Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 49: Poster Session: Superconductivity
TT 49.35: Poster
Mittwoch, 3. April 2019, 15:00–18:30, Poster D
Spectral properties of a SQUID-terminated tunable coplanar resonator at high microwave frequencies — •Sergey Lotkhov — Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig Germany
An integrated superconducting circuit including a shunted Josephson junction as an irradiation source and a single-electron transistor as a photon detector (see, e.g., Ref. [1] for a similar setup), was implemented for an in−situ study at T = 15 mK and up to f ∼ 100 GHz of the transmission spectrum of a tunable high-frequency resonator. The resonator was composed of a sub-mm-long coplanar waveguide connected to a magnetic-flux-tunable Josephson interferometer (SQUID). All basic components were made of Aluminum in the same shadow-deposition cycle. The transistor was operated as a threshold-type detector utilizing photon-activated sequences of Cooper pair – Electron cotunneling cycles to produce the current signal. Varying the applied flux Φext over multiple flux quanta Φ0 demonstrated significant signal suppression within limited, frequency-dependent ranges centered around the frustration points Φext=Φ0(n+1/2). Sharp and almost flux independent geometric resonances were observed outside of the suppression ranges. The reported deep modulation of the transmitted signal is promising for application in fast frequency-selective propagation switches and microwave routing on-chip. The developed chip-scale spectrometric circuit provides an invaluable microwave tool for the point-of-use study of microscopic objects.
[1] B. Jalali-Jafari et al., Appl. Sci. 6, 35 (2016).