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ジョセフソン接続の配列に基づくカスケードスイッチング電流検出器

Roger Cattaneo¹, Artemii E Efimov^1,2, Kirill I Shiianov¹

¹Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden.

Nature communications

|August 25, 2025

まとめ

新しい超伝導検出器は,カスケード増幅のためのジョセフソン結合配列を使用し,テラヘルツ (THz) とマイクロ波 (MW) 範囲での感度を大幅に高めます. この画期的な発明により信号とノイズの比率が向上します

科学分野:

凝縮物質物理学
超伝導装置
フォトン検出

背景:

フォトン検出器の感度は,しばしばカスケード倍数を用いて強化されます.
従来の検出器 (真空管,半導体) は,高い作業機能のために低周波性能が制限されています.
超伝導検出器はテラヘルツ (THz) とマイクロ波 (MW) の周波数帯にソリューションを提供します.

研究の目的:

カスケード増強型超伝導検出器の新概念を導入する.
信号増幅のためにジョセフソン・ジャンクション・アレイを活用する
感度と信号対ノイズ比がMWとTHzで改善されたことを実証する.

主な方法:

ジョセフソン結合配列を用いたカスケード増強型超伝導検出器を開発した.
フォトンの吸収時に雪崩のようなスイッチングを誘発するインタージュンクションカップリングを使用します.
低T_cのNb基と高T_cのBiSCCO固有ジョセフソン結合を用いてプロトタイプを製造および試験した.

主要な成果:

ジョセフソン接続配列の読み出し電圧のカスケード増幅が実証された.
従来のシングルジャンクション検出器と比較して,信号対ノイズ比が向上した.
製造された検出器のプロトタイプでMWとTHz応答が確認された.

結論:

ジョセフソン結合配列は,非常に敏感な超伝導検出器のカスケード増幅を可能にします.
開発された検出器は,ブロードバンドMWからTHzのアプリケーションに重要な利点を示しています.
この技術は,MW-THzスペクトルの次世代感受性検出器に期待されます.

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