In a new article published in ACS Nano, working with Dr Valentin Flauraud and Dr Frank Demming-Janssen, LSME scientist Dr Duncan Alexander uses advanced electron spectroscopy and finite element simulations to analyse the spatial and spectral signatures of different optical excitations supported in patterned silicon photonic nanocavities. By sampling nanocavities of different shapes and sizes, the work demonstrates the ability of electron energy-loss spectroscopy (EELS) to map the photonic eigenmodes in the near-field, with a high degree of precision and subtlety in the spatial–spectral domain. It further connects the results to key eigenmodes of interest for engineering the scattering of light, and contrasts the dielectric nanocavity response to that of the better known case of EELS mapping of localised surface plasmon resonances
