Collective modes of self-assembled supercluster metamaterials: towards label-free sensing

Lithographically-produced plasmonic structures, while offering exceptional control of light through light-matter interactions, have seen limited implementation into sensing technologies. This has been due to several factors, such as large ohmic losses and high cost of fabrication. The use of self-assembled superclusters of chemically-synthesized metallic nanoparticles has been proposed as means of overcoming some of these limitations, by exploiting their collective modes. In this work, the existence of such modes is successfully verified by 3D Raman tomography. Proof-of-principle experiments are also conducted to demonstrate the potential of superclusters in sensing schemes.