Light-field dressing of transiently excited electronic states by time-resolved ARPES

Strong time-periodic light-field can be used to generate hybrid photon–electron states. Along this line, the interaction of light-field with Bloch states leads to Floquet–Bloch states, which can tailor properties of quantum materials. So far, most of our understanding on the Floquet engineering of topological insulators has been focused on the filled electronic states, however, little is known about the dressing of the electronic states above the Fermi level. For example, whether photo-excited electronic states above the Fermi energy can also be dressed by the light-field remains elusive. Revealing their dynamics of photo-excited carriers, light-field dressing and their interplay is an important question. Here by using time-and angle-resolved photoemission spectroscopy (Tr-ARPES) with mid-infrared (MIR) pumping, I will present new experimental results to address these interesting questions.