In this article, a novel design of a dielectric vein type zero-index metamaterial (ZIM) has been proposed, which can be made to operate for any of the two polarisations (transverse electric (TE) or transverse magnetic (TM)) by specifically choosing the geometrical parameters. The zero-index behaviour of the metamaterial is due the linear dispersion and existence of Dirac point at the center of the Brillouin zone. Although, ZIM sturctures comprising periodic arrays of rods-in-air and holes-in-dielectric have already been proposed, their zero-index property is restricted to TM and TE polarization, respectively. However, the structure proposed in this articles exhibits effectively zero refractive index in the TM as well as the TE mode, and hence, has an upper hand over existing dielectric ZIM structures.

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In this article, a highly directive all-dielectric zero-index metamaterial (ZIM) based nanoantenna has been proposed which has the ability to directionally transmit the radiation from an isotropic quantum emitter. The zero-index metamaterial (ZIM) used here, is basically a rods-in-air type photonic crystal, which exhibits zero-index behaviour owing to the existence of a Dirac-cone at the Gamma (Γ) point in its photonic band structure. The emitter is embedded inside the ZIM and the radiation pattern can be controlled by varying the shape and size of the array.