Optical metamaterials have presented an innovative method of manipulating light. Hyperbolic metamaterials have an extremely high anisotropy with a hyperbolic dispersion relation. They are able to support high-k modes and exhibit a high density of states which produce distinctive properties that have been exploited in various applications, such as super-resolution imaging, negative refraction, and enhanced emission control. Here, state-of-the-art hyperbolic metamaterials are reviewed, starting from the fundamental principles to applications of artificially structured hyperbolic media to suggest ways to fuse natural two-dimensional hyperbolic materials. The review concludes by indicating the current challenges and our vision for future applications of hyperbolic metamaterials.

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Metasurface holography, the reconstruction of holographic images by modulating the spatial amplitude and phase of light using metasurfaces, has emerged as a next‐generation display technology. However, conventional fabrication techniques used to realize metaholograms are limited by their small patterning areas, high manufacturing costs, and low throughput, which hinder their practical use. Herein, a high efficiency hologram using a one‐step nanomanufacturing method with a titanium dioxide nanoparticle‐embedded‐resin, allowing for high‐throughput and low‐cost fabrication is demonstrated. At a single wavelength, a record high theoretical efficiency of 96.9% is demonstrated with an experimentally measured conversion efficiency of 90.6% and zero‐order diffraction of 7.3% producing an ultrahigh‐efficiency, twin‐image free hologram that can even be directly observed under ambient light conditions. Moreover, a broadband meta‐atom with an average efficiency of 76.0% is designed, and a metahologram with an average efficiency of 62.4% at visible wavelengths from 450 to 650 nm is experimentally demonstrated.

A single-step printable platform for ultraviolet (UV) metasurfaces is introduced to overcome both the scarcity of low-loss UV materials and manufacturing limitations of high cost and low throughput. By dispersing zirconium dioxide (ZrO2) nanoparticles in a UV-curable resin, ZrO2 nanoparticle-embedded-resin (nano-PER) is developed as a printable material which has a high refractive index and low extinction coefficient from near-UV to deep-UV. In ZrO2 nano-PER, the UV-curable resin enables direct pattern transfer and ZrO2 nanoparticles increase the refractive index of the composite while maintaining a large bandgap. With this concept, UV metasurfaces can be fabricated in a single step by nanoimprint lithography. As a proof of concept, UV metaholograms operating in near-UV and deep-UV are experimentally demonstrated with vivid and clear holographic images. The proposed method enables repeat and rapid manufacturing of UV metasurfaces, and thus will bring UV metasurfaces more close to real life.

Optical vortices (OVs) carrying orbital angular momentum (OAM) have attracted considerable interest in the field of optics and photonics owing to their peculiar optical features and extra degree of freedom for carrying information. Although there have been significant efforts to realize OVs using conventional optics, it is limited by large volume, high cost, and lack of design flexibility. Optical metasurfaces have recently attracted tremendous interest due to their unprecedented capability in the manipulation of the amplitude, phase, polarization, and frequency of light at a subwavelength scale. Optical metasurfaces have revolutionized design concepts in photonics, providing a new platform to develop ultrathin optical devices for the realization of OVs at subwavelength resolution. In this article, we will review the recent progress in optical metasurface-based OVs. We provide a comprehensive discussion on the optical manipulation of OVs, including OAM superposition, OAM sorting, OAM multiplexing, OAM holography, and nonlinear metasurfaces for OAM generation and manipulation. The rapid development of metasurface for OVs generation and manipulation will play an important role in many relevant research fields. We expect that metasurface will fuel the continuous progress of wearable and portable consumer electronics and optics where low-cost and miniaturized OAM related systems are in high demand.