Optical modulation of coherent phonon emission in optomechanical cavities

TL;DR

This paper demonstrates optical modulation of coherent phonon emission in optomechanical cavities, enabling phonon switching at ambient conditions, which advances phononic circuit integration and control.

Contribution

It introduces a novel method to modulate phonon emission via optical pumping, including harmonic and chaotic switching, facilitating controllable phonon networks.

Findings

Achieved phonon switching at 5 MHz speed.

Demonstrated harmonic and chaotic switching schemes.

Enabled selective control of individual optomechanical structures.

Abstract

Optomechanical structures are well suited to study photon-phonon interactions, and they also turn out to be potential building blocks for phononic circuits and quantum computing. In phononic circuits, in which information is carried and processed by phonons, optomechanical structures could be used as interfaces to photons and electrons thanks to their excellent coupling efficiency. Among the components required for phononic circuits, such structures could be used to create coherent phonon sources and detectors. Complex functions other than emission or detection remain challenging and addressing a single structure in a full network proves a formidable challenge. Here, we propose and demonstrate a way to modulate the coherent emission from optomechanical crystals by external optical pumping, effectively creating a phonon switch working at ambient conditions of pressure and temperature and the working speed of which (5 MHz) is only limited by the mechanical motion of the optomechanical structure. We additionally demonstrate two other switching schemes: harmonic switching in which the mechanical mode remains active but different harmonics of the optical force are used, and switching to- and from the chaotic regime. Furthermore, the method presented here allows to select any single structure without affecting its surroundings, which is an important step towards freely controllable networks of optomechanical phonon emitters.