Maximal Anderson Localization and Suppression of Surface Plasmons in Two-Dimensional Random Au Networks

2D random metal networks possess unique electrical and optical properties, such as almost hundred percent optical transparencies and low sheet resistance, which are closely related to their disordered structure and may be exploited in various applications. Here we present a detailed experimental and theoretical investigation of their plasmonic properties, revealing Anderson (disorder-driven) localized surface plasmon (LSP) resonances of very large quality factors and spatial localization close to the theoretical maximum. The LSPs typically consist of multiple field hotspots with a well-defined correlation distance and couple to electromagnetic plane waves. Moreover, they disappear above a geometry-dependent threshold at ca. 1.6 eV in the investigated networks, explaining their large transparencies in the optical spectrum.