Characteristics of surface plasmon resonances in thick metal film perforated with nanohole arrays

The dependence of optical properties on the hole shape, period of nanohole arrays and metal film thickness, in thick silver film perforated with “high density nanohole arrays” is investigated using the finite difference time domain technique. The physical mechanism behind the light phenomena is discussed: the coupling between localized plasmon resonances and surface plasmon polaritons is found to play a crucial role on the optical properties, while the hole shape plays an important role on the coupling mechanism. Interesting light phenomena are observed in thick metal films perforated with rectangle nanohole arrays; the antisymmetric coupling between surface plasmon polaritons near the top and bottom film plane, and the antisymmetric coupling between localized surface plasmon resonances near the two long sides of the rectangular hole are excited in it.