Nonlinear coupling of phononic resonators induced by surface acoustic waves

TL;DR

This paper demonstrates how surface acoustic waves induce nonlinear interactions in coupled phononic resonators, enabling advanced control of their dynamics for high-frequency phononic circuits in classical and quantum tech.

Contribution

It reveals a new nonlinear coupling mechanism between surface acoustic waves and mechanical resonators, expanding the functionalities of phononic circuits.

Findings

Frequency softening of resonators due to SAW amplitude

Control of resonator motion including circular polarization

Nonlinear effects beyond geometrical Duffing models

Abstract

The rising need for hybrid physical platforms has triggered a renewed interest for the development of agile radio-frequency phononic circuits with complex functionalities. The combination of travelling waves with resonant mechanical elements appears as an appealing means of harnessing elastic vibration. In this work, we demonstrate that this combination can be further enriched by the occurrence of elastic non-linearities induced travelling surface acoustic waves (SAW) interacting with a pair of otherwise linear micron-scale mechanical resonators. Reducing the resonator gap distance and increasing the SAW amplitude results in a frequency softening of the resonator pair response that lies outside the usual picture of geometrical Duffing non-linearities. The dynamics of the SAW excitation scheme allows further control of the resonator motion, notably leading to circular polarization states. These results paves the way towards versatile high-frequency phononic-MEMS/NEMS circuits fitting both classical and quantum technologies.