Structural symmetry of two-dimensional metallic arrays: Implications for surface plasmon excitations

We report our recent investigation of the (0, ±1)-type SPP excitation of a gold two-dimensional nano-cavity array using finite-difference time-domain methodology. Our particular focus is on the symmetry properties of (0, ±1)-SPPs excited by different polarizations of light. Based on a group theory approach, we have shown that these (0, ±1) modes are originated from different symmetry modes at the Γ-point, and the B-(0, ±1) dispersion curve converges to the A-(−1, 0) dispersion curve at the Γ-point. This indicates these (0, ±1) modes are very different in their symmetry properties. As a result, the control of polarization may provide important insights into the manipulation of SPPs.