Terahertz mode selector based on multimode resonances in corrugated waveguides

Abstract

We propose a magnetically switchable terahertz (THz) mode selector based on four transverse mode resonances in corrugated waveguides. The theoretical and numerical results show that two passbands can be obtained in the transmission spectra around the resonance points. The passband of 0.9611–1.0006 THz outputs a single second-order transverse mode with the highest ratio of 99.03% while the passband of 0.8712–0.9111 THz contains the multiple transverse mode output with the first two modes. A tunable THz mode selector with frequency band of 0.5572–0.5926 THz is realized by filling the waveguide core with a liquid crystal (E7). The widest working frequency range of the mode selector reaches 28.4 GHz when the molecular steering angle θ lies between 71.22° and 90°.