Spintronic terahertz emission from a Ni/Pt bilayer film with a spoof surface plasmonic structure
A spintronic terahertz (THz) emitter with one-dimensional metal line structures at the THz output side was fabricated. The spintronic THz emitter consists of nanometer-thick Ni/Pt bilayer films grown by electron beam deposition, and the metal line structures consist of an array of micron-width Au metal lines fabricated using UV photolithography and resistive evaporation process. Using THz time-domain spectroscopy, a three-fold increase in the THz signal amplitude (ten-fold increase in the integrated THz power) was measured from the spintronic THz emitter coupled with the metal line array compared with the bare spintronic THz emitter. The enhancement is attributed to an extraordinary transmission resulting from spoof surface plasmon resonance. The excitation power dependence of the spintronic THz emission was also investigated.