Fig. 3. Simulation of the near-field distribution of polaritons launched by a dipole source in a conductivity sheet.

The conductivity was obtained from Eq. (2) with $k_{\mathrm{p}}$ = 0.55 + 0.17i μm⁻¹. a Dipole source is located far away from edges. b Dipole source is located at the sheet edge. The lower panels show the electric field along the horizontal red dashed line in upper panel (red data). The black lines of the lower panels show fits according to a radially propagating damped wave, $\mathrm{Re}\left[A{e}^{i{k}_{\mathrm{p}}x}/\sqrt{x}\right]$. The height of the dipole above the sheet is 1.5 μm and the electric field was calculated in a height of 200 nm.