arXiv subjects

I. E. Zadeh

Publications and source records attributed to I. E. Zadeh.

2 recordsLinked to original sources

arXiv2025

Laser-Induced Relaxation Oscillations in Superconducting Nanobridge Single Photon Detectors

We demonstrate novel laser-induced relaxation oscillations in superconducting nanowire single photon detectors (SNSPDs). These oscillations appear when a voltage biased NbTiN nanobridge detector is illuminated with intense pulsed laser light at a repetition rate of $\sim19\text{MHz}$. They differ from the well-known relaxation oscillations by a step-wise increase in frequency and phase locking of the oscillations to the laser pulses. We create a model that incorporates electrical feedback and excludes thermal effects to simulate and explain the origin of the observed laser-induced relaxation oscillations. Qualitative agreement to the experiment is achieved using realistic values for the parameters in the model.

cond-mat.supr-con↗

arXiv2025

Markov chain Monte Carlo Detector Tomography applied to a NbTiN nanobridge

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 1-photon threshold detector as compared to a detector with non-unity 1-photon internal quantum efficiency. From a statistical analysis of our measurements (at $T=4.23\pm0.01K$, $I=29.4\pm0.1μA$, $I/I_\text{switch}=0.90\pm0.01$) we find an external quantum efficiency $η=(1.60\pm0.05)\cdot10^{-6}$, a 1-photon internal quantum efficiency $p_1=0.568\pm0.008$ and unity multi-photon (2 or more) internal quantum efficiency.

quant-ph↗