Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 12: Symposium: Cryodetectors and SQUID

TT 12.7: Vortrag

Dienstag, 26. Februar 2008, 12:15–12:30, H 0104

Scanning THz-Microscopy of microwave devices with a Josephson-Cantilever — •Christian Brendel, Felix Stewing, and Meinhard Schilling — TU Braunschweig, Institut für Elektrische Messtechnik und Grundlagen der Elektrotechnik, Hans-Sommer-Strasse 66, D-38106 Braunschweig, Germany

Microwave devices are operated at very high frequencies ranging up to the THz-regime. For characterization of transmission lines, filters and directional couplers at these very high frequencies new instruments are required. We present the set-up and applications of our scanning THz-electronics prober STEP. As scanning sensor we employ a Josephson junction from the high-temperature superconductor YBa₂Cu₃O₇ on a vibrating cantilever prepared from a SrTiO₃-bicrystal. This superconducting detector is cooled to a temperature of about 30 K by a cryocooler. Despite this low temperature of the cantilever, which is about 10 µ m above its surface, the microwave device under investigation remains at room temperature. Based on this set up in a vacuum chamber we investigate the microwave properties of devices at frequencies of up to 768 GHz with a spatial resolution of 10 µ m far below the corresponding wavelengths. For the higher frequencies we couple far-infrared laser radiation from a CO₂-laser pumped molecular laser system into the chamber. Applications of this novel instrument to microwave devices are demonstrated.