Research on Fabrication of Superconducting Receiver for Submillimeter-Wave Measurement

本研究的目的是研制一种新型的亚毫米波超导振荡器。在本研究中，我们得到了以下结果：1。利用NbN/Pb Josephson结和Nb/Al/Nb Josephson结，成功地观察了FFO在100GHz ~ 1500GHz频率范围内的振荡特性。使用前一结，我们证明了在带状线中可以感应到1-3 mA的电流。使用后一个结，我们成功地获得了频率超过1thz - 2的振荡输出。采用电感耦合方法的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，我们用NbN/Pb Josephson结和NbN/Nb_2O_5/Nb制成的带状线制作了FFO，并成功地证明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.