Tuning Triangular Prism Dimer into Fano Resonance for Plasmonic Sensor

We theoretically investigate the plasmonic Fano resonance in a triangular nanoprism dimer. By adjusting the geometry parameters, we have observed a Fano line shape in the scattering spectra, which is induced by the competence of bonding and antibonding modes in the triangular nanoprism dimer. The Fano line shape can be well described by a theoretical model of two harmonic oscillators. A figure of merit value as high as 16.1 is achieved in the triangular nanoprism dimer, which is caused by the Fano resonance. The electric field at the corner of the triangular prisms is the highest among the circular cylinder dimer and square rod dimmers, which shows that the triangular prism dimer is more suitable for the detection of biomolecules. The triangular prism dimer may also used in plasmonic circuits.