Interface Edge Mode Confinement in Dielectric-Based Quasi-Periodic Photonic Crystal Structure

Abstract

In this paper, the localization of optical interface edge-states is analyzed for a dielectric material-based quasi-periodic photonic crystal (QPhC) structure. The design comprises a bilayer PhC structure, where layers are arranged in a Fibonacci configuration to introduce quasi-periodicity. The impact of local symmetric sub-structures on Eigenstate coupling is considered over a wider wavelength range. This confirms the localization of interface edge modes for different wavelengths at the structural local resonators, where the number of local resonators depends on the length of the QPhC. The proposed seven-element QPhC structure shows a strong Tamm-like top interface edge mode localization for a 45.04° incident angle at 750 nm operating wavelength, whereas a bulk interface guided mode is also excited for a higher incident angle of around 79°. The investigation facilitates the development of reconfigurable devices to excite both bulk interface and surface interface edge modes with improved field intensities for spectroscopy and sensing applications.