Figure 1

(a) A simple bilayer comprising a semiconducting slab of thickness \(h_1\) and relative permittivity \(\varepsilon _1\) as well as a metallic layer of thickness \(h_2\) and relative permittivity \(\varepsilon _2\). The structure is placed into a dense dielectric of relative permittivity \(\varepsilon\) and gets obliquely illuminated by a plane wave of light with wavelength \(\lambda\) that propagates along a direction making angle \(\theta\) with the normal direction. The setup is designed to host surface plasmon resonances regarding the magnetic field magnitude \(|\textbf{H}(z)|\) along the interface between the two media (\(z=0\)). (b) The variation of the decimal logarithm of the normalized propagation constant \(\log (\beta /k_0)\) across the map of the two permittivities \((\varepsilon _1,\varepsilon _2)\) of the used media. Lossless designs are considered (\(\textrm{Im}[\varepsilon _1]=\textrm{Im}[\varepsilon _2]=0\)).