Efficiency Enhancement of Scattering Near-Field Probes

We measure, for the first time, the scattering efficiency of resonant terahertz (THz) probes for scattering-type THz near-field microscopy. We fabricate the probes by placing an indium `antenna' directly on the tine of a quartz tuning fork (QTF), which we use as an atomic force microscope (AFM) probe in tapping mode. THz time-domain spectroscopy (TDS) of the THz field scattered from the probe shows that the scattering efficiency of the indium antenna exhibits resonant enhancement determined by the antenna length. These resonant scattering probes can enable THz near-field imaging applications where THz contrast is weak, such as 2D materials or biological systems.