Asymmetric Negative Refraction in Nonlocal Double-Wire Metamaterials

Abstract

We demonstrate that heterogeneous double-wire metamaterials, comprising two dissimilar and nonconnected wire arrays, enable loss-asymmetric hyperbolic dispersion and strongly asymmetric negative refraction. We unveil that, owing to their strongly nonlocal response and distinctive microstructure, such geometry supports two independent hyperbolic propagation channels with unequal losses, which can be selectively excited by free-space propagating waves incident at opposite angles. This angular selectivity gives rise to asymmetric negative refraction at the air-metamaterial interfaces, characterized by strong angular asymmetry in transmission and absorption, while preserving reciprocity. This phenomenon is scalable and can be realized with metallic wire arrays over a broad frequency spectrum extending from microwave to infrared frequencies, showing that nonlocality can emulate shear-like dissipative asymmetry that, in local media, requires lower spatial symmetry. Our findings open new avenues for directional energy transport and angle-selective wave control in photonic platforms.