Talk given by Mikko Kataja @EMRS Fall Meeeting, Magnetoplasmonics

Phase-matching conditions are exploited to enable nonreciprocal optical propagation and enhanced magneto-optic responses in magnetoplasmonic systems [1]. Here we show that exploiting diffraction in conjunction with plasmon excitations adds further versatility and flexibility in the design of photonic systems. As a testbed we analysed transverse magneto-optic Kerr (TMOKE) responses in magnetoplasmonic gratings etched into gold/cobalt multilayers [2]. The grating coupler was chosen as the simplest system where we can combine the three distinct phenomena: magneto-optics, diffraction and plasmonics. Angular resolved measurements revealed narrow line-shape plasmon resonances, enabling large diffracted magneto-optical intensity effects. We show that exploiting diffraction in magnetoplasmonic crystals allows unexpectedly large TMOKE responses above that exceed 3% – one of order of magnitude larger than conventional TMOKE. Our results pave the way towards using magneto-optical modulation of SPPs to build non-reciprocal, active photonic components. We anticipate that our results can be used to design more complex diffractive surfaces, such as plasmonic metasurfaces, with the objective to enable creation of novel non-reciprocal photonic devices. [1] V. I. Belotelov et al., Nat.Nanotechnol. 6, 370 (2011). [2] R. Cichelero et al., submitted.