Plasmonic Interference in Superstructured Metal Photonic Crystals

Abstract

Surface plasma waves (SPWs) excited by illumination of 2-dimensional superstructured metal photonic crystals (SMPCs) are investigated with extraordinary optical transmission (EOT). An m × m lattice of holes (m = 3 with the period p of 3 μm) fabricated in an Au film atop a GaAs substrate (refractive index nd), referred to as a basis plasmonic antenna (BPA), forms an SMPC that consists of 24 × 24 BPAs with varying spacing between BPAs, d. Two categories of d are examined: κ = d/p = i (i an integer), where SPWs generated at each BPA interfere constructively and κ ≠ i (<1), where the interference leads to drastic changes in the EOT. In the first category, the EOT associated with the fundamental SPW wavelength, T1, decreases with increasing κ, but has an almost invariant peak wavelength, λ1, at ∼10.1 μm (≅ndp), as expected. In the second category, however, the λ1 for the dominant EOT peak clearly shows a red-shift to ∼12 μm with T1 reduced to ∼0 at κ = 0.5, and T1 has a damped oscillatory dependence on κ. The ...