Nanoscale Fabry–Pérot Interferometer using channel plasmon-polaritons in triangular metallic grooves

In this letter, we demonstrate the possibility of an effective nano-scale Fabry-Perot 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 o groove angle. Possible ways of increasing this factor are discussed. 1 1 A major current problem in modern photonics is the diffraction limit of light [1-3] that does not allow localization of electromagnetic waves in regions noticeably smaller than half the wavelength in the structure. This results in a much lower level of integration and miniaturization of optical devices, compared to that achieved in modern