Microfabricated scanning near-field probe for sub-terahertz spectroscopy

Abstract

This paper reports design, fabrication and evaluation of a novel scanning near-field probe for terahertz (THz) local time domain spectroscopy (THz-TDS). A microfabricated scanning near-field optical microscopy (SNOM) probe was assembled with a low-temperature-grown gallium arsenide (LT-GaAs) photoconductive antenna. The probe structure was evaluated and determined by a finite-difference time-domain (FDTD) numerical simulation. The assembly was used as the THz emitter and local THz source. Another LT-GaAs antenna situated at the opposite side was used as the detector. A THz-TDS measurement using the microfabricated SNOM probe and photoconductive antenna was performed.