Yu Luo

TL;DR: The first realization of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals is reported, capable of hiding, for a specific light polarization, three-dimensional objects of the scale of centimetres and millimetres.

TL;DR: A local analogue model is presented and it is shown that spatial nonlocality can be represented by replacing the nonlocal metal with a composite material, comprising a thin dielectric layer on top of a local metal.

Abstract: Metasurfaces are engineered surfaces that consist of subwavelength periodic elements and can be used to manipulate electromagnetic waves. Multifunctional or reconfigurable electromagnetic meta-devices based on a direct-current biasing system can be built using lumped electronic components. However, such meta-devices require bulky power supplies, field-programmable gate arrays, electrical wires and complex control circuits. Here, we report a digital metasurface platform that can be programmed optically to implement electromagnetic functions. Our digital platform has 6 × 6 subarrays, each of which contains 4 × 4 metasurface elements based on electronic varactors integrated with an optical interrogation network based on photodiodes. The interrogation network can convert visible light illumination patterns to voltages and applies bias to the metasurface elements, generating specific microwave reflection phase distributions. To illustrate the capabilities of our approach, we use the optically driven digital metasurface for external cloaking, illusion and dynamic vortex beam generation. A digital platform that integrates a metasurface based on electronic varactors with an optical interrogation network based on photodiodes can be programmed by visible light to implement electromagnetic functions, including microwave cloaking, illusion and vortex beam generation.

TL;DR: In this paper, a broadband dual-polarized antenna array with five elements for the band is developed for base station application, and the measured results show achievement of impedance bandwidth of 45% for both ports, port-to-port isolation $>$ 25 dB, a stable radiation pattern with 3-dB beamwidth $68^{\circ}\pm 2^{circ}$ at H-plane and V-plane.

TL;DR: In this paper, the authors investigated a general class of electromagnetic devices created with any continuous transformation functions by rigorously calculating the analytical expressions of the electromagnetic field in the whole space, and they proposed a spherical field rotator which functions as not only a wave vector rotator but also a polarization rotator depending on the orientations of the spherical rotator with respect to the incident wave direction.