Erratum: Highly Subwavelength, Superdirective Cylindrical Nanoantenna (Physical Review Letters (2018) 120 (237401): DOI: 10.1103/PhysRevLett.120.237401)

A superdirective cylindrical nanoantenna is demonstrated with a multilayered cylindrical metamaterial-inspired structure. Targeting specific scattering coefficients for the dipole and higher-order modes, the ideal limit of needle radiation is demonstrated. A five-layer system is optimized to demonstrate its approach to the theoretical directivity bound. While the resulting structure is scalable to any frequency regime, its highly subwavelength overall size takes advantage of combinations of positive and negative permittivity materials in the optical regime.