Figure 5.

Contour plot of Q _sca for graphene coated cylinders illuminated by a TE^z-polarized plane wave, when (a) The chemical potential μ is varied, keeping ε _d = 3.9 and R = 0.5 μm, and (b) the permittivity ε _d of the dielectric core varies and the environment medium has a dielectric constant ε = 1, maintaining fixed R = 0.5 μm and μ = 0.5 eV. We also represent the curve of resonance given by Eq. (7) in dot-dashed line, and the invisibility condition of Eq. (8) drawn in dashed line, when the external medium has a permittivity ε = 1 (in black) and, for comparison, when ε = 4 (in yellow).