Large-bandwidth transduction between an optical single quantum-dot molecule and a superconducting resonator

TL;DR

This paper demonstrates a quantum transducer using a quantum dot molecule that efficiently couples microwave and optical photons with high bandwidth and low noise, advancing quantum network technology.

Contribution

It introduces a novel quantum transducer leveraging a quantum dot molecule's large electric dipole to achieve high coupling strength and broad bandwidth without external optical pumps.

Findings

Single-photon coupling strength of 16 MHz

Transduction bandwidth of several hundred MHz

Efficient microwave-optical photon conversion

Abstract

Quantum transduction between the microwave and optical domains is an outstanding challenge for long-distance quantum networks based on superconducting qubits. For all transducers realized to date, the generally weak light-matter coupling does not allow high transduction efficiency, large bandwidth, and low noise simultaneously. Here we show that a large electric dipole moment of an exciton in an optically active self-assembled quantum dot molecule (QDM) efficiently couples to a microwave resonator field at a single-photon level. This allows for transduction between microwave and optical photons without coherent optical pump fields to enhance the interaction. With an on-chip device, we demonstrate a sizeable single-photon coupling strength of 16 MHz. Thanks to the fast exciton decay rate in the QDM, the transduction bandwidth between an optical and microwave resonator photon reaches several 100s of MHz.