Mode Regulation of Terahertz Waves Based on Periodically Corrugated Metallic Tubes

Here, we propose a special type of wall corrugations of metallic waveguides to realize mode regulation in bandgaps. The selected tube structures result in the transparency of forbidden bands to the high-order transverse mode. Complex interactions between guided wave modes attenuate all undesired modes and enhance the development of the left perfect one. The numerical simulations show that a single high-order mode can be generated efficiently in the stop band and a special terahertz beam can be obtained with wanted transverse distributions of electromagnetic fields. In addition, the proposed mode interactions can offer potential applications to the future terahertz devices.