Ultrafast THz nonlinear modulation in an electrically tunable graphene thin film perfect absorber

We demonstrate an electrically tunable, ultrafast, nonlinear, terahertz absorption modulator operating at 2.3 THz. The device consists of a uniform graphene sheet placed on a Au-grounded ionic liquid substrate. An electrostatic gating applied between the graphene sheet and the back-plate controls the underlying conditions for the graphene while nonlinear modulation is assessed via self-action when the THz field strength increases from 145 to 654 kV/cm. The time-dependent thermodynamic response of the system during interaction with ultrafast electric fields is further supported via the theoretical analysis of the experimental findings.