Presentation
28 August 2024 Single photon response of MKIDs made of disordered superconductors
Steven de Rooij, Thomas Rugers, Kevin Kouwenhoven, Yannic Alkemade, Tonny Coppens, Jochem Baselmans, Pieter de Visser
Author Affiliations +
Abstract
Using disordered superconductors, like β-Ta, TiN, Hf and PtSi, for MKIDs has the potential to improve the photon absorption efficiency, η, over a broad wavelength range. However, the resolving power, R, of these MKIDs is not higher than 20 at 1µm, while the fundamental Fano limit is around 65. To improve R, the signal-to-noise ratio must be increased. We measure the single photon pulse response of β-Ta MKIDs and show that the pulse duration is limited by disorder in two ways. First, the initial pulse decay is faster than exponential, which we attribute to slow quasiparticle diffusion. Second, the decay time of the pulse tail is faster due to low energetic, localized quasiparticles. Both these effects do not occur in conventional Al at the same experimental conditions. These results imply a trade-off between η and R and shows that improving MKIDs by using disordered superconductors is not straightforward.
Conference Presentation
© (2024) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Steven de Rooij, Thomas Rugers, Kevin Kouwenhoven, Yannic Alkemade, Tonny Coppens, Jochem Baselmans, and Pieter de Visser "Single photon response of MKIDs made of disordered superconductors", Proc. SPIE PC13103, X-Ray, Optical, and Infrared Detectors for Astronomy XI, PC1310304 (28 August 2024); https://doi.org/10.1117/12.3017931
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