Electromagnetic Response of Subwavelength Wire Arrays with Double Period

M. LESTER; D. SKIGIN; R. DEPINE

Ciudad Universitaria, Buenos Aires, Argentina

Conferencia; 10th International Conference on Near-field Optics. Nanophotonics and Related Techniques; 2008

In this work we analyze the response of dual-period finite arrays of cylinders, i.e., arrays comprising several cylinders in each unit cell. We adapted a rigorous integral method to deal with such structures, and show that these systems can be designed either to cancel or to intensify the intensity in a given diffraction order [3,4]. In addition, a simple model based on the scalar diffraction theory is introduced, which predicts the behavior observed in the curves calculated by the rigorous method. Although the scalar model was developed for rectangular slits in an opaque screen with negligible thickness -a case far from the actual system under study-, it qualitatively reproduces the behavior and helps understand the basic physics underlying the phenomenon involved. We also compare the results obtained with those corresponding to rectangular perfectly conducting compound gratings and show that the same properties in their response are found. The particular characteristics of the response of dual-period structures predicted by the scalar model are also present for other materials and other geometries of the scatterers, suggesting that this behavior is basically governed by the two periodicities present in the array.