Metasurfaces are traditionally 2D metamaterials that manipulate light. In article number 2005454, Shu Yang and co-workers bring them into 3D by photoengraving diverse metasurfaces onto different facets of monolithic, 3D microstructured arrays in a high-throughput and on demand fashion. By patterning locally confined metasurfaces on a cube, each cube becomes a multiplexing pixel for color reflection and filtering.

Metasurfaces present a potent platform to manipulate light by the spatial arrangement of sub-wavelength patterns with well-defined sizes and geometries, in thin films. Metasurfaces by definition are planar. However, it would be highly desirable to integrate metasurfaces with diverse, spatially programmed sub-wavelength features into a 3D monolith, to manipulate light within a compact 3D space. Here, a 3D photoengraving strategy is presented; that is, generation of such composite metasurfaces from a single microstructure via the irradiation of multiple interference laser beams onto different facets of the parent azopolymeric microstructure. Through "photofluidization," this technique enables independent inscription and erasing of metasurfaces onto and from individual facets of 3D monoliths with arbitrary shapes and dimensions, in a high-throughput fashion (over approximately a few cm² at a time). By engraving discrete sub-wavelength 1D surface relief gratings of different pitches on different facets of an inverse pyramidal array, a multiplexing structure-color filter is demonstrated.

A new solution for enhancing interfacial adhesion between the hydrocarbon (HC) membrane and a perfluorinated catalyst layer (CL) in polymer electrolyte fuel cells (PEMFCs) is successfully demonstrated by J.-K. Park, H.-T. Kim, and co-workers on page 2974. This is realized by the intrusion of micrometer-sized pillars fabricated on the HC membrane into the perfluorinated CL, forming an interlocking interface, like Lego blocks. Owing to a higher expansion with hydration for the HC membrane than for the perfluorinated CL, a strong normal force occurs at the interface of the pillars and the holes, resulting in an eight-fold increase of the interfacial bonding strength.

A physical interlocking interface that can tightly bind a sulfonated poly(arylene ether sulfone) (SPAES) membrane and a Nafion catalyst layer in polymer electrolyte fuel cells is demonstrated. Owing to higher expansion with hydration for SPAES than for Nafion, a strong normal force is generated at the interface of a SPAES pillar and a Nafion hole, resulting in an 8-fold increase of the interfacial bonding strength at RH 50% and a 4.7-times increase of the wet/dry cycling durability.

The field-gradient, superficial photo fluidization of azomaterials allows a specific 3D nano-silhouette to be shaped over a large area, so as to get easy access to a 3D-tapered, deep sub-wavelength Au nanohole (20 nm spatial size) array. The squeezing of visible light into the deep sub-wavelength point and the relevant extraordinary optical transmission (EOT) are achieved using this 3D-tapered, 20 nm Au nanohole.

• Developed a high-resolution, maskless laser ablation technique for localized patterning of WO 3 electrochromic films. • Achieved simultaneous optical modulation and infrared shielding with thermally controlled patterning. • Demonstrated segment-addressable electrochromic devices with enhanced design flexibility and process scalability. • Provided a cost-effective and versatile fabrication route for next-generation patterned electrochromic applications. Tungsten trioxide (WO 3 ) is a promising electrochromic material owing to its reversible structural and optical modulation under applied voltage. Despite advantages such as rapid switching and electrochemical stability, the functional diversification of electrochromic devices (ECDs) remains limited, largely due to the absence of effective patterning strategies. Here, we present a facile laser ablation approach for precise and controllable patterning of WO 3 thin films, enabling on-demand optical transmittance modulation. The laser-defined patterns can further serve as simple informative display elements, demonstrating localized visual switching based on patterned geometries. The process removes both the WO 3 layer and the underlying fluorine-doped tin oxide (FTO) layer from the glass substrate, as confirmed by UV–vis spectrometry and X-ray diffraction. The influence of patterning density on thermal management performance is further evaluated under infrared irradiation, revealing its potential for heat-shielding functionality in optoelectronic applications.

This study aims to enhance the electrochemical performance of supercapacitors by maximizing the specific surface area and surface treatment of carbon-material electrodes through fluorination doping. Polyacrylonitrile (PAN)-based carbon fibers (PCFs) were produced via electrospinning and subsequently activated with potassium hydroxide (KOH) at 800 °C to obtain activated PAN-based carbon fibers (APCFs). Direct fluorination was then used to synthesize fluorinated PAN-based carbon fibers (FPCFs). The specific surface area of the electrode materials was maximized by adjusting the concentration of the electrospinning solution. The effect of fluorination on changes in surface elemental content was precisely managed to mitigate the decrease in porosity. The pore size distribution, vital for determining the specific capacitance of supercapacitors, was thoroughly assessed. After the activation and fluorination processes, the specific surface area of the FPCFs increased significantly to 1753.2 m2 g–1. This value is notably higher than that of commercial activated carbons, which typically range from 1200 to 1500 m2 g–1. The supercapacitor properties of the resulting materials were evaluated, revealing a specific capacitance of 176.2 F g–1 for FPCF with an electrospun PAN concentration of 7 wt %.