Via experimental measurements and full-wave numerical simulations, we characterize these resonant phenomena with specific reference to the Ammann-Beenker (quasi-periodic, octagonal) tiling lattice geometry, and investigate the underlying physics.
In particular, we show that, by comparison with standard periodic structures, a richer spectrum of resonant modes may be excited, due to the easier achievement of phase-matching conditions endowed by its denser Bragg spectrum. Such modes are characterized by a distinctive plasmonic or photonic behavior, discriminated by their field distribution and dependence on the metal thickness. Moreover, the response is accurately predicted via computationally-affordable periodic-approximant-based numerical modeling.
The enhanced capability of QCs to control number, spectral position and mode distribution of hybrid resonances may be exploited in a variety of possible applications in order to outperform the periodic counterpart. To assess this aspect, we first focus on label-free biosensing, through the characterization of the surface sensitivity of the proposed structures with respect to local refractive index changes. Moreover, we also show that the resonance-engineering capabilities of QC nanostructures may be effectively exploited in order to enhance the absorption efficiency of thin-film solar cells.