Development of SIS mixers for 1 THz
Development of SIS mixers for 1 THz
复制标题
开发 1 THz 的 SIS 混频器
DOI：
10.1117/12.317386
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
J. A. Stern
中科院分区：
文献类型：
--
作者：
J. Zmuidzinas;J. Kooi;J. Kawamura;G. Chattopadhyay;B. Bumble;H. Leduc;J. A. Stern
基于铌隧道结的SIS外差混频器技术现在已经被推到超过1 THz的频率，清楚地表明SIS结能够以高达能隙频率（4（Delta）/h）的两倍的频率进行混频。然而，由于片上调谐电路中的大量欧姆损耗，性能在铌的差距频率（2（Delta）/h约等于700 GHz）以上迅速下降。为了解决这个问题，调谐电路应该使用具有更大能隙的超导膜来制造，例如NbN;不幸的是，NbN膜通常在亚毫米波段具有大量的过量表面电阻。相比之下，SIS混频器的测量，我们在本文中提出的NbTiN薄膜的损耗可以是相当低的。
SIS heterodyne mixer technology based on niobium tunnel junctions has now been pushed to frequencies over 1 THz, clearly demonstrating that the SIS junctions are capable of mixing at frequencies up to twice the energy gap frequency (4(Delta) /h). However, the performance degrades rapidly above the gap frequency of niobium (2(Delta) /h approximately equals 700 GHz) due to substantial ohmic losses in the on-chip tuning circuit. To solve this problem, the tuning circuit should be fabricated using a superconducting film with a larger energy gap, such as NbN; unfortunately, NbN films often have a substantial excess surface resistance in the submillimeter band. In contrast, the SIS mixer measurements we present in this paper indicate that the losses for NbTiN thin films can be quite low.