Microwave Detection with a Superconducting Kinetic Inductance Amplifier*

Parametric amplifiers constructed from non-linear superconducting microwave resonators have become essential components in circuit quantum electrodynamics experiments. Most parametric amplifiers are driven at powers where they linearly amplify incoming microwave fields, but it is also possible to realize highly non-linear amplifiers by driving with a strong pump [1]. One class of non-linear amplifier is based on parametric self-oscillations induced by strong flux-pumping of a Joesphson parametric amplifier and has and has been used to measure superconducting qubits [2,3]. In this work, we present a new non-linear microwave amplifier based on parametric self-oscillations, whose nonlinearity is engineered instead from kinetic inductance [4]. We characterize the device’s sensitivity using calibrated microwave pulses. We also use it to implement a high-gain latched-readout of spin echo signals from an ensemble of ²⁰⁹Bi that are directly inductively coupled to the device.

 

[1] I. Siddiqi., et. al. RF-driven Josephson bifurcation amplifier for quantum measurement. Phys. Rev. Lett. 93(20):207002 (2004)

[2] Z. Lin., et. al. Josephson parametric phase-locked oscillator and its application to dispersive readout of superconducting qubits. Nature Comm. 5:4480 (2014)

[3] P. Krantz, et. al. Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator. Nature Comm. 7:11417 (2016)

[4] D. J. Parker, et. al. A near-ideal degenerate parametric amplifier. arXiv. 2108.10471 (2021)