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Microwave photon detection
E. Il’ichev
Leibniz Institute of Photonic Technology, P.O. Box 100239, D-07702 Jena, Germany
We demonstrate the narrow switching distribution of an underdamped Josephson
junction from the zero to the finite voltage state at millikelvin temperatures. The width
of the switching distribution at a nominal temperature of about 20mK was 4.5 nA,
which corresponds to an effective noise temperature of the device below 60 mK. We
argue that such junctions can be used as ultrasensitive detectors of the single
photons in the GHz range, operating close to the quantum limit: a given initial (zero
voltage) state can be driven by an incoming signal to the finite voltage state. The
Hamiltonian for a λ/4 resonator shunted by a current-biased Josephson junction is
derived and it explicitly includes a quantum treatment of the switching dynamics. The
full quantum dynamics of the system are analyzed numerically. Results of the first
experimental realization of this system are shown.
References
C. Andersen et.al. Phys.Rev. A 87, 052119 (2013)
G. Oelsner et al., Appl. Phys. Lett. 103, 142605 (2013).
C. Andersen et.al. Phys.Rev. A 89, 033853 (2014)