Markus B. Raschke
CU Boulder, JILA
Abstract: Understanding and ultimately controlling the properties of matter, from molecular to quantum systems, requires imaging the elementary excitations on their natural time and length scales. To achieve this goal, we developed scanning probe microscopy with ultrafast and shaped laser pulse excitation for multiscale spatio-temporal optical nano-imaging. In corresponding ultrafast movies, we resolve the fundamental quantum dynamics from the few-femtosecond coherent to the thermal transport regime. I will discuss specific examples visualizing in space and time the nanoscale heterogeneity in competing structural and electronic dynamic processes in matter. In photovoltaic perovskites with far-from equilibrium excitation we visualize the polaron dynamics and its spatial, temporal and fluence dependence on the nanoscale, reflecting the elementary processes underling their photoresponse. In the extension to coherent nonlinear nanoimaging, we resolve competing ultrafast intra- and interlayer dynamic processes in graphene and 2D semiconductors and their heterostructures. As a perspective I will show that we are reaching the ultimate goal of functional imaging and control, to link macroscopic properties to microscopic interactions in materials at their fundamental spatio-temporal scales.
All lectures held in CTLM102 unless otherwise specified
Pre-seminar snacks will be offered in CoorsTek 140 from 3:30pm-4:00pm.