Multi-order phononic frequency comb generation within a MoS₂electromechanical resonator

In this work, we measure and tune simultaneously the vibration of a 1-nm thick MoS2 suspended monolayer with standard electrical excitation and optical techniques. At ambient temperature, we first investigate the strong parametric coupling between two different mechanical modes (ω1 and ω2). We demonstrate a high and quasi-linear tunability of the mode frequencies with the parametric pump voltage. Then, we couple the highly tunable main vibration (ω1) to a parametric pump frequency (ωp) to obtain a high number of sidebands at frequencies ω1 ± m ωp, driving the mechanical mode with a large external electrical force. This oscillating force, applied via the gate voltage, acts as a stress onto the MoS2 sheet. The obtained frequency comb has a large spectral band and contains up to 100 harmonics, with potential applications in quantum information processing and heat or sound transport.