Local Whole-Device Scanning of Distortion in Superconducting Microwave Resonators

Using a near-field microwave technique, two-dimensional images have been made of the second- and third-order intermodulation distortion (IMD) of Tl
₂
Ba
₂
CaCu
₂
O
₈
and YBa
₂
Cu
₃
O
₇
thin film microwave resonators. It was found that second- and third-order IMD do not have identical spatial distributions, which indicates that physical mechanisms play different roles in their generation. This technique enables the investigation of the roles of these mechanisms. As an illustration, the sensitivity to magnetic fluxons of the two orders is described, with second order being more sensitive to fluxon density.