Cattaneo Roger, Efimov Artemii E, Shiianov Kirill I, Kieler Oliver, Krasnov Vladimir M
Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden.
Department of Physics, University of Basel, Basel, Switzerland.
Nat Commun. 2025 Aug 25;16(1):7927. doi: 10.1038/s41467-025-63360-y.
Cascade multiplication is widely used to enhance photon detector sensitivity. While vacuum tube and semiconductor photomultipliers achieve high gains in the optical range, their performance at lower frequencies is limited by large work functions. Superconducting detectors overcome this constraint, enabling operation in the terahertz (THz) and microwave (MW) ranges. Here we introduce a concept of cascade-amplified superconducting detectors based on Josephson junction arrays. Interjunction coupling in an array triggers avalanche-like switching of multiple junctions upon photon absorption, resulting in cascade amplification of the readout voltage and an increased signal-to-noise ratio. We present prototypes using either low-T linear Nb/NbSi/Nb arrays or BiSrCaCuO high-T stacked intrinsic Josephson junctions. Both MW and THz responses are analyzed and the advantages of the cascade detector over a conventional single-junction detector are demonstrated. Our findings suggest that Josephson junction arrays hold promise for the development of highly sensitive, broadband MW-to-THz detectors.
级联倍增被广泛用于提高光子探测器的灵敏度。虽然真空管和半导体光电倍增管在光学范围内能实现高增益，但其在较低频率下的性能受到大逸出功的限制。超导探测器克服了这一限制，能够在太赫兹（THz）和微波（MW）波段工作。在此，我们介绍一种基于约瑟夫森结阵列的级联放大超导探测器概念。阵列中的结间耦合在光子吸收时触发多个结的雪崩式开关，导致读出电压的级联放大和信噪比的提高。我们展示了使用低T线性铌/铌硅/铌阵列或铋锶钙铜氧高温堆叠本征约瑟夫森结的原型。对微波和太赫兹响应都进行了分析，并证明了级联探测器相对于传统单结探测器的优势。我们的研究结果表明，约瑟夫森结阵列在开发高灵敏度、宽带微波到太赫兹探测器方面具有潜力。
