Exploiting long-ranged order in quasiperiodic structures for broadband plasmonic excitation

A comparison of transmission spectra from periodic, quasiperiodic, and randomly spaced slit arrays in thick gold films reveals resonant plasmonic excitations that arise solely due to the long-range order of the quasiperiodic structures. Specifically, first-order plasmonic resonances at the air-gold interface of the quasiperiodic arrays are identified at a broader range of wavelengths than those observed from periodic structures with the same average slit distance. Thus, a quasiperiodic plasmonic coupler that couples both visible and near-infrared light to surface plasmon polaritons is designed and demonstrated.