The absence of inversion symmetry in chiral tellurium (Te) creates exotic spin textures within its electron waves. However, understanding textured optical waves within Te remains a challenge due to the semi-classical limitations of long-wavelength approximation. To unveil these textured optical waves, we develop a spin-resolved deep-microscopic optical bandstructure for Te analogous to its electronic counterpart. We demonstrate that the degeneracies in this optical bandstructure is lifted by the twisted lattice of Te, which induces optical gyrotropy. Our theory shows excellent agreement with experimental optical gyrotropy measurements. At the lattice level, we reveal that the chirality of Te manifests as deep-microscopic optical spin texture within the optical wave. Our framework uncovers the finite-momentum origin of optical activity and provides a microscopic basis for light-matter interactions in chiral crystalline materials.

Dramatic fluorescence enhancement in two-dimensional (2D) van der Waals materials (vdWMs) coupled to plasmonic nanostructures has the potential to enable ultrathin, flexible, and high-brightness illumination devices. However, addressing the limitation of locally scattered small plasmon-enhanced areas remains challenging. Here, we present a 2D plasmonic enhancement of photoluminescence (PL) spanning nearly 800 μm 2 , enabled by surface lattice resonance (SLR) in a 2D vdWM-Au slot lattice hybrid. The Au slot lattice is designed and fabricated using Babinet’s principle and Rayleigh’s anomaly to maximize radiative decay rate and induce non-local photo-excitation in a MoSe 2 monolayer. For emitted PL coupled with SLR, enhanced by up to 32-fold, we investigate its in-plane directivity and long-range propagation using angle- and space-resolved spectroscopic PL measurements. Our experiment reveals that a nearly 800 μm 2 2D luminescent sheet can be achieved regardless of the size of the MoSe 2 crystal, even with a sub-μm 2 flake. This work provides a new type of ultrabright, large-area 2D luminescent material, suitable for a range of optical illumination, communication, and sensing devices.

Monolayer transition metal dichalcogenides are promising materials that not only are atomically thin but also have direct bandgaps, making them highly regarded in optics and optoelectronics. However, their photoluminescence exhibits almost random polarization at room temperature. The emission is also omnidirectional and weak due to the low quantum yield. These limitations hamper the development of practical optoelectronic devices and solid-state single-photon sources for quantum technologies. Here, we demonstrate the spatial control of photoluminescence polarization by coupling monolayer tungsten disulfide with photonic bands having bound states in the continuum. We design a dielectric photonic crystal slab with bound states in the continuum that spectrally overlap with the excitonic resonance of the monolayer of tungsten disulfide. Integration with the photonic crystal slab modulates the directionality and improves the intensity of photoluminescence through extraction and excitation enhancement. Our results will enable the development of compact on-chip optoelectronic and quantum photonic devices based on two-dimensional materials.

2D perovskite (PVSK) single crystals have received significant attention due to their unique optical and optoelectronic properties. However, current synthesis methods face limitations, particularly in large-area fabrication, which remain critical barriers to practical applications. In this study, the synthesis of red/green/purple-blue-colored 2D PVSK nanocrystals over a large area (4-inch wafer) and the fabrication of high-performance photodetector arrays are presented via a facile yet efficient spray-coating approach with a liquid-bridge transport effect. The photodetector array achieves 100% working yield, high photo-responsivity (1.5 × 106 A W-1) and specific-detectivity (1.1 × 1016 Jones) with competitive photomapping characteristics. An intelligent vision system for automatic shape recognition is further demonstrated with a recognition rate exceeding 90%. This study provides significant advances in the scalable synthesis of nanoscale 2D PVSK crystals, their integration into large-area optoelectronic devices, and their potential use in artificial-intelligence systems.

Nanoimprint lithography is gaining popularity as a cost-efficient way to reproduce nanostructures in large quantities. Recent advances in nanoimprinting lithography using high-index nanoparticles have demonstrated replication of photonic devices, but it is difficult to confer special properties on nanostructures beyond general metasurfaces. Here, we introduce a novel method for fabricating light-emitting metasurfaces using nanoimprinting lithography. By utilizing quantum dots embedded in resin, we successfully imprint dielectric metasurfaces that function simultaneously as both emitters and resonators. This approach to incorporating quantum dots into metasurfaces demonstrates an improvement in photoluminescence characteristics compared to the situation where quantum dots and metasurfaces are independently incorporated. Design of the metasurface is specifically tailored to support photonic modes within the emission band of quantum dots with a large enhancement of photoluminescence. This study indicates that nanoimprinting lithography has the capability to construct nanostructures using functionalized nanoparticles and could be used in various fields of nanophotonic applications.

AbstractThe field of high-bandwidth holography has been extensively studied over the past decade. Orbital angular momentum (OAM) holography, which utilizes vortex beams with theoretically unbounded OAM modes as information carriers, showcases the large capacitance of hologram storage. However, OAM holography has been limited to a single wavelength, restricting its potential for full-color holography and displays. In this study, we propose wavelength and OAM multiplexed holography that utilizes the multiple dimensions of light—wavelength and OAM—to provide a multi-color platform that expands the information capacity of holographic storage devices. The proposed wavelength-OAM multiplexed holography is physically realized by a metasurface, the state-of-the-art optical element consisting of an array of artificially engineered nanostructures. Hydrogenated silicon meta-atoms, the constituents of the metasurface, are engineered to possess wavelength selectivity by tailoring the dispersion of polarization conversion. These meta-atoms are used to encode the calculated OAM-preserved phase maps based on our design. The sampling grid of the phase map is rotated by 45°, which effectively suppress higher-order diffraction, providing a great strategy for achieving large field-of-view (FOV) holography. We successfully demonstrate six holographic images that are selectively reconstructed under the illumination of light with specific wavelengths (λ = 450, 635 nm) and topological charges (l = -2, 0, 2), without high-order diffraction. Our work suggests that ultrathin meta-holograms can potentially realize ultrahigh-bandwidth full-color holography and holographic video displays with large FOV.

Plasmonic nanostructures can enhance the performance of photodetectors (PDs) owing to their amplification effect in light absorption, leading to overcoming the inherent properties of the photoactive layer. Herein, hierarchical plasmonic nanopatterns have been prepared and used for high‐performance flexible perovskite PDs. The developed hierarchical nanostructures, featuring nanoposts on cross‐nanograting patterns, exhibit a notably enhanced light trapping effect compared to hierarchical nanostructures based on a unidirectional simple nanograting structure. Moreover, hierarchical pattern‐based perovskite PDs show a photoresponsivity of 580 mA W −1 and a specific detectivity of 3.2 × 10 12 Jones, which are 420% and 990% higher than those of perovskite PDs without plasmonic nanostructures, respectively. Furthermore, a flexible 10 × 10 PD array has been developed, which enables the accurate mapping of light signals with exceptional operational and mechanical stabilities, under a bending radius as small as 8 mm and after undergoing more than 1000 bending cycles. Comprehensive analyses using finite‐difference time‐domain calculations and photoluminescence mapping reveal the effective light trapping effect of hierarchical plasmonic patterns in the perovskite layers. This work provides an efficient approach to achieve high‐performance perovskite optoelectronic devices.

Practical human biofluid sensing requires a sensor device to differentiate patients from the normal group with high sensitivity and specificity. Label-free molecular identification from human biofluids allows direct classification of abnormal samples, providing insights for disease diagnosis and finding of new biomarkers. Here, we introduce a label-free surface-enhanced Raman scattering sensor based on a three-dimensional plasmonic coral nanoarchitecture (3D-PCN), which has strong electromagnetic field enhancement through multiple hot spots. The 3D-PCN was synthesized on a paper substrate via direct one-step gold reduction, forming a coral-like nanoarchitecture with high absorption property for biofluids. This was fabricated as a urine test strip and then integrated with a handheld Raman system to develop an on-site urine diagnostic platform. The developed platform successfully classified the human prostate and pancreatic cancer urines in a label-free method supported by two types of deep learning networks, with high clinical sensitivity and specificity. Our technology has the potential to be utilized not only for urinary cancer diagnosis but also for various human biofluid sensing systems as a future point-of-care testing platform.

A label-free detection method for noninvasive biofluids enables rapid on-site disease screening and early-stage cancer diagnosis by analyzing metabolic alterations. Herein, we develop three-dimensional plasmonic hexaplex nanostructures coated on a paper substrate (3D-PHP). This flexible and highly absorptive 3D-PHP sensor is integrated with commercial saliva collection tube to create an efficient on-site sensing platform for lung cancer screening via surface-enhanced Raman scattering (SERS) measurement of human saliva. The multispike hexaplex-shaped gold nanostructure enhances contact with saliva viscosity, enabling effective sampling and SERS enhancement. Through testing patient salivary samples, the 3D-PHP sensor demonstrates successful lung cancer detection and diagnosis. A logistic regression-based machine learning model successfully classifies benign and malignant patients, exhibiting high clinical sensitivity and specificity. Additionally, important Raman peak positions related to different lung cancer stages are investigated, suggesting insights for early-stage cancer diagnosis. Integrating 3D-PHP senor with the conventional saliva collection tube platform is expected to offer promising practicality for rapid on-site disease screening and diagnosis, and significant advancements in cancer detection and patient care.

Hydrogen energy is promising renewable energy and specifically, hydrogen storage is a bottleneck to commercializing hydrogen energy. Researchers have relied on the synthesis of porous materials in physisorption and lowering the H2 binding energy of hydride materials in chemisorption, all of which have been conducted in a similar manner respectively. However, the development of hydrogen storage materials applicable to onboard system isn't found yet. Hence, we examined the phenomenon of eccentric H2 storage in carbon nanopores with sub-1 nm diameters reported earlier, finding a lack of deep research on the fundamentals of this phenomenon. We formulate a hypothesis of H2 storage by intrinsic EMF (IEMF) interaction and firstly discover that in contrast to general intuition, the neutral carbon nanopore forms a significant IEMF even without an external EMF. Moreover, we confirm the difference of IEMF inside the nanopore from that outside the nanopore due to the overlap between the graphene layers and demonstrate that the resultant IEMF inside the nanopore governs the H2 storage in the carbon nanopore. This result will shed light on all the other areas related to abnormal phenomena in nanopores with sub-1 nm diameters.

One of the most widely-held beliefs was that no such thing as a bound state existed in a continuum. Notably, it only lately emerged to disclose such a state in several domains of wave physics. Here we report the presence of elastic quasi-bound states in the continuum (QBICs) by balancing local Fano and Fabry–Pérot resonant states, with vanishing linewidths nearby which indicate BICs. The rational design is made by directly integrating an acoustic cavity into an elastic bar, which enables the two to interact. The proposed continuum elastic bar is in analogy to the Fano–Anderson discrete model, which further satisfies a criteria for both Fano and Fabry–Pérot resonances to obtain optimal QBIC modes. Experiments are also carried out for proof-of-concept purposes to uncover these states with a good agreement. This platform would be versatile in illustrating generic Fano lineshapes and high Q-factors, bringing up a new avenue for using the acoustoelastic nature. We hope that our findings would also contribute to the understanding of quantum-driven phenomena in classical contexts with sharing the comparable underlying wave physics.

While the anomalous phenomenon of H2 densification in sub-1 nm carbon nanopores have attracted the attention of many researchers, there have been few in-depth studies on the fundamentals. Recently, we discovered that significant intrinsic electromagnetic fields (IEMFs) inside carbon nanopores with diameters below 1 nm are modulated with the difference in morphology, and it seems to be linked to the anomalous phenomenon. As a follow-up study, we find that the IEMFs inside carbon nanopores can be modulated by tuning pore diameter or atomic composition. Moreover, it is suggested that these modulations are highly correlated to the degree of molecular hydrogen densification. Particularly, given the widely accepted fact that the H2 densification is possible in only sub-1 nm nanopore, it is notable that the nanopores larger than 1 nm may play a substantial role in H2 densification by controlling atomic composition. This paper carefully suggests that this concept can be applied to the field of hydrogen storage materials so that the development of H2 storage materials with high performance may be achievable.

Over the last two decades, the capabilities of metasurfaces in light modulation with subwavelength thickness have been proven, and metasurfaces are expected to miniaturize conventional optical components and add various functionalities. Herein, various metasurface design strategies are reviewed thoroughly. First, the scalar diffraction theory is revisited to provide the basic principle of light propagation. Then, widely used design methods based on the unit-cell approach are discussed. The methods include a set of simplified steps, including the phase-map retrieval and meta-atom unit-cell design. Then, recently emerging metasurfaces that may not be accurately designed using unit-cell approach are introduced. Unconventional metasurfaces are examined where the conventional design methods fail and finally potential design methods for such metasurfaces are discussed.

Chiral metamaterials have received significant attention due to their strong chiroptical interactions with electromagnetic waves of incident light. However, the fabrication of large-area, hierarchically manufactured chiral plasmonic structures with high dissymmetry factors ( g- factors) over a wide spectral range remains the key barrier to practical applications. Here we report a facile yet efficient method to fabricate hierarchical chiral nanostructures over a large area (>11.7 × 11.7 cm 2 ) and with high g -factors (up to 0.07 in the visible region) by imparting extrinsic chirality to nanostructured polymer substrates through the simple exertion of mechanical force. We also demonstrate the application of our approach in the polarized emission of quantum dots and information encryption, including chiral quick response codes and anti-counterfeiting. This study thus paves the way for the rational design and fabrication of large-area chiral nanostructures and for their application in quantum communications and security-enhanced optical communications.

. The article comments on the the impact on diverse fields of R. A. Beth's direct detection of the angular momentum of light.

We investigated the chain-length and fluorination effects on photophysics within push-pull conjugated polymer (CP, M-w 40k/100k PBDB-T and M-w 100k PM6) aggregates using transient absorption spectroscopy. Our findings reveal that J-type excitons were more induced in relatively ordered domains than in disordered domains of PBDB-T. Interestingly, the ordered domains of M-w 100k PBDB-T aggregates induce interchain packing with localized chain cross-linked points, referred to as quasi-interchain packing, due to chain folding and increased intrachain rigidity. Two fluorination effects were observed in the PM6 aggregates. First, the intrachain rigidity decreased in the PM6 film compared to the PBDB-T films. Second, the formation of localized chain cross-linked points was suppressed in the ordered domains, resulting in the conversion of the quasi- to the normal interchain packing and the enhanced H-type excitonic couplings. Our findings provide new insights into the exciton dynamics study in CP aggregates and the bulk-heterojunction blends of polymer solar cells.

Background: A nondestructive test is commonly used to inspect the surface defects and internal structure of an object without any physical damage. X-rays generated from an electron accelerator or a tube are one of the methods used for nondestructive testing. The high penetration of X-rays through materials with low atomic numbers makes it difficult to discriminate between these materials using X-ray imaging. The interaction characteristics of neutrons with materials can supplement the limitations of X-ray imaging in material discrimination.Materials and Methods: The radiation image acquisition process for air-cargo security inspection equipment using X-rays and neutrons was simulated using a GEometry ANd Tracking (Geant4) simulation toolkit. Radiation images of phantoms composed of 13 materials were obtained, and the R-value, representing the attenuation ratio of neutrons and gamma rays in a material, was calculated from these images.Results and Discussion: The R-values were calculated from the simulated X-ray and neutron images for each phantom and compared with those obtained in the experiments. The R-values obtained from the experiments were higher than those obtained from the simulations. The difference can be due to the following two causes. The first reason is that there are various facilities or equipment in the experimental environment that scatter neutrons, unlike the simulation. The other is the difference in the neutron signal processing. In the simulation, the neutron signal is the sum of the number of neutrons entering the detector. However, in the experiment, the neutron signal was obtained by superimposing the intensities of the neutron signals. Neutron detectors also detect gamma rays, and the neutron signal cannot be clearly distinguished in the process of separating the two types of radiation. Despite these differences, the two results showed similar trends and the viability of using simulation-based radiation images, particularly in the field of security screening. With further research, the simulation-based radiation images can replace ones from experiments and be used in the related fields.Conclusion: The Korea Atomic Energy Research Institute has developed air-cargo security inspection equipment using neutrons and X-rays. Using this equipment, radiation images and R-values for various materials were obtained. The equipment was reconstructed, and the R-values were obtained for 13 materials using the Geant4 simulation toolkit. The R-values calculated by experiment and simulation show similar trends. Therefore, we confirmed the feasibility of using the simulation-based radiation image.

We elucidated chain-extension effects of a benzo-dithiophene (BDT) and thienopyrroledione-based push-pull conjugated polymer (CP) on its exciton-dissociation mechanism within aggregate systems using transient absoption spectroscopy. The side-group extension CP with benzothiophene on the BDT unit induced H-type excitons with excess energy owing to decreased chain stiffness. This led to interchain polaron-pair (PP)-mediated exciton dissociation. The stiff side-group extended with thienothiophene on the BDT unit also induced H-type excitons, but the decreased energy and breadth of the density of states suppressed the interchain PP-mediated exciton dissociation. The main-chain-extension CP with two thiophenes on either side of the BDT unit has a curved structure disturbing the interchain packing. Thus, the driving force of exciton dissociation between the chains decreased, leading to intrachain PP-mediated exciton dissociation. Our findings can facilitate the development of novel CPs to further increase the efficiencies of polymer solar cells.