Resonant optical tunnel effect through dielectric structures of subwavelength cross sections

We show that optical tunnel effects through elongated structures of subwavelength cross sections can be enhanced by the appropriate structuration of the local dielectric function. Even under total internal reflection, transfer channels can be excited to perform spatially confined photonic transfer between transparent media linked by such subwavelength structures. The optical properties of such systems are analyzed using field susceptibilities, also known as electromagnetic Green's dyadics, which determine both the local density of photon states and the optical transmittance of the system. Green's dyadics obtained by solving numerically a set of dyadic Dyson equations are applied to study the optical properties of subwavelength structures connecting two semi-infinite materials.