Frequency-tunable superconducting resonators via nonlinear kinetic inductance

Tunable Superconducting Split Ring Resonators

Tunable Resonators for Nonlinear Modal Interactions

Understanding the various mechanisms of nonlinear mode coupling in micro and nano resonators has become an imminent necessity for their successful implementation in practical applications. However, consistent, repeatable, and flexible experimental procedures to produce nonlinear mode coupling are lacking, and hence research into well-controlled experimental conditions is crucial. Here, we demon...

Superconducting Microstrip-Fed Antenna Coupled to a Microwave Kinetic Inductance Detector

A proper antenna to couple to a microstrip Microwave Kinetic Inductance Detector (MKID) is designed and simulated. A twin-slot microstrip-fed inline antenna is designed for frequency band of 600-720~GHz integrated with an elliptical lens and coupled to the MKID. A systematic design procedure for design of such antenna with microstrip inline feeding is presented. Whole structure of lens and twin...

Intermodulation gain in nonlinear NbN superconducting microwave resonators

We report the measurement of intermodulation gain greater than unity in NbN superconducting stripline resonators. In the intermodulation measurements we inject two unequal tones into the oscillator—the pump and signal—both lying within the resonance band. At the onset of instability of the reflected pump we obtain a simultaneous gain of both the idler and the reflected signal. The measured gain...

Unusual Nonlinear Dynamics Observed in NbN Superconducting Microwave Resonators

We report on some unusual nonlinear dynamics observed in several NbN superconducting stripline microwave resonators. Among the nonlinear effects observed: abrupt bifurcations within the resonance lineshape, hysteretic behavior, hysteresis loops changing direction, resonance shift and critical coupling. Weak links forming at the boundaries of the columnar structure of the NbN films are hypothesi...