Speaker
Description
Quasiparticle interactions in low-dimensional and hybrid materials give rise to optical phenomena that do not exist in their isolated constituents. By coupling excitons, plasmons, phonons, and quantum emitters within engineered nanostructures, new opportunities emerge for controlling light–matter interactions, long-range energy transfer, and quantum coherence at the nanoscale. In this colloquium, I will discuss how correlative photoluminescence and cathodoluminescence spectroscopy can uncover the optical fingerprints of interacting quasiparticles with high spectral, spatial, and temporal resolution. I will further introduce a recently developed electron-beam Ramsey interferometry approach that enables direct access to decoherence dynamics of quasiparticle interactions with deep subwavelength spatial resolution and femtosecond temporal precision. This opens a path toward mapping coherence loss, energy exchange, and emergent many-body effects in quantum materials on their natural scales.