Longitudinal shift in coupled nanobeams and mode degeneracy

Abstract

Coupled modes of two nanobeams brought together are shown to have pronounced frequency dependence on a spatial displacement of the resonators, while the quality factor of the coupled modes preserves the same order of magnitude as that of a single nanobeam. Both a longitudinal shift and transversal displacement of nanobeams with respect to each other are under investigation. We show that the mode degeneracy occurs at the longitudinal shift of about a half a modified lattice constant in the center of the defect region. To perform eigenmode analysis of the coupled system we used a 3D finite-difference frequency-domain method and a 48 Gb station.