Terahertz near-field imaging using a Y splitter and Sommerfeld wire waves on bare metal rods

We describe a near-field experiment using a Y splitter supporting cw THz Sommerfeld wire modes coupled and decoupled with differential phase plates. Owing to a taper up to ~50 μm of one of the Y ends, a near-field imaging resolution of ~90 μm is demonstrated in agreement with calculations.