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 explore temporal dynamics of charge transfer plasmon (CTP) resonances. By fitting scattering curves and near-field oscillations, we determine the dephasing time of CTP modes in conductively connected gold nanodisk dimers. We show that, compared with the well-known particle plasmon and dimer plasmon modes, the CTP mode has a narrow spectral width and longer lifetime. Moreover, quantitative analysis of optical near-fields reveals that CTP modes oscillate completely out-of-phase with the particle plasmon and dimer plasmon modes. The dephasing time, near-field decay rate and charge transfer time of the 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.