ABSTRACT In recent years, perovskite nanocrystals (PNCs), an emerging class of fluorescent materials, exhibit exceptional optical properties. Nevertheless, PNCs (especially red PNCs) are susceptible to structural degradation, phase segregation, and fluorescence wavelength shifts upon ultraviolet light. In this work, we propose a dual passivation strategy using conjugated linoleic acid (CLA) and guanidinium iodide (GAI) to achieve the full‐process photostability of red PNCs. In the early stage of UV irradiation, GAI firmly binds to PNCs via the coordination between N atoms and Pb atoms to ensure the structural stability of PNCs, while the CLA gradually crosslinks and forms a polymer to encapsulate PNCs in the late stage of UV exposure. This sequential passivation approach effectively enhances the stability of PNCs. Finally, by incorporating several types of red PNCs with distinct photostabilities and color changes, a photo‐responsive and dynamic anti‐counterfeiting application is constructed. This work not only expands the passivation strategies for red PNCs, but also provides a new way for advanced anti‐counterfeiting applications.
ABSTRACT Microwave imaging, a non‐invasive technique that reconstructs object features by analyzing the reflected electromagnetic signals, has become a cornerstone in critical domains, such as target recognition, remote localization, and medical diagnostics. As a countermeasure, imaging illusion aims to generate fake electromagnetic signatures to deceive radar detection systems. However, a key challenge persists in preserving the spatiotemporal consistency of these illusive signatures with high‐resolution range detection. Here, we propose tailoring composite dispersion over a broad bandwidth using multi‐mode resonant meta‐structures, enabling imaging illusion at the theoretical resolution limit corresponding to the working bandwidth. We design and fabricate an imaging meta‐illusion to replicate a car model's electromagnetic signature; experiments confirm near‐identical characteristics, with a structural similarity index exceeding 0.86 and strong correlation across the entire X‐band in both far and near fields. This work offers insights for real‐world electromagnetic illusion, paving the way for next‐generation broadband meta‐devices and advanced imaging cloaking technologies.
ABSTRACT Investigating the mechanism of persistent luminescence (PersL) enhancement is crucial for designing PersL materials and their applications. In this work, a remarkable green PersL enhancement in Zn 2 GeO 4 :Mn 2+ (ZGO:Mn) via cation engineering using Sb 3+ co‐doping is achieved. After UV excitation, the initial and 500 s PersL intensities of ZGO:Mn/Sb are 6.9–19.2 times higher than those of ZGO:Mn, with a PersL duration exceeding 100 h. The improved PersL originates from Sb 3+ co‐doping, which generates new traps at 0.759 eV and raises the intrinsic defect density of ZGO, leading to enhanced PersL intensity and extended PersL duration. Besides, the ZGO:Mn/Sb sample shows negligible luminescence intensity degradation after 6 months of storage in air and unchanged performance over 100 charge‐decay cycles, and can be effectively excited by natural light at different times of day and various weather conditions. Besides, the scintillation intensity of the sample reaches 47.47 times that of a commercial Bi 4 Ge 3 O 12 crystal, achieves resolution exceeding 16.6 LP/mm in X‐ray imaging, and supports delayed X‐ray imaging up to 10 min. This work not only develops a green PersL phosphor for information storage, safety indication, and X‐ray imaging, but also offers an effective strategy for designing and optimizing PersL materials.
ABSTRACT The exponential growth of artificial intelligence (AI)‐driven data traffic is accelerating the evolution of optical interconnects toward chip‐scale integration. However, conventional electro‐optic (EO) modulators suffer from limited modulation efficiency and large device footprint, which restrict integration density and system performance. Here, by leveraging the strong slow‐light effect at the topological interface states (TIS) of the TPhC waveguide, a TPhC‐assisted EO modulator based on the Mach‐Zehnder Interferometer (MZI) was constructed, enabling the realization of an EO modulator with ultra‐high efficiency and an ultra‐compact configuration. The TPhC‐assisted‐MZI (TPhC‐A‐MZI) modulator has a compact modulation length of 63.56 µm, exhibiting a simulated modulation efficiency of 0.08 V∙cm and reaching 0.159 V∙cm in experiments. The modulator achieves a 3 dB EO bandwidth exceeding 110 GHz in both theoretical predictions and experimental measurements, with a peaking enhancement effect. We also demonstrate the transmission of 140 Gb/s non‐return‐to‐zero (NRZ) and 180 Gb/s 4‐level pulse amplitude (PAM4) modulation signals experimentally. Our proposed TPhC‐A‐MZI modulator with ultra‐high modulation efficiency and ultra‐compact structure shows great potential and paves the way for the development of high‐density, high‐speed, and large‐scale photonic integrated circuits (PICs) in the future.
ABSTRACT Optical computing offers a promising avenue for high‐speed, low‐power information processing but is fundamentally constrained by the inherent linearity of standard diffractive architectures, which severely restricts representational capacity. Existing solutions often rely on exotic nonlinear materials, imposing fabrication complexity and limiting hardware compatibility. Here, we propose an adaptive modulation strategy driven by the initial input that synthesizes effective nonlinearity within a standard linear optical framework. By directly mapping the original input instance to the phase modulation parameters, we break the linearity constraint without requiring exotic media or optical gain. We demonstrate this paradigm through end‐to‐end optical edge extraction, achieving SSIM values consistently exceeding 0.9. Notably, our results reveal that shallow nonlinear architectures can outperform significantly deeper linear counterparts, demonstrating that computational nonlinearity can effectively substitute physical depth. The proposed system exhibits exceptional robustness against occlusion and noise, alongside scalable parallelism with minimal inter‐channel crosstalk. When deployed as an optical front‐end, it consistently enhances downstream classification performance, establishing a pathway for physically realizable, high‐performance intelligent optical sensors.
ABSTRACT Tin–lead mixed perovskites have emerged as promising candidates for amplified spontaneous emission (ASE) and lasing applications, owing to their exceptional optoelectronic properties and facile solution‐processability. Here, morphology‐smooth MAPb 0.25 Sn 0.75 I 3 polycrystalline thin films are synthesized by combing spin‐coating with thermal imprinting. Upon cooling from 300 to 100 K, the ASE threshold decreases by a factor 15 (from 93.1 µJ cm −2 to 5.9 µJ cm −2 ), accompanied by an increase of a factor of 2.5 in the net modal gain coefficient (from 374 cm −1 to 948 cm −1 ). Notably, the films maintained robust phase stability throughout the cooling process. Using these high‐quality films as gain media, distributed feedback (DFB) lasers are fabricated, for the first time operating in single‐mode infrared lasing at both 300 and 100 K with pronounced linear polarization characteristics. At 300 K, the lasing threshold is 52.7 µJ cm −2 with stable operation over 6.6 × 10 7 excitation pulses. While at 100 K, the threshold is further reduced to 2.6 µJ cm −2 (of about 20‐fold reduction), with operational stability exceeding 9.6 × 10 7 pulses. These results demonstrate a lead‐reduced gain medium with superior lasing performance and operational robustness, positioning as pivotal building blocks for next‐generation photonic technologies.
ABSTRACT A dual‐band device that can simultaneously possess high sensitivity and neuron‐like processing capabilities is highly desirable for next‐generation intelligent optoelectronic systems. However, traditional single‐material devices have the problems of poor performance and low integration level. Furthermore, due to their high‐power consumption, they are limited in applications such as integrated sensing, computing and storage, optical encryption communication, and imaging. Here, we report a multifunctional CuInP 2 S 6 (CIPS)/Ga 2 O 3 heterojunction that integrates ultraviolet (UV–Visible photodetection, artificial synaptic function, neuron‐like recognition, and dual‐wavelength optical communication and imaging. Notably, this constructed type‐II CIPS/Ga 2 O 3 van der Waals heterojunction provides an opportunity to modulate the interface charge carrier transport, then enhance the light absorbance, thereby achieving high responsivity (275 A/W), and enhanced detectivity (1.95 × 10 15 Jones) under irradiation of 245 nm UV light. Significantly, the device also exhibits vital synaptic plasticity, including dual‐pulse promotion and adjustable memory retention capability. By mapping the experimentally extracted single‐device forgetting dynamics to a simulated convolutional neural network framework, high accuracy has been achieved on both simple and complex datasets. Additionally, wavelength‐selective light response supports dual‐band UV‐visible light communication and imaging. This work establishes a multifunctional heterojunction platform, advancing the research and development of modern optoelectronics.
ABSTRACT Band degeneracies representing symmetry properties of two‐dimensional (2D) periodic photonic structures are widely observed. In momentum space, exotic photonic phenomena have been demonstrated in the vicinity of such degeneracies, while studies on intrinsic properties of those isolated points remain limited. In this letter, we show that chiral quasi‐bound states in the continuum (quasi‐BICs) can be achieved through a Γ‐point degeneracy in resonant metasurfaces with C 4 symmetry. We demonstrate that, depending on their enantiomeric property, three‐dimensional (3D) chiral perturbations enable a ±π/2 phase difference between two degenerate and orthogonally orientated linear polarizations, resulting in the strong chiral selectivity at the Γ point. The proposed chiral quasi‐BIC is experimentally observed in a 3D‐printed dielectric metasurface. Our results reveal the potential of high‐symmetry degeneracy points as a means for empowering sophisticated light‐matter coupling.
ABSTRACT Laser‐driven lighting demands robust color converters with broad, continuous spectra to achieve high‐fidelity illumination, yet conventional phosphors often suffer from spectral deficiencies that lower the color rendering index (CRI) and cause visual discomfort. To address this, we develop CaF 2 ‐Cs 2 Na 0.7 Ag 0.3 In 0.97 Bi 0.03 Cl 6 composite phosphor ceramics (CPCs) utilizing spark plasma sintering at temperatures below 490°C. A fluoride‐mediated defect compensation mechanism, in which F − ions migrate from the CaF 2 matrix into Cl − vacancies of the double perovskite, simultaneously facilitates full densification and passivates non‐radiative recombination centers. This dual effect enables the CPCs to emit warm white light with a full width at half maximum of 224 nm and a near‐unity relative photoluminescence quantum yield. The CPCs also exhibit superior stability against heat, moisture, and laser irradiation, together with a high thermal conductivity of 9.4 W·m − 1 ·K − 1 at 25°C. A prototype laser‐driven lighting device based on these CPCs delivers high‐quality warm white light with a CRI (R a ) of 96. This work establishes a fluoride‐compensation low‐temperature sintering strategy for robust lead‐free double perovskite‐embedded CPCs with broadband emission, targeting high‐fidelity laser‐driven lighting.
ABSTRACT Nonlinear chiroptical effects, such as second‐harmonic generation circular dichroism (SHG‐CD), hold significant application value for chiral sensing, multidimensional optical logic, and polarization‐encrypted communications. To enhance the multi‐scenario adaptability of devices, various active tuning approaches have been developed, including electrical tuning, thermal tuning, and mechanical tuning. However, thermal tuning typically suffers from low sensitivity, limited tuning range, and nonlinear response, limiting its practical performance. In this work, we integrate 2D ferroelectric material NbOCl 2 with a ferroelectric DLATGS crystal. By leveraging the continuous second‐order phase transition of the DLATGS substrate, which generates stage‐dependent thermal expansion mismatch, we effectively overcome the above‐mentioned bottlenecks of thermal tuning. The device preserves the intrinsic linear polarization anisotropy of NbOCl 2 while inducing a pronounced SHG‐CD response, with a nonlinear chiroptical anisotropy factor of 1.246. Crucially, benefiting from the continuous anisotropic variation of the substrate's thermal expansion coefficients during the phase transition, we achieve multi‐stage thermal modulation of the SHG‐CD signal. The device delivers a global modulation depth of 91.7%, a linear tuning range of 81.2%, and a tuning sensitivity of 5.6% K − 1 . This work provides a new and effective strategy for constructing dynamically tunable, ultracompact SHG‐CD devices.
ABSTRACT Polarization‐sensitive photodetection provides a critical degree of freedom for multidimensional optical information processing; however, achieving both high polarization selectivity and direct extraction of the angle of linear polarization (AoLP) within a single compact device remains a significant challenge. Here, we report a photodetector based on twisted Ta 2 NiSe 5 /MoSe 2 /Ta 2 NiSe 5 van‐der‐Waals heterostructure with dual junctions and oppositely oriented built‐in fields. The bias‐driven carrier competition mechanism enables enhanced polarization selectivity, yielding high polarization ratios of 23.1, 21.0, and 12.5 at 405, 638, and 808 nm, respectively, with an 11 µs response time. Furthermore, distinct from conventional intensity‐based detection, the dual‐channel photocurrents establish an intrinsic mapping between polarization states and electrical‐phase space, enabling direct extraction and imaging of AoLP within a single device, without external optics. The device also shows wavelength‐dependent dichroic inversion from visible (405 nm) to near‐infrared (808 nm), enabling orthogonal polarization responses. Leveraging this mechanism, we further demonstrate polarization–spectral multiplexed imaging, multi‐channel optical communication, and ∼99% accurate information decoding via a dual‐channel neural network, as well as a “two‐shot” polarization imaging strategy for low‐contrast enhancement. This work provides a filter‐free approach to polarization‐resolved photodetection, and opens a new avenue toward reconfigurable and multifunctional polarization optoelectronic devices.
ABSTRACT Two‐photon lithography (2PL) is a high‐resolution additive manufacturing technique achieving complex three‐dimensional (3D) microstructures with sub‐micrometer precision. This capability has driven applications across optics, microfluidics, bioelectronics, metamaterials, and biomedical engineering. Beyond geometry, the functionality of 2PL‐fabricated structures critically depends on their mechanical properties, which are influenced by resin chemistry, printing parameters, and post‐processing treatments. Understanding the mechanical behavior of 2PL‐fabricated structures at both macro‐ and micro‐scales is essential for the rational design and development of advanced devices and systems. Accordingly, this review provides the reader with a concise yet comprehensive overview of the current knowledge on the mechanical properties of materials usually employed in 2PL. Common photoresist classes (e.g., hydrogel‐like, elastomeric polymer networks, rigid glassy polymers, and hybrid organic–inorganic networks) offer distinct trade‐offs in stiffness, with Young's modulus spanning several orders of magnitude. Mechanical performance can be further tuned via laser settings, environmental conditions, or post‐processing approaches such as UV curing, pyrolysis, or incorporation of responsive chemistries for dynamic “4D” behavior. We then examine the methodologies applied—or specifically developed—to characterize 2PL materials and microstructures in terms of stiffness, toughness, and viscoelastic response at the micro‐ and nanoscale. Finally, we discuss the applications where mechanical properties are critical to the functionality of 2PL structures, such as tissue engineering, microfluidics, and tunable metamaterials. Looking ahead, advances in material design, adaptive characterization, and predictive modeling will enable rational, data‐driven workflows. Treating mechanical properties as fundamental design parameters will be key for developing reliable microdevices for next‐generation technologies.
ABSTRACT Metasurfaces offer a compact and scalable platform for multidimensional optical field manipulation and engineering. By judiciously designing subwavelength scatterers to tailor the complex transmitted field, a single metasurface can encode a prescribed near‐field distribution at its exit plane while simultaneously generating a desired far‐field response after propagation, thereby significantly increasing the degrees of freedom for high‐dimensional information encoding. However, achieving these near‐/far‐field functional responses across wavelength‐ and polarization‐multiplexed channels in a single device remains challenging. Here, we present an end‐to‐end data‐driven framework for multiwavelength and multipolarization metasurface design. A deep neural network is embedded in a gradient‐based optimization loop to design coherent superpixels, enabling simultaneous nanoprinting and holography across multiple channels. Using this framework, we experimentally demonstrate a single‐layer metasurface that supports nanoprinting and holography at three wavelengths and in three polarization channels, with multiplane holographic reconstruction. This strategy provides a versatile platform for high‐dimensional optical‐field manipulation, multifunctional optical displays, and integrated nanophotonic systems.
ABSTRACT Light detection and ranging (LiDAR) systems are increasingly required to provide long‐range operation, high axial resolution, and velocity estimation within a single platform. However, conventional time‐of‐flight (ToF) and frequency‐modulated continuous‐wave (FMCW) methods demand a high electrical bandwidth to satisfy these requirements simultaneously. Here, we present a simultaneous ToF/FMCW LiDAR enabled by a dual‐mode light source that alternately generates nanosecond pulses and FMCW waveforms through synchronized optical‐intensity and frequency‐modulation. This single‐architecture design enables concurrent acquisition of time‐domain ToF and spectral‐domain FMCW ranging without additional optical paths or auxiliary light sources. Under bandwidth‐limited conditions, ToF measurement maintained absolute distance accuracy despite a loss of resolution, whereas the FMCW measurement preserved high axial resolution but experienced aliasing due to subsampling. By integrating these complementary datasets through a reconstruction algorithm, the system achieves high‐resolution short‐range performance together with alias‐free long‐range detection. Moreover, Doppler analysis of the FMCW interferograms verified accurate velocity estimation within the Nyquist limit. These results demonstrate that a dual‐mode light source can unify ToF and FMCW ranging in a compact single architecture, overcoming electrical bandwidth constraints while enabling simultaneous distance and velocity measurements.
ABSTRACT Integrated sensing‐memory‐processing neuromorphic vision hardware is critical to overcoming traditional computing limitations. However, the fundamental physical conflict between fast carrier recombination for photodetection and slow relaxation processes for neuromorphic analog operations hinders integrating high‐performance dual modes in one device. Here, we report a reconfigurable optoelectronic device based on In‐doped SnS 2 , which enables dynamic reversible switching between broadband high‐speed photodetection and synaptic emulation in a single device via optical pulse frequency control. In photodetection mode, the device exhibits a 405–980 nm broadband response, with a detectivity of 3 × 10 7 Jones, an on/off ratio of 185, and ultrafast response times of 50/275 µs, and supports secure near‐infrared optical communication. In synaptic mode, the device emulates synaptic plasticity, including paired pulse facilitation, short‐term to long‐term plasticity transition, and “learning‐forgetting‐relearning” behavior. Furthermore, a reservoir computing system built on this device achieves 100% accuracy in high‐noise fingerprint recognition tasks. This work provides an efficient solution for integrating sensing and processing functions, and lays the foundation for developing next‐generation neuromorphic vision chips for complex real‐world scenarios.
ABSTRACT Gas‐filled hollow‐core fibers (HCFs) are versatile platforms for high‐power nonlinear optics, yet integrating robust polarization control remains crucial for advanced practical applications. Here, we demonstrate the generation of highly polarized Stokes light via stimulated Raman scattering (SRS) in a nitrogen‐filled polarization‐maintaining anti‐resonant HCF (PM‐HCF). By exploiting strong structural birefringence, the Raman interaction decouples along the principal axes, enabling threshold‐selective amplification and an intrinsic polarization purification mechanism. Consequently, the vibrational Raman Stokes emission achieves a polarization extinction ratio (PER) of 35 dB, even with an incident pump PER as low as ∼2 dB. Analytical theory and numerical modeling validate the polarization‐selective dynamics and identify the fiber platform as the dominant factor governing PER saturation. Furthermore, high polarization purity and conversion efficiency persist under tight bending with radii down to 5 cm. These results establish PM‐HCFs as a robust architecture for generating polarization‐stable, frequency‐shifted light, paving the way for practical applications in fields such as optical communications and remote sensing.
ABSTRACT Enhancing the luminescence efficiency of scintillators is essential for achieving high‐performance x‐ray imaging; however, many existing materials face limitations, such as lead toxicity or insufficient light yield. Herein, we report a phosphonium salt‐directed strategy for synthesizing a novel coordination complex, Tb(phen) 2 Cl 3 (hereinafter referred to as TPC), and its europium‐doped derivative, Tb(phen) 2 Cl 3 : Eu (hereinafter referred to as TPC: Eu). We find that the ethyltriphenylphosphonium chloride additive is effective in suppressing rare‐earth ion hydrolysis and directing the growth of highly crystalline materials, as confirmed by control experiments. Doping with europium ions induces a substantial structural reorganization that optimizes the crystal field and enables an efficient Tb 3 + →Eu 3 + energy‑transfer pathway, as evidenced by concentration‑dependent lifetime variations and control experiments with the Eu‑only analog. This results in a near‐unity photoluminescence quantum yield of 97.41% and a long‐emission lifetime. Leveraging these superior luminescent properties, TPC: Eu functions as an efficient x‐ray scintillator with a high light yield (40 000 photons MeV −1 ), low detection limit, and excellent radiation stability. Furthermore, flexible composite films fabricated from this material enable high‐resolution x‐ray imaging capabilities. This work provides a viable crystal‐engineering approach for designing efficient, stable, and lead‐free scintillators, demonstrating their significant potential for applications in flexible and high‐resolution radiation detection.
ABSTRACT Real‐time ranging of thermal targets holds critical importance for defense, surveillance, and autonomous navigation, yet remains fundamentally constrained by the inherently low texture of thermal imagery. A metasurface‐Transformer architecture is presented to enable monocular four‐dimensional (4D) thermal light‐field imaging and subsequent ranging. The optical front end uses an all‐silicon metasurface microlens array directly integrated into a commercial thermal camera module, forming a compact light‐field imager. The computational back end, a thermal disparity transformer (TDiT), resolves sub‐pixel disparities from the texture‐scarce thermal light‐field through dedicated pre‐processing and Transformer‐based inference. The system achieves centimeter‐scale accuracy, with a mean ranging error of 1.87% at 25 ms per frame, enabling real‐time dynamic ranging of moving thermal targets. By combining metasurface‐enabled light‐field capture with high‐precision disparity estimation, this work provides a promising approach for effective, real‐time perception in texture‐scarce thermal environments.
ABSTRACT High quality factor (Q‐factor) optical resonances in photonic crystals in the visible range are considered as a powerful tool for advanced sensors, lasers, modulators, and quantum optics. In many practical applications resonances away from the Γ point of the Brillouin zone are essential, as they provide intrinsic angular selectivity and momentum control of light. However, these modes are inherently more radiative, and this limitation becomes particularly severe in hybrid or plasmonic systems, where metal‐induced absorption and scattering losses further suppress the achievement of high‐Q resonances at off‐Γ point. Here we demonstrate that in a hybrid plasmonic‐dielectric periodic metasurfaces with a broken symmetry, the strongly coupled interfering resonances maintain the Friedrich‐Wintgen bound states in the continuum (FW‐BICs), resulting in record‐high values of the leaky mode Q‐factors among the off‐Г‐point BIC type of modes in the visible range. The hybrid design consists of an Al 2 O 3 photonic crystal slab on a corrugated aluminum substrate with a period of 400 nm, covered with a thin layer of CdSe/CdZnS colloidal nanoplatelets as the light‐emitting material. The white‐light reflection and photoluminescence spectra measurements reveal FW‐BIC states with a Q‐factor reaching 709 around wavelength 605 nm, which is in good agreement with our numerical full‐wave simulations.
