Plasmonic waveguide ring resonator at terahertz frequencies

The authors theoretically demonstrate a plasmonic waveguide ring resonator (WRR) working at terahertz frequencies considering that surface plasmon polaritons (SPPs) can effectively propagate on bended plasmonic waveguides with dielectric claddings possessing high refractive index. A free spectral region of 110GHz has been achieved by decreasing ring radius of the WRR, which could be much smaller than the operating wavelength. By introducing dielectric and plasmonic waveguides at both sides of the resonant ring, respectively, SPPs can be efficiently excited at the output of the WRR through mode coupling. The plasmonic WRRs may find great applications in the integration of terahertz generation and control platform.