Abstract

The usage of magnetic field of terahertz (THz) wave provides novel means to control spin dynamics in ultrafast time scales [1, 2]. While previous studies revealed coherent spin dynamics in linear or small perturbation regime, much more drastic change of the permanent magnetic order is expected under stronger excitation fluence [3, 4]. For this purpose, tight focusing effect of THz waves in plasmonic waveguide is quite useful for enhancing the available magnetic fields [5]. In this paper, we report on the direct enhancement of terahertz magnetic near-field amplitude in a tapered waveguide, observed by the magneto-optic sampling in a double split-ring resonator (D-SRR) coupled Tb3Ga5O12 (TGG) crystal.

© 2016 Japan Society of Applied Physics, Optical Society of America