Development of a Terahertz detector Array based on superconducting tunnel junctions coupled to a thin superconductor film

研究了一种利用超导隧道结(STJ)耦合到大的太赫兹吸收超导膜上的太赫兹探测器。我们还提出了一种具有传输线STJ的新型太赫兹探测器的设计。后一种探测器在对数周期天线的两翼上集成了两个长结。在这种情况下，长结是一种基于库珀对断裂过程的高损耗传输线，其长度和宽度分别决定了吸收效率和频带宽度。制作了Nb/Al/AlOx/Al/Nb结探测器，验证了探测器的工作原理。我们基于库珀对破裂(CPB)测量了太赫兹辐射，证实了灵敏度从0.35太赫兹逐渐增加，该值对应于Nb/Al双层膜的有效禁带频率。我们还识别了工作在光子辅助隧穿(PAT)过程中的第三/4波长共振及其谐波信号。STJ检测器具有两种检测过程都可用的新功能。这一功能将允许探测器在未来的太赫兹成像中应用，具有广泛的频率选择性。

A terahertz detector using a superconducting tunnel junction (STJ) coupled to a large terahertz-absorbing superconductor film was investigated. We also proposed a design of a new terahertz detector with transmission-line STJs. The latter detector has two long junctions integrated on both wings of a log-periodic antenna. In this type, the long junction is a high-loss transmission-line working based on the Cooper-pair breaking process, in which the junction length and width determine the absorption efficiency and frequency bandwidth, respectively. A detector using Nb/Al/A1Ox/Al/Nb junctions was fabricated, and the principle of the detector was verified. We have detected terahertz radiation based on the Cooper-pair breaking (CPB), and confirmed that the sensitivity has a gradual increase from 0.35 THz, a value that corresponds to the effective gap frequency of the Nb/Al bilayer. We have also identified the third quarter-wavelength resonance and its harmonic signals working on the photon-assisted tunneling (PAT) process. The STJ detector has the new functionality that both detection processes are available. This functionality will allow the detector to be applied in future THz imaging with wide frequency selectivity.