-term durability for future applications across various fields, this study selected phenylthiophene with UV-absorbing properties as the dye electron donor, cyanoacetic acid as the electron acceptor, and a colorless biphenyl dye (6OBA) as the co-sensitizer. The effects of different alkyl chain lengths, densities, branching positions, and co-sensitization on the photovoltaic (PV) performance of the devices are investigated. In addition, the effect of dye molecules adsorbed on TiO2 films of different thicknesses on the optical transmittance of the devices was also analyzed. The results show that the developed dyes exhibit UV-selective absorption properties. The power conversion efficiencies (PCEs) of the semi-transparent DSSCs ranged from 0.51% to 0.89% under one sun illumination (100 mW cm−2) and from 3.78% to 5.94% under UVA LED illumination (365 nm, 150 μW cm−2). The corresponding visible light transmittance varied between 33.47% and 63.71%. At the same time, the DSSCs demonstrated long-term PCE stability after soaking for 1000 hours of full light irradiation. [ABSTRACT FROM AUTHOR]

Optical metasurfaces with pronounced spectral characteristics are promising for sensor applications. Currently, deep learning (DL) offers a rapid manner to design various metasurfaces. However, conventional DL models are usually assumed as black boxes, which is difficult to explain how a DL model learns physical features, and they usually predict optical responses of metasurfaces in a fuzzy way. This makes them incapable of capturing critical spectral features precisely, such as high quality (Q) resonances, and hinders their use in designing metasurface sensors. Here, a transformer‐based explainable DL model named Metaformer for the high‐intelligence design, which adopts a spectrum‐splitting scheme to elevate 99% prediction accuracy through reducing 99% training parameters, is established. Based on the Metaformer, all‐dielectric metasurfaces based on quasi‐bound states in the continuum (Q‐BIC) for high‐performance metasensing are designed, and fabrication experiments are guided potently. The explainable learning relies on spectral position encoding and multi‐head attention of meta‐optics features, which overwhelms traditional black‐box models dramatically. The meta‐attention mechanism provides deep physics insights on metasurface sensors, and will inspire more powerful DL design applications on other optical devices. [ABSTRACT FROM AUTHOR]

Efficient heat management and control in optical devices, facilitated by advanced thermo‐optic materials, are critical for many applications such as photovoltaics, thermal emitters, mode‐locked lasers, and optical switches. Here, a range of thermo‐optic properties of 2D graphene oxide (GO) films are investigated by precisely integrating them onto microring resonators (MRRs) with control over the film thicknesses and lengths. The refractive index, extinction coefficient, thermo‐optic coefficient, and thermal conductivity for the GO films with different layer numbers and degrees of reduction, as well as reversible reduction and enhanced optical bistability induced by the photo‐thermal effects, are comprehensively characterized. Experimental results show that the thermo‐optic properties of 2D GO films vary widely with the degree of reduction. In addition, significant anisotropy is observed for the thermo‐optic response, enabling efficient polarization‐sensitive devices. The versatile thermo‐optic response of 2D GO substantially expands the scope of functionalities and devices that can be engineered, making it promising for a diverse range of thermo‐optic applications. [ABSTRACT FROM AUTHOR]

Non-Hermitian systems can be tuned to exhibit exceptional points, where both eigenvalues and eigenstates coalesce concurrently. The inherent adaptability of photonic non-Hermitian systems in configuring gain and loss has allowed us to observe a plethora of counterintuitive phenomena, largely as a consequence of the eigenspace reduction at these exceptional points. In this work, we propose a non-Hermitian metasurface that, through the incorporation of gain, enables complete asymmetric polarization conversion at an exceptional point with a zero eigenvalue. Specifically, we provide numerical evidence for this concept by designing a non-Hermitian metasurface that facilitates polarization conversion from right to left circular polarization, while preventing conversion in the reverse direction and co-polarized transmission. Furthermore, our investigation reveals that this specific form of complete asymmetric polarization conversion results in maximum circular dichroism in transmission, thereby eliminating the need for external chirality or three-dimensional helical structures. This non-Hermitian technique offers an intriguing approach to designing polarization-sensitive optical devices and systems, further expanding their functionalities and capabilities. [ABSTRACT FROM AUTHOR]

In this study, we comprehensively investigate thermal lens (TL) spectroscopy, known for its ultra-sensitivity in probing molecular properties through nonlinear heating responses to femtosecond lasers. Using time-resolved TL spectroscopy and numerical simulations, we focus on the influence of convection on heat generation and the resulting phase shift in the probe beam. We examined single-beam, dual-beam same wavelength, and dual-beam different wavelength scenarios, systematically investigating power dependence, pump beam spot size, and sample length limitations. Our findings reveal a direct relationship between the TL effect and pump power, resulting in decreased probe beam transmittance with increasing convection. Additionally, the TL strength grows within the Rayleigh regime as the sample length increases. Utilizing the same wavelength for the probe beam enhances the TL effect in dual-beam setups. Notably, tight focusing of the pump beam substantially reduces the lag between convection and conduction. Our empirical results closely match the experimental data, providing a thorough explanation of the TL process and its underlying principles. These insights can be applied to design and optimize TL-based optical devices and systems for higher sensitivity, highlighting the potential of TL spectroscopy in advanced molecular property probing. [ABSTRACT FROM AUTHOR]

This paper introduces a Hybrid Plasmonic Nano-Antenna (HPNA) with a gradient-index dielectric flat lens modeled with different materials to enhance and steer the radiation in a particular direction based on a phase shift array. Firstly, the design of hybrid plasmonic Nano-Antenna (NA) is introduced and analyzed considering different horn-shapes such as diamond, hexagonal, circular, rectangular, and square shapes. The commercial software Computer Simulation Technology-Microwave Studio (CST-MWS) is used to analyze the radiation characteristics of the plasmonic NAs at the standard telecommunication wavelength of 1,550 nm. The produced horn-shaped nano-antenna made up from gold cladding with low- and high-index dielectric materials of SiO2 and InGaAs, respectively. The gain of the Square Horn shape Hybrid Plasmonic Nano-Antenna (SHHPNA) achieves the greatest gain with a value of 10.7 dBi at the desired frequency and the return loss reached -18.09 dB due to the wide aperture area for SHHPNA, which results in a narrower beam-width and higher gain. Moreover, by using two different shapes of dielectric flat lens to enhance the antenna's performance by improving directivity while correspondingly reducing beam-width, the gain is enhanced and reaches 16.7 for SHHPNA with a circular lens and 16.9 for SHHPNA with a rectangular lens compared with the traditional NA that equal to 9.03 dBi. The main lobe for SHHPNA with each lens is more directed, with Side Lobe Level (SLL) and Half Power Beam-Width (HPBW) of -13.1 dB and 16.5° for SHHPNA with a circular lens and -15.1 dB and 15.4° for SHHPNA with a rectangular lens, respectively. In addition, the array configuration was investigated, and the gain was found to be 21 dBi for the single row array of 4×1 and 23.2 dB for the array of 3×3. Moreover, the array of 4×1 and 3×3 with +90° showed gains of 18.6 dBi and 20.7 dBi, respectively, compared to traditional paper with gains of 11.20 dBi and 13.1 dBi. [ABSTRACT FROM AUTHOR]

Single-pixel detectors are popular devices in optical sciences because of their fast temporal response, high sensitivity, and low cost. However, when being used for imaging, they face a fundamental challenge in acquiring high-dimensional information of an optical field because they are essentially zero-dimensional sensors and measure only the light intensity. To address this problem, we developed a cascaded compressed-sensing single-pixel camera, which decomposes the measurement into multiple stages, sequentially reducing the dimensionality of the data from a high-dimensional space to zero dimension. This measurement scheme allows us to exploit the compressibility of a natural scene in multiple domains, leading to highly efficient data acquisition. We demonstrated our method in several demanding applications, including enabling tunable single-pixel full-waveform hyperspectral light detection and ranging (LIDAR) for the first time. [ABSTRACT FROM AUTHOR]

Single-photon avalanche diodes (SPADs) are essential for photon-based measurements and metrology, enabling measurement comparisons at the few-photon level and facilitating global traceability to the SI. A spatially uniform detector response is crucial for these applications. Here, we report on interference effects in commercially available silicon SPADs that are detrimental to their spatial uniformity. Contrasts as high as 18% are observed, posing problems for metrology and general applications that utilize coherent light and require stable detection efficiencies. We eliminate the device optical window as a contributing interface, isolating likely causes to anti-reflective coatings, the semiconductor surface, and the SPAD's internal structure. We also present results where we leverage this sub-optimal behavior by aligning an incident beam with the position of maximum constructive interference, yielding an effective detection efficiency of 51.1(1.7)% compared to the normal value of 44.3(1)% obtained with the interference suppressed. We anticipate that this work will significantly impact the continuing development of these devices, the methods for characterizing them, and their use in accurate measurements. [ABSTRACT FROM AUTHOR]

Molecular spectroscopic and nonlinear features can indicate positive changes by solvent molecules. In this work, DFT and spectroscopic techniques were used to study the polarity effects of different solvent environments. Polarity-based models were used for studying solvent induced interactions on the optical features of new groups of biomolecules. Despite the significant contribution of general effects on the molecular absorption spectra, there is considerable competition between general and specific environmental effects on the molecular emission properties. Under this condition, strong hydrogen bonds tend to increase molecular nonlinear responses. The same results were observed for the low order (first and second order) nonlinearity of biomolecules. Therefore, the studies on the environment effects on the biomolecules' first order nonlinearity can give valuable information about higher-order optical responses. Moreover, 1-Indanone compounds with high nonlinearity can be considered as an effective element in designing optical devices. [ABSTRACT FROM AUTHOR]

In this study, the lasing characteristics of GaInAsP laser diodes (LDs) grown on directly bonded InP/Si substrates with a gas out channel (GOC) structure are investigated. GOC InP/Si substrates are fabricated using hydrophilic direct bonding and metal–organic vapor phase epitaxy growth methods and subsequently their surface conditions, bonding strength, and lasing performance are examined. Herein, it is observed that the introduction of a GOC substantially reduces void formation and improves the threshold current density of the LDs. In the results, it is demonstrated that the performance of the GOC InP/Si substrates is comparable to that of InP substrates, highlighting their potential for use in high‐performance optical devices. [ABSTRACT FROM AUTHOR]

Nitride ferroelectrics have recently emerged as promising alternatives to oxide ferroelectrics due to their compatibility with mainstream semiconductor processing. ScAlN, in particular, has exhibited remarkable piezoelectric coupling strength (K2) comparable to that of lithium niobate, making it a valuable choice for RF filters in wireless communications. Recently, ScAlN has sparked interest in its use for nanophotonic devices, chiefly due to its large bandgap facilitating operation in blue wavelengths coupled with promises of enhanced nonlinear optical properties such as a large second-order susceptibility (χ(2)). It is still an open question whether ScAlN can outperform oxide ferroelectrics concerning the Pockels effect—an electro-optic coupling extensively utilized in optical communications devices. In this paper, we present a comprehensive theoretical analysis and experimental demonstration of ScAlN's Pockels effect. Our findings reveal that the electro-optic coupling of ScAlN, despite being weak at low Sc concentration, may be significantly enhanced and exceed LiNbO3 at high levels of Sc doping, which points the direction of continued research efforts to unlock the full potential of ScAlN. The authors predict the Pockels effect of ScAlN with varying Sc concentration, realizing a ScAlN-on-insulator-on-silicon material platform, which allows the formation of low-loss, electrically-tunable microring resonators for accurate measurement of ScAlN's Pockels coefficients. [ABSTRACT FROM AUTHOR]

In present work we report the structural and optical behaviour of (99-x) SiO2 + 1ZnS + xPr (NO3)3·6H2O glass system where Pr (NO3)3·6H2O ions is doped in different molar concentrations (x = 1.0, 3.0 and 5.0 mol %) have been prepared by sol–gel method. X-ray diffraction (XRD) spectra confirmed that the formation of glassy amorphous nature. FTIR spectra results confirmed the incorporation of the dopants into the ZnS lattice structure. The average particle size calculated from Transmission electron microscopy (TEM) spectra is around 10 nm and Selective area electron diffraction (SAED) image confirmed that studied glass is polycrystalline in nature. Judd–Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6) have been evaluated from the emission spectrum. The radiative parameters such as radiative transition probability (AR), branching ratio (βR), stimulated emission cross-section (σse) and radiative lifetimes (τR) were obtained using the JO parameters. According to the CIE chromaticity, this glass can produce green light and be helpful for laser applications in the visible spectrum. It may be used as optical amplifier devices as indicated by the values of the Figure of Merit (FOM). [ABSTRACT FROM AUTHOR]

We report the smectic layer reorientation process in a surface-stabilized ferroelectric liquid crystal subject to the surface mode dominance at certain temperature and application of the controlled measuring field strength. The process is investigated by dielectric spectroscopy and optical textures analysis simultaneously in heating and cooling cycle. First the smectic layers are reoriented just 1–2 oC below Tc by applying a bias of 0.5 V as the material is soft here and cooled the sample to room temperature in absence of bias field which we call this a treated cell. In second type, the cell was taken to just above the Tc and taken the measurement in cooling cycle which we call an untreated cell. We have observed that there is a distinct molecular dynamic in the heating and cooling cycles of the material due to reoriented smectic layering and surface effect which assists the reorientation. It has also been observed that in heating cycles, the surface effect phenomenon is dominant, and in cooling cycles, it is weaker. Sometimes, the heating and cooling of the sample under electric field has been found affecting the optical performance of sample due to the readjustment of smectic layers. This study may clarify the control over the layer reorientation by surface effect and may open the possible application in displays and optical communication devices. [ABSTRACT FROM AUTHOR]

Small punch test (SPT) is a conventional technique to determine material properties. Crack tip opening displacement (CTOD) and J-integral methods are two methods applied to pre-notched SPT specimens for fracture resistance estimation. In the CTOD method, the test is interrupted at certain forces less than the maximum force, and then, the specimen is put under microscopes to study the specimen notch status and measure the crack opening. This interruption leads to changes in deformations due to removing of forces. This study aims to remove the interruption problem. To this end, a new setup is introduced to embed an optical microscope under SPT specimens, thereby enabling online monitoring and real-time deformation measurement. This online deformation measurement where the specimen is under force can reduce the error in CTOD measurement. It helps to achieve more accurate results in fracture resistance estimation. To evaluate the method, a few SPT specimens were prepared from an aged compressor named Nevski. Mechanical properties were first conventionally determined by analyzing the SPT force-displacement curves according to standards. Then, prenotched SPT specimens with lateral notches and 4.5 mm and 5 mm notch lengths were employed for fracture energy estimation. Fracture energy was calculated according to the J-integral method that its accuracy is proven. Then, CTODs were measured at various forces using the images taken during the test, and the fracture energy was calculated from the CTOD method. There was a great agreement between the fracture energy calculated by the CTOD method and the proven J-integral method. The accuracy of online measurement was better than interruption measurement in previous studies, proving that the new approach is useful. [ABSTRACT FROM AUTHOR]

In the design of optical devices and components, geometric structures and optical properties of materials, such as absorption, refraction, reflection, diffraction, scattering, and trapping, have been utilized. Finding the ideal material with certain optical and geometric characteristics is essential for a customized application. Herein, unoxidizable achromatic copper films (ACFs) are fabricated on Al2O3 substrates utilizing an atomic sputtering epitaxy apparatus. ACFs are made up of two regions vertically: a comparatively flat layer region and a 3D porous nanostructured region on top of the flat region. The measured specular reflectance displays low‐pass filter behavior with a sharp cutoff frequency in the infrared spectrum. Furthermore, the measured diffusive reflectance spectra show light‐trapping behavior in the spectral region above the cutoff frequency, where there are no known absorption mechanisms, such as phonons and interband transitions. A focused ion beam scanning electron microscope is utilized to study the thin film's nanostructured region through 3D tomographic analysis in order to comprehend the phenomena that are observed. This work will shed fresh light on the design and optimization of optical filters and light‐trapping employing porous nanostructured metallic thin films. [ABSTRACT FROM AUTHOR]

Fluorinated polyurethaneimide (PUI) electro-optic waveguide polymer with polyurethane and polyimide chain segment structures was synthesized by stepwise polymerization using the synthesized amino ester oligomer pu and imide oligomer pi as monomers. Since the main chain structure of the synthesized PUI had the functionality of both polyurethane and polyimide chain segment structures, it combines the excellent thermal and film-forming properties of polyurethanes and polyimides, as well as lower optical transmission loss in the near-infrared wavelength band. The glass transition temperature (Tg) of PUI was 182 °C, and the 5% heat loss decomposition temperature was 325 °C. The PUI had good optical properties with an optical propagation loss of 1.10 dB/cm and an electro-optic (EO) coefficient (γ33) of 86 pm/V at a wavelength of 1550 nm. A Mach-Zehnder interferometric polymer waveguide EO modulator had been designed and fabricated by using the PUI as a waveguide electro-optic core layer. The prepared polymer waveguide EO modulator showed a good electro-optic modulation response at a wavelength of 1550 nm under an applied 1 kHz sinusoidal modulation signal. The results showed that the synthesized PUI met the performance requirements for the preparation of polymer optical waveguide devices and was a polymer electro-optic waveguide material with good overall performance. [ABSTRACT FROM AUTHOR]

In semiconductor materials, doping is used mainly for controlling the electrical properties. There have been attempts to grow low‐resistivity n‐type gallium nitride (GaN) crystals by doping oxygen, germanium, and silicon, because a low‐resistivity GaN substrate is required to reduce the power losses of optical and electrical devices. However, in those efforts, the crystal color turns black with the increase in the concentration of the n‐type additives, even though they are shallow donors. Herein, it is explained why heavily doped n‐type GaN crystals exhibit low transparency. From optical absorption profiles, the appearance of a band tail from the band edge to 1.5 eV is observed. Considering the band tail theory and our observations, it is concluded that Ga vacancy or Ga vacancy complexes behaving as acceptors induce the band tail and the black color. It is proposed that neutralizing the high charge of defects ensures that low‐colored GaN crystals with low resistivity can be obtained. Moreover, the fabrication of low‐resistivity wafers sliced from a large crystal with a laser produces inexpensive wafers and allows the spread of high‐efficiency GaN devices fabricated on low‐resistivity substrates for saving electric power. [ABSTRACT FROM AUTHOR]

The determination of sulcus-to-sulcus measurements has been challenging due to the limitations of current approaches. Ultrasound methods are highly operator-dependent and require extensive training, while traditional optical devices cannot visualize structures posterior to the iris. However, modern optical anterior segment coherence tomography (AS-OCT) devices are changing this paradigm by identifying some anatomical landmarks posterior to the iris. This study evaluates the reproducibility of optical sulcus measurements in the context of sizing a novel accommodative intraocular lens (IOL). Preoperative OCT scans of patients scheduled for cataract surgery were analyzed regarding the dimensions of the ciliary sulcus using a custom scan method with a clinically available anterior segment optical coherence tomographer. Measurements were compared between two different readers, and various derived parameters were compared. The measurements by both readers were highly correlated (R2 > 0.96), and their agreement was excellent (mean difference 0.02 mm with 95% limits of agreement from −0.11 to 0.15 mm). In contrast, the sulcus diameter measurement did not agree well with automatically calculated values, such as the anterior chamber width or white-to-white. This leads to the conclusion that modern swept-source AS-OCT measurements of the ciliary sulcus dimensions are feasible, reproducible, and may be a clinically useful tool. [ABSTRACT FROM AUTHOR]

Within this manuscript, we provide a novel Fano resonance-driven micro-nanosensor. Its primary structural components are a metal-insulator-metal (MIM) waveguide, a shield with three disks, and a T-shaped cavity (STDTC). The finite element approach was used to study the gadget in theory. It is found that the adjustment of the structure and the change of the dimensions are closely related to the sensitivity (S) and the quality factor (FOM). Different model structural parameters affect the Fano resonance, which in turn changes the transmission characteristics of the resonator. Through in-depth experimental analysis and selection of appropriate parameters, the sensor sensitivity finally reaches 3020 nm/RIU and the quality factor reaches 51.89. Furthermore, the installation of this microrefractive index sensor allows for the quick and sensitive measurement of glucose levels. It is a positive contribution to the field of optical devices and micro-nano sensors and meets the demand for efficient detection when applied in medical and environmental scenarios. [ABSTRACT FROM AUTHOR]

Electrically tunable optical devices present diverse functionalities for manipulating electromagnetic waves by leveraging elements capable of reversibly switching between different optical states. This adaptability in adjusting their responses to electromagnetic waves after fabrication is crucial for developing more efficient and compact optical systems for a broad range of applications, including sensing, imaging, telecommunications, and data storage. Chalcogenide‐based phase‐change materials (PCMs) have shown great promise due to their stable, nonvolatile phase transition between amorphous and crystalline states. Nonetheless, optimizing the switching parameters of PCM devices and maintaining their stable operation over thousands of cycles with minimal variation can be challenging. Herein, the critical role of PCM pattern as well as electrical pulse form in achieving reliable and stable switching is reported on, extending the operational lifetime of the device beyond 13000 switching events. To achieve this, a computer‐aided algorithm that monitors optical changes in the device and adjusts the applied voltage in accordance with the phase transformation process is developed, thereby significantly enhancing the lifetime of these reconfigurable devices. The findings reveal that patterned PCM structures show significantly higher endurance compared to blanket PCM thin films. [ABSTRACT FROM AUTHOR]

Metal halide perovskites have aroused worldwide efforts for developing optoelectronic devices due to their unique optical properties and low‐cost simple fabrication process. In recent years, various perovskites‐based miniaturized optical devices have been actively investigated due to their record‐breaking efficiency in different fields, including environmental monitoring, remote sensing, biomedical imaging, and optical communications. In this review, a succinct and critical survey of recently discovered organic–inorganic perovskite photodetectors providing insights into their structural properties and key performance parameters is staged. First, key features of perovskites‐based photodetectors emphasizing their optoelectronic and electrical properties are introduced. Then, the polarization‐sensitive detection of metal halide perovskites using polarization‐selective optical structures is discussed. The bandgap engineering for tailoring the properties of perovskite photodetectors by changing the chemical composition and material structures is also highlighted in this report. Finally, a perspective on future opportunities and current challenges for designing perovskite‐based optoelectronic devices is presented. [ABSTRACT FROM AUTHOR]

Femtosecond laser two-photon polymerization (TPP) technology, known for its high precision and its ability to fabricate arbitrary 3D structures, has been widely applied in the production of various micro/nano optical devices, achieving significant advancements, particularly in the field of photonic wire bonding (PWB) for optical interconnects. Currently, research on optimizing both the optical loss and production reliability of polymeric photonic wires is still in its early stages. One of the key challenges is that inadequate metrology methods cannot meet the demand for multiphysical measurements in practical scenarios. This study utilizes novel in situ scanning electron microscopy (SEM) to monitor the working PWBs fabricated by TPP technology at the microscale. Optical and mechanical measurements are made simultaneously to evaluate the production qualities and to study the multiphysical coupling effects of PWBs. The results reveal that photonic wires with larger local curvature radii are more prone to plastic failure, while those with smaller local curvature radii recover elastically. Furthermore, larger cross-sectional dimensions contribute dominantly to the improved mechanical robustness. The optical-loss deterioration of the elastically deformed photonic wire is only temporary, and can be fully recovered when the load is removed. After further optimization based on the results of multiphysical metrology, the PWBs fabricated in this work achieve a minimum insertion loss of 0.6 dB. In this study, the multiphysical analysis of PWBs carried out by in situ SEM metrology offers a novel perspective for optimizing the design and performance of microscale polymeric waveguides, which could potentially promote the mass production reliability of TPP technology in the field of chip-level optical interconnection. [ABSTRACT FROM AUTHOR]

Chiral 2D perovskites synthesized using (R‐+)‐α‐Methylbenzylamine (R‐MBA) and (S–)‐α‐Methylbenzylamine (S‐MBA) as barrier molecules exhibit chirality at low n values, as confirmed by circular dichroism (CD) analysis. The Anisotropy factor decreases significantly with increasing the n value, reaching 0.0032 for pure 2D perovskite. These synthesized quasi‐2D chiral perovskites have been successfully integrated into light‐emitting diodes (LEDs), demonstrating polarized emission for the first time. Remarkably, n = 3, R enantiomer achieves a total external quantum efficiency (EQE) of 12.1%, with polarized EQE of 4%. In the case of n = 2, the total EQE for both enantiomers is 4.3%, with polarized EQE of 3.4%, higher than the non‐polarized EQE of 0.9%. Degree of Polarization (DOP) is employed to characterize the fraction of an electromagnetic wave that exhibits polarization. The DOP analysis reveals a significant increase for low dimensional perovskite. Particularly for n = 2, R enantiomer exhibits a DOP of 53% compared to 2.5% for the non‐chiral molecule BzA. These findings demonstrate efficient polarized emission in 2D chiral perovskite LEDs, indicating promising avenues for advanced optical device applications. [ABSTRACT FROM AUTHOR]

Doro-e refers to a genre of Japanese folk paintings: it is a group of works, likely to be produced from the mid-eighteenth to the nineteenth century, that emerged during a time when some of the techniques of European paintings, such as vanishing point, perspective, and mirror image were being incorporated into traditional Japanese paintings. Indeed, doro-e paintings played an important role in familiarising the Japanese public with these new techniques. However, the process of painting doro-e including materials and painting techniques used has not been interpreted, and the definition of doro-e remains elusive. This article begins by exploring Kamigata doro-e, particularly megane-e (vue d'optique), which was painted in the initial period of doro-e works. Materials analysis indicates the use of smalt, which is not often found in traditional Japanese paintings. Indigo was also used to depict landscapes, indicating that traditional blue dye was still the preferred colour for European-influenced paintings during the Edo period (1603–1868). This study also discusses the application of gold-coloured outlines identified as brass. A diversity of colourants and techniques was used in doro-e, a fact that is not reflected in the current definition regarding doro-e, and is discussed in this article. [ABSTRACT FROM AUTHOR]

In this paper, the generalized (3+1)-dimensional nonlinear wave equation in fluid with gas bubbles is studied in soliton theory and produced by taking the Hirota bilinear operators. The first- to third rogue wave solutions through numerous rogue wave strategy by Maple typical estimations are recovered. The made conditions for the analyticity and positively of the gotten arrangements can be effectively accomplished by utilizing the specific determinations of the included values. The most merits of this plot are to recoup the Hirota bilinear models and their generalized equivalences. Also, the rational tan (Π (ξ)) technique on the generalized nonlinear wave equation is examined. The perturbed solution of the generalized nonlinear wave equation through the way of Modulational stability is studied. Finally, the graphical reenactments of the precise arrangements are portrayed. By selecting suitable values for the parameters involved in the solutions, 3D graphs, 2D contour graphs and line graphs are presented to provide graphical demonstration of the results. The reported results will be helpful to design new and better optical devices. The findings of this work may also help in problems arising in ocean engineering. [ABSTRACT FROM AUTHOR]

Emerging miniaturized atomic sensors such as optically pumped magnetometers (OPMs) have attracted widespread interest due to their application in high-spatial-resolution biomagnetism imaging. While optical probing systems in conventional OPMs require bulk optical devices including linear polarizers and lenses for polarization conversion and wavefront shaping, which are challenging for chip-scale integration. In this study, an integrated optical probing scheme based on localized-interference metasurface for chip-scale OPM is developed. Our monolithic metasurface allows tailorable linear polarization conversion and wavefront manipulation. Two silicon-based metasurfaces namely meta-polarizer and meta-polarizer-lens are fabricated and characterized, with maximum transmission efficiency and extinction ratio (ER) of 86.29 % and 14.2 dB for the meta-polarizer as well as focusing efficiency and ER of 72.79 % and 6.4 dB for the meta-polarizer-lens, respectively. A miniaturized vapor cell with 4 × 4 × 4 mm3 dimension containing 87Rb and N2 is combined with the meta-polarizer to construct a compact zero-field resonance OPM for proof of concept. The sensitivity of this sensor reaches approximately 9 fT/Hz1/2 with a dynamic range near zero magnetic field of about ±2.3 nT. This study provides a promising solution for chip-scale optical probing, which holds potential for the development of chip-integrated OPMs as well as other advanced atomic devices where the integration of optical probing system is expected. [ABSTRACT FROM AUTHOR]

Despite the importance of positive and negative pressure sensing in numerous domains, the availability of a single sensing unit adept at handling this dual task remains highly limited. This study introduces a compact optical device capable of swiftly and precisely detecting positive and negative pressures ranging from −35 kPa to 35 kPa. The GaN chip, which serves as a core component of the device, is monolithically integrated with light-emitting and light-detecting elements. By combining a deformable PDMS film coated with a hydrophobic layer, the chip can respond to changes in optical reflectance induced by pressure fluctuations. The integrated sensing device has low detection limits of 4.3 Pa and −7.8 Pa and fast response times of 0.14 s and 0.22 s for positive and negative pressure variations, respectively. The device also demonstrates adaptability in capturing distinct human breathing patterns. The proposed device, characterized by its compactness, responsiveness, and ease of operation, holds promise for a variety of pressure-sensing applications. [ABSTRACT FROM AUTHOR]

Transparent alumina ceramics are known for high toughness and the ability to withstand high temperatures, making them ideal materials for use in extreme environments and high-power optical devices. However, polycrystalline alumina, which has a hexagonal crystal structure, is difficult to make highly transparent due to birefringent scattering loss. Research has shown that birefringent scattering can be reduced by having finer grains and/or aligned grains. Here, we present an analytical birefringence scattering model that can model realistic microstructures, by including chord length distributions and grain orientations, and predict the birefringence scattering loss quantitatively. Our modeled results match well with existing experimental data for transparent fine grained and aligned alumina. This model is derived from first-principles and is applicable to other transparent ceramics. [ABSTRACT FROM AUTHOR]

2D materials, particularly 2D semiconductors, and layered antiferromagnetic (AFM) compounds, exhibit rich light‐matter coupling phenomena in low‐dimensional systems. In this work, the occurrence of interlayer exciton–magnon coupling (EMC) is observed in Néel‐type AFM of MnPX3 (X = S or Se) and monolayer (1L) WS2 heterostructures. The energy of neutral exciton in 1L WS2 can be tuned by the adjacent AFM order, resulting in an additional energy shift of 10–14 meV. Furthermore, by filtering the photoluminescence spectrum with graphene and conducting magnetic measurements, the correlation is elucidated between the interlayer EMC and AFM transition process. In MnPS3, this coupling behavior exhibits sensitivity to the changes of magnetic structures, manifesting with a correlated length ξ of 8.34 Å at temperatures higher than Néel temperature (TN). The decoupling process in WS2/MnPS3 heterostructure below 50 K is originated from a weak out‐of‐plane ferromagnetic order, confirming the presence of an XY‐type magnetic phase transition in MnPS3 at sub‐TN temperature. This study provides a fundamental understanding of EMC and its potential applications in the integration of optical and magnetic devices. [ABSTRACT FROM AUTHOR]

Conventional absorbing, reflective and scattering polarizers are facing various issues, such as severe optical loss, necessary oblique incidence, humidity sensitivity or aging‐caused failure. Subnanowires (SNWs) with polymer‐analogue properties, intrinsic order, and multi‐level interactions attract widespread attention as superior candidates for building blocks of polarizers. Herein, freestanding and flexible liquid crystal (LC)‐SNW films are prepared through a facile directional coating method, not only exhibiting good stability for water and repeated temperature fluctuations, but also showing good polarization performance for visible and near‐infrared (NIR) light, with the polarization degree (P) values of 93%, 84%, and 63% at the wavelengths of 580, 780 and 960 nm. And the average haze achieves 85%. The LC‐SNW films have great potential in applications for polarizers, holographic projection imaging and flexible optical devices. [ABSTRACT FROM AUTHOR]

1T-CrTe2 is one of the typical two-dimensional transition metal dichalcogenides (TMDCs) and has attracted great attention in the field of spintronics due to its fascinating magnetic properties. However, the optical properties such as the nonlinear optical characteristics of 1T-CrTe2 films have rarely been reported. Here, the CrTe2 thin films were prepared on highly oriented pyrolytic graphite and gold-coated plane mirrors via molecular beam epitaxy. By adjusting the growth temperature and the flux of the source, CrTe2 thin films with various morphologies were obtained. In addition, the CrTe2 thin films were used as saturable absorbers (SAs) and incorporated into Er-doped fiber lasers. A modulation depth of 43.5% and mode-locking at 1560 nm with a pulse width of 316 fs were achieved, showing extremely outstanding nonlinear optical response among TMDCs. This work demonstrates the growth of high-quality CrTe2 films and verifies that CrTe2 films have enormous prospects in ultrafast optical devices. [ABSTRACT FROM AUTHOR]