Tapered Sommerfeld wire terahertz near-field imaging

摘要

We explore the potential of tapered Sommerfeld wire waveguides for terahertz near-field imaging. The electric field confinement in the vicinity of the tapered wire tip is exploited to achieve subwavelength resolution. After coupling onto the Sommerfeld wire, terahertz pulses propagate as surface-plasmon waves along the waveguide and subsequently reflect at the imaging target surface. The reflected signal is then detected at the waveguide surface using a freestanding photoconductive terahertz probe. The resolution achieved is on the order of the tip diameter. This subwavelength resolution is demonstrated in a proof-of-principle experiment.