Wireless sensing systems enable real-time, non-contact monitoring for next-generation intelligent platforms. Ideal wireless sensing systems feature compact, low power consumption, and long communication range. Here we report a miniaturized wireless sensing system with an integrated acoustic-resonance-driven piezoelectric microantenna (PE μ-antenna) with a 0.0196 mm2 active area. The PE μ-antenna integrated on a film bulk acoustic resonator (FBAR) achieves dual-frequency radiation at 1.85 GHz and 3.91 GHz with gains of -32.96 dBi and -20.5 dBi, respectively. The μ-antennas achieve over four orders of magnitude radiation efficiency enhancement and volume reduction compared with existing piezoelectric transmitters. We further extend this approach to high-overtone bulk acoustic resonators with high quality factors for wireless sensing. The system enables temperature and strain sensing with a transmission range up to 1 m, demonstrating state-of-the-art miniaturization and transmission performance among wireless sensing systems. This work establishes a scalable platform for ultracompact wireless sensors and communication nodes in biomedical, wearable, and aerospace applications.

Conventional coherent light-field manipulation techniques inherently conflict with the spatiotemporal incoherence of thermal radiation sources. While recent advances in thermophotonics have facilitated directional thermal emission, arbitrary thermal wavefront control—a cornerstone for advanced functionalities like focusing and holography—remains an unaddressed challenge. Here, we report a generalized recipe of designing meta-emitters with lossy and lossless outer boundaries, that enables thermal emission with arbitrarily tailored wavefront. Lossy and lossless surfaces on two sides of the meta-emitter are synergistically coupled by a single-mode waveguide, transforming incoherent thermal photons to coherent surface waves for wavefront shaping functionalities. Designer surface mode of meta-emitter permits the independent optimization of photon lifetime and propagation length, thus enabling scalable spatial coherence engineering. For the proof of concept, we experimentally demonstrate near-diffraction-limited self-focusing emission, quasi-two-dimensional (quasi-2D) high-quality thermal holography without speckle noise and spatial-multiplexed holography. Coupling optimization further suggests that spatial coherence exceeding 1000λ0 are achievable. Our proposed meta-emitter establishes a paradigm-shifting framework to integrate stochastic thermodynamic emission with precision photonic engineering, opening avenues for information-rich thermal radiation technologies. Wavefront control is inherently incompatible with thermal incoherence in general. To address this challenge, the authors propose a meta-emitter architecture featuring two tailored grooves interconnected by a waveguide tunnel enabling the conversion of thermal photons into coherent surface waves, thereby experimentally demonstrating feasible thermal wavefront manipulation— including thermal self-focusing and holography.

Due to the process fluctuations in the fabrication of magnetic storage devices and the competitive relationship among the write error rate, the endurance and power consumption, the effective write window of these devices is limited. In this work, we investigated various switching modes that occur in magnetic tunnel junctions with perpendicular magnetic anisotropy under conditions of high write voltage and low write error rate. The curve of the write error rate versus voltage shows multiple anomalous branches. Through simulations, it is found that the balloon and hump - type anomalies are more significantly related to the intermediate states caused by defects in the free layer. The local stress and pinning fields induced by these defects impede the magnetization switching process, and their intensities are independent of temperature. Additionally, experiments demonstrate that both the balloon and hump - type anomalous branches can be suppressed by applying a small vertical magnetic field. Reducing the device size and enhancing the perpendicular magnetic anisotropy of the free layer can mitigate the occurrence of the above anomalies. All these findings provide extensive solutions for improving the write margin of spin-transfer torque magnetic random access memory.

Structured light in space and time has become a powerful playground in which to explore the fundamental physics of wave systems, while simultaneously introducing new exotic forms of light, from spatio-temporal vortices to toroidal pulses of light. Yet their creation remains restricted by complex optical systems while directly observing their evolution in arbitrary channels remains elusive, complicated by the interplay of dispersion and diffraction and exacerbated by the lack of suitable detection tools. Here we create topological space-time beams in a single step by a resonant response of a symmetry-broken metasurface, mixing spatial, temporal and polarisation degrees of freedom in a single microwave field. Our realisation in the microwave regime allows us to directly observe their dynamics in arbitrary channels, from free-space to complex random media, showing the preservation of topology while the foundational degrees of freedom are scrambled. We use our control to show how to unscramble the space-time properties for the first crosstalk-free transmission of space-time waves. Our work advances the physics of space-time waves, introduces a new toolkit for their creation and control, and offers an exciting roadmap to their exploitation in real-world scenarios, e.g., for robust communications through noisy channels.

Topological structuring of light inevitably leverages on optical coherence to ensure that the imparted spatial phases are preserved, requiring highly coherent sources or coherence engineering embedded in the design. Now we show that thermal light can be spatially engineered to carry optical topologies in the form of Skyrmions. Such topologies are immune to time averaged decoherence, a fact we leverage on in reverse to create metasurface mediated incoherent topologies from a thermal source. The pristine nature of our measured Skyrmions validates the approach, while simulations reveal how coherence management in the metasurface design would further enhance the functionality. Remarkably, the generation stage inherits robustness from the topology, remaining immune to material and fabrication defects. Our work reports the first topologies from purely thermal light, opening a path to exploiting topology in ubiquitous everyday light sources.

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.

Long-wave infrared thermal imaging has become indispensable for critical applications ranging from industrial facility maintenance to advanced security surveillance. While refractive-diffractive hybrid lenses offer potential for compact infrared optics, existing implementations face fundamental limitations in achieving performance parity with conventional thermal lenses-particularly regarding spatial resolution, restricted field of view (FOV), and inherent challenges in phase control under group delay constraints. Considering these issues, herein, a refractivemetasurface-based hybrid lens, enabled by equal-group-delay metasurfaces (EGDMs), was studied. The design combines optimized optical geometry to minimize oblique light incidence on the metasurface with the unique capabilities of EGDMs in providing large-aperture continuous phase modulation. The resulting system achieves diffraction-limited performance across the full 8-12 mu m spectral band without requiring aspheric components, featuring an F-number of 1.08 while maintaining a wide 60 degrees FOV. Notably, the lens demonstrates exceptional optical performance with a modulation transfer function of 0.44 at 29.4 lp/mm. Its compact size makes it compatible with handheld thermal imagers for versatile deployment scenarios. This work demonstrates the viability of EGDM-enabled hybrid designs for next-generation thermal imaging systems that combine commercial-grade performance with unprecedented compactness. (c) 2026 Chinese Laser Press

Significance Over the past decade, the fundamental principles, design strategies, fabrication techniques, and practical applications of metadevices have been extensively investigated and remarkably advanced. By precisely manipulating light-matter interactions at the nanoscale, metadevices can flexibly tailor electromagnetic fields, thus enabling dynamic control over the amplitude, phase, polarization, and frequency of incident light. Such exceptional capabilities have endowed metadevices with a broad spectrum of functionalities, including beam steering, high-resolution imaging, holographic display, and orbital angular momentum manipulation. Distinguished from conventional bulky optical components, ultra-compact metadevices feature superior multifunctionality, dynamic tunability, and facile integration. Consequently, metadevices are increasingly evolving into versatile integrated photonic platforms, with their applications expanding into cutting-edge fields such as tunable photonic components, perfect absorbers, optical communications, artificial intelligence (AI), augmented/virtual reality (AR/VR), biomedical devices, and quantum computing. However, the cross-scale fabrication of metadevices remains a critical challenge, stemming from the inherent trade-off between nanoscale fabrication precision and large-area manufacturing throughput. Conventional micro-nano fabrication techniques-such as electron-beam lithography (EBL) and focused ion beam (FIB) etching-often fail to simultaneously satisfy the core requirements of high precision, cost-effectiveness, and scalable production. In recent years, a diverse array of cross-scale manufacturing strategies, including ultrafast laser processing, photolithography, self-assembly, and nanoimprinting, have been proposed and advanced to address these long-standing challenges. Ultrafast lasers, particularly femtosecond lasers, have emerged as powerful tools for micro-nano optical fabrication. Their distinctive advantages-including maskless, flexible, and high-precision processing procedures as well as minimal environmental constraints-render them highly appealing for advanced manufacturing applications. Unlike continuous-wave lasers, the interaction between ultrafast laser pulses and materials involves intricate dynamic processes driven by photon-electron-ion coupling, enabling material removal or modification with negligible heat-affected zones (HAZ) and excellent material compatibility. These unique effects and phenomena are nearly impossible to achieve via other physical or chemical fabrication approaches. In recent years, laser-based fabrication techniques have been extensively adopted for metadevice manufacturing, enabling a broad range of optical applications such as structural-color metasurfaces, photothermal converters, broadband absorbers, thermal infrared (IR) radiators, metalenses, and integrated photonic components. The operating spectrum of these devices spans from the visible region to the terahertz region, which is governed by the feature sizes of their subwavelength structures. More importantly, given the paucity of dedicated reviews focusing on laser-based fabrication of optical metadevices, this paper aims to provide a comprehensive overview and novel insights into metadevice design principles and practical applications from the perspective of laser manufacturing. Progress This review focuses on the recent advances in ultrafast laser processing technologies and their cutting-edge applications in metadevice fabrication. We first present a comprehensive overview of the modulation strategies for ultrafast lasers (Fig. 1, left). In the temporal domain, high-resolution fabrication performance hinges critically on the pulse width and temporal profile of ultrafast lasers, which dominate the nonequilibrium laser-matter interaction processes. Temporal modulation techniques, such as burst mode operation and double-pulse excitation, can effectively mitigate adverse thermal effects including debris ejection and heat accumulation. In the spatial domain, spatially shaped laser beams enable flexible manipulation of light intensity, phase, and polarization based on diffraction principles, thereby facilitating the arbitrary construction of tailored spatial light fields-with typical applications including patterned laser printing, spatial vector beam generation, and adaptive wavefront correction. Furthermore, spatiotemporal modulation techniques further expand the versatility of laser processing, enabling multifunctional and highly tunable fabrication across a broad range of materials and dimensional scales. Laser-based fabrication methodologies are systematically introduced herein to elucidate the underlying mechanisms of laser-matter interactions, particularly the intricate physicochemical processes involved. This review briefly outlines three fundamental mechanisms of laser processing, namely ultrafast laser ablation, laser additive manufacturing, and laser-induced modification (Fig. 1, right). Laser ablation demonstrates broad material compatibility, whereas the latter two techniques-laser additive manufacturing and laser-induced modification-are primarily applicable to dielectric materials. Owing to the exceptional versatility of laser processing techniques, a diverse array of applications has been developed for metasurfaces and metadevices, endowing these devices with a host of unprecedented optical characteristics. By adopting tailored laser processing strategies, the morphological and chemical properties of laser-induced microstructures can be precisely manipulated, thereby enabling either partial spectral modulation (e. g., structural colors, Fig. 2) or full spectral modulation (e. g., broadband absorbers, Fig. 3). Through laser processing, thermal infrared metasurfaces can be engineered to exhibit versatile functionalities, including directional radiation, gradient radiation intensity, and thermal encryption (Fig. 4). Furthermore, based on the principles of Fresnel zone plates and geometric-phase metasurfaces, ultrafast lasers have been employed to fabricate subwavelength metalenses and holographic metasurfaces that operate across the visible (VIS), near-infrared (NIR), and terahertz (THz) spectral regimes (Fig. 5). In addition, the excitation of nonlinear optical effects in transparent materials via ultrafast lasers enables super-resolution machining and the realization of unique physical phenomena, which in turn facilitates the development of a broad range of applications such as micro-optical components, optical data storage, and on-chip integrated spectrometers (Fig. 6). Finally, we present a comprehensive summary and discuss the future prospects of laser-fabricated metadevices. Conclusions and Prospects Metadevices, which typically demand cross-scale fabrication, remain a major challenge for conventional micro-nano manufacturing processes. Ultrafast laser processing has therefore emerged as a highly promising fabrication approach, offering the combined merits of cost-effectiveness, large-area patterning capability, high processing repeatability, and nanoscale resolution. Recent studies have demonstrated that leveraging nonlinear optical effects, near-field enhancement, and spatiotemporal pulse shaping strategies can break through existing physical limitations, enabling high-throughput, cross-scale nanofabrication while simultaneously expanding the design space for multifunctional metadevices. However, owing to the intricate and not yet fully elucidated mechanisms governing laser-material interactions, as well as the relative immaturity of current processing protocols, this technology still confronts numerous limitations and challenges in high-precision micro-nano fabrication. First and foremost, ultra-hard, ultra-thin, and composite materials generally exhibit poor machinability, which in turn underscores the unique advantages of laser processing. To further improve processing quality and stability, it is imperative to advance laser processing technologies and maximize their inherent merits. Second, a deeper understanding of laser-matter interaction mechanisms, coupled with the implementation of advanced in-situ monitoring and control techniques, is critical for enhancing fabrication precision and stability, and will consequently drive technological advancements in ultra-high-precision applications such as metadevices. Finally, AI-driven joint optimization of processing parameters and device performance-via machine learning or end-to-end deep learning models trained on integrated datasets of processing parameters and optical performance metrics- can simultaneously streamline laser manufacturing workflows and realize the target performance and multifunctionalities of metadevices.

Chiral imaging encryption, which encodes information in meta-atoms revealed under specific polarization states, is a promising security technology. However, conventional methods rely on external light sources and offer only a single polarization channel, which hinders miniaturization and integration. Herein, we demonstrate an intelligent metasurface based on vanadium dioxide (VO2) phase-change material (PCM) that overcomes these limitations. The metasurface generates linearly polarized thermal radiation with a linear dichroism (LD) of 0.71 in the insulating VO2 phase and chiral emission with a circular dichroism (CD) of 0.58 in the metallic VO2 phase, enabling dynamic switching between polarization states via temperature control. In addition, the LD and CD can be broadly tuned by modifying geometric parameters. Based on this mechanism, we designed a digitally encoded metasurface composed of diverse meta-atoms, which conceals specific patterns that are only revealed under the proper combination of operating temperature and polarization state, thus achieving image dual-encryption. Furthermore, the metasurface could display distinct images with low crosstalk under non-orthogonal polarization states, which stems from the different capabilities of geometric parameters to modulate elliptically polarized radiation. Our work establishes a new paradigm for eco-friendly optical devices, providing key theoretical and technical support for intelligent thermal radiation modulation.

ABSTRACT Chiral imaging encryption, which encodes information in meta‐atoms revealed under specific polarization states, is a promising security technology. However, conventional methods rely on external light sources and offer only a single polarization channel, which hinders miniaturization and integration. Herein, we demonstrate an intelligent metasurface based on vanadium dioxide (VO 2 ) phase‐change material (PCM) that overcomes these limitations. The metasurface generates linearly polarized thermal radiation with a linear dichroism (LD) of 0.71 in the insulating VO 2 phase and chiral emission with a circular dichroism (CD) of 0.58 in the metallic VO 2 phase, enabling dynamic switching between polarization states via temperature control. In addition, the LD and CD can be broadly tuned by modifying geometric parameters. Based on this mechanism, we designed a digitally encoded metasurface composed of diverse meta‐atoms, which conceals specific patterns that are only revealed under the proper combination of operating temperature and polarization state, thus achieving image dual‐encryption. Furthermore, the metasurface could display distinct images with low crosstalk under non‐orthogonal polarization states, which stems from the different capabilities of geometric parameters to modulate elliptically polarized radiation. Our work establishes a new paradigm for eco‐friendly optical devices, providing key theoretical and technical support for intelligent thermal radiation modulation.

ABSTRACT The fractional Fourier transform (FrFT), a generalization of the classical Fourier transform (FT) with a fractional‐order parameter, enables flexible tuning between time and frequency domains, making it a powerful tool in signal processing. However, its utility in optics is constrained by the lack of compact, efficient analog implementation platforms, limiting progress in optical information processing. Herein, a compact analog optical FrFT system based on metasurface phase planes able to realize accurate analog FrFT computation is presented. Building on this platform, and leveraging FrFT's unique advantages of tunable fractional orders and independent time‐frequency domains, two novel image encryption algorithms are developed: a single‐image scheme integrated with Arnold transform for enhanced scrambling, and a dual‐image scheme enabled by iterative computation for parallel data processing. Comprehensive numerical calculations, optical simulations, and physical experiments validate the robustness and reliability of the proposed system and algorithms. Notably, the tunable fractional order of FrFT provides a large encryption key space and high key sensitivity, significantly boosting encryption security. This work establishes a versatile analog optical FrFT platform and two high‐security encryption schemes, offering a new paradigm for advancing optical information processing, paving the way toward developing practical optical cryptosystems.

Conventional blackbody cavities, known for their near-unity broadband omnidirectional emissivity (absorptivity), are however constrained by their large volume (e.g., >104 cm3), imposing crucial restrictions on integration with existing devices. Here, we introduce the concept of metal blackbody microcavities, comprising thousands of microscale periodic pores created on metals, demonstrating excellent emissivity across visible and infrared (IR) ranges (exceeding 0.94 on average from 0.25 to 20 μm). In the long-wavelength IR (8 to 14 μm) region, near-unity emissivity was successfully achieved by 100-μm-deep metal microcavities with ultralow structural aspect ratios, facilitated by laser-textured multiscale surface morphologies that substantially enhance the light-trapping capabilities. Our findings demonstrate that microcavity-based patterns can produce local emissivity, tunable radiative intensity gradients, wide-angle feasibility, and high-temperature resistance, thereby enabling diverse applications in thermal IR displays such as thermal illusion, IR encryption, and grayscale thermal imaging. Notably, these blackbody microcavities are applicable to various metals, presenting considerable potential for use in extreme environments.

Recently, thermal chiral metasurfaces have attracted significant attentions due to their remarkable ability to manipulate thermal radiation, finding broad applications in chiral imaging, and holographic technologies. However, the design of symmetry‐broken structures with both high circular dichroism (CD) and practical manufacturability remains challenging. This work reports a mid‐infrared (MIR) chiral metasurface with spin‐selective absorption, achieving near‐unity left‐handed circular polarization emissivity at 5.77 μm induced by localized resonance enhancement, which is more than eight times higher than that in the opposite polarization, corresponding to a high CD of 0.84. Momentum‐space analysis of angular emissivity spectra demonstrate that the proposed metasurface achieves a high circular polarization response across wide angular range, and the net optical helicity reaches 54% of the fundamental limit. The experimentally measured absorptivity spectrum and thermal images further prove that the proposed metasurface can function directly as a compact wide‐angle MIR thermal emitter, opening avenues for high‐performance on‐chip sensing and imaging applications.

This study explores the radiative heat transfer (RHT) between a silica microsphere and a grating, focusing on the nanoscale heat transfer enhancement enabled by engineered nanostructures. The near-field thermal radiation is measured using a custom-fabricated micro-thermocouple with nanometer-scale spatial resolution. The key results reveal the substantial RHT enhancement at subwavelength gaps (<100 nm), driven by surface phonon polariton excitation in the structured silica medium. Theoretical analysis shows that while the effective medium theory qualitatively captures the fundamental coupling mechanisms, it systematically overestimates the heat flux in the deep near-field regime (<50 nm)—highlighting the limitations of homogenization approaches in resolving the nanoscale structural effects. This work underscores the critical roles of nanostructure geometry and material phonon dispersion in regulating the near-field heat flux, providing critical insights for establishing the design principles for next-generation thermal management devices based on phonon-polariton materials.

The recent demonstrations of van der Waals (vdW) nanophotonics have opened new pathways for manipulating the light-matter interaction in an intrinsic manner, leading to fascinating achievements in tunable magneto-optics by self-hybrid polaritons, indirect bandgap lasering, and exceptionally enhanced optical nonlinearity. However, the anisotropic atomic lattice, chemically active side walls, and distinct enthalpies of formation across vdW materials, pose significant challenges in nanofabrication and material choices, hindering the realization of high-Q resonant mode on arbitrary materials. In this work, we propose an etch-free vdW structure that mimics the shallow etching, termed "artificial etching". This approach utilizes a low refractive index (LRI) perturbation layer made of photoresist, drastically reducing radiation loss and experimentally achieving a remarkable Q factor of up to 348, which is comparable to the highest values reported in vdW nanophotonics. We demonstrate room-temperature polaritons in etch-free structures using four representative materials (WS_2, MoS_2, WSe_2, and MoSe_2) through self-hybridization of high-Q (quasi-)bound states in the continuum (BIC) modes and excitons, achieving a Rabi-splitting of approximately 80 meV, which significantly surpasses the intrinsic excitonic loss. Furthermore, we showcase optical modulation of indirect bandgap emission in bulk WS_2 and direct exciton emission in heterostructures, achieving substantial polarization-dependent enhancement of their emission efficiencies. The proposed etch-free vdW structure provides a versatile platform for high-Q nanophononics while preserving material integrity, advancing applications in photoelectronic and quantum devices.

Thermal metamaterials represent a transformative paradigm in modern physics, synergizing thermodynamic principles with metamaterial engineering to master heat flow at will. As next-generation technologies demand multi-scale thermal control, this field urgently requires systematic frameworks to unify its multidisciplinary advances. Curated through a global collaboration involving over 50 specialists across 25 subdisciplines, this review primarily summarizes two decades of advancements, ranging from theoretical breakthroughs to functional implementations. The review reveals groundbreaking innovations in heat manipulation through the exploration of both classical and non-classical transport regimes, topological thermal control mechanisms, and quantum-informed phonon engineering strategies. By bridging physical insights like non-Hermitian thermal dynamics and valleytronic phonon transport with cutting-edge applications, we demonstrate paradigm-shifting capabilities: environment-adaptive thermal cloaks, AI-optimized metamaterials, and nonlinear thermal circuits enabling heat-based computation. Experimental milestones include 3D thermal null media with reconfigurable invisibility and thermal designs breaking classical conductivity limits. This collaborative effort establishes an indispensable roadmap for physicists, highlighting pathways to quantum thermal management, entropy-controlled energy systems, and topological devices. As thermal metamaterials transition from laboratory marvels to technological cornerstones, this work provides the foundational lexicon and design principles for the coming era of intelligent thermal matter.

We study near-field radiative heat exchange between a pair of equal and unequal radii of spheres, exploring the effects of material properties, sphere radii, and separation distances by following the exact mathematical solution. Previous studies suggested that larger area of the object transfer larger heat compared to smaller area of the object. However, our study reveals that this is not always true. We propose the first way to achieve unique results such that the conductance can be higher for a smaller area of the spheres. For equal-sized spheres, the thermal conductance increases with radius due to enhanced resonant coupling in tellurium and surface phonon polaritons in silicon dioxide. For unequal radii, we observe non-monotonic conductance trends in tellurium caused by hybridization of resonant modes. The role of Mie resonance in SiC, which is associated with size dependent effects and non-monotonic trends in both symmetric and asymmetric configurations, is highlighted. Quasi-Normal Mode analysis highlights the role of coupled resonances in modulating heat transfer.

Chiral imaging, which utilizes chiral nanostructures to produce grayscale images, has attracted significant attention due to its potential for precise object and environmental perception. However, conventional chiral imaging techniques primarily rely on external light sources and other necessary optical components to create desired chiral patterns, which are compatible with device integration and miniaturization. In this study, a passive chiral imaging technique is presented by fully exploiting the spontaneous thermal emission of patterned metasurfaces to generate high‐resolution chiral thermal images. It is shown that the circular dichroism of emitted thermal photons can be precisely engineered by controlling the degree of broken symmetries of resonant meta‐atoms, achieving a wide range of tunability from 0 to 0.85 around 4 µm experimentally. Based on this approach, thermal metasurfaces encoded with distinct helicity states are fabricated to achieve passive high‐resolution image encryption using thermal radiation. In addition, these findings demonstrate that chirality‐based encryption is highly effective in reducing noise. The present study demonstrates the significant potential of integrating metasurface designs with thermal emission as a sophisticated framework for producing environmentally friendly, economically viable, and highly integrated optical devices and technologies.