Research on ultra-wideband Terahertz transmission lines based on silicon photonic crystals

High-throughput screening of bladder cancer exosome biomarkers by barcodes integrated herringbone microfluidics.

Robustness of quantum states against induced fabrication defects in J(x) photonic lattices

Thermal Phase Sensitivity Reduction in Hollow-Core Photonic Bandgap Fibers Enabled by a Stress-Buffering Coating Architecture

Metasurfaces excel at local, spatially varying control of wavefronts, whereas photonic crystals (PhCs) are admired for their nonlocal resonances such as bound states in the continuum (BICs). These two regimes-local control and nonlocal collective response-have long been viewed as difficult to integrate within a single platform. Here, we introduce local-nonlocal assisted multifunctional PhCs unifying wavefront shaping and BICs by embedding meta-notches within PhC pillars. The locally tunable notches generate spectral-zero-assisted topological phase for efficient 2π coverage, while the strongly confined BIC modes remain largely unperturbed, preserving high-Q nonlocal resonances. This constructive local-nonlocal integration synthesizes the design freedom of metasurfaces with the dispersive resonance of PhCs in a single planar device. Our approach extends the capabilities of flat optics, enabling multifunctional PhCs and opening pathways toward higher-order topologies, advanced imaging, communication, and analogue optical computing.

The growing demand for anticounterfeiting of high-value goods calls for advanced technologies that integrate multiple security features. Here, we demonstrate a triple-information encryption system based on fluorescent microspheres. Monodisperse polystyrene fluorescent microspheres doped with the rare-earth complex Eu(TTA)3(TOPO)2 were synthesized via emulsion polymerization, achieving tunable diameters (132-288 nm) and intense red emission at 612 nm. By optimizing the rheological properties of the colloidal ink and precisely controlling the electrohydrodynamic printing process, high-quality full-color structural color patterns were fabricated. Crucially, by exploiting the Purcell effect of the photonic crystal, we engineered a spatially graded fluorescence enhancement across the patterns, thereby establishing the triple-encryption mechanism. The resulting patterns exhibit angle-dependent structural colors under ambient light, switch to uniform red fluorescence under UV illumination, and conceal a microscopic fluorescence intensity gradient that acts as a unique "spectral key" for authentication. This work offers a cost-effective strategy for high-security dynamic anticounterfeiting.

ABSTRACT In this work, we investigate novel one-dimensional photonic crystals theoretically constructed from primitive building blocks of rectangular, sinusoidal, sawtooth and triangular shapes. The central idea is to combine the filtering properties of these structures so that if one structure fails to filter a wave within a given frequency interval, subsequent layers with different shapes will filter it. As expected, this approach proves effective in some cases, while in others, we encounter specific conditions, as described in the text. Our results are obtained using the transfer matrix method. We study the effects of various parameters – such as the number of layers, their dielectric constant and the total system length – on the transmission coefficient. The core novelty of this work lies in the systematic investigation of hybrid refractive index profiles (e.g. rectangular-sinusoidal, sawtooth-triangular) that combine basic geometric shapes. A key finding is that these hybrid structures exhibit distinct and tunable photonic band gap (PBG) properties, such as the complete absence of a band gap in the Rec-Saw profile at lower frequencies.

This work proposes a simulation-based photonic–AI sensing framework for soil nutrient and microplastic detection. This framework integrates a 2D dual-ring cavity photonic crystal (PhC) sensor with a Deep & Cross Network model (DCN). The PhC sensor demonstrates strong optical confinement and spectral selectivity, achieving quality factors up to 18,244, with resonance wavelengths spanning 1528.5–1824.4 nm, high sensitivity as 631 nm/RIU for nutrients and 432 nm/RIU for Low density polyethylene (LDPE) microplastic detection. The PhC sensor further achieves figures of merit up to 3440 RIU⁻¹ and detection limits as low as 3 × 10⁻⁵ RIU, and stable operation under fabrication tolerances and temperature variations. The proposed DCN architecture effectively analyzes the resultant spectral responses of the different soil elements and contaminants. It precisely captures nonlinear spectral patterns without relying on refractive index as an explicit feature, avoiding classification ambiguity at similar concentration levels of soil elements. The introduced DCN model achieves high classification/identification performance of 99.87% accuracy and near-perfect precision, recall, and F1-score. For explainability, SHAP and LIME are employed to quantify spectral feature contributions and explain individual predictions. This explainable AI (XAI) analysis confirms the physical relevance of dominant spectral features used for decision-making. The performed Fabrication tolerance and temperature analyses confirm stable operation within practical limits. Although experimental validation is beyond the scope of this study, the compact sensor design and lightweight inference model support future hardware integration. These results demonstrate the potential of physics-based photonic sensing combined with explainable AI for intelligent soil monitoring.

Simultaneous photonic and phononic bandgaps in a hexagonal lattice geometry with gradually transforming circular-to-triangular air gap holes

Hand-foot-mouth disease (HFMD), mainly caused by Enterovirus 71 (EV71), Coxsackievirus A6 (CVA6), and Coxsackievirus A16 (CVA16), poses a serious threat to children due to its high transmissibility and potential to induce severe complications. Herein, a spatially encoded fluorescence biosensing platform that integrates a parallel entropy-driven circuit (EDC) with a combinatorial photonic crystal (cPC) array was reported for ultrasensitive, multiplex, and rapid detection of HFMD viruses. In this system, three parallel entropy-driven circuits were designed to specifically recognize the VP1 gene sequences of EV71, CVA6, and CVA16, generating distinct fluorescence signals (FAM, Cy3, and Cy5) upon target binding. Simultaneously, the cPC array, constructed from polystyrene nanospheres of three different diameters (220, 245, and 293 nm), not only acted as a spatial encoder that enabled the simultaneous discrimination of multiple signals through predefined physical zones but also served as a signal amplifier by matching its photonic band gaps to the emission wavelengths of the fluorophores. Under optimized conditions, the sensing array exhibited excellent linearity across broad dynamic ranges with the detection limits down to the femtomolar level (100.55 fM for EV71, 23.06 fM for CVA6, and 52.76 fM for CVA16). This assay also demonstrated high specificity against non-HFMD viruses and satisfactory recovery rates (94.52-102.68%) in spiked serum samples. This work reports the first application of integrating a combinatorial PC array with a parallel EDC for the detection of HFMD, offering a low-cost, user-friendly, and versatile strategy with promising potential for clinical diagnostics and public health surveillance.

Photonic skyrmions are topological textures that exhibit remarkable resilience to environmental perturbations and support deeply subwavelength features, making them promising candidates for high-resolution microscopy, optical computing devices and ultrahigh-density information encoding. However, in contrast to free-space optical skyrmions, all existing approaches to generate polaritonic field skyrmions are limited by a lack of dynamic tunability. In general, without engineering the phase of the incident light, both their lattice site diameter and total topological charges remain fixed after fabrication. These constraints originate from a shared reliance on wavelength-dependent coupling structures or complex excitation conditions. To overcome these limitations, we introduce the concept of dynamically controllable polaritonic topologies generated by non-local photonic modes. Here we leverage quasi-bound states in the continuum resonances in dielectric metasurfaces to launch hyperbolic phonon polaritons in hexagonal boron nitride that interfere to create highly confined photonic skyrmion lattices with diameters down to 271 nm (λ/25). Thanks to the steep dispersion of hexagonal boron nitride, we can change the excitation frequency to achieve control over the size of individual photonic skyrmions within the same physical resonator structure. In addition, our platform is not limited to one type of topology but can generate optical meron lattices and kπ-twist skyrmions through straightforward variations in resonator shape, providing a feasible path towards skyrmion multiplexing and near-arbitrary topologies. The synergistic integration of resonant metasurfaces with polaritonic topologies has potential applications for nanophotonics, such as topological lasing, nonlinear optics and twistronics, as well as for condensed matter physics, such as Chern insulators and topological edge states.

Bound states in the continuum (BICs), first proposed by von Neumann and Wigner in 1929, describe localized states embedded within a continuum yet completely decoupled from radiative channels. Once regarded as a theoretical curiosity in quantum mechanics, BICs have since been realized across diverse physical systems, including electronic, acoustic, and photonic platforms, where they exhibit effectively infinite quality factors and negligible radiative loss. In photonics, the advent of metasurfaces and photonic crystals has enabled precise control of geometry and permittivity, transforming ideal BICs into experimentally accessible quasi-BICs that provide extreme spectral confinement and enhanced light–matter interactions. These unique properties offer robust and tunable platforms for quantum state generation and control at the nanoscale. This Review summarizes recent progress in BIC research from a quantum photonic perspective, covering their roles in quantum light generation, nonlinear optics, and strong light–matter coupling. It also highlights emerging frontiers, including topologically protected coherent BIC platforms, compact on-chip BIC architectures, and plasmonic BICs for room-temperature quantum devices. Together, these developments mark the evolution of BICs from a quantum mechanical concept to a cornerstone of next-generation quantum photonic technologies.

The escalating demand for advanced anti-counterfeiting and information encryption technologies has driven the exploration of luminescent materials with high quantum yield, multi-level encoding capability, and long-term stability. This study extends the high-entropy paradigm to I-III-VI quantum dots (QDs) for the first time, successfully synthesizing CuZnCrGaSe/ZnSe/ZnS (CZCrGSe/ZnSe/ZnS) core/shell/shell high-entropy QDs via a one-pot nucleation strategy combined with stepwise hot-injection shell coating. By optimizing reaction parameters and composition ratios, combined with a precisely designed ZnSe/ZnS double shell for efficient defect passivation, the QDs achieve an emission wavelength of 540nm and a record-breaking photoluminescence quantum yield (PLQY) of 100%, which stands as the highest PLQY reported for alloy QDs to date. Integrating these high-performance QDs into stimulus-responsive photonic crystals (PCs) yields dual-mode nanocomposite films capable of exhibiting two reversible optical states: structural color and fluorescent color. The luminescent properties of high-entropy QDs synergistically modulate with the photonic bandgap of the PCs, enabling multidimensional information encryption. This functionality was validated through a visual encoding/decoding system capable of secure binary code conversion. This work achieves a significant breakthrough in the luminescent performance of alloy QDs and provides a novel strategy for developing eco-friendly, high-performance optical encryption materials.

A compound-eye-shaped photonic crystal SERS substrate for synergistic enhancement of Raman scattering.

Near-infrared (NIR) circularly polarized luminescent (CPL) materials are highly desirable for optical communication, bioimaging, night-vision applications, and chiral encrypted information transfer, yet their practical use is limited by extremely low luminescence asymmetry factors (glum). Here, we establish a helical photonic confinement strategy by embedding NIR-emissive Au13 nanoclusters into chiral nematic mesoporous silica (CNMS). Precise matching between the chiral photonic bandgap and cluster emission yields strongly enhanced NIR-CPL with a glum of -0.4, enabling direct discrimination of left- and right-handed circularly polarized emission in the NIR region. This system realizes the first high-contrast, CPL-resolved near-infrared (night-vision) imaging based on intrinsic cluster emission, without external polarization optics. The Au13 clusters undergo reversible assembly-disassembly within helical nanochannels, allowing controllable NIR-CPL switching and handedness inversion. Mechanistic studies confirm that the CPL enhancement originates from chiral photonic propagation modulation rather than intrinsic emitter chirality. This helical-confinement principle is extendable to multicolor metal clusters, offering a general route toward high-efficiency CPL materials.

ABSTRACT Asymmetric electromagnetic (EM) mode conversion is a fundamental requirement for photonic devices such as filters and logic elements. We demonstrate strong reciprocal directional wave transport in an asymmetric photonic crystal (PhC). The system is linear, passive, time‐independent, and obeys Lorentz reciprocity. A semi‐asymmetric square‐lattice PhC composed of alumina rods, where the broken unit‐cell mirror symmetry along vertical and horizontal directions produces direction‐dependent modal coupling. Full‐wave simulations reveal pronounced unidirectional transport at the resonance frequency (5.765 GHz), quantified by a stopping factor (SF) of −23 dB and an insertion loss of 7 dB. An effective three‐site tight‐binding Hamiltonian is constructed, and its eigen frequencies and eigen vectors accurately reproduce the observed reciprocal directional transport response. Specifically, the resonance responsible for isolation and the SF of the numerical simulation are well‐matched with the analytical formalism. Experimental validation using a 10 × 10 PhC fabricated using alumina rods (99% Al 2 O 3 ) demonstrates near‐perfect agreement with the numerical results. To further demonstrate the potential of the designed asymmetric PhC array, a directional sensor is modeled, and its frequency and amplitude sensitivities are 0.5 MHz/RIU and 0.1 dB/RIU. These findings establish a connection between structural asymmetry and macroscopic transport behavior, advantageous for implementing unidirectional photonic components for interdisciplinary photonic applications.

ABSTRACT Chiral nematic liquid crystals are one‐dimensional photonic bandgap materials whose reflection wavelength can be tuned by temperature, but only limited and irreversible tuning can be achieved by electric fields. Oblique heliconical chiral nematic materials blueshift under electric fields applied along the helix axis, whereas chiral ferroelectric nematic ( liquid crystals can be redshifted by fields applied perpendicular to the helix axis. Here we demonstrate that in liquid crystals, the reflection color can be reversibly tuned by electric fields applied along the helix axis. In sandwich cells assembled with bare conducting indium tin oxide (ITO) substrates, the reflectivity peak wavelength increases by up to 200 nm under fields up to 0.4 V/µm. When the ITO substrates are treated with an electrically insulating polymer layer, the reflectivity shift is suppressed. We propose a theoretical model assuming helical deformation of the helix axis under an electric field. This model accounts for all experimental observations and yields an estimate of the splay elastic constant, which is challenging to determine by other methods. Our findings expand understanding of ferroelectric nematic liquid crystals and suggest potential applications in both tunable reflectors and energy‐efficient smart windows.

ConspectusChirality imparts spin to light─the intrinsic fingerprint of asymmetric matter. When optical spin interacts with molecular or supramolecular chirality, it generates distinctive chiroptical phenomena, with circularly polarized luminescence (CPL) attracting significant attention due to its optical activity and spin angular momentum. This asymmetric coupling enables the development of functional CPL-active materials, driving advancements in intelligent information interactions, including stereoscopic displays, secure information technologies, advanced imaging, and quantum photonics. For practical use, effective CPL-active materials demand the integration of high chiroptical activity for strong signals, robust stability for reliable performance, and processability for device integration. Conventional chiral nanomaterials and organic emitters typically exhibit dissymmetry factors of only 10-4-10-2, far below the theoretical maximum of ±2. In contrast, structural engineering strategies─such as supramolecular assemblies, chiral photonic crystals (particularly chiral liquid crystals), and plasmonic coupling─can amplify chiroptical activity to dissymmetry factors above 10-1. However, in some cases, these systems are restricted to fluidic or film states, hindering their further integration into applicable devices. The key challenge, therefore, is to create CPL-active materials with strong performance and, subsequently, to endow these materials with sufficient stability and processability to enable device construction for practical applications.To address this challenge, we leverage supramolecular helical templates and coassemble them with diverse emitters─such as quantum dots, phosphors, and molecular dyes─to amplify emission asymmetry. Building on this foundation, we develop helical-confinement chiroptical superstructures (HCCSs) by stabilizing the confined helical architectures through covalent interactions or in situ polymerization. This approach not only amplifies CPL activity to achieve large dissymmetry factors but also converts fragile helical assemblies into durable architectures. Moreover, the confinement imparts outstanding processability, enabling the resulting materials to be printed, woven, or continuously manufactured, providing sufficient performance for applications within a single chemical framework. In this context, we first introduce the photophysical properties of CPL and the material requirements for practical systems, particularly for intelligent information interaction. We then discuss strategies for CPL generation and amplification, focusing on chiral liquid crystal photonic templates and helical coassembly methods. Subsequently, we highlight the helical-confinement assembly process that produces HCCSs with enhanced processability and scalability. We further showcase how such advances translate into functional applications, ranging from (i) information security and recognition including a multimodal encryption system and high-dimensional optical mapping, (ii) flexible three-dimensional displays and spatial imaging devices, and (iii) imaging and sensing under complex conditions using polarization-differential technologies. Finally, we outline future directions in programmable, scalable, and multifunctional chiral luminescent materials for multidisciplinary applications. We envision that these materials will provide a genetic toolkit of chemical materials to meet application demands and, going forward, will bridge chemistry, materials science, and photonics, paving the way for next-generation optoelectronic devices and systems.

Ultrahigh-Q Fano resonance based on coupled topological corner states in kagome photonic crystals

Mechanically tunable structural color hydrogel with MXene/PEDOT:PSS conductive networks for dual-channel information encoding.