Theoretical insights into charge transfer plasmon lifetime

In this Letter, we present a theoretical study based on the Lorentz function and harmonic oscillator model to describe the temporal dynamics of charge transfer plasmon (CTP) resonances. By fitting the scattering curves and near-field oscillations, we determine the dephasing time of charge transfer plasmons in conductively connected gold nanodisk dimers. We show that compared with the well-known particle plasmon and dimer plasmon modes, charge transfer plasmon mode has narrow spectral width and longer lifetime. Moreover, quantitative analyses of optical near-fields reveal that charge transfer plasmon modes show completely out-of-phase oscillation with the particle plasmon and dimer plasmon modes. The dephasing time, near-field decay rate and charge transfer time of CTP mode are found to be on a few femtosecond timescales, implying that conductively connected plasmonic nanoparticles hold great promise as channels for ultrafast transfer of information in all-optical computing and optoelectronic devices.