Generating optical orbital angular momentum at visible wavelengths using a plasmonic metasurface

Abstract Light beams with a helical phase-front possess orbital angular momentum along their direction of propagation in addition to the spin angular momentum that describes their polarisation. Until recently, it was thought that these two ‘rotational’ motions of light were largely independent and could not be coupled during light–matter interactions. However, it is now known that interactions with carefully designed complex media can result in spin-to-orbit coupling, where a change of the spin angular momentum will modify the orbital angular momentum and vice versa . In this work, we propose and demonstrate that the birefringence of plasmonic nanostructures can be wielded to transform circularly polarised…

• CE
  Canada Excellence Research Chairs, Government of Canada
• DA
  Defense Advanced Research Projects Agency