Research on Fabrication of Superconducting Receiver for Submillimeter-Wave Measurement

本研究的目的是研制一种新的测量亚毫米波的超导振荡器。1.磁通流振荡器（FFO）的性能评价我们成功地观察到了NbN/Pb约瑟夫森结和Nb/Al/Nb约瑟夫森结在100 ~ 1500 GHz频率范围内的振荡特性。使用前结，我们表明，1-3 mA的电流可以在带状线中感应。利用后一种结，我们成功地获得了频率大于1 THz的振荡输出。2.电感耦合法阻抗匹配电路的研制通过仿真表明，利用双谐振效应可以实现宽带匹配电路。利用这种设计，我们制作了一个由NbN/Nb_2O_5/Nb组成的带状线和NbN/Pb约瑟夫森结构成的FFO，成功地验证了电感耦合方法的有效性。

The propose of this research is to develop a new superconducting oscillator for measuring submillimeter waves. In this research we obtained the following results:1.Evaluation of the Performance of the Flux-Flow Oscillator (FFO)We succeeded in the observation of the oscillation characteristics in the frequency range between 100GHz and 1500GHz using NbN/Pb Josephson junctions and Nb/Al/Nb Josephson junctions. Using the former junction we showed that the currents of 1-3 mA can be induced in the striplines. Using the latter junction we succeeded in obtaining oscillation output at frequencies more than 1THz.2.Development of Impedance Matching Circuit with Inductive Coupling MethodWe showed by simulation that broad band matching circuits can be realized using double resonance effects. Using this design we fabricated an FFO using NbN/Pb Josephson junction and a stripline made of NbN/Nb_2O_5/Nb, and succeed in demonstrating the validity of the inductive coupling method.