  In recent years, there has been intensive investigation of surface plasmon
polaritons (SPPs) in the science and engineering fields. Understanding the
physics of surface plasmon excitation is essential to the manipulation of SPPs,
and most existing studies focus on (-1,0)-type SPP excitation. In this article,
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. It is found that
polarization has strong implications for the field distribution of the
corresponding SPPs. As a result, the control of polarization may provide
important insights into the manipulation of SPPs.
