In this paper, a high-order dielectric metasurface based on silicon nanobrick array is proposed and investigated. By controlling the length and width of the nanobricks, the metasurfaces could supply two different incremental transmission phases for the X-linear-polarized (XLP) and Y-linear-polarized (YLP) light with extremely high efficiency over 88%. Based on the designed metasurface, two polarization beam splitters working in high-order diffraction modes have been designed successfully, which demonstrated a high transmitted efficiency. In addition, we have also designed two vortex-beam generators working in high-order diffraction modes to create vortex beams with the topological charges of 2 and 3. The employment of dielectric metasurfaces operating in high-order diffraction modes could pave the way for a variety of new ultra-efficient optical devices.

Metasurfaces are capable of tailoring the amplitude, phase, and polarization of incident light to design various polarization devices. Here, we propose a metasurface based on the novel dielectric material gallium nitride (GaN) to realize high-efficiency modulation for both of the orthogonal linear polarizations simultaneously in the visible range. Both modulated transmitted phases of the orthogonal linear polarizations can almost span the whole 2π range by tailoring geometric sizes of the GaN nanobricks, while maintaining high values of transmission (almost all over 90%). At the wavelength of 530 nm, we designed and realized the beam splitter and the focusing lenses successfully. To further prove that our proposed method is suitable for arbitrary orthogonal linear polarization, we also designed a three-dimensional (3D) metalens that can simultaneously focus the X-, Y-, 45°, and 135° linear polarizations on spatially symmetric positions, which can be applied to the linear polarization measurement. Our work provides a possible method to achieve high-efficiency multifunctional optical devices in visible light by extending the modulating dimensions.

In this article, an ultrabroadband electromagnetic wave absorber with wide angular stability is proposed. The absorber matrix is formed by multilayers of foams and resistive films with different patterns, and two dielectric matching layers are superimposed on the surface of the absorber to improve the absorption effect of the absorber in the case of oblique incidences. Simulations show that the absorptivity of the proposed design reaches more than 90% in the frequency range of 4.0–50.9 GHz, with a relative absorption bandwidth of 171%. In addition, when the incidence angle reaches 60°, the absorber absorbs more than 90% within the frequency band of 15.3–47.3 GHz and 11.3–52 GHz when transverse electric (TE-) and tra nsverse magnetic TM-polarized waves are incident, respectively. The broadband absorption mechanism of the absorber and the role of the dielectric matching layers on the stability of oblique incidence are analyzed, and samples are prepared and tested to validate the design. The ultra-broadband absorbing bandwidth and wide angular stability make the absorber potentially useful for energy absorption and radar scattering cross section reduction applications.

An electrically tuned phase shifter based on the single slot unit cell and liquid crystal for a reconfigurable reflectarray antenna was presented. The simulation and measured results obtained at the F-band were used to demonstrate that the dielectric properties of a nematic state liquid crystal could be exploited to realize a slot unit cell phase shifter for the reconfigurable reflectarrays antennas. By reducing the inhomogeneous of the external electric field in the liquid crystal layer, a lower control voltage and improved model accuracy was obtained. In the experiments test, the achieved saturation bias voltage (10 V) was smaller than the previously reported structure, and the phase shift of the reflectarray greater than 300° was achieved in the frequency range 121.5–126 GHz. The maximum phase shift of 306° occurred at 124.5 GHz.

A rapid response reconfigurable intelligent surface (RIS) based on liquid crystals (LCs) is demonstrated for terahertz beam steering. A wire-controlled metasurface array is achieved by substituting the metal backplane of conventional reconfigurable metasurfaces with pixelated grating electrodes. Notably, the RIS employs bias voltage control across its full states, facilitating accelerated transitions between them. It significantly enhances the response speed of the proposed LC device. Simulation and test results consistently indicate that the RIS exhibits outstanding beam steering capability at the optimal operating frequency of 415 GHz. Specifically, the proposed RIS realizes wide-angle beam scanning from 20° to 60°. Our work is expected to have potential applications in 6G communications, vortex beam generation and imaging.

The authors present a triple‐band metamaterial absorber operating at mm wave frequency band. The absorber is composed of periodic unit cells, which consists of a new pattern and a ground plane, placed in two sides of a dielectric substrate made of polyimide film. To best understand the absorption mechanisms, full‐wave simulation results for the electric field, surface current, and power loss distributions are presented. The experimental results, for a transverse electric‐polarised normal incident wave, show three distinctive absorption peaks, at frequencies 101.25, 108.75, and 129 GHz with absorptivities of 92.5, 94.9, and 88.6%, respectively. The absorber is independent of the wave polarisation, where high absorption is achieved for a wide range of oblique angles of incidence.