Controllable Dual Hybrid Tamm Plasmon Modes in Binary Gold Nanodisk Arrays and Distributed Bragg Reflector Structure

Optical Tamm plasmon (TP) can be excited at the boundary of photonic crystal and metal film. In this work, we propose a composite structure consisting of binary Au nanodisk arrays on top of a distributed Bragg reflector (DBR) of TiO₂/SiO₂ 1D photonic crystal; the structure supports the confined dual hybrid TP modes that benefited from the excitation of a localized lattice collective resonance on the vicinity of the nanoparticles array. The hybrid TP modes possess enhanced confinement, controllable hybrid TP frequency, and broadened spectral width compared with that of TP mode within the gold film/DBR structure. Moreover, the hybrid TP mode that due to the in-phased localized lattice resonance is dominated when the nanodisk radius increases, while the hybrid TP mode resulted from weak coupling of in-phased and anti-phased localized lattice resonance is weakened, especially when the radii of binary arrays approach identical. Thus, the tunable dual confined TP states can be realized through adjusting the arrays radii rather than changing the properties of DBR. Importantly, the enhancement of confined hybrid TP modes with controllable resonant frequency has a potential application in perfect absorption.