| Invited Talk

Name of the Speaker: Gregor Sauer
Venue: ESB-234 (Malaviya Hall)
Date/Time: 5th November 2024 (Tuesday), 3:00 PM
Title: Resolving Photon Numbers Using Ultra-High-Resolution Timing of a Single Superconducting Nanowire Detector

Abstract :

(1) Photon-number-resolving (PNR) detectors play a crucial role in advancing photonic quantum communications, computing, and sensing. PNR is commonly achieved by multiplexing onto several superconducting nanowire single-photon detectors (SNSPD) or using transition-edge sensors. This comes at the cost of resource overhead or long recovery times. In this work, we showcase the PNR capability of conventional SNSPDs through ultraprecise time-tagging of the rising and falling edges of electrical pulses generated by the detector. This technique offers a practical method for achieving PNR with high detection efficiency, fast operation, and little resource overhead.

(2) We show the relevance and implementation of a polarization compensation system for QKD with polarization-entangled photon pairs on a 75km long deployed inter-city fiber link between the cities of Jena and Erfurt.

Speaker Bio:

Gregor is a PhD student at the Max Plant School of Photonics, University of Jena, and Fraunhofer Institute for Applied Optics and Precision Engineering in Jena, Germany. His research focuses on building QKD systems for real-world applications, including the development of entangled photon pair sources, quantum link monitoring and stabilization systems, as well as quantum state and detector tomography.