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Observation of optical spin symmetry breaking in nanoapertures


  Yuri Gorodetski  ,  Nir Shitrit  ,  Itay Bretner  ,  Vladimir Kleiner   ,  Erez Hasman  
 Micro and Nanooptics Laboratory, Faculty of mechanical engineering, and Russell Berrie Nanotechnology Institute, Technion – Israel Institute of Technology,

Plasmonic systems have been shown to be resonantly excited when the linear momentum selection rule is fulfilled. However, conservation of total angular momentum (AM) in a closed physical system results in additional selection rules related to AM. The AM of an optical beam comprises the intrinsic component – the spin, associated with the handedness of the circular polarization, and the extrinsic component – orbital AM (OAM), associated with a spiral phase front2. Here, we demonstrate a plasmonic nanostructure which exhibits a crucial role of an AM selection rule in a light-surface plasmon scattering process1,2. In our experiment, the intrinsic AM of the incident radiation is coupled to the extrinsic momentum of the surface plasmons via spin-orbit interaction, which is manifested by a geometric Berry phase1-5. Due to this effect, we achieved a symmetry breaking resulting in a spin-dependent enhanced transmission through coaxial nanoapertures even in rotationally symmetric structures5.

 

References

  1. K. Y. Bliokh, Y. Gorodetski, V. Kleiner and E. Hasman, Phys. Rev. Lett. 101, 030404 (2008).
  2. Y. Gorodetski, A. Niv, V. Kleiner, and E. Hasman, Phys. Rev. Lett. 101, 043903 (2008).
  3. A. Niv, Y. Gorodetski, V. Kleiner, and E. Hasman, Opt. Lett. 33, 2910 (2008).
  4. K. Y. Bliokh, A. Niv, V. Kleiner, and E. Hasman, Nature Photon. 2, 748 (2008).
  5. Y. Gorodetski, N. Shitrit, I. Bretner, V. Kleiner, and E. Hasman, Nano Lett. 9, 3016 (2009); Research Highlights, Nature Mater. 8, 612 (2009).