Superconducting Integrated Microcircuits Based on NbTiN/Al Transmission Lines Operating at Frequencies Above 1 THz

The results of the development and testing of superconducting integrated microcircuits based on NbTiN/Al transmission lines at the frequencies up to 1.1 THz are presented. The integrated circuits consist of a slot planar antenna made of thin film of NbTiN coupled to a NbTiN/Al microstrip line, and a superconductor-insulator-superconductor (SIS) junction based on Nb/AlN/NbN operating as a terahertz (THz) detector. Two different designs having the operating range of 0.9-1.2 THz were numerically simulated, fabricated and experimentally tested. A strong pumping of SIS detector by a signal of the backward wave oscillator (BWO) around frequency of 1.05 THz was observed, which demonstrated the applicability of fabricated transmission lines at frequencies higher than 750 GHz, where the traditionally used Nb/Nb transmission lines cannot operate.