In situ magneto-optical imaging of superconducting resonators under radio-frequency excitation

Abstract

From quantum processors to single-photon detectors, planar superconducting resonators are key to future technologies. However, understanding their limitations is crucial for unlocking their full potential. This work aims to investigate the influence of radio-frequency (RF) excitation on thermomagnetic instabilities leading to magnetic flux avalanches in the superconducting thin film, a phenomenon that significantly compromises the quality factor of the resonators. To gain deeper insight into these flux dynamics, magneto-optical imaging (MOI) is combined, for the first time, with concomitant radio-frequency measurements. These findings provide insight into the role of RF excitation in superconducting resonators and lay the groundwork for future studies. Furthermore, we demonstrate that the MOI indicator substantially alters the electromagnetic environment and affects the magnetic flux dynamics, providing first direct evidence of the invasiveness of the MOI indicator.