This study is conducted in collaboration with Maciej Klemm, Department of Electrical and Electric Engineering, University of Bristol, UK.
In the past few years, important efforts have been deployed to find alternatives to on-chip, low-performance metal interconnects between devices. Because of the ever-increasing density of integrated components, intra- and inter-chip data communications have become a major bottleneck in the improvement of information processing. Given the compactness and the simple implantation of the devices, communications via free-space optics between nanoantenna-based arrays have recently drawn more attention. Here, we focus on a specific low-loss design of dielectric reflectarray (DRA), whose geometry is based on a periodic repartition of anisotropic dielectric cylinders on a metallic plate. When illuminated in normal incidence, specific patterns of such resonators provide a constant phase gradient along the dielectric/metal interface, thus altering the phase of the incident wavefront. The gradient of phase shift generates an effective wavevector along the interface, which is able to deflect light from specular reflection.
Here, we illustrate the effects of lithography flaws on the scattering regime of a 1D resonator array. The array is declined in two versions: the first one is made of ideal resonators, while the second one is composed of realistic resonators, with representative lithography flaws. The ideal array provides a very good directivity toward 18.0° (see below), with nearly 60% of the incident power deflected with a non-cartesian angle. On the other hand, the realistic array presents more imperfections in its directivity patterns, with a peak directivity around 14.5° and a lower efficiency (around 50%).
Simulation of electromagnetic waves propagation in nano-optics with a high-order discontinuous Galerkin time-domain method