Recently, metasurfaces composed of artificially fabricated subwavelength structures have shown remarkable potential for the manipulation of light with unprecedented functionality. Here, we first demonstrate a metasurface application to realize a compact near-eye display system for augmented reality with a wide field of view. A key component is a see-through metalens with an anisotropic response, a high numerical aperture with a large aperture, and broadband characteristics. By virtue of these high-performance features, the metalens can overcome the existing bottleneck imposed by the narrow field of view and bulkiness of current systems, which hinders their usability and further development. Experimental demonstrations with a nanoimprinted large-area see-through metalens are reported, showing full-color imaging with a wide field of view and feasibility of mass production. This work on novel metasurface applications shows great potential for the development of optical display systems for future consumer electronics and computer vision applications.

Recent years have witnessed an expanding interest in the application of flexible polymer materials (e.g., polyimide, polyester, etc.) as the substrates for electronic and display devices. These applications include flexible organic light-emitting displays, [1,2] thin film transistors, [3][4][5] sensors, [6,7] and polymer MEMS. [8,9] The advantages of polymer-based materials are their mechanical flexibility, light weight, enhanced durability, and low cost compared with rigid materials (such as silicon and quartz). However, it can be difficult to integrate polymers into an integrated circuit (IC) microfabrication process due to their low thermal stability (low melting and low glass transition temperatures) and solvent susceptibility. In practice, conventional IC fabrication processes are subject to limitations, in that they are multi-step, involve high processing temperatures, caustic baths and strong solvents. In order to address the current problems of microfabrication on flexible substrate, many alternative approaches to conventional photolithography-based process have been introduced by a number of researchers. These include microcontact printing (lCP) combined with metal etching, [10] electroless plating, [11] electropolymerization, [12] and direct metal layer transfer [13] for the microscale metal patterning on flexible substrates. Stencil lithography [14] was mainly applied for dielectric layer patterning on polymer substrates for the formation of electrical capacitors [15,16] due to its limited resolution. Inkjet printing was used for a drop-on-demand patterning of conductive polymer PEDOT [17] and gold [18] layers for drain-source and gate electrodes. However, its best resolution is 20-50 lm [19,20] limited by the nozzle diameter, the statistical variation of the droplet flight, and spreading on the substrate. Organic semiconducting materials are being widely used as semiconducting layers in flexible electronics due to their costeffectiveness, mechanical flexibility, and ease of application via specific chemical modification. However, further channel size down-scaling is essential for better performance of organic field effect transistor due to the lower carrier mobility of the organic semiconducting materials. While the abovementioned methods cannot achieve ultrafine features (a few lm's down to ∼ 100 nm) in high aerial density and good reproducibility, nanoimprinting lithography (NIL) allows easy fabrication of precise nanoscale structures. NIL has been applied for nanopatterning in various fields such as biological nanostructures, [21] nanophotonic devices, [22,23] organic electronics, [24,25] and the patterning of magnetic materials. [26] Especially, metal nanopatterning via nanoimprinting is widely employed in nanoscale electronics and biosensing platforms. However, metal nanoimprinting has been typically an indirect process where a polymer (e.g., PMMA) pattern is first created by nanoimprinting, and then used as a mask for metal film etching or metal lift-off process. [27] This involves multiple and ...

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The fabrication of uniformly interconnected cupronickel (CuNi) micromesh films on glass and polymer substrates with seamless junctions has been achieved using a simple transfer printing method. When used as a transparent heater, these CuNi micromesh films exhibited an effective and rapid heating performance at low input voltages (below DC 9 V) that can be attributed to the creation of a high quality network over the whole surface area that offers a relatively high transmittance, strong adhesion to its substrate and good mechanical flexibility. A high thermal stability and reliability was also observed relative to a pure Cu micromesh film. Transparent heaters based on CuNi micromesh are therefore considered suitable for providing anti-fogging or de-icing in optics and optoelectronic devices, as well as for wearable heating systems.

The common behaviour of a wave is determined by wave parameters of its medium, which are generally associated with the characteristic oscillations of its corresponding elementary particles. In the context of metamaterials, the decoupled excitation of these fundamental oscillations would provide an ideal platform for top–down and reconfigurable access to the entire constitutive parameter space; however, this has remained as a conceivable problem that must be accomplished, after being pointed out by Pendry. Here by focusing on acoustic metamaterials, we achieve the decoupling of density ρ, modulus B−1 and bianisotropy ξ, by separating the paths of particle momentum to conform to the characteristic oscillations of each macroscopic wave parameter. Independent access to all octants of wave parameter space (ρ, B−1, ξ)=(+/−,+/−,+/−) is thus realized using a single platform that we call an omni meta-atom; as a building block that achieves top–down access to the target properties of metamaterials.