Enhanced optical transmission through sub-wavelength centered-polygonal hole arrays in silver thin film on silica substrate

Abstract

We numerically investigated the enhanced optical transmission through sub-wavelength centered-polygonal hole arrays (CPHA) in a thin Ag film deposited on the silica substrate. In octagonal and decagonal-CPHAs, we observed new hybrid transmission characteristics that were inherited from both crystalline and quasi-crystalline hole arrays. This peculiar nature was attributed to the unique arrangement of CPHAs which can be covered with copies of a single unit cell as in crystalline arrays, and their rotational symmetry as observed in quasi-crystalline arrays. Hybrid natures in CPHAs were further investigated in the transmission spectra and Fourier space representations of the arrays. Contributions from the nearest neighbor hole-to-hole distance to enhanced transmission were analyzed in order to quantify the plasmonic contributions from the Air/Ag interface and Silica/Ag interface. We also investigated the impact of layer structure, Air/Ag/Air versus Air/Ag/Silica in the transmissions and found that in CPHAs in Air/Ag/Silica structures, contributions from the Air/Ag interface became dominant in contrast to crystalline hole arrays with lower fold symmetry.

Synthesis of multifunctional plasmonic nanopillar array using soft thermal nanoimprint lithography for highly sensitive refractive index sensing

“…These results are consistent with those of previous reports. 33 According to the equations above, at normal incidence in a medium with a refractive index of 1.3 RIU, the wavelengths of SPP-BW(1.1) 1.3 , SPP-BW(1.0) 1.3 and WA (1.0) 1.3 are 387 ( peak 1), 549 ( peak 3), and 506 (dip 2) nm, respectively. These calculated wavelengths are in good agreement with the experimental ones, confirming that the peaks originate from the SPP-BWs at the liquid-metal interface and that dip 2 originates from WA(1.0) at the liquid-metal interface.…”

Simple analytical model to use in CAD tools for designing FSS devices: plasmonic transmission through hole arrays in thin films

“…In the long-wavelength limit, the study showed that the transmission coefficient depends on hole area, not shape. Also, in 2011, for thickness = 320 nm, transmission through subwavelength centered-polygonal hole arrays in silver film was numerically investigated, the study observed new hybrid transmission characteristics in octagonal and decagonal hole array [16]. Numerical modeling for nano-structured plasmonic surfaces is regularly performed with different techniques, such as wave concept iterative procedure (WCIP) [17], finite difference time domain (FDTD) [18], finite element method (FEM) [19] and hybrid FDTD/GSM [20,21].…”

Local rotational symmetry effects on Fano resonances with constant non-resonant transmission channel

“…7 Due to the important role played by the hole array in SPP excitation, intensive efforts have been devoted to investigating the effects of the geometric configuration of the hole array on the resonant transmission channel of Fano resonances in EOT. [8][9][10][11][12][13][14] However, it is a challenge to compare the resonant transmission channels directly between different geometric configurations while keeping both the non-resonant transmission channel and the Fano resonance peak wavelength unchanged. We also notice that previous research on Fano resonances in EOT mainly focuses on the visible 7,15 and terahertz 11,16 regimes.…”