Investigating ultrafast system dynamics at the nanoscale by photoemission electron microscopy (Conference Presentation)

To disentangle the ultrafast dynamics of individual system constituents at the nanoscale we combine photoemission electron microscopy, providing a resolution of ~3 nm, and a 1 MHz NOPA (20 fs pulse duration, tunable from 215 to 970 nm). Specifically, I will focus on a two-pulse experiment in which we detect subtle differences in the local field evolution of individual hot-spots within a plasmonic nanoslit resonator. By using the concept of quasinormal modes we explain these local differences by crosstalk of adjacent resonator modes.[1] Moreover, I will present first results about selecting specific excitation pathways, described by double-sided Feynman diagrams, within single systems using phase-cycled three-pulse sequences, which are provided by a home-built LCD pulse shaper. We aim at adding nanoscale resolution to the well-established method of coherent multidimensional spectroscopy. [1] M. Hensen et al., Nano Lett. 19, 4651-4658 (2019)