Strong coupling between mechanical modes in a nanotube resonator

TL;DR

This paper demonstrates strong nonlinear coupling between mechanical modes in a nanotube resonator, revealing exotic lineshapes and controllable interactions with potential applications in quantum and classical signal processing.

Contribution

It provides experimental evidence of mode coupling in nanotube resonators and shows how to control this coupling via gate voltage, advancing understanding of nanoscale mechanical interactions.

Findings

Revealed nonlinear coupling between mechanical modes.

Observed exotic lineshapes at specific frequency ratios.

Controlled coupling strength with gate voltage.

Abstract

We report on the nonlinear coupling between the mechanical modes of a nanotube resonator. The coupling is revealed in a pump-probe experiment where a mode driven by a pump force is shown to modify the motion of a second mode measured with a probe force. In a second series of experiments, we actuate the resonator with only one oscillating force. Mechanical resonances feature exotic lineshapes with reproducible dips, peaks, and jumps when the measured mode is commensurate with another mode with a frequency ratio of either 2 or 3. Conventional lineshapes are recovered by detuning the frequency ratio using the voltage on a nearby gate electrode. The exotic lineshapes are attributed to strong coupling between the mechanical modes. The possibility to control the strength of the coupling with the gate voltage holds promise for various experiments, such as quantum manipulation, mechanical signal processing, and the study of the quantum-toclassical transition.