Optimal broad-band frequency conversion via a magnomechanical transducer

TL;DR

This paper proposes a two-stage magnomechanical transducer protocol for efficient, broad-band quantum frequency conversion between microwave and optical signals, advancing quantum communication technology.

Contribution

It introduces a novel two-stage conversion scheme utilizing magnetic-mechanical interactions, achieving near-unity efficiency without matching cooperativities.

Findings

Predicts near-unity conversion efficiency under optimized conditions.

Estimates a broad conversion bandwidth comparable to coupling strengths.

Shows bandwidth can be increased at the cost of efficiency.

Abstract

Developing schemes for efficient and broad-band frequency conversion of quantum signals is an ongoing challenge in the field of modern quantum information. Especially the coherent conversion between microwave and optical signals is an important milestone towards long-distance quantum communication. In this work, we propose a two-stage conversion protocol, employing a resonant interaction between magnetic and mechanical excitations as a mediator between microwave and optical photons. Based on estimates for the coupling strengths under optimized conditions for yttrium iron garnet, we predict close to unity conversion efficiency without the requirement of matching cooperativities. We predict a conversion bandwidth in the regions of largest efficiency on the order of magnitude of the coupling strengths which can be further increased at the expense of reduced conversion efficiency.