Imaging local sources of intermodulation in superconducting microwave devices

• Published in: IEEE transactions on applied superconductivity 2003-06, Vol.13 (2), p.340-343
• Main Authors: Zhuravel, A.P., Ustinov, A.V., Abraimov, D., Anlage, S.M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; High temperature superconductors; High-tc films; Integrated optics. Optical fibers and wave guides; Laser beams; Masers; Microscopy; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwave imaging; Optical and optoelectronic circuits; Optical modulation; Physics; Radio frequency; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Superconducting devices; Superconducting films and low-dimensional structures; Superconducting materials; Superconducting microwave devices; Superconductivity
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2003.813731

This work presents new experimental results on low-temperature (LT) characterization of local RF properties of passive superconducting (SC) microwave devices using a novel laser scanning microscope (LSM). In this technique, a modulated laser beam is focused onto and scanned over the surface of a resonant SC device to probe the spatial distribution of RF current. The highly localized photo-induced change of the kinetic inductance of the SC device produces both a shift of the resonant frequency f/sub 0/ and change of the quality factor Q. An image of these changes is recorded as the laser spot is scanned over the device. We present the first measurements of spatially resolved intermodulation response in a high temperature superconducting (HTS) co-planar waveguide resonator, opening up a new window into the local origins of nonlinearity in the HTS materials.