Nonlinear Mode Coupling and One-to-One Internal Resonances in a Monolayer WS₂ Nanoresonator

Abstract

Nanomechanical resonators make exquisite force sensors due to their small footprint, low dissipation, and high frequencies. Because the lowest resolvable force is limited by ambient thermal noise, resonators are either operated at cryogenic temperatures or coupled to a high-finesse optical or microwave cavity to reach sub aN Hz −1/2 sensitivity. Here, we show that operating a monolayer WS 2 nanoresonator in the strongly nonlinear regime can lead to comparable force sensitivities at room temperature. Cavity interferometry was used to transduce the nonlinear response of the nanoresonator, which was characterized by multiple pairs of 1:1 internal resonance. Some of the modes exhibited exotic line shapes due to the appearance of Hopf bifurcations, where the bifurcation frequency varied linearly with the driving force and forms the basis of the advanced sensing modality. The modality is less sensitive to the measurement bandwidth, limited only by the intrinsic frequency fluctuations, and therefore, advantageous in the detection of weak incoherent forces.

Chasing Plasmons in Flatland

“…This is the case of the WS 2 -based nanoresonator operating in the strongly nonlinear regime to obtain force sensors that achieve high sensitivities at room temperature. 36 In conclusion, we have reported the most recent advances on the coupling between the field of plasmonics and 2D materials published in Nano Letters in the past decade. As well, we have discussed how we can exploit this coupling to achieve better performance in some specific areas, above all photodetection.…”

“…Finally, it is worth noticing that 2D materials can also be used as detectors of weak incoherent forces. This is the case of the WS 2 -based nanoresonator operating in the strongly nonlinear regime to obtain force sensors that achieve high sensitivities at room temperature …”

Dynamics of 2D Material Membranes

“…Mode coupling effects can be studied by driving both modes near their resonance frequency simultaneously, or by exciting one mode and study its ringdown 34,102 while monitoring the effects of interactions with other modes. However, most commonly these coupling effects are studied 27,35,99,159,160 by driving one mode j directly or parametrically with an external sinusoidal force F ext,j = F ext,j0 sin(ωt) while tuning its resonance frequency until interactions with other modes become noticeable. These interactions can be understood as follows: at sufficiently high driving force and when driving the mode close to its resonance frequency, the motion q j (t) = q j,0 sin ω j t reaches large amplitudes, and as a consequence, mode i experiences a mode-coupling force, e.g.…”

Internal resonance in the higher-order modes of a MEMS beam: experiments and global analysis

“…The exchange of energy between the modes is discussed, showing the sensitivity of the involved ranges to the system parameters. Nathamgari et al [24] report on a force sensor utilizing the nonlinear mode coupling in a monolayer tungsten disulfide nanoresonator, showing multiple pairs of 1:1 internal resonance.…”