A Nano-scale Fabry-perot Interferometer Using Channel Plasmon-polaritons in Triangular Metallic Grooves

In this letter, we demonstrate the possibility of an effective nano-scale FabryPerot interferometer in a sub-wavelength plasmonic waveguide in the form of a triangular groove on a metal surface, guiding channel plasmon-polaritons (CPPs). The resonant cavity is formed by two semitransparent metal membranes (mirrors) placed into the groove. Effective filtering effect of the cavity is demonstrated, resulting in single-mode output from the cavity. Typical quality factor for the cavity of the resonant length is determined to be Q ~ 100 for the silver-vacuum structure with the 30 groove angle. Possible ways of increasing this factor are discussed.