Phase-enhanced nonreciprocal photon-phonon conversion via coupled optomechanical cavities

TL;DR

This paper theoretically demonstrates phase-controlled nonreciprocal photon-phonon conversion in coupled optomechanical cavities, achieving high isolation without breaking time reversal symmetry.

Contribution

It introduces a novel phase-dependent mechanism for nonreciprocal photon-phonon conversion that does not require dissipation or time reversal symmetry breaking.

Findings

Achieves up to 40 dB isolation in photon-phonon conversion.

Demonstrates nonreciprocal phonon transport requires dissipation and phase-induced symmetry violation.

Shows nonreciprocal photon-phonon conversion can occur without breaking time reversal symmetry.

Abstract

Nonreciprocity, characterized by direction-dependent signal propagation, is fundamental to technologies such as isolators, signal routing, and precision sensing. This letter theoretically demonstrates nonreciprocal phonon transport and the conversion between photon and acoustic phonon signals in coupled optomechanical cavities via phase-dependent driving. It is demonstrated that, in contrast to nonreciprocal phonon transport, which necessitates both dissipation and phase-induced violation of time reversal symmetry, the nonreciprocity in photon-phonon conversion can occur without violating time reversal symmetry. We demonstrate that such nonreciprocity arises due to the path-dependent asymmetry in photon-phonon conversion. Furthermore, we demonstrate that the nonreciprocity of photon-phonon conversion can be further enhanced, achieving isolation levels of up to 40 dB by suitably modifying the phase difference of the driving lasers.