Ice-assisted electron-beam lithography (iEBL) utilizes cryogenic ice layers as resists for micro/nanofabrication. Water ice, the most widely used positive-tone resist, exhibits a high critical dose that limits lithographic efficiency. Here, we investigate solid carbon dioxide (CO2) as a potential alternative. Lithographic characterization via SEM shows that solid CO2 has a critical dose an order of magnitude lower than that of water ice. To investigate electron-induced chemical pathways, mixed cryogenic CO2/H2O ices were irradiated with a 10 MeV linear electron beam. Volatile products were monitored in situ using quadrupole mass spectrometry. Hydrogen and methane were detected as reaction products, with methane formation strongly dependent on the repetition frequency. These results establish CO2 as a promising resist material and provide mechanistic insight into electron-stimulated decomposition in iEBL.

High-power laser systems increasingly rely on multi-beam processing to enhance manufacturing throughput. However, conventional multifocal systems remain constrained by bulky architectures, stringent alignment requirements, and susceptibility to laser-induced degradation under intense irradiation. Here, we demonstrate a monolithic multifocal diamond metalens with a 7.2 mm aperture that maintains exceptional thermal stability and power tolerance. The device employs high-aspect-ratio truncated-cone diamond nanopillars to generate two focal spots separated by 200 μm at a focal length of 4 mm. Under sustained 25 W pulsed-laser irradiation for 1 h, the diamond metalens exhibits a focal shift of only 25.5 μm, resulting in a maximum processing-depth variation of 33.2 μm during 4H silicon carbide (SiC) laser scribing, far below the 319.1 μm deviation observed for a commercial objective lens combined with a beam-splitting diffractive optical element (DOE). Even under extreme optical loading, the metalens withstands continuous-wave laser irradiation up to 8.25 kW for 30 s without structural degradation, while complementary pulsed testing yields a laser-induced damage threshold (LIDT) of 2.45 J/(cm^2) for diamond. This work broadens the operating envelope of transmissive meta-optics to extreme optical loads, opening new opportunities across high-power photonic systems.

Multiscenario adaptability is a core target of emerging human-machine interaction (HMI) technologies, but conventional visual HMI relies on ambient light illumination, failing to adapt to low-/no-light scenarios. Here, we propose a static-electricity-induced luminescence (SEL) trajectory tracking model, and develop a portable SEL platform integrated with SrAl2O4:Eu2+/polydimethylsiloxane film, featuring 5 to 50 kV operating voltage, 13 mm noncontact distance, ≥150-day stability, 400 K thermal tolerance, and <1 nA body current for high biosafety. Comprehensive mechanism investigations offer a deep and scientific mechanistic understanding of SEL, focusing on the interactions between air ionization, electron bombardment, and trap-state dynamics. Integration with a centroid displacement tracking algorithm and convolutional neural network, it achieves high-accuracy digit recognition and complex robot arm interactive motions, with 2.4× shorter training time and two orders of magnitude faster recognition speed (6.6 ms versus 730 ms in 192.5 lux) than mainstream gesture recognition. This work not only breaks illumination constraints for adaptive HMI but also provides a promising SEL-based HMI paradigm.

In low-temperature infrared detection, conventional cooling systems such as liquid nitrogen dewars are often bulky and inconvenient. Although micromachined Joule-Thomson (MJT) coolers offer a more compact alternative, the overall system remains large due to gas cylinders whose volume scales with required operational duration. This work overcomes this fundamental trade-off in open-cycle MJT systems by introducing a dual-gas-cylinder architecture. We designed and fabricated an ultra-compact gas management system (198 × 153 × 294 mm3; total volume ≈ 9 L) integrating a 0.5 L main cylinder and a 0.1 L buffer cylinder. The main cylinder was designed to be swappable during stable low-temperature operation. To test feasibility, we coupled this system with an MJT cooler featuring a relatively high mass flow rate (21 mg/s at 122 K). By performing in-situ main cylinder replacements at nearly hourly intervals, the system achieved stable cooling below 130 K for over 4.5 h after 3 replacements and over 10 h after 9 replacements, with vibration levels comparable to passive liquid nitrogen systems. The results demonstrate that cooling durations can be extended on demand via in-situ main cylinder replacements. This work presents a miniaturized low-vibration cryogenic cooling system that decouples operational duration from a fixed system volume, greatly enhancing portability and flexibility for field-deployable high-sensitivity infrared sensing.

This research explores the advancement of a highly directional all-dielectric thermal emitter. It illustrates that a coupled photonic device-a directional thermal emitter based on resonance metagratings integrated with a band-pass filter utilizing distributed Bragg reflectors-can function as a distinctive thermal emitter. This thermal emitter emits an extremely narrow band of electromagnetic waves in only two specific, distinct directions, exhibiting a discrete dispersion curve. With a peak emissivity of epsilon similar to 0.9 and a Q-factor of approximately 243, this coupled thermal emitter demonstrates an angular spread (Delta theta) of about 0.5 degrees. Since the device is composed entirely of dielectric materials, its spatial coherence length is high, estimated to be around 115 lambda. Furthermore, the device parameters can be customized to manipulate the emitting wavelength and angle across a wide range. By introducing a new class of highly directional thermal emitters, this research deepens our understanding of thermal radiation principles and offers practical implications for various thermal-engineering applications.

Mid-infrared (MIR) refractive index (RI) sensing holds significant potential for applications in chemical detection, environmental monitoring, and biomedical diagnostics due to the strong molecular vibrational fingerprints in this spectral range. However, conventional metasurface-based sensors face challenges in fabrication complexity, toxic solvents, and performance optimization. Here, we introduce ice-lithographed 2.5-dimensional (2.5D) plasmonic metasurfaces featuring vertically asymmetric gold cross-pillar resonators to overcome these challenges. The solvent-free ice lithography enables in situ scanning electron microscopy (SEM) alignment with high precision, residue-free surfaces, and multilayer stacking in a single vacuum process. Simulations reveal that vertically graded pillars (height 0-800 nm) linearly redshift resonance wavelengths while concentrating electric fields at analytebinding sites, boosting experimentally measured sensitivity from 735 nanometers per refractive index unit (nm/RIU) to 2 266 nm/RIU. This work demonstrates a three-dimensional (3D) architectural strategy for enhancing sensing performance, while simultaneously unveiling the potential of ice lithography in fabricating low-toxicity and flexible 2.5D sensing devices.

Metasurfaces offer design freedom and compact morphology for next-generation integrated photonics. Yet the optical performance of planar architectures is bounded by the structural degrees of freedom within the single lithographic layer. Three-dimensional (3D) height modulation offers a pathway for independent phase and spectral manipulation, but its realization is impeded by fabrication efficiency, precision, and process incompatibility with standard lithography. In this work, we report a wafer-scale topography-decoupled manufacturing technique. By integrating chemical mechanical polishing (CMP) into a multi-cycle overlay process, the construction of vertical profiles is resolved into a superposition of planarized two-dimensional (2D) patterning steps. The efficacy of this platform is validated on a 4-inch fused silica wafer, achieving precise height control with a standard deviation of 2.2 nm. A combinatorial library containing 46,072 silicon nanopillar metasurface units is constructed, demonstrating an expanded sRGB gamut coverage of 78.20%, representing a 20.7% enhancement over planar architecture.

Humans can efficiently predict transient events with a low latency of approximately 80 ms. Simulating this capability to achieve accurate and rapid transient prediction at the edge is essential for advancing bionic machine vision. This task is, however, challenging due to the intricate nonlinear characteristics of dynamic motion, which requires high-throughput data processing and training on digital computers. In this work, we report an optoelectronic artificial neuron (OAN) array to implement in-sensor prediction without training and high-throughput data processing, achieved by emulating spike-temporal patterns of human vision for nonlinear spike encoding and memory. The OAN can nonlinearly encode light intensity into first-spike time (ranging from 7.37 to 0.24 µs) and has a memory ability of 60 s due to oxygen vacancy dynamics. The nonlinear perception and memory capabilities spontaneously generate a spike-recurrent spatiotemporal information equation in situ, allowing the OAN arrays to predict future states using limited data without training. As a result, the array can rapidly and accurately predict pedestrian motion with a high executable frame rate (∼125 fps) and low root mean square error (∼0.014). Combined with spiking neural networks, the array achieves 100

A fundamental hurdle for multimode fiber (MMF) integrated photonics is achieving robust and deterministic wavefront shaping against fiber perturbation, which induces random modal interference and scrambles the real-space output into speckle patterns. Existing wavefront shaping methods typically rely on pixelated phase or polarization pre-compensation, rendering them highly sensitive to fiber deformation. Here, we show that in-situ integration of a silicon nonlocal metasurface onto an MMF end facet enables direct conversion of arbitrary speckle patterns into optical vortex beams without pre-compensation. The metasurface supports overlapped Mie resonances and nonlocal bound states in the continuum (BICs), yielding high-transmission bands by satisfying the generalized nonlocal Huygens condition. Through momentum-space coupling between MMF modes and Huygens-BICs with topological polarization-vortex nature, the output maintains doughnut-shaped profiles under static and dynamic perturbations, demonstrating exceptional robustness against fiber deformation. This approach provides a compact, alignment-tolerant platform for robust structured light generation in MMFs for endoscopy, optical trapping and communications.

Augmented reality eyewear offers a transformative interface poised to reshape human information interaction. In this context, silicon carbide (SiC) offers unique advantages for diffractive waveguides with its high refractive index and excellent thermal conductivity. However, in single-layer full-color displays, existing SiC waveguides generally remain thicker than 0.5 mm to reduce the bounce count of total internal reflection, thereby avoiding severe spatial variations in luminance and color. Here, we demonstrate a 0.35 mm SiC diffractive waveguide with an ultra-lightweight of only 1.98 g. The challenge of spatial non-uniformity is addressed by dual-parameter apodized gratings with continuously varying depth and duty cycle, enabling fine spatial control over local diffraction efficiency. To realize high-throughput production, a parallel gradient transfer method compatible with nanoimprint lithography is introduced, enabling wafer-scale patterning of four lens pairs per 8-inch SiC wafer. Furthermore, magnesium fluoride planarization suppresses grating visibility and achieves a high see-through transmittance of 92

Femtosecond laser direct writing is highly effective for fabricating three-dimensional photonic waveguides deep inside ultra-hard crystals. Extending this capability to the surface realm, where waveguides interact directly with the sample interface, has been challenging due to pronounced susceptibility to structural cracking. To address this, we introduce a strategy that avoids direct laser modification of fragile crystal-air interfaces. Our approach employs a novel, to the best of our knowledge, surface-integrated, partial-ring cladding architecture, unlike the conventional full-ring design for buried waveguides. By precisely controlling the laser focal depth and cladding geometry, we demonstrate crack-free surface waveguides in sapphire with strong optical confinement and a propagation loss of ~2 dB/cm at 1500-1600 nm. Experiments and simulations confirm that buried waveguides with full-ring cladding support near-Gaussian modes, whereas partial-ring surface waveguides exhibit minor modal distortion owing to interfacial effects. This work advances the integration of high-performance surface waveguides in hard optical materials for applications in surface sensing and photonic circuits.

Significance Structural colors, arising from the interaction of light with engineered micro-and nano-structures, provide a fundamentally distinct approach to color generation compared to conventional pigments and dyes. By harnessing interference, diffraction, scattering, and resonance effects, structural colors generate high-resolution, wide-gamut, and environmentally benign colors, with inherent advantages in spatial resolution, long-term stability, and material sustainability. These attributes render structural colors highly promising for next-generation displays, high-security anti-counterfeiting, wearable and implantable sensors, and eco-friendly decorative coatings. Concurrently, rapid advances in micro-and nano-fabrication, ultrafast laser processing, nanoimprint lithography, and additive manufacturing are transitioning the field from "beautiful physics" to engineering implementation and potential industrial deployment. In this context, a comprehensive review is needed-not only to catalog physical mechanisms, but also to systematically link structure, material, color performance, fabrication processes, and application requirements-thereby clarifying the pathway from optical principle to manufacturable, reliable devices. Progress This review first summarizes the fundamental physical mechanisms of structural color across four primary categories: thin-film interference and Fabry-P & eacute;rot cavities, photonic crystals and diffraction gratings, plasmonic and all-dielectric metasurfaces, and scattering-based or quasi-disordered systems. For each mechanism, we outline representative architectures and material platforms, and discuss how structural parameters govern color gamut, spectral bandwidth, angular dependence, spatial resolution, and reflectance. Particular emphasis is placed on the structure - material -color relationships that enable rational design. Building on this foundation, we survey recent advances in dynamic and reconfigurable structural colors enabled by phase-change materials, liquid crystals, responsive polymers, two-dimensional materials, and tunable plasmonic or photonic architectures. These systems exhibit predictable and reversible color shifts under thermal, mechanical, electrical, magnetic, or chemical stimuli, enabling colorimetric readout in multi-physics sensing and intelligent interfaces. From an engineering standpoint, we comparatively evaluate scalable fabrication strategies, including ultrafast laser direct writing, spray-assisted self-assembly and coating, roll-to-roll nanoimprint lithography, and micro-/nano-3D printing. For each technique, we qualitatively assess process complexity, throughput, accessible area, material compatibility, and cost, offering guidance for process selection across diverse application scenarios. We then organize recent progress in displays and artistic coloration, optical anti-counterfeiting and data encoding, mechanical and thermal sensing, biochemical and biomedical detection, and environmental monitoring. Rather than enumerating examples, we emphasize how optical metrics-such as color gamut, viewing-angle robustness, response speed, and durability-translate into application-level performance indicators, including readability, uniqueness, sensitivity, operational lifetime, and integration compatibility with existing device platforms. Conclusions and Prospects Overall, the field of structural color is transitioning decisively from mechanism-driven exploration to engineering-oriented development. Advances in functional materials, micro-and nano-structure design, and scalable fabrication now enable the production of high-resolution, wide-gamut, and environmentally stable coloration on both rigid and flexible substrates at technologically relevant scales. Dynamic structural-color systems further enable applications in intelligent and multifunctional devices, where color serves as a compact, intuitive, and often passive readout mechanism. Despite significant progress, several critical challenges must be addressed before structural colors can be widely adopted in industrial applications. These include: managing trade-offs among color purity, angular dependence, and fabrication tolerance; integrating structural-color elements into existing industrial process flows, such as roll-to-roll manufacturing and microelectronic back-end-of-line processes; and establishing standardized protocols for colorimetric characterization, angular-resolved optical measurements, and accelerated environmental and mechanical reliability testing. Looking ahead, future research will increasingly rely on the co-optimization of materials, structures, and fabrication processes, supported by optical simulation, data-driven modeling, and inverse-design methodologies. The development of comprehensive structure - material -color database-incorporating realistic process constraints and reliability requirements-will be essential to shift from intuition-based design to predictive, application-driven engineering. With continued advances in scalable manufacturing and a clearer definition of application-specific requirements, structural colors are poised to transition from laboratory demonstrations to engineering-grade technologies, enabling transformative applications in next-generation displays, secure identification, wearable and implantable sensors, and environmentally sustainable coloration and monitoring systems.

ABSTRACT The development of next‐generation optical networks demands miniaturization, polarization discrimination, and broadband operation. Compared to current complex systems with numerous bulky opto‐electro‐mechanical elements arranged in tandem along the optical path, the integration of a polarization‐sensitive detector within optical fiber systems provides a new route for realizing compact polarized optical networks. However, most of these devices cannot be seamlessly integrated with mainstream optical fiber systems. Here, we propose a fiber‐integrated polarimeter by stacking a PdSe2/2H‐MoTe2 van der Waals (vdW) heterojunction onto the facet of a standard optical fiber, constructing a high‐performance polarization detector with a responsivity of 25 mA/W, a polarization ratio of approximately 2, and a relatively fast response time of 59 µs at 1550 nm. Additionally, benefiting from the broadband light absorption of PdSe2/2H‐MoTe2 heterojunction, the devices demonstrate a broad spectral response range from 532 nm to 1630 nm. Leveraging its intrinsic polarization sensitivity, we demonstrate a polarization‐encoded secure communication scheme. Combining broadband operation, polarization selectivity, and structural simplicity in a fiber‐native form, this work establishes a compact and multifunctional platform for polarization demodulation, monitoring, and secure optical communication in integrated fiber systems.

Modern targets are increasingly exposed to multispectral detection systems spanning the visible, infrared, and microwave bands, making compatible stealth design substantially more challenging. Here, we demonstrate a visible-transparent infrared-microwave compatible stealth metasurface that simultaneously combines high visible transmittance, ultralow infrared emissivity, and broadband microwave absorption. The device consists of an infrared shielding layer (IRSL), a transition layer (TL), and a microwave absorption layer (MAL). The IRSL is implemented using a high-duty-cycle dielectric/metal/dielectric (DMD) frequency selective surface, which provides low infrared emissivity together with high microwave transmittance. The MAL is formed by a circular-ring metasurface optimized through an equivalent circuit model combined with particle swarm optimization, while the inserted TL is introduced to improve impedance matching and broaden the microwave absorption bandwidth. A 200 × 200 mm2 sample is fabricated and experimentally characterized, which shows a low infrared emissivity of 0.15, a visible transmittance of 50% at 510 nm, and broadband microwave absorptivity above 90% from 3.7 to 10.2 GHz. This work provides a practical route toward transparent multispectral stealth devices operating across the visible, infrared, and microwave bands.

In the human brain, dendrites exhibit nonlinear integration and sparse parallel processing capabilities, which can effectively perform visual tasks by integrating only a small subset of neuronal signals and play a crucial role in high-level information inference. However, conventional neuromorphic devices often ignore these important properties and require all neurons to perceive complete information. This makes it difficult to effectively replicate the efficient spatiotemporal processing capabilities of biological neuron dendrites. In this study, we present an artificial neuron dendrite array that integrates neurons, synapses, and dendrites, emulating the spatiotemporal spike integration properties of biological dendrites for precise parallel computation. Through multigate threshold regulation, the array enables parallel sparse spiking inference with random spatial distribution. This inference process forms a sparse dendritic spiking neural network (SD-SNN) that can perform compression, depth detection, and prediction. As a result, the SD-SNN achieves high-efficiency static and dynamic object processing while using only 0.5% of neuronal activity, slashing the power consumption by 98 and 65%, respectively. Our work reduces neural activity in the perception process by 99.5% while enhancing spatiotemporal computing capabilities and computational efficiency.

Abstract Computational spectral imaging overcomes the trade-off between spectral resolution and light throughput, but its performance still remains fundamentally limited by the geometric separability of spectral signatures in the encoding space. Current encoder designs predominantly focus on minimizing correlation or coherence, often overlooking the direct maximization of distinguishability among diverse spectra. Here we show that maximizing the minimum Euclidean distance in the encoding space (EDE) serves as a physically direct criterion for designing high-fidelity spectral encoders. To navigate the complex, high-dimensional design space under fabrication constraints, we developed a stochastic-deterministic optimization framework that couples global exploration via genetic algorithms with efficient local refinement using automatic differentiation on the transfer-matrix method. We demonstrate that EDE-optimized encoders significantly extend the minimum distance between distinct spectra in encoding space, yielding improvements in peak signal-to-noise ratio of 3.60 dB, 2.82 dB, and 4.52 dB compared with random, correlation-optimized, and coherence-optimized benchmarks, respectively, and achieving a reconstruction spectral fidelity exceeding 98.63% across diverse targets. Our approach enables high-precision spectral reconstruction, establishing a new geometric paradigm for the design of intelligent computational optical systems.

Wavelength-division multiplexing (WDM) continues to drive the need for optical receivers with compact and integrated spectral discrimination. Conventional demultiplexers based on gratings, or filter arrays remain bulky, sensitive to alignment, and difficult to co-package with fibers. Here we report a proof-of-concept fiber-endface heterojunction spectral sensor (FIHSS) with an electrically tunable transport-mediated spectral response. In the continuous regime, the FIHSS reconstructs spectra over the wavelength of 1510-1610 nm with a root mean square error of 0.11 relative to a commercial spectrometer. In the discrete regime, it resolves CWDM-type channels with wavelength spacings down to 1 nm and channel power ratios from 1:1 to 1:100. Further, benefiting from a robust fabrication process that shields the vdW layers from developer exposure, rapid rise (155 & micro;s) and decay times (125 & micro;s) are obtained, representing an outcome one order of magnitude faster than the values currently in the literature. Ultracompact device structure, free from external optical and mechanical modules, makes the FIHSS a promising configuration for portable spectrometer applications.

Metasurfaces, artificial two-dimensional layered materials with a sub-wavelength thickness, have gained significant interest due to their unparalleled ability to precisely manipulate the amplitude, polarization, phase, and other intrinsic properties of electromagnetic waves. In addition, the development of metasurfaces provides a new idea of "structure instead of material," through the local enhancement of the optical field and resonance modulation, which can break through the limitations of the material's intrinsic nonlinear effects, to realize the significant improvement of performance parameters in the sub-ps time domain. This review discusses the design principles, fabrication, and numerical simulation methods of metasurfaces, as well as their modulation characteristics of light in space and time domains. In the applications, the contribution of metasurfaces to optical modulation and imaging in the space domain is summarized, with a focus on their phase and polarization manipulation capabilities. Particularly, we are attentive to the application of metasurfaces in the time domain, probing into the relationship between metasurface structure and nonlinear optical properties, as well as the generation of pulsed lasers via mode-locked and Q-switched techniques. Finally, the developments and challenges of metasurfaces are summarized with an outlook provided to give a comprehensive understanding of metasurfaces and to facilitate their practical applications.