Claude Monney : A momentum-resolved view of quantum materials under optical control

Time- and angle-resolved photoemission spectroscopy (ARPES) is an ideal experimental technique to access the transient electronic structure of quantum materials. In the pump-probe scheme, a first pulse of light excites the material of interest before a second pulse probes it at a given time delay.

Here I will exemplify how quantum material can be probed with time-resolved ARPES using two recent results from our laboratory at the University of Fribourg, with a focus on optical control. First, I will show how a tailored optical pulse can be used to generate a band inversion in a semiconductor to create a transient topological cone through Floquet engineering. Second, I will discuss how a resonant generation of excitons in a small gap semiconductor allows us to follow their decoherence into dark excitons.