A new approach to make low-density and high-porosity graphene foams in film form is presented. The foam thickness can be readily tuned. The graphene foam has excellent electrical conductivity and is hydrophobic. It provides superior EMI shielding and rapid absorption of organic solvents. CVD of few-layer graphene on porous Cu/Ni generated by electrodeposition of Ni on Cu followed by heat treatment and dissolution of Cu/Ni yields the graphene foam by a method that appears to be scalable to mass production.

The spin Hall effect of light (SHEL) refers to the spin-dependent and transverse splitting of oblique incidence that occurs in both refraction and reflection. Enhancement of the SHEL is generally accompanied by a degradation in the efficiency. Recently, an anisotropic metamaterial has been proposed to attain a large SHEL with near-unity efficiency, but is limited to a horizontally polarized incidence. Here, a new approach to achieve a large SHEL and high efficiency simultaneously for arbitrarily polarized incidence is proposed by exploiting total external and internal reflection. The total reflection at the interface of a dense-to-sparse medium yields a theoretical maximum of the shift that is allowed for a unity efficiency. The SHEL can be further enhanced by increasing the refractive index contrast. Furthermore, we suggest a three-dimensional isotropic metamaterial that is designed to have an index below unity as a platform to experimentally demonstrate the SHEL with high efficiency. Our work will find wide applications in spin-dependent photonic devices.

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In this article, we investigate bandwidth‐enhancement of a circularly‐polarized (CP) Fabry‐Perot antenna (FPA) using single‐layer partially reflective surface (PRS). The FPA is composed of a single‐feed truncated‐corner square patch antenna, which is covered by the PRS formed by a square aperture array. We revealed that the finite‐sized PRS produces extra resonances and CP radiations for the antenna system, which broadened the impedance matching and axial ratio (AR) bandwidths significantly. For verification, a broadband CP FPA prototype operating near 5.8 GHz was realized and tested. The fabricated antenna with overall size of 125 mm × 125 mm × 23.5 mm achieves a |S11| < −10 dB bandwidth of 31.7% (5.23‐7.2 GHz), an AR < 3‐dB bandwidth of 13.7% (5.45‐6.25 GHz), the peak gain of 13.3 dBic, a 3‐dB gain bandwidth of 22.38% (5.0‐6.26 GHz), and a radiation efficiency of >91%.

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