Correlation between extraordinary optical transmission and polarization in metallic sub-wavelength structures

Extraordinary optical transmission (EOT) of both transverse-electric (TE) and transverse-magnetic (TM) polarizations was investigated for sub-wavelength metallic structures by the rigorous coupled-wave analysis, implemented as the Airy-like internal reflection series. Generally, because of the absence of coupled surface plasmon polaritons (SPPs), the SPP-produced EOT is not achievable for TE polarization in one-dimensional structures, unlike for TM one. We show that the TE-polarized EOT is also possible by the excitation of trapped modes in simply modified structures. Eventually, the polarization-independent EOT was illustrated at a certain wavelength.