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International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)

Evidence of 1.5 THz single-photon detection in quantum capacitance detectors via telegraph rate distribution asymmetry

Brian J. Pepper, Charles Mathias Bradford, Theodore Reck, P. M. Echternach

Published Aug 1, 2015• 0 citations
Publisher

Abstract

Quantum Capacitance Detectors (QCDs) are shot noise limited terahertz detectors. Radiation breaks Cooper pairs, causing quasiparticle poisoning of a charge qubit, read out by a microwave resonator. We find asymmetry in the distribution of telegraph transition rates, interpreted as resulting from discrete single-photon events.
DOI
10.1109/irmmw-thz.2015.7327828

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We observed a sweep rate dependence of the quantum capacitance in a single Cooper-Pair box used as the readout of a Quantum Capacitance Detector. A model was developed that fits the data over five orders of magnitude in sweep rate and optical signal power and provides a natural calibration of the absorbed power. We are thereby able to measure the noise equivalent power of the detector as a function of absorbed power. We find that it is shot-noise-limited in detecting 1.5 THz photons with absorbed power ranging from 1 × 10−22 W to 1 × 10−17 W.
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