Full text loading...
SQUID photographs and circuit schematic. [(a) and (b)] Photographs of two SQUID designs. A low-pass filter takes up the bottom half of each photograph and the waveguide is just visible at the top. In (a), the SQUID is wired in series with the resonator. In (b), the SQUID inductively couples to the resonator. Both designs are gradiometric to reduce coupling to the environment. (c) Simplified schematic of the readout circuit, with the resonators modeled as parallel resonators.
Flux dependence of resonators 30 at 40 pW incident power. (a) Transmitted power as a function of frequency at three different values of flux through the SQUID, 0 (red), (green), and (blue). (b) Resonance circles for the same three values of flux, where 4.4654 GHz is marked (x) on each circle. (c) Angle of 4.4654–Ghz on the resonance circle.
Flux noise spectrum of resonator 30. The inset magnifies the spectrum around a 100 kHz flux tone injected through the input coil to calibrate the noise.
(Red line) A flux signal applied to resonator 17. (Blue dots) Flux in the SQUID determined from the phase shift of the transmitted phase response, each dot corresponding to a single multiple flux quanta ramp of the modulation. The two insets show the transmitted phase as a function of time (expanded scale) for both a reference signal of 0 (black line) and the input signal (blue dots).
Article metrics loading...