Superconducting detectors with high-speed and high-resolution at THz band.

太赫兹波段高速高分辨率超导探测器。

基本信息

批准号：
11555106
负责人：
YAMASHITA Tsutomu
金额：
$ 8.77万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Using high Tc superconducting (HTS) grain boundary Josephson junctions (GBJJs) made of YBa_2Cu_3O_<7-x> (YBCO) deposited across bicrystal boundary, we have successfully demonstrated wide band detections at frequency as high as 2.5 THz and at operating temperature up to 70K.Also, up to 2.5 THz, the high-order harmonic mixing at zero and finite bias voltage have been demonstrated. The effect of applied dc magnetic field on the THz responses of GBJJs has been investigated in detail. The enhancement of the Shapiro step height could be obtained in the high-quality wider GBJJs when a dc field was applied. For this effect, simulation by an equivalent double-junction SQUID model is justified. It was found that the obtained restults agreed with the simulation results very well. So, the high-quality wider GBJJs with an external dc magnetic field may be more useful than the small GBJJs for detecting system at THz band. Also, it was found that the HTS planar antenna, which is useful to improve the coupling between the devices and THz signals, could be simply characterized at low temperature using HTS GBJJs. Furthermore, using the quasi-optical technology, the detecting system with a mind-refrigerator, which will minimize the whole system, has been designed and made-up. The THz responses have been measured when the HTS GBJJs was load in the small-sized refrigerator and it was found the formed system worked quite well. Finally, to make the measurements simply during a short time, a program with Hilbert transform and so on has been developed to collect and analyze tlue data. The results show that it is very hopeful using HTS GBJJs to form the detecting system with high-speed and high-resolution operating at the high temperature.

Using high Tc superconducting (HTS) grain boundary Josephson junctions (GBJJs) made of YBa_2Cu_3O_<7-x> (YBCO) deposited across bicrystal boundary, we have successfully demonstrated wide band detections at frequency as high as 2.5 THz and at operating temperature up to 70K.Also, up to 2.5 THz, the high-order harmonic mixing at zero and finite bias电压已被证明。已详细研究了应用直流磁场对GBJJS THz响应的影响。当应用DC场时，可以在高质量的较宽的GBJJS中获得夏皮罗步进高度的增强。为了这种效果，通过等效的双结模型模拟是合理的。发现所获得的恢复与仿真结果一致。因此，具有外部直流磁场的高质量较宽的GBJJ可能比用于检测THZ频段的小型GBJJS更有用。同样，发现可以使用HTS GBJJS在低温下简单地表征HTS平面天线，可用于改善设备和THZ信号之间的耦合。此外，使用准精光技术，具有思维式冰箱的检测系统（将最小化整个系统）的检测系统是设计和化妆的。当HTS GBJJS在小型冰箱中负载时，已经测量了THZ响应，发现形成的系统效果很好。最后，为了简单地在短时间内进行测量，已经开发了一个具有希尔伯特转换的程序，以收集和分析TLUE数据。结果表明，使用HTS GBJJS以高速和高分辨率在高温下运行的检测系统非常有希望。