세미나 및 강연

Abstract:

Terahertz (THz) radiation is electromagnetic radiation whose frequency lies between the microwave and infrared regions of the spectrum. Because of technical difficulties involved in making efficient and compact THz source and detector, the THz band being called the “THz gap”. This technological gap has been rapidly diminishing for the last two decades. In recent years, there has been increased interest in understanding the guided-wave propagation of THz radiation and efficient broadband coupling between guiding and freely propagating THz waves. THz waveguides for single-mode coupling, such as circular and rectangular metals, coplanar and single metal wires, coaxial cables, and parallel-plate waveguides (PPWGs) have been demonstrated. Among these waveguides, PPWG has been used in spectroscopy, sensing, and Bragg resonances. All these PPWG applications have used the transverse-electromagnetic (TEM) mode, which offers many advantages such as very low absorption, negligible group-velocity dispersion, and no cutoff frequency. Especially, Bragg and non-Bragg band gaps studies were carried out by using metal slit arrays positioned at the center of the air gaps in tapered parallel-plate waveguides. In this presentation, I will show experimental studies on THz time-domain spectroscopy and THz propagation using the several PPWGs.