Ultrawideband 3-bit multifunctional metasurfaces by completely spin-decoupled meta-atom.

The achievement of distinct wavefront reconstruction for orthogonally polarized electromagnetic (EM) waves in a broadband frequency range is extremely important in modern wireless communications. However, the development of circularly polarized wavefront modulation devices is hindered by conjugate symmetric phase responses introduced by the rotation-induced geometric phase. Herein, a spin-decoupled meta-atom with a novel structure is designed to independently tailor left-hand and right-hand circularly polarized incident waves over a broadband range of 12-28 GHz with a fractional bandwidth of 80%.

Ultra-Broadband Refractory All-Metal Metamaterial Selective Absorber for Solar Thermal Energy Conversion.

A full-spectrum near-unity solar absorber has attracted substantial attention in recent years, and exhibited broad application prospects in solar thermal energy conversion. In this paper, an all-metal titanium (Ti) pyramid structured metamaterial absorber (MMA) is proposed to achieve broadband absorption from the near-infrared to ultraviolet, exhibiting efficient solar-selective absorption. The simulation results show that the average absorption rate in the wavelength range of 200-2620 nm reached more than 98.

High-sensitivity refractive index of Au@Cu S core-shell nanorods.

A high refractive index sensitivity of Au@Cu S core-shell nanorods working in the near-infrared is theoretically demonstrated. The sensitivity of our sensor reaches 1200 nm per Refractive Index Unit (RIU), which is higher than that of other metal-metal core-shell nanorods. The reason is that the new materials and structure of Au@Cu S core-shell nanorods lead to a unique sensing principle.

Double-exponential refractive index sensitivity of metal-semiconductor core-shell nanoparticles: the effects of dual-plasmon resonances and red-shift.

In order to improve the refractive index sensitivity of a localized surface plasmon resonance (LSPR) sensor, we present a new type of LSPR sensor whose refractive index sensitivity can be improved by greatly increasing the plasmon wavelength red-shift of metal-semiconductor core-shell nanoparticles (CSNs). Using extended Mie theory and Au@Cu S CSNs, we theoretically investigate the optical properties of metal-semiconductor CSNs in the entire near-infrared band. Compared with dielectric-metal and metal-metal CSNs under the same conditions, the metal-semiconductor CSNs have a higher double-exponential sensitivity curve because their core and shell respectively support two LSPRs that greatly increase the LSPR red-shift to the entire near-infrared range.

Terahertz reflectarray as a polarizing beam splitter.

A reflectarray is designed and demonstrated experimentally for polarization-dependent beam splitting at 1 THz. This reflective component is composed of two sets of orthogonal strip dipoles arranged into interlaced triangular lattices over a ground plane. By varying the length and width of the dipoles a polarization-dependent localized phase change is achieved on reflection, allowing periodic subarrays with a desired progressive phase distribution.

Experimental demonstration of reflectarray antennas at terahertz frequencies.

Reflectarrays composed of resonant microstrip gold patches on a dielectric substrate are demonstrated for operation at terahertz frequencies. Based on the relation between the patch size and the reflection phase, a progressive phase distribution is implemented on the patch array to create a reflector able to deflect an incident beam towards a predefined angle off the specular direction. In order to confirm the validity of the design, a set of reflectarrays each with periodically distributed 360 × 360 patch elements are fabricated and measured.