Dynamically induced robust phonon transport and chiral cooling in an optomechanical system

TL;DR

This paper demonstrates a novel method to achieve robust, disorder-resistant phonon transport and cooling in an optomechanical system by inducing chirality through parity-selective optical coupling, surpassing traditional cooling limits.

Contribution

It introduces a new approach to suppress disorder effects in phononic systems via optomechanical chirality, enabling robust phonon transport and cooling without added damping.

Findings

Chiral cooling of phonons achieved through asymmetric optical pumping.

Disorder-induced scattering is suppressed in a non-topological phononic system.

Optical cooling of mechanics exceeds traditional sideband cooling limits.

Abstract

The transport of sound and heat, in the form of phonons, can be limited by disorder-induced scattering. In electronic and optical settings the introduction of chiral transport, in which carrier propagation exhibits parity asymmetry, can remove elastic backscattering and provides robustness against disorder. However, suppression of disorder-induced scattering has never been demonstrated in non-topological phononic systems. Here we experimentally demonstrate a path for achieving robust phonon transport in the presence of material disorder, by explicitly inducing chirality through parity-selective optomechanical coupling. We show that asymmetric optical pumping of a symmetric resonator enables a dramatic chiral cooling of clockwise and counterclockwise phonons, while simultaneously suppressing the hidden action of disorder. Surprisingly, this passive mechanism is also accompanied by a chiral reduction in heat load leading to optical cooling of the mechanics without added damping, an effect that has no optical analogue. This technique can potentially improve upon the fundamental thermal limits of resonant mechanical sensors, which cannot be attained through sideband cooling.