Light scattering by a subwavelength plasmonic array: anisotropic model

We calculate the light transmission by a subwavelength plasmonic array using the boundary element method for parallel cylinders with different cross-sections: circular or elliptic with axes ratio 4:1. We demonstrate that the plasmonic resonance is sharper for the case of ellipses with a large horizontal axis. This structure is susceptible to the refractive index variations of media since the high derivative of reflection and transmission coefficients are near the angle of total internal reflection. To obtain an approximate analytical expression, we use the model of a metallic layer. We explore the "sandwich" structure with an anisotropic film between two dielectrics and demonstrate its quantitative agreement with numerical results.