We have designed, fabricated and tested a frequency-tunable high-Qsuperconducting resonator made from a niobium titanium nitride film. Thefrequency tunability is achieved by injecting a DC current through acurrent-directing circuit into the nonlinear inductor whose kinetic inductanceis current-dependent. We have demonstrated continuous tuning of the resonancefrequency in a 180 MHz frequency range around 4.5 GHz while maintaining thehigh internal quality factor $Q_i> 180,000$. This device may serve as a tunablefilter and find applications in superconducting quantum computing andmeasurement. It also provides a useful tool to study the nonlinear response ofa superconductor. In addition, it may be developed into techniques formeasurement of the complex impedance of a superconductor at its transitiontemperature and for readout of transition-edge sensors.
展开▼
