High-efficiency microwave photodetection by cavity coupled double dots with single cavity-photon sensitivity

TL;DR

This paper introduces a superconducting cavity-coupled double quantum dot photodiode capable of detecting single microwave photons with 25% efficiency, advancing quantum information processing and photon statistics studies.

Contribution

The work demonstrates a novel microwave photodetector with improved efficiency and sensitivity, utilizing cavity-DQD coupling and optimized device design for single-photon detection.

Findings

Achieved 25% photon-to-electron conversion efficiency.

Detected microwave signals down to 100 aW power level.

Identified key improvements for near-unity detection efficiency.

Abstract

We present a superconducting cavity-coupled double quantum dot (DQD) photodiode that achieves a maximum photon-to-electron conversion efficiency of 25% in the microwave domain. With a higher-quality-factor cavity and improved device design to prevent photon leakages through unwanted pathways, our device measures microwave signals down to 100 aW power level and achieves sensitivity to probe microwave signals with one photon at a time in the cavity. We analyze the photodiode operation using Jaynes-Cummings input-output theory, identifying the key improvements of stronger cavity-DQD coupling needed to achieve near-unity photodetection efficiency. The results presented in this work represent a crucial advancement toward near unity microwave photodetection efficiency with single cavity-photon sensitivity for studies of photon statistics in the microwave range and applications related to quantum information processing.