Maximal Anderson localization and suppression of surface plasmons in two-dimensional random Au networks

Two-dimensional random metal networks possess unique electrical and optical properties, such as almost total optical transparency and low sheet resistance, which are closely related to their disordered structure. Here we present a detailed experimental and theoretical investigation of their plasmonic properties, revealing Anderson (disorder-driven) localized surface plasmon resonances of very large quality factors and spatial localization close to the theoretical maximum, which couple to electromagnetic waves. Moreover, they disappear above a geometry-dependent threshold of approximately 1.7 eV in the investigated Au networks, explaining their large transparencies in the optical spectrum.