Tunneling rectification in ring shaped nanogaps

Abstract

In this work, we show a ring-shaped metallic nanogap exposed to electromagnetic fields to manipulate ultrafast tunneling electrons. Eddy currents induced by incoming terahertz pulses project upon the ring, changing the local potentials in vectorial way. Contour-integrated along the perimeter of the ring, the total tunneling currents are critically dependent upon the ring shape. Furthermore, the spatiotemporal dynamics of the fully rectified terahertz pulses can be visualized by the femtosecond optical pulses.