Ultrafast real-time observation of double Fano resonances in discrete excitons and single plasmon-continuum

Abstract

Ultrafast observation of multiple asymmetric Fano line shapes in energetically overlapped single continuum and multiple discrete states is of great theoretical interest in different domains of physics, though their real-time experimental demonstrations are yet to be achieved. Here, we present an experimental observation on time-domain response of the double Fano asymmetries in a metal--two-dimensional semiconductor hybrid prototype at room temperature. The ultrafast interactions in two discrete spin-resolved excitons of ${\mathrm{MoS}}_{2}$ and a single metal plasmon-continuum allow us to observe the generation and evolution of the double Fano line profiles in real time. Apart from the subpicosecond development of double Fano line shapes, we calculate all the time-dependent nonlinear double Fano parameters. These results suggest a better understanding of ultrafast Fano physics in condensed-matter systems and have potential prospects in ultrafast photonic devices using double Fano resonances even at room temperature.