Helicity-multiplexed metasurfaces based on symmetric spin–orbit interactions (SOIs) have practical limits because they cannot provide central-symmetric holographic imaging. Asymmetric SOIs can effectively address such limitations, with several exciting applications in various fields ranging from asymmetric data inscription in communications to dual side displays in smart mobile devices. Low-loss dielectric materials provide an excellent platform for realizing such exotic phenomena efficiently. In this paper, we demonstrate an asymmetric SOI-dependent transmission-type metasurface in the visible domain using hydrogenated amorphous silicon (a-Si:H) nanoresonators. The proposed design approach is equipped with an additional degree of freedom in designing bi-directional helicity-multiplexed metasurfaces by breaking the conventional limit imposed by the symmetric SOI in half employment of metasurfaces for one circular handedness. Two on-axis, distinct wavefronts are produced with high transmission efficiencies, demonstrating the concept of asymmetric wavefront generation in two antiparallel directions. Additionally, the CMOS compatibility of a-Si:H makes it a cost-effective alternative to gallium nitride (GaN) and titanium dioxide (TiO2) for visible light. The cost-effective fabrication and simplicity of the proposed design technique provide an excellent candidate for high-efficiency, multifunctional, and chip-integrated demonstration of various phenomena.

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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.

We present that the tailored nanopatterning with tunable shape, depth, and dimension for diverse application-specific designs can be realized by utilizing controlled dynamic nanoinscribing (DNI), which can generate bur-free plastic deformation on various flexible substrates via continuous mechanical inscription of a small sliced edge of a nanopatterned mold in a compact and vacuum-free system. Systematic controlling of prime DNI processing parameters including inscribing force, temperature, and substrate feed rate can determine the nanopattern depths and their specific profiles from rounded to angular shapes as a summation of the force-driven plastic deformation and heat-driven thermal deformation. More complex nanopatterns with gradient depths and/or multidimensional profiles can also be readily created by modulating the horizontal mold edge alignment and/or combining sequential DNI strokes, which otherwise demand laborious and costly procedures. Many practical user-specific applications may benefit from this study by tailor-making the desired nanopattern structures within desired areas, including precision machine and optics components, transparent electronics and photonics, flexible sensors, and reattachable and wearable devices. We demonstrate one vivid example in which the light diffusion direction of a light-emitting diode can be tuned by application of specifically designed DNI nanopatterns.