Circuit approach to the minimal configuration of terahertz anomalous extraordinary transmission

In this letter we present an in-depth circuit analysis of anomalous extraordinary transmission (ET) through subwavelength slit and hole arrrays loaded by a dielectric slab. We show the key role played by the thickness of the dielectric slab in order to enhance the transmission for TE-polarized waves (incident electric field parallel to the slits or to the short in-plane period in hole arrays arranged in rectangular lattice) within the cut-off regime of the apertures and to suppress Wood's anomaly. Analytical and numerical results together with experimental data are presented, showing good agreement among them. This work provides physical insight of the underlying mechanism governing anomalous ET and offers further independent control over orthogonal polarized waves impinging into subwavelength aperture arrays.