Understanding photoluminescence of coupled metallic nanostructures based on a coupling classic harmonic oscillator model

Photoluminescence (PL) phenomenon from metallic nanostructures has been explained and understood by several point of views. One of them is based on the classic harmonic oscillator model, which describes PL of single mode. In this study, we continue to expand this classic model to a coupling case, which involves two oscillators that interact with each other together with the excitation electric field. The new generated modes due to the coupling are carefully analyzed, including their behaviors varying with the coupling coefficients in different cases. Furthermore, for practical purpose, PL spectra and white light scattering spectra of two individual metallic nanostuctures are calculated as examples employing the model to verify its validity. This work would give a deeper understanding on coupling PL phenomena and is helpful to relative applications.