Novel Techniques of Terahertz Spectroscopy and Imaging

Abstract

Terahertz (THz) spectroscopy and imaging has been developed mainly based on THz time-domain spectroscopy (THz-TDS) using ultra-fast pulse lasers. Though THz-TDS is unique approach especially for the evaluation of physical properties of various kinds of materials, it is often pointed that the sensitivity and spatial resolution are not enough. In order to improve such insufficiencies, we developed near-field THz emitting spectroscopy imaging system. Fabrication of metamaterials and optimization of their structure provide higher sensitivity. By using ultra-thin film made of polydimethyl siloxane (PDMS) fabricated microflow channels stuck on GaAs as a THz emitter, a calibration curve was obtained for D-glucose solution in the concentration range lower than 0.5 M. This novel technique is expected to acquire physical properties for various kinds of liquid including biological samples, which were difficult to be evaluated by the conventional THz measurements.