Amplitude stabilization in a synchronized nonlinear nanomechanical oscillator

Synchronization, a ubiquitous phenomenon in nature, has been extensively studied from the frequency point of view for micro- and nano-electromechanical systems, but less so when amplitude stability is concerned. The authors investigate, theoretically and experimentally, the amplitude stabilization in an externally harmonic drive synchronized noisy nonlinear oscillator, showcasing the effect of the amplitude noise reduction in these devices. In contrast to the well-known phenomenon of frequency stabilization in a synchronized noisy nonlinear oscillator, little is known about its amplitude stability. In this paper, we investigate experimentally and theoretically the amplitude evolution and stability of a nonlinear nanomechanical self-sustained oscillator that is synchronized with an external harmonic drive. We show that the phase difference between the tones plays a critical role on the amplitude level, and we demonstrate that in the strongly nonlinear regime, its amplitude fluctuations are reduced considerably. These findings bring to light a new facet of the synchronization phenomenon, extending its range of applications beyond the field of clock-references and suggesting a new means to enhance oscillator amplitude stability.