The optical properties of a plasmonic crystal composed of gold nanorod particles have been studied. Because of the strong coupling between the incident light and vibrations of free electrons, the long-wavelength optical properties such as the dielectric abnormality and polariton excitation etc., which were suggested originally in ionic crystals, can also be present in the plasmonic crystal. The results show that the plasmonic and ionic lattices may share a common physics.

• Received 17 September 2009

DOI:https://doi.org/10.1103/PhysRevLett.104.016402