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。

• 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
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555106/
• 关键词: THz band; High Tc superconductor (HTS); Josephson junction; Planar antenna; Small-sized refrigerator; Quasi-optical technology; Detecting system; Harmonic mixing; 広帯域平面型アンテナ; ヒルベルト変換; テラヘルツ; スペクトロコピー

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.

利用YBa_2Cu_3O_（YBCO）的高温超导晶界约瑟夫森结（GBJJ s）<7-x>，成功地实现了频率高达2.5THz、工作温度高达70K的宽带探测，并在2.5THz范围内实现了零偏压和有限偏压下的高次谐波混频。详细研究了外加直流磁场对GBJJ的太赫兹响应的影响。当施加直流电场时，可以在高质量的宽GBJJ中获得Shapiro台阶高度的增强。对于这种效应，模拟的等效双结SQUID模型是合理的。计算结果与模拟结果吻合较好。因此，在太赫兹波段的探测系统中，具有外磁场的高质量宽GBJJ可能比小GBJJ更有用。此外，有人发现，高温超导平面天线，这是有用的，以提高设备和太赫兹信号之间的耦合，可以简单地在低温下使用高温超导GBJJ。利用准光学技术，设计并制作了一个具有思维冰箱的检测系统，使整个系统达到最小化。在小型制冷机上测试了高温超导结结的THz响应，发现所形成的系统工作良好。最后，为了在短时间内简单地进行测量，利用希尔伯特变换等方法编制了一个程序来采集和分析实际数据。结果表明，利用高温超导超导结束器构成高温下高速、高分辨率的检测系统是很有希望的。

项目成果

T.Yamashita and J.Chen: "Science of high temperature superconductivity. (Edit by : M.Tachiki and T.Fujita)"SHOKABO, TOKYO (in Japanese). 498 (1999)

T.Yamashita 和 J.Chen：“高温超导科学。（编辑：M.Tachiki 和 T.Fujita）”SHOKABO，东京（日语）。

J.Chen,E.Kobayashi,K.Nakajima,T.Yamashta et al.: "Response Properties at 2.525 Terahertz using High-Tc Josephson Junctions on Silicon BicrystaI Substrates"lEEE Trans. Appl. Supercond.. 9・2. 4479-4482 (1999)

J.Chen、E.Kobayashi、K.Nakajima、T.Yamashta 等人：“在硅双晶衬底上使用高温约瑟夫森结的 2.525 太赫兹响应特性”1EEE Trans. 9・2。 4482 (1999)

山下 努: "微小単結晶で超伝導単電子トンネル素子"化学と工業. 52・7. 884-886 (1999)

山下努：“使用微单晶的超导单电子隧道装置”化学与工业52・7（1999）。

K.Nakajima,N.Yamada,J.Chen,T.Yamashita et al.: "Bi-Sr-Ca-Cu-O intrinsic Josephson junctions fabricated by inhibitory ion implantation"lEEE Trans. Appl. Supercond.. 9・2. 4515-4518 (1999)

K. Nakajima、N. Yamada、J. Chen、T. Yamashita 等人：“通过抑制离子注入制造的 Bi-Sr-Ca-Cu-O 本征约瑟夫森结”lEEE Supercond.. 9・2。 4515-4518 (1999)

K.Nakajima,T.Yamashita,S.Sudo,and T.Tachiki: "High speed vortex motion in Bi_2Sr_2CaCu_2Oy intrinsic Josephson junctions fabricated by inhibiting ion implantation"Physica C. 341-348・1-4. 1599-1600 (2000)

K. Nakajima、T. Yamashita、S. Sudo 和 T. Tachiki：“通过抑制离子注入制造的 Bi_2Sr_2CaCu_2Oy 本征约瑟夫森结中的高速涡流运动”Physica C. 341-348・1-4 (2000)。