Friday, April 27, 2018

Abstract-Surface plasmon-mediated nanoscale localization of laser-driven sub-THz spin dynamics in magnetic dielectrics

Alexander Chekhov, Alexander I. Stognij, T. Satoh, Tatiana V. Murzina, I. Razdolski, Andrzej Stupakiewicz,

We report spatial localization of the effective magnetic field generated via the inverse Faraday effect employing surface plasmon polaritons (SPPs) at a hybrid Au/rare-earth iron garnet interface. Analyzing, both numerically and analytically, the electric field of the SPPs at a hybrid interface, we corroborate our study with a proof-of-concept experiment showing efficient SPP-driven excitation of coherent spin precession with a 0.41 THz frequency. We argue that the sub-diffractional confinement of the SPP electric field enables strong spatial localization of the SPP-mediated excitation of spin dynamics. We demonstrate a two orders of magnitude enhancement of the excitation efficiency at the surface plasmon resonance within a 100 nm layer of a dielectric garnet. Our findings broaden the horizons of ultrafast spin-plasmonics and open pathways towards non-thermal opto-magnetic recording on the nanoscale.

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