Observing the Sub-Femtosecond Dynamics of Plasmonic Bragg Reflectors by Time-Resolved Photoemission Electron Microscopy

摘要

The estimation of electric field amplitudes of surface plasmon polaritons, or at least ratios of field amplitudes, can be cumbersome if they need to be determined from time-resolved photoemission electron microscopy mea-surements. We discuss a Fourier-based strategy for the data analysis of two-photon photoemission electron microscopy images that adresses this issue and allows distinguishing surface plasmon polariton pulses that overlap in space but propagate in different directions. The Fourier-based strategy is applied to determine the coefficients of transmission and reflection of plasmonic Bragg reflectors. The reflection coefficient increases with the number of reflector grooves. Our work demonstrates that 2PPE-PEEM can be routinely used to quantitatively analyze the performance of plasmonic Bragg reflectors.