Dispersion relation of Al/Si surface plasmon in hexagonally ordered aluminum hole arrays

This investigation examines the extraordinary light transmission through periodic hexagonally ordered aluminum hole arrays on silicon substrates. The holes are circular and the arrays with various hole diameters were fabricated. The transmission spectra through the hole arrays were measured as a function of the incident angle of the light beam. It is observed that the transmission peak splits into two when the diameter of the hole is close to half of the lattice constant. At larger incident angles, the six degenerate (1,0) AlSi surface plasmon modes split into four or three modes depending on the symmetry axis, and even higher order modes can be identified for small hole diameters. © 2007 American Institute of Physics.