Abstract
Unidirectional scattering from circularly polarised dipoles has been demonstrated in near-field optics, where the quantum spin-Hall effect of light translates into spin-momentum locking. By considering the whole electromagnetic field, instead of its spin component alone, near-field directionality can be achieved beyond spin-momentum locking. This unveils the existence of the Janus dipole, with side-dependent topologically protected coupling to waveguides, and reveals the near-field directionality of Huygens' dipoles, generalising Kerker's condition. Circular dipoles, together with Huygens' and Janus sources, form the complete set of all possible directional dipolar sources in far- and near-field. This allows designing of directional emission, scattering and waveguiding, fundamental for quantum optical technology, integrated nanophotonics and new metasurface designs.
| Original language | English |
|---|---|
| Article number | 117402 |
| Pages (from-to) | 117402-1-117402-6 |
| Journal | Physical Review Letters |
| Volume | 120 |
| Issue number | 11 |
| Early online date | 15 Mar 2018 |
| DOIs | |
| Publication status | Published - 16 Mar 2018 |