HIGH T_C SUPERCONDUCTING ELECTROMAGNETIC WAVE DETECTORS FOR MILLIMETER AND SUBMILLIMETER BANDS USING SILICON SUBSTRATES

使用硅衬底的毫米波和亚毫米波带高温超导电磁波探测器

基本信息

批准号：
07555410
负责人：
NAKAJIMA Kensuke
金额：
$ 3.84万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

It is expected that high Tc superconducting millimeter and submillimeter wave devices such as a low loss transmission line and a high sensitivity detector, which can be operated with a simple cryogenic system, are applicable for a ultra high speed communication system in order to supply a communication demand. Specific high frequency properties of high T_C superconductors caused by the characteristic layred structure is also attractive from the application point of view. In this research project we aimed to develop fundamental technologies of electromagnetic wave detectors for millimeter and submillimeter bands using high T_C superconducting YBCO grain boundary Josephson junctions (GBJJ) on silicon bicrystal substrates. We have first succeeded a video detection of 2.525THz signal using YBCO GBJJs operated at 70K as a result of improvements of junction parameters such as the supercondcuting transition temperature, Tc and the I_CR_N product. Furthermore, we found that high frequency response (Shapiro step) was enhanced by a weak magnetic field application for wide frequency range up to submillimeter wave through microwave. This is a quite useful knowledge to develop a practical submillimater wave spectrometer using the GBJJ.Harmonic heterodyne mixing experiments were also performed using GBJJ for a submillimeter signal of f_S=2.525THz and a microwave signal of f_<LO>=19.4176268GHz then we had 130th harmonic mixing output {IF (Intermediate Frequency) output}. For the harmonic mixing we had the signal and noise ratio (S/N) of about 20dB and the spectrum resolution of 100KHz. The S/N would be improved to some extent by optimizing high frequency circuit design. In conclusion we have substantiated that the harmonic heterodyne mixing using GBJJs performs the high spectrum resolution for millimater and submillimeter waves and a precise spectrometer for the entire frequency range will be practical together with the video detection.

预计可以用简单的低温系统操作的高Tc超导毫米波和亚毫米波器件，例如低损耗传输线和高灵敏度探测器，可适用于超高速通信系统，以提供通信服务。要求。从应用的角度来看，由特征层状结构引起的高T_C超导体的特定高频特性也很有吸引力。在这个研究项目中，我们的目标是开发使用硅双晶衬底上的高T_C超导YBCO晶界约瑟夫森结（GBJJ）的毫米和亚毫米波段电磁波探测器的基础技术。由于超导转变温度、Tc 和 I_CR_N 乘积等结参数的改进，我们首次使用运行于 70K 的 YBCO GBJJ 成功实现了 2.525THz 信号的视频检测。此外，我们发现通过微波在高达亚毫米波的宽频率范围内应用弱磁场可以增强高频响应（夏皮罗阶跃）。这对于使用 GBJJ 开发实用的亚毫米波谱仪来说是非常有用的知识。还使用 GBJJ 对 f_S=2.525THz 的亚毫米信号和 f_<LO>=19.4176268GHz 的微波信号进行了谐波外差混频实验，然后我们得到了130次谐波混频输出{IF(中频)输出}。对于谐波混频，我们的信噪比 (S/N) 约为 20dB，频谱分辨率为 100KHz。通过优化高频电路设计，可以在一定程度上提高信噪比。总之，我们已经证实，使用 GBJJ 的谐波外差混频可以实现毫米波和亚毫米波的高频谱分辨率，并且整个频率范围的精确光谱仪将与视频检测一起实用。