Femtosecond nano-imaging of the few-femtosecond coherent dynamics of two-dimensional materials

Using plasmonic nanofocusing coupled with ultrafast femtosecond pulses, we perform spatio-temporal nonlinear optical imaging of graphene and MoSe2. We resolve for the first time the nanoscale heterogeneity in the few-femtosecond coherent dynamics in two-dimensional materials.