Subradiant resonances in Au and Ag bipartite lattices in the visible spectrum

Subradiant surface lattice resonances are of interest due to their remarkably high quality factors. In this work, these high quality resonances are experimentally investigated in the visible spectrum with Au and Ag bipartite disk lattices fabricated with electron beam lithography. Subradiant resonances are also compared to unipartite surface lattice resonance with angle-resolved extinction measurements, which are supported by numerical models. Finally, the lattice parameters are optimized to show high quality factors in lattices where the elements have a diameter difference as small as 10 nm.