Markov chain Monte Carlo detector tomography applied to a NbTiN nanobridge

Journal Article (2025)
Author(s)

Frederik B. Baalbergen (Universiteit Leiden)

Iman Esmaeil Zahed (TU Delft - ImPhys/Esmaeil Zadeh group)

M. P. van Exter (Universiteit Leiden)

M. J.A. de Dood (Universiteit Leiden)

Research Group
ImPhys/Esmaeil Zadeh group
DOI related publication
https://doi.org/10.1063/5.0271909
More Info
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Publication Year
2025
Language
English
Research Group
ImPhys/Esmaeil Zadeh group
Issue number
24
Volume number
126
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Abstract

We demonstrate the use of a flexible and highly accurate Markov chain Monte Carlo quantum detector tomography method as a minimization algorithm to best describe the response of an efficient 120 nm wide NbTiN superconducting nanobridge single photon detector. Separation of the internal quantum efficiency and external quantum efficiency is possible due to the difference in saturation behavior of an ideal one-photon threshold detector as compared to a detector with non-unity one-photon internal quantum efficiency. From a statistical analysis of our measurements (at T = ( 4.23 ± 0.01 ) K , I = ( 29.4 ± 0.1 ) μ A , I / I switch = ( 0.90 ± 0.01 ) ), we find an external quantum efficiency of η = ( 1.60 ± 0.05 ) × 10 − 6 , a one-photon internal quantum efficiency of p 1 = 0.568 ± 0.008 , and a unity multi-photon (two or more) internal quantum efficiency.