Resonant transmission enhancement at one-dimensional metal gratings

Abstract

An analysis of phenomena leading to high transmission at a one-dimensional metal grating is presented. It is shown that high resonant transmission can be obtained either for thick or thin gratings for a wide range of filling factors and that the origins of the enhanced transmission are different in each case. We analyse the optical response of structures with subwavelength slits and of various thicknesses. The role of different pure (dielectric cavity modes, surface plasmon polaritons) and coupled resonances on the enhanced transmission is presented.

Explanation of extraordinary transmission on 1-D and 2-D metallic gratings

“…6 In fact, we have also contributed to partial explanation of this interesting phenomenon, [21][22][23] together with the application of our models to both fishnet metamaterial structures 24 and resonant studies in localized plasmonic nanostructures. 25 An attempt for a complex description has been given in, 26 where was shown that the resonances are importantly affected with the depth of a metallic film, and can be controlled via engineered combination of structural parameters. Clearly, in spite of active investigations of this topic, a well-established response to all EOT and accompanying effects issues is still missing.…”

“…Clearly, in spite of active investigations of this topic, a well-established response to all EOT and accompanying effects issues is still missing. Therefore, in this paper, inspired with the complex approach, such as in, 26 we performed our study in a similar complex manner.…”

Transmission and reflection properties of two-dimensional finite metal crystals

“…The wavelength dependence of dielectric function of silver was numerically fitted to the experimental data [13]. The wavelength range in the analysis is chosen to be within the range of low loss of silver and thereby the field-structure interactions could be analysed with use of Drude model as well [14]. Reflection or transmission coefficients are calculated as the ratio of the field components -of the real power carried by the reflected or transmitted wave normal to the boundary -to the corresponding component of the real power associated with the incident wave [15].…”

“…These resonances are excited between the gratings in the structure [21] and are shifted spectrally to longer wavelengths with increasing thickness of d (the transmission maximum for configuration with d = 60 nm indicates in fact the first Fabry-Perot resonance). The cavity modes accumulate energy in the near field, leading to enhanced absorption (10-15%), apparent as a high field intensity inside crystal structure [14].…”

Origin of the positional offset of FP-like enhanced transmission peaks in a one-dimensional gold grating

“…Up to now, two physical mechanisms have been widely accepted to account for the ET phenomenon: the excitation of surface plasmons (SPs) [1][2][3][4] (or spoof surface plasmons [SSPs] [5] in the long wavelength range) and the Fabry-Perot (FP) resonances [6,7]. In the thin grating limit (h ( k), excitation of plasmons dominates the transmission of light, whereas for an optically thick grating both mechanisms contribute to the ET [8,9]. For FP-like resonant peaks arising in the transmission spectrum of an optically thick grating, their positions have offsets from the simple FP prediction, k FP;t ¼ 2n g h=m; m ¼ 1; 2; 3 Á Á Á, where n g is the refractive index of the material in the slit and h is grating thickness.…”