Comparing the transmission through ellipse and double-hole nano-photonic arrays in gold films

The coupling mechanism in surface-plasmon enhanced optical transmission through square lattice arrays of nanoholes was investigated by considering two different bases for the array: ellipses and double-holes. A comparison was made between the transmission properties of these bases, and for different orientations of each basis. The two cases showed similar results when the bases were aligned along the lattice vector of the array. When the bases were rotated, however, the surface-plasmon resonance amplitude and polarization showed very different behavior between the double holes and the ellipses. These differences in behavior give insight into the surface-plasmon mode coupling through the nano-holes, which may be used to optimize these arrays for nano-photonic applications.