Optical skyrmions are topological textures of electromagnetic fields with promising applications in information processing, transport, and storage. Exquisitely tailoring the optical fields of diverse physical quantities has expanded the family of skyrmions, yet such skyrmions only exhibit a single-quantity texture in free space. Herein, dual skyrmionic textures concurrently portraying spin and Poynting vectors are unveiled in the tight focus of an annular second-order circularly polarized vortex beam. The focal electric and magnetic fields exhibit an elongated and identical spatial distribution but a phase difference of π/2, leading to dual skyrmionic textures with vector orientations that are either opposite or identical, depending on the handedness of the incident beam. Unlike conventional optical skyrmions that are exclusively regarded as quasiparticles distributed in a two-dimensional plane, a skyrmionic tube structure that extends over a longitudinal depth approaching 10λ while preserving its topology is demonstrated. Our Letter enhances the comprehensiveness of optical skyrmions and paves the way toward their practical applications by bolstering skyrmion-matter interactions.

Structured light projection serves as a commonly utilized technique for depth perception in facial recognition and anti-counterfeiting identification systems. As a core component in such optical arrangements, diffractive optical elements (DOEs) effectively transform collimated laser beams into uniformly illuminated dot patterns through precise light field modulation. However, when integrating DOEs with vertical cavity surface emitting laser arrays (VCSELs), collimated light from VCSELs exhibits multiple oblique incident angles beyond the normal 0 degrees angle. Conventional DOEs suffer from degraded diffraction efficiency and intensity uniformity under large-angle illumination. This study introduces an end-to-end inverse design method by directly linking the metasurface to the reconstructed diffraction intensities, and employs a figure of merit (FOM) to guide the update of the metasurface structured parameter. The optimized metasurface achieves wide-angle structured light generation spanning a 49.8 degrees & times; 56.1 degrees field of view (FOV), preserving super optical performance with diffraction efficiency > 83% and uniformity error < 0.1 for incident angles within +/- 9 degrees in both x-and y-directions. Our proposed method is promising for advanced applications, including 3D metrology, holography, and beam shaping, benefiting from the multi-objective optimization.

In polarization fields, Stokes skyrmions are continuous vectorial textures that encode integer-valued topological invariants across real space, enabling robust optical information encoding under complex perturbations. This topological resilience, however, fails when singular points occur where the Stokes vector has no unique limiting value, placing a fundamental constraint on skyrmion-based information manipulation. Here, we show, paradoxically, that the very defects that destroy conventional resilience can become the carriers of topological information. We introduce the resulting structures as Stokes defect skyrmions, in which singular Stokes responses constitute measurable topological degrees of freedom with theoretically minimal size. We design and realize one class of them using all-dielectric metasurfaces that combine arbitrarily controlled distinguished fast-axis singularities with customized retardance profiles. The resulting fields are then described by high-dimensional integer-valued topological tuples, providing theoretically unbounded information capacity at the nanoscale. As a proof-of-concept demonstration, selected tuple components are mapped to represent predefined alphabetic symbols, realizing controlled high-dimensional information representation within a single optical field. Our results establish Stokes defects as functional units for higher-dimensional topological encoding, expanding the role of defects from failure points to engineerable carriers of optical information.

Although conductive polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) are pivotal for flexible organic electronics, achieving tunable conductivity in high-resolution micro/nanoarchitectures remains a significant challenge. Conventional methods like inkjet writing and laser ablation not only offer limited resolution but also fail to provide the dynamic conductivity control required for advanced applications. To address these challenges, we developed a two-step nanofabrication strategy to produce PEDOT-based nanoarchitectures with tunable conductivities. A femtosecond direct laser writing technique was utilized to firstly create 3,4-ethylenedioxythiophene (EDOT)-based pH responsive nanostructures, and subsequently chemical oxidation was employed to convert EDOT-based nanostructures into conductive PEDOT-based ones, which enabled high-resolution conductive nanostructures with feature sizes as small as 250 nm and conductivity of 679 S m-1. Additionally, the structures exhibited tunable conductivity ranging from 454 S m-1 (pH = 13) to 1041 S m-1 (pH = 1), due to the swelling/contraction of the pH responsive acrylate-functionalized derivative matrix. This work demonstrates a scalable strategy for creating high-resolution, pH-stimuli-responsive conductive polymer-based nanostructures such as PEDOT nanostructures, offering significant potential for advanced applications in nanoelectronics and biosensors.

Abstract Chiral metasurfaces leveraging bound states in the continuum (BICs) offer a powerful route for enhancing light–matter interactions. However, existing quasi-BIC architectures typically face a fundamental trade-off between high quality (Q) factors and wide-angle chiral operation. Most designs confine strong circular dichroism (CD) to isolated points in momentum space (k-space) and often rely on intricate three-dimensional (3D) meta-atoms, rendering them highly sensitive to fabrication imperfections and angular misalignment. Here, we experimentally realize a planar dielectric metasurface that supports a wide k-domain chirality arising from accidental BICs with a net zero-topological-charge (ZTC). By lifting a Dirac-type degeneracy through controlled in-plane and out-of-plane symmetry breaking, we induce a deterministic topological evolution in which the same-handed circularly polarized (C) points migrate toward and accumulate near the Γ point, while the opposite-handed singularities annihilate or shift to higher k-space. This mechanism delivers record-level performance—an ultrahigh Q-factor (~ 104), near-unity linear and nonlinear CD (0.99/0.999), and robust angular coverage (|k x P/2π, k y P/2π|< 0.06)—all within a fabrication-friendly, single-layer dielectric platform. These results establish a new regime for chiral photonics, unifying high chiral purity, angular robustness, and topological stability in a scalable planar architecture.

3D printing of conducting polymers has garnered increasing interests owing to their emerging potentials in nanoelectronics, nanophotonics and bioelectronics. Even though direct laser printing techniques surpassing conventional inkjet printing offer nanoscale resolution and advanced 3D capability, disordered molecular main chain, insulating side chain and irregular phase separation impose additional energy barriers to charge transport kinetics in photocurable polymer framework, thereby compromising overall conductivity performance of as-fabricated devices. Here, we develop a novel poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) hydrogel photoresin for realizing highly conductive organic 3D nanostructures by using multiphoton direct laser printing technique. High pulse energy of the polarized femtosecond laser has been shown to induce the arrangement of the PEDOT:PSS nanofibrils and side chains of PSS detaching from PEDOT, which enables fabricated nanowires with a record-high conductivity of approximately 1010 S/cm and a deep sub-diffraction limit feature size of 78 nm. The facile printability allows sophisticated 3D bioelectronics to be in-situ fabricated and integrated with microfluidic chips, enabling precise sensing water contents. Leveraging its biocompatibility, we further demonstrate 3D bioelectronic sensors for real-time monitoring of ethanol yields throughout the yeast fermentation process.

Multidimensional light-field control is opening new frontiers in photonics. Recent breakthroughs in metasurface design and the integration of Dammann optimisation with spin-decoupled phase modulation enable the simultaneous manipulation of phase, amplitude, polarisation, and orbital angular momentum to project information into three-dimensional space. This paradigm shift towards full-parameter control in stereoscopic volumes is promising for revolutionising applications from high-capacity optical communications to secure encryption and parallel computing, marking a significant advancement in integrated photonic systems.

Upconversion detection of infrared radiation by cost-effective silicon photodetectors in visible bands has spurred a revolution in infrared imaging technology,unlocking a wide range of applications in biological imaging,optical spectroscopy,and optical data storage.Despite significant progress in upconversion detection,real-time,concurrent,complex-amplitude imaging of both phase and amplitude information,indispensable for disclosing the full signature of infrared scenes,remains a daunting challenge,impeding their widespread applications.By integrating the unique advantages of both coherent and incoherent approaches,we propose the concept of upconversion optical entropy encoding and demonstrate a video-rate infrared complex-amplitude imaging system.This is achieved by leveraging the synergistic interaction between light scattering in disordered photonic structures and lanthanide upconversion photoluminescence.By tailoring the information entropy of upconversion speckles,infrared light-field information can be captured in a single visible snapshot and explicitly reconstructed,assisted by a deep learning network,enabling infrared complex-amplitude imaging at a video rate of 25 frames per second(fps)and with high-fidelity 8-bit grayscale modulation.The high photosensitivity of the developed infrared imaging system enables a power detection limit of 0.2 nW μm-2,three orders of magnitude lower than that of conventional parametric upconversion imaging.As a proof of concept,we demonstrate its applications in capturing video frames of natural scene images and classifying images of speed-limit signs for autonomous driving.This approach can be readily integrated with other cross-band imaging methods,paving the way for various infrared application scenarios that require video-rate,high-photosensitivity,and high-fidelity protocols.

Orbital angular momentum (OAM) multiplexing offers a promising approach to high-capacity optical communication by harnessing the orthogonality of vortex beams. However, its practical deployment is severely limited in real-world settings where dynamic scattering media, such as turbulent atmosphere, distort multiplexed fields into random speckles and disrupt OAM demultiplexing. Although existing wavefront shaping and deep learning methods can mitigate static distortions, they fail under time-varying scattering conditions, leading to significant crosstalk and unreliable recovery. Here, we introduce a new concept, correlation invariance, which enables scattering-immune, robust OAM multiplexed transmission through dynamic media. By capturing orthogonally polarized speckle holograms in a compact common-path geometry and computing their intensity cross-correlation, dynamically imposed scattering phases are cancelled out while deterministic object information is preserved. This allows single-shot reconstruction of both amplitude and phase of the input OAM-multiplexed fields, without any pre-calibration or training. As a proof of principle, we demonstrate high-fidelity transmission of 24-bit RGB data with 99.61

With the rapid advances of optical information technology, numerous optical systems in both scientific and industrial fields are pursuing a resolution that surpasses the classical diffraction limit. Super-resolving pupil filters, whose transmittance or phase can be spatially modulated, have attracted intense interest for squeezing the focal spot of optical systems through wavefront manipulation, and have also been implemented in the fields of optical microscopy, optical storage, telescopes, etc. However, all the previously reported super-resolving pupil filters are tailored exclusively to specific optical systems with fixed focal lengths, rendering them incompatible with zoom or variable-focus optical platforms. In this work, we introduce a multi-adaptive super-resolving pupil filter that retains sub-diffraction-limited performance across a range of variable focal lengths. Such a pupil filter is composed of concentric annular belts in a binary phase configuration, designed via a two-step optimization algorithm and fabricated by using the ultraviolet optical lithography technique. Both numerical simulation and experimental results demonstrate that the sub-diffraction-limited focal spot can be consistently yielded at the designed wavelength of 633 nm when the super-resolving pupil filter is paired with plano-convex lenses of 50 mm,75 mm,100 mm, and 150 mm focal lengths, respectively. As a proof-of-concept demonstration, we integrate the filter into an optical imaging system and experimentally verify its resolution enhancement performance over the full focal-length range. Owing to its planar geometric structure and negligible insertion loss, the proposed multi-adaptive super-resolving pupil filter offers a practical way for the development of super-resolution zoom microscopy and zoom telescopes.

Laser-based three-dimensional (3D) metal printing emerges as a transformative technology that enables fabrication of functional components for applications ranging from aerospace and automobile industries1 to micro-electronics2 and photonics3. Conventional approaches typically rely on high-power lasers to join metallic composites into complex geometries4,5. In addition to the unbearable cost of high-power lasers, however, intensive laser heating of the absorptive metallic composites parasitically causes thermal diffusions6-9, which limits printing resolution and surface roughness to sub-micron levels10-20 and thus impair their electrical and optical performances. Here, we develop thermoplasmonic laser printing (TPLP), a technique that transduces diffusive heat into a confining Coulombic potential to directly assemble metallic composites into 3D nanostructures. Unlike existing nanoprinting strategies10-15 where pulsed lasers with peak power up to 0.1 MW scale are required, our method can be operated using continuous-wave lasers at powers of 100 μW scale, which is 9 order-of-magnitude lower. We demonstrate 3D metal nanoprinting with finest feature size down to 86 nm, surface roughness as low as 1.6 nm and electrical conductivity up to 0.1×107 S/m, which are inaccessible by conventional methods. Our method opens a cost-efficient pathway to fabricate miniaturized 3D metallic devices for multifarious optoelectronic applications.

PT- or anti-PT-symmetric non-Hermitian photonic systems can exhibit responses such as phase transitions, slow light, and asymmetric modal evolution near an exceptional point (EP), but realizing a phase-transition process that satisfies anti-PT symmetry and passes through an EP on an integrated platform remains challenging. A smart research from Xiankai Sun's group at the Chinese University of Hong Kong (CUHK) recently demonstrated that two quasi-BIC modes generate dissipative coupling to the same radiative continuum, enabling anti-PT phase transitions and EPs on a silicon-based integrated photonic platform without additional lossy materials or auxiliary lossy waveguides. This provides a new physical framework for exploring the intersection of BIC photonics and non-Hermitian photonics.

Polarization imaging has the powerful ability to detect unique features invisible to human eyes, which is challenging for conventional intensity imaging systems. Metasurface emerges as a transformative platform for compact polarization imaging systems, but prior strategies suffer from limited imaging field-of-view (FOV) and coarse-grained polarization pixels. Here, we demonstrate a meta-grating-lens (MGL)-based monolithic polarization camera achieving 14° FOV and real-time full-Stokes polarization imaging in the near-infrared region. The optimized MGL exhibits >60% focusing efficiency with <3% zeroth-order noise, enabling simultaneous polarization analysis, beam-splitting, and imaging functionalities in a fine-grained pixel level. This synergistic design enables both efficient light utilization and accurate polarization reconstruction. The proposed polarization camera has the potential to unlock wide range of applications including autonomous navigation, biomedical diagnostics, and even compact Muller matrix imaging systems.

A supercritical lens(SCL)can achieve far-field sub-diffraction-limited focusing by elaborately manipulating the interference effect in the focal region,which makes it strongly dependent on the wavelength of the illuminating light.In addition to the strong chromatic aberrations it suffers,the micrometer-scale clear aperture of reported SCL represents another compelling challenge that excludes their practical imaging applications demand.In this work,we proposed and experimentally demonstrated an achromatic supercritical lens(ASCL)with a centimeter-scale clear aperture.The ASCL was designed by a two-step optimization algorithm and constructed in a multilevel phase configuration which consists of 1251 concentric polymer rings with 52 phase levels.By utilizing the gray-scale laser lithography technique,we successfully fabricated an ASCL with a diameter of 10 mm.Such a centi-meter-scale ASCL showcases a distinguished performance with full visible working bandwidth covering from 400 nm to 700 nm and simultaneous achromatic sub-diffraction-limited focusing of 0.88 times of the Airy spot.The demonstrations of white light microscopic imaging further validate our design and show decent performance.Our work paves the way for practical applications of SCL in high-density optical data storage,super-resolving optical telescope,and high-precision optical trapping.

Holography can reconstruct immersive light fields for virtual and augmented reality by modulating optical wavefront. Due to huge pixel sizes, current spatial light modulators (SLMs) have small field-of-view (FOV) for holographic displays. Despite various methods for etendue expansion, the largest full-screen FOV for dynamic holography is only 70 ° X 70 °, which remains insufficient for large-scale, high-resolution, three-dimensional displays. Here, we report a pixel-interpolation-assisted holographic meta-projector that substantially expands the FOV by integrating multiple subwavelength metasurface pixels within each microscale pixel of a traditional SLM. Leveraging large-angle diffraction of the metasurface and implementing k-space distortion correction for ultra-wide angles, we experimentally demonstrate dynamic holographic image reconstruction with a FOV of 160 ° X 160 ° -equivalent to a system numerical aperture of 0.985-at a high framerate of 60 Hz, surpassing the temporal resolution threshold of human vision. This system represents the state-of-the-art near-full-screen holographic dynamic display, thereby opening the door to high-dynamic-range and large-FOV holographic displays.

Planar metalenses have distinct advantages over their traditional bulky refractive lens in terms of being lightweight and integrable. Their remarkable ability to modulate the phase and amplitudes of incident light without restrictions offers a revolutionary approach for a multitude of frontier applications. In recent years, tunability has become a prominent direction to pursue for the investigation of planar metalens. However, existing studies on tunable metalenses predominantly concentrate on adjusting the focal length to achieve zooming effects in optical imaging, while less attention has been dedicated to the tunability of the focal field itself. This aspect, if explored, could significantly broaden the scope and flexibility of their applications, particularly in multi-mode optical imaging. In this work, a flexible and stretchable metalens is proposed and theoretically demonstrated for the dynamic tuning of the focal field morphology. To fulfill the phase requirement during dynamic modulation, the diatomic coupled resonator is applied as the basic element, which possesses higher-order freedom of phase modulation capability. Through the symmetry reforming process by transverse stretching along the horizontal direction, the focal field of the metalens can be converted from a diffraction-limited airy spot into a uniform transverse optical needle. The length of the transverse optical needle can be precisely tailored according to the degree of deformation of the metalens. This research presents a method for light field modulation and holds extensive potential for applications in dual-mode laser-scanning confocal microscopy, laser processing, optical manipulation, etc.

Artificial nanostructures with ultrafine and deep-subwavelength features have emerged as a paradigm-shifting platform to advanced light-field management, becoming key building blocks for high-performance integrated optoelectronics and flat optics. However, direct optical inspection of integrated chips remains a missing metrology gap that hinders quick feedback between design and fabrications. Here, we demonstrate that photothermal nonlinear scattering microscopy can be used for direct imaging and resolving of integrated optoelectronic chips beyond the diffraction limit. We reveal that the inherent coupling among deep-subwavelength nanostructures supporting leaky resonances allows for the pronounced heating effect to access reversible nonlinear modulations of the confocal reflection intensity, yielding optical resolving power down to 80 nm (~λ/7). The versatility of this approach has been exemplified by imaging silicon grating couplers and metalens with minimum critical dimensions of 100 nm, as well as central processing unit chip with 45-nm technology, unfolding the long-sought possibility of in situ, nondestructive, high-throughput optical inspection of integrated optoelectronic and nanophotonic chips.

In this work, we demonstrate perfect optical vortex microlenses (POVMLs) using a 3D direct laser writing technique. The POVMLs transform incident light into vortex focal spots, generating stable bright rings at the focal plane. By precisely designing and implementing the phase distribution, the POVMLs produce focal spots with significantly suppressed sidelobe intensity (less than 10% of the main lobe) while maintaining the topological charge up to 7. Experimental characterization demonstrates that the vortex focal spot maintains a consistent radius of 5.7 µm on average across different topological charges, exhibiting exceptional stability with a relative standard deviation (RSD) of merely 1.94%. The maximum deviation from theoretical simulations is limited to 5.3%, which clearly indicates the superior robustness of the focal spot radius against topological charge variations.