Force sensitivity of multilayer graphene optomechanical devices

Abstract

Mechanical resonators based on low-dimensional materials are promising for force and mass sensing experiments. The force sensitivity in these ultra-light resonators is often limited by the imprecision in the measurement of the vibrations, the fluctuations of the mechanical resonant frequency and the heating induced by the measurement. Here, we strongly couple multilayer graphene resonators to superconducting cavities in order to achieve a displacement sensitivity of 1.3 fm Hz−1/2. This coupling also allows us to damp the resonator to an average phonon occupation of 7.2. Our best force sensitivity, 390 zN Hz−1/2 with a bandwidth of 200 Hz, is achieved by balancing measurement imprecision, optomechanical damping, and measurement-induced heating. Our results hold promise for studying the quantum capacitance of graphene, its magnetization, and the electron and nuclear spins of molecules adsorbed on its surface.

Quantum Acoustomechanics with a Micromagnet

“…According to the results in Fig. 4, this lies well within the sensitivity range of most state-of-the-art ultra-sensitive micromechanical sensors [32,[42][43][44][45][46], which can even resolve motion on the quantum level [31,47,48]. Thus, the acoustic-induced mode splitting is experimentally measurable.…”

High Quality Factor Graphene-Based Two-Dimensional Heterostructure Mechanical Resonator

“…Summary of gate dependent dissipation in different resonators (from Refs 14,26. ) in comparison with our heterostructure membrane regarding effective resistance and internal quality factor.…”

Theory of quantum acoustomagnonics and acoustomechanics with a micromagnet

“…This is shown in Fig. 10, where we display the power spectral density at T e = 300K, Q p = 10 7 , and a moderate value Q x = 10 5 , reachable in most experimental platforms [80, [88][89][90][91][92]. Upon increasing the magnetic field gradient b, the power spectral density transitions from a single peak, corresponding to a single mechanical oscillator, at zero coupling, i.e.…”

“…10, this measurement is experimentally feasible, especially for acoustic quality factors Q p > 10 7 , as the two peaks reach values ∼ 1pm/Hz 1/2 , even when the center-of-mass motion is only driven by thermal noise. This is within the sensitivity regime of most state-of-the-art ultra-sensitive displacement sensors [79,80,88,90,91,[94][95][96][97][98] and the signal-to-noise ratio in the power spectral density can be largely increased by resonant excitation of the center-of-mass mode. Remarkably, probing the internal modes remains feasible for higher-order acoustic phonons, as evidenced by Fig.…”