# Nanosecond thermometry with Josephson junction

## TL;DR

This paper introduces a new superconducting weak link-based thermometry method that achieves nanosecond temporal resolution, enabling ultra-fast temperature measurements at the nanoscale with potential applications in calorimetry and radiation detection.

## Contribution

The paper presents the first demonstration of nanosecond thermometry using a Josephson junction, significantly surpassing previous temporal resolution limits in mesoscopic thermometry.

## Key findings

- Achieved nanosecond temporal resolution in electron temperature measurement.
- Demonstrated fast relaxation dynamics in a superconducting wire.
- Extended the temporal resolution of thermometry by over two orders of magnitude.

## Abstract

We demonstrate a novel approach to thermometry at the nanoscale exploiting a superconducting weak link. Such a weak link probed with nanosecond current pulses serves as a temperature sensing element and, due to the fast inherent dynamics, is capable of delivering unprecedented temporal resolution. We employ the thermometer to measure dynamic temperature of electrons in a long superconducting wire relaxing to the bath temperature after application of the heating pulse. Our measurement delivers nanosecond resolution thus providing the proof-of-concept of the fastest-todate all-solid-state thermometry. Our method improves the state-of-the-art temporal resolution of mesoscopic thermometry by at least two orders of magnitude, extending temporal resolution of existing experiments and introducing new possibilities for ultra-sensitive calorimeters and radiation detectors.