Resonant transmission of light through finite chains of subwavelength   holes
  In this paper we show that the extraordinary optical transmission phenomenon found before in 2D hole arrays is already present in a linear chain of subwavelength holes, which can be considered as the basic geometrical unit showing this property. In order to study this problem we have developed a new theoretical framework, able to analyze the optical properties of finite collections of subwavelength apertures and/or dimples (of any shape and placed in arbitrary positions) drilled in a metallic film. 
J. Bravo-Abad, F.J. Garcia-Vidal, L. Martin-Moreno