# Phase-Controlled Phonon Laser

## TL;DR

This paper proposes a phase-controlled phonon laser with ultralow threshold powered by tunable optical amplifiers, enabling enhanced photon-phonon interactions and applications in quantum phononics and sensitive motion detection.

## Contribution

It introduces a novel phase-controlled phonon laser using tunable amplifiers in a coupled-cavity system, achieving giant enhancement of interactions and low-power operation.

## Key findings

- Achieved giant enhancement of photon-phonon interactions.
- Enabled single-photon optomechanics and low-power phonon lasing.
- Potential applications in quantum phononics and ultrasensitive detection.

## Abstract

A phase-controlled ultralow-threshold phonon laser is proposed by using tunable optical amplifiers in coupled-cavity-optomechanical system. Giant enhancement of coherent photon-phonon interactions is achieved by engineering the strengths and phases of external parametric driving. This in turn enables single-photon optomechanics and low-power phonon lasing, opening up novel prospects for applications, e.g. quantum phononics and ultrasensitive motion detection.