Multiple trains of same-color surface plasmon-polaritons guided by the planar interface of a metal and a sculptured nematic thin film

A sculptured nematic thin film (SNTF) is an assembly of parallel nanowires that are shaped in a fixed plane orthogonal to the substrate on which the film is deposited. The absorbance, reflectance, and transmittance of a linearly polarized, obliquely incident plane wave were calculated for a planar metal/SNTF interface in the Kretschmann configuration, the wave vector of the plane wave lying wholly in the morphologically significant plane of the SNTF. The permittivity profile of the chosen SNTF was supposed to have been sculptured during physical vapor deposition by varying the vapor incidence angle sinusoidally about a mean value. Calculations revealed that (i) multiple surface-plasmon-polariton (SPP) trains of the same color can be independently guided by the metal/SNTF interface, (ii) not all SPP trains have to be co-propagating, and (iii) not all SPP trains have to be of the same linear polarization state. As different SPP trains move with different speeds, guided by the interface, exciting prospects emerge for error-free sensing and plasmonics-based communication.