Cross-Diabolo Nanoantenna for Localizing and Enhancing Magnetic Field With Arbitrary Polarization

A nanoantenna that consists of a pair of perpendicular diabolo metal elements with a common central junction is proposed for creating magnetic field enhancement. It is shown that such a nanoantenna can generate a single magnetic hot spot for any polarization state in near-infrared frequency range, strongly confining and enhancing magnetic field under less restrained conditions. The magnetic spectral response of the nanoantenna can be tailored as will by altering its geometric parameters. Moreover, this cross-diabolo nanoantenna can preserve the polarization character of any in-plane dipole in the far-field patterns with high fidelity.