Optical energy optimization at the nanoscale by near-field interference

Employing plasmonic antennas for subdiffraction focusing of light on recording media requires to take into account the complete structure of the medium, including dielectric cover layers. We find, with finite difference time domain simulations, that optical energy transfer to the magnetic recording layer is most efficient for an off-resonant antenna. Furthermore, we show that the focal spot in the magnetic film is well below the diffraction limit, making nanoscale all-optical magnetic data recording achievable. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4733292]