Temporal dynamics of strongly coupled epsilon near-zero plasmonic systems

Abstract

Subwavelength epsilon-near-zero (ENZ) films with decorated nanoantennae are an emerging platform for coupling radiation into the ENZ mode: recent experiments have shown how strong coupling between the two systems underpins significant nonlinear effects. Field enhancement and the temporal dynamic of the radiation in ENZ films strongly coupled with plasmonic antennae play a substantial role in the light–matter interaction, and the latter has not yet been fully disclosed. We numerically investigate the pulse shaping of radiation impinging on two representative strongly coupled systems: a transparent conductive oxide with ENZ in the NIR band (ITO) and a polar material with ENZ in the MIR (SiC). In both cases, we demonstrate that the temporal dynamics and field enhancement are particularly pronounced within the strong coupling region, and we highlight the different polarization responses of the ITO-based case from the SiC one. The latter, owing to lower losses, shows extreme reshaping of resonant radiation close to the ENZ spectral region and is, therefore, a promising candidate for slow-light-enhanced effects.