Accurate Real-Time Monitoring of Quality Factor and Center Frequency of Superconducting Resonators
Journal article, 2014

In this paper, we track both center frequency and quality factor of a superconducting microwave resonator with very high precision using a modified Pound-Drever-Hall frequency locking scheme. The quality factor measurements can be done with high enough bandwidth to study different processes in a superconducting resonator in real time. With this added functionality, the frequency readout remains unaffected, with typical accuracy around 10-30 Hz/root Hz, whereas the cavity loss rate can be determined to within 0.1% on a millisecond time scale (34 dB/root Hz). As we demonstrate, this can be particularly useful for electron spin resonance measurements, where we achieve a minimum number of detectable spins coupled to the resonator N = 5 . 10(5) spins/root Hz, based on quality factor measurements. It also enables the study of fast dynamic processes, for example, vortex dynamics, in these devices on a short time scale.

Electron spin resonance (ESR)

Pound-Drever-Hall (PDH) locking

superconducting microwave resonators


Sebastian Erik de Graaf

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Andrey Danilov

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Sergey Kubatkin

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

IEEE Transactions on Applied Superconductivity

1051-8223 (ISSN)

Vol. 24 6

Subject Categories

Electrical Engineering, Electronic Engineering, Information Engineering



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