Multi-order phononic frequency comb generation within a MoS₂ electromechanical 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 (ω_p) to obtain a high number of sidebands at frequencies ω₁ ± m ω_p, 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.