Multiple surface‐plasmon‐polariton waves localized to a metallic defect layer in a sculptured nematic thin film

Abstract

The propagation of a surface‐plasmon‐polariton (SPP) wave guided by a thin metallic defect layer in a sculptured nematic thin film (SNTF) – a periodically nonhomogeneous, anisotropic, dielectric material – was studied theoretically. If the defect layer is sufficiently thick, SPP waves propagate independently along the two metal/SNTF interfaces formed by the presence of the defect layer in the SNTF. As the thickness of the defect layer is reduced, SPP wave propagation is modified by the coupling of the two interfaces. The number of SPP waves increases and lower attenuation rates along the direction of propagation become possible.magnified image(© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Surface plasmon–polariton wave propagation guided by a metal slab in a sculptured nematic thin film

“…Pursuing this line of thinking, we decided to solve the canonical problem of wave propagation localized to a sufficiently thin metallic slab inserted in an SNTF. As our supposition was confirmed in a preliminary study [29], we conducted a full-scale investigation, the details and the results of which are reported here. In Sec.…”

“…The skin depth of aluminum at the chosen wavelength is ∆ met = Im k 0 √ ε met −1 = 13.24 nm, a quantity of interest in relation to the thickness of the metal slab. The SNTF was chosen to be made of titanium oxide [29,32], with…”

“…Thus, there is sufficient flexibility in the formulation with respect to the twist γ + − γ − of the two morphologically significant planes. Note that γ + = γ − in our preliminary report [29], but that restriction was removed for the full-scale investigations reported here. Without loss of generality, let us choose the direction of SPP-wave propagation in the xy plane to be parallel to the x axis.…”

“…γ − = γ +Let us begin with the case when the morphologically significant planes of the SNTF on both sides of the metal slab are aligned with each other and make an angle γ − = γ + with respect to the direction of SPP-wave propagation in the xy plane. This case had been briefly studied in a predecessor communication[29], but is now discussed in detail.The real and imaginary parts of κ/k 0 which satisfies Eq. (25) are presented in Fig.…”

Compound guided waves that mix characteristics of surface-plasmon-polariton, Tamm, Dyakonov–Tamm, and Uller–Zenneck waves

“…We found that a multiplicity of CGWs with plasmonic and polaritonic constituents can propagate bound to both metal/dielectric interfaces with energy distributed in both the dielectric materials if the metal layer is sufficiently thin. Long-range CGWs are also guided by a thin metal layer inserted in a periodically non-homogeneous anisotropic material such that the direction of non-homogeneity is the same as the thickness direction of the metal film [35] with non-homogeneity on the wavelength scale; furthermore, CGWs resembling Dyakonov-Tamm waves in their characteristics are guided, if the sandwiched metal is replaced by an isotropic dielectric material [36]. Finally, CGWs that fuse together the characteristics of SPP waves and Dyakonov waves have been theoretically shown to excited via a uniaxial dielectric layer inserted between a HID material and a metal [37].…”