Floquet engineering of a model semiconductor by time-resolved ARPES

Time-periodic light field has emerged as a control knob for manipulating quantum states in solid-state materials via hybridization with photondressed Floquet states in the strong coupling limit, dubbed as Floquet engineering. Such interaction leads to tailored properties of quantum materials, for example, modifications of the topological properties of Dirac materials and emergence of Floquet topological insulators. Despite extensive research interests over the past decade, there is no experimental evidence of Floquet engineering of semiconductors, which is a crucial step to extend Floquet engineering to a wide range of solid-state materials. Here, based on time- and angle-resolved photoemission spectroscopy measurements, we report the experimental evidence of Floquet band engineering in a model semiconductor. Floquet sidebands and strong band renormalization are both successfully realized.