Resolving Power of Visible-To-Near-Infrared Hybrid β-Ta/Nb-Ti- N Kinetic Inductance Detectors

Resolving Power of Visible-To-Near-Infrared Hybrid β-Ta/Nb-Ti- N Kinetic Inductance Detectors

Kouwenhoven, K. (TU Delft Tera-Hertz Sensing; SRON Netherlands Institute for Space Research)
Fan, D. (TU Delft Team Carlas Smith)
Biancalani, Enrico (Leiden Observatory)
de Rooij, S.A.H. (TU Delft Tera-Hertz Sensing; SRON Netherlands Institute for Space Research)
Karim, A.T. (TU Delft Team Raf Van de Plas)
Smith, C.S. (TU Delft Team Carlas Smith)
Murugesan, Vignesh (SRON Netherlands Institute for Space Research)
Thoen, David (TU Delft Tera-Hertz Sensing)
Baselmans, J.J.A. (TU Delft Tera-Hertz Sensing; SRON Netherlands Institute for Space Research)
de Visser, P.J. (SRON Netherlands Institute for Space Research)

2023

Kinetic inductance detectors (KIDs) are superconducting energy-resolving detectors, sensitive to single photons from the near-infrared to ultraviolet. We study a hybrid KID design consisting of a β-phase tantalum (β-Ta) inductor and a Nb-Ti-N interdigitated capacitor. The devices show an average intrinsic quality factor Qi of 4.3×105±1.3×105. To increase the power captured by the light-sensitive inductor, we 3D print an array of 150×150μm resin microlenses on the backside of the sapphire substrate. The shape deviation between design and printed lenses is smaller than 1μm, and the alignment accuracy of this process is δx=+5.8±0.5μm and δy=+8.3±3.3μm. We measure a resolving power for 1545-402 nm that is limited to 4.9 by saturation in the KID's phase response. We can model the saturation in the phase response with the evolution of the number of quasiparticles generated by a photon event. An alternative coordinate system that has a linear response raises the resolving power to 5.9 at 402 nm. We verify the measured resolving power with a two-line measurement using a laser source and a monochromator. We discuss several improvements that can be made to the devices on a route towards KID arrays with high resolving powers.

http://resolver.tudelft.nl/uuid:cdfbf2e5-a153-4c53-bee1-61b8adafc98c

https://doi.org/10.1103/PhysRevApplied.19.034007

2331-7019

Physical Review Applied, 19 (3)

Institutional Repository

journal article

© 2023 K. Kouwenhoven, D. Fan, Enrico Biancalani, S.A.H. de Rooij, A.T. Karim, C.S. Smith, Vignesh Murugesan, David Thoen, J.J.A. Baselmans, P.J. de Visser