Experimental demonstration of linear and spinning Janus dipoles for polarisation- and wavelength-selective near-field coupling

Michela Picardi, Martin Neugebauer, Joerg Eismann, Gerd Leuchs, Peter Banzer, Francisco Jose Rodriguez Fortuno, Anatoly Zayats

Research output: Contribution to journalLetterpeer-review

39 Citations (Scopus)

Abstract

The electromagnetic field scattered by nano-objects contains a broad range of wave vectors and can be efficiently coupled to waveguided modes. The dominant contribution to scattering from subwavelength dielectric and plasmonic nanoparticles is determined by electric and magnetic dipolar responses. Here, we experimentally demonstrate spectral and phase selective excitation of Janus dipoles, sources with electric and magnetic dipoles oscillating out of phase, in order to control near-field interference and directional coupling to waveguides. We show that by controlling the polarisation state of the dipolar excitations and the excitation wavelength to adjust their relative contributions, directionality and coupling strength can be fully tuned. Furthermore, we introduce a novel spinning Janus dipole featuring cylindrical symmetry in the near and far field, which results in either omnidirectional coupling or noncoupling. Controlling the propagation of guided light waves via fast and robust near-field interference between polarisation components of a source is required in many applications in nanophotonics and quantum optics.
Original languageEnglish
Article number52
JournalLight: Science & Applications
Volume8
Issue number1
DOIs
Publication statusPublished - 5 Jun 2019

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