Plasmonic cloaking of cylinders: finite length, oblique illumination and cross-polarization coupling

Metamaterial cloaking has been proposed and studied in recent years by following several interesting approaches. One of them, the scattering-cancelation technique or plasmonic cloaking, exploits the plasmonic effects of suitably designed thin homogeneous metamaterial covers to drastically suppress the scattering of moderately sized objects within specific frequency ranges of interest. In addition to its inherent simplicity, this technique also holds the promise of an isotropic response and weak polarization dependence. Its theory has been applied extensively to symmetrical geometries and canonical three-dimensional (3D) shapes, but the application of it to elongated objects has not been explored with the same level of detail. We derive here closed-form theoretical formulae for infinitely long cylinders under arbitrary wave incidence, and validate their performance with full-wave numerical simulations, also considering the effects of finite lengths and truncation effects in cylindrical objects. In particular, we find that a single isotropic (idealized) cloaking layer may successfully suppress the dominant scattering coefficients of moderately thin elongated objects, even for finite lengths comparable with the incident wavelength, providing weak dependence on the incidence angle. These results may pave the way for application of plasmonic cloaking in a variety of practical scenarios of interest.