“…Alongside the proliferation of advanced lithographic processes, the emergence of low cost and high-resolution laser processing, has allowed metamaterials to be explored more rapidly and for designs to be greatly more complex. In the optical domain, plasmonic absorbers [10], photonic crystals (PC) [11][12][13], negative index lenses [14] and metamaterial antennas [3,15,16] have all been simulated and experimentally tested. The analogies that exist between acoustic waves and electromagnetic waves [17] led to the subsequent study of Phononic Crystals (PnCs) [18,19] and acoustic lenses [20,21].…”