Pieter de Visser and Jochem Baselmans: 'Superconducting detector fulfills 10 year old promise'


Pieter de Visser, Jochem Baselmans, Juan Bueno, Nuria Llombart and Teun Klapwijk have proven for the first time that a special superconducting detector is sensitive enough to be used on a space telescope. Read their article in the magazine Nature Communications here and/or read more in Dutch here.


In a superconductor, in which electrons are paired, the density of unpaired electrons should become zero when approaching zero temperature. Therefore, radiation detectors based on breaking of pairs promise supreme sensitivity, which we demonstrate using an aluminum superconducting microwave resonator. Here we show that the resonator also enables the study of the response of the electron system of the superconductor to pair-breaking photons, microwave photons and varying temperatures. A large range in radiation power (at 1.54 THz) can be chosen by carefully filtering the radiation from a blackbody source. We identify two regimes. At high radiation power, fluctuations in the electron system caused by the random arrival rate of the photons are resolved, giving a straightforward measure of the optical efficiency (48±8%) and showing an unprecedented detector sensitivity. At low radiation power, fluctuations are dominated by excess quasiparticles, the number of which is measured through their recombination lifetime.