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

Journal article (2023)

Authors

K. Kouwenhoven SRON Netherlands Institute for Space Research, Tera-Hertz Sensing - EEMCS
D. Fan Team Carlas Smith - Mechanical, Maritime and Materials Engineering
Enrico Biancalani Leiden Observatory
S.A.H. de Rooij Tera-Hertz Sensing - EEMCS , SRON Netherlands Institute for Space Research
A.T. Karim Team Raf Van de Plas - Mechanical, Maritime and Materials Engineering
C.S. Smith Team Carlas Smith - Mechanical, Maritime and Materials Engineering
Vignesh Murugesan SRON Netherlands Institute for Space Research
David Thoen Tera-Hertz Sensing - EEMCS
J.J.A. Baselmans SRON Netherlands Institute for Space Research, Tera-Hertz Sensing - EEMCS
P.J. de Visser SRON Netherlands Institute for Space Research
Research Group
Tera-Hertz Sensing (EEMCS) (TU Delft)
Copyright: © 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
DOI: https://doi.org/10.1103/PhysRevApplied.19.034007
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Published Date

2023

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Tera-Hertz Sensing

Abstract

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.