Single-Layer Achiral Metasurface with Independent Amplitude–Phase Control for Both Left-Handed and Right-Handed Circular Polarizations

Abstract

Amplitude–phase control for circular polarized (CP) waves is experiencing a research upsurge in electromagnetics owing to the kaleidoscopic electromagnetic responses and promising application prospects of circular polarizations, and chiral metasurfaces are more facile to achieve a series of intriguing chiral phenomena than natural materials. However, it is difficult for most existing chiral metasurfaces to independently tailor the amplitude and phase of left-handed circular polarized and right-handed circular polarized waves at the same frequency as they suffer the drawbacks of large thickness, multiple layers, and complex structure. Herein, an innovative strategy of single-layer achiral metasurfaces of thickness 0.13λ0 is proposed to independently and simultaneously manipulate the amplitude and phase of orthogonal CP waves. As a proof of concept, an amplitude and phase controlled dual-channel meta-hologram is designed to reconstruct diverse images with high fidelity under orthogonal CP illumination, and the simulated and experimental results collectively validate the availability of our methodology. Significantly, the meta-hologram is also applicable to full polarization states according to the decomposition of electromagnetic waves. The inspiring design of single-layer achiral metasurfaces provides a simple and effective approach to explore chiral effects, and they possess enormous application potential in multitudinous microwave devices.

Dual-Channel Surface Waves Directional Radiation with Customizable Intensity and Switchable Pattern

“…Intuitively, the surface current induced by LCP (RCP) incident waves evolves with the varying central angle of the left (right) arm and generates the phase shift of corresponding co-polarized reflected waves, which is hardly affected by the varying central angle of the right (left) arm. In other words, the phase shift only depends on the variation of relevant central angle, and the accumulated phase can return to the same final state after undergoing cyclic evolutions on different paths, which are completely consistent with the characteristics of Aharonov–Anandan (AA) geometric phase originating from the Coriolis effect. − And according to the Coriolis effect, the rotational Doppler shift will occur when the incident waves carrying angular momentum pass through a rotating object along the rotation axis, which can cause the angular frequency shift Δω to generate the geometric phase φ , as expressed in eq , φ = prefix∫ Δ ω d t = prefix∫ σ Ω z d t where Ω z denotes the rotational angular velocity of the rotating object and σ = ±1 denotes the spin directions of orthogonal CP incident waves. Actually, the rotation of the object can be regarded as the rotation of the polarization state, so the rotational angular velocity of the object is equivalent to the rotation velocity of the polarization ellipse in the Poincare sphere, which can be written as Ω z = d (2τθ)/d t . , Here, θ represents the rotation angle of the object, and τ = ±1 represents the rotation directions of the polarization ellipse.…”

Performance analysis and prediction of tunable metasurface filter based on electrochemical metallization

“…Metasurface is an artificial plane material with smaller thickness than the wavelength [1]. Metasurfaces have excellent electromagnetic properties beyond the limitation of natural materials [2], which showing a variety of flexible control of parameters such as amplitude [3], phase [4,5], polarization [6], etc. Therefore, due to the application in the spectrum range from terahertz to visible light [7], such as filters [8,9], biosensors [10][11][12][13], perfect absorbing materials [14,15] * Author to whom any correspondence should be addressed.…”

Broadband spin-decoupled metasurface for independent wavefront manipulations of orthogonal circularly-polarized waves

“…And the operating bandwidth of metasurface is limited. (3) achiral metasurface with weak resonance characteristics based on propagation phase and geometric phase [34][35][36][37][38][39][40][41][42][43]. The modulation strategy achieves a large propagation phase shift through the rational design of weak-resonant unit cells in a wide frequency range.…”