A comparison study of the born-kuhn model and the finite-difference-time-domain calculations on stacked plasmonic nanorods

Abstract

Abstract A detailed analysis of the Born-Kuhn (BK) model for two coupled oscillators and comparison to the chiral optical properties of the corner-stacked plasmonic nanorods (CSPNs) have been investigated. Based on the normalized coupling constant c (= coupling frequency ω c /resonance frequency ω 0 ) and the damping constant g (= dissipation γ/ ω 0 ), the chiral optical response of the BK model could be significantly different, and the c-g space can be divided into two phase regions, a weak coupling and a strong coupling region. Once the c and g parameters are extracted from CSPN structures based on finite-difference time domain (FDTD) calculations, the BK model can be directly applied to predict the chiral plasmonic response of the CSPNs. In particularly, at c = g , the BK model suggests the strongest optical rotation dispersion while stronger circular dichroism occurs with a small g and a large c. These predictions have been confirmed by the FDTD calculations of CSPN structures. The detailed analysis of the BK model and the use of the model to direct fit the optical property of CSPNs demonstrate that the BK model is a very versatile class model to predict the chiral response of a chiral plasmonic structure or help to design and optimize a specific chiral plasmonic structure for a specific application.