Detection and Measurement of Picoseconds-Pulsed Laser Energy Using a NbTiN Superconducting Filament

K. Harrabi*, K. Gasmi, A. Mekki, H. Bahlouli, S. Kunwar, M. V. Milosevic

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


We investigate non-equilibrium states created by a laser beam incident on a superconducting NbTiN filament subject to an electrical pulse at 4 K. In absence of the laser excitation, when the amplitude of the current pulse applied to the filament exceeds the critical current value, we monitored the delay time t d that marks the collapse of the superconducting phase which is then followed by a voltage rise. We linked the delay time to the applied current using the time-dependent Ginzburg-Landau (TDGL) theory, which enabled us to deduce the cooling (or heat-removal) time from the fit to the experimental data. Subsequently, we exposed the filament biased with a current pulse close to its critical value to a focused laser beam, inducing a normal state in the impact region of the laser beam. We showed that the energy of the incident beam and the incurred delay time are related to each other by a simple expression, that enables direct measurement of incident beam energy by temporal monitoring of the transport response. This method can be extended for usage in single-photon detection regime, and be used for accurate calibration of an arbitrary light source.

Original languageEnglish
Article number2400205
JournalIEEE Transactions on Applied Superconductivity
Issue number5
StatePublished - 1 Aug 2023

Bibliographical note

Publisher Copyright:
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  • Critical current density
  • hotspot
  • non-equilibrium superconductivity
  • superconducting single photon detection

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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