Thermally Control of Light Propagation in Plasmonics Waveguide and Filter

Abstract

An active ultra-compact plasmonic waveguide composed of a subwavelength slit and perforated in vanadium dioxide (VO 2 ) followed by a metallic layer is proposed and numerically analyzed. Refractive index variation of VO 2 by external stimuli provides a feasible way for tuning the optical properties of the waveguide. Varying the refractive index of VO 2 corresponds with changing the phase of VO 2 to the metallic state (“on” state). Consequently, the entire structure becomes a typical metal–insulator–metal (MIM) waveguide that routes the incident light through the slit. In addition, during the “off” state, the incident light thereby propagates in the slit and VO 2 medium and mitigates rapidly. By adding a MIM waveguide attached to the Fabry–Perot (FP) cavity, spectrally wide stopband and passband filtering features in telecommunication frequency regime are demonstrated. Tailoring the resonance wavelength can be performed through the geometrical parameters. Such active plasmonic waveguides with high transmission, coupling, and compact size can be utilized in future fully integrated all plasmonic chip technology.