The electromagnetic field scattered by nano-objects contains a broad range of wavevectors and can be efficiently coupled to waveguided modes.The dominant contribution to scattering from subwavelength dielectric and pl...The electromagnetic field scattered by nano-objects contains a broad range of wavevectors 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.展开更多
基金supported by European Research Council Starting Grant ERC-2016-STG-714151-PSINFONI,EPSRC(UK)ERC iCOMM project(789340)support from the Royal Society and the Wolfson Foundation.
文摘The electromagnetic field scattered by nano-objects contains a broad range of wavevectors 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.
