Modulated optical reflectance characterization of high temperature superconducting thin film microwave devices

The modulated optical reflectance (MOR) technique is shown to provide a room temperature, noncontact, nondestructive and high spatial resolution means of assessing high temperature superconducting (HTS) thin film quality. Room temperature MOR characterizations of a number of 8 GHz planar HTS resonators indicating a range of property variations and local degradations in HTS film performance are shown to be consistent with results obtained at low temperatures by the electron beam induced voltage contrast technique. The microwave performances of some of the resonators are found to exhibit nonlinear characteristics that can be explained by HTS defects revealed by the MOR technique.