Ultra-high-rate detection of entangled photon pairs

TL;DR

This paper demonstrates ultra-high-rate detection of entangled photon pairs using advanced superconducting detectors, achieving over 3 million counts per second, significantly surpassing previous limits and enabling faster quantum information processing.

Contribution

The study introduces the use of 16-pixel SNSPDs to overcome detector dead time, enabling multi-Mcps coincidence detection of entangled photons for the first time.

Findings

Achieved over 3 million coincidence counts per second.

Demonstrated high-speed two-photon interference and CHSH inequality tests.

Enabled faster quantum information processing applications.

Abstract

The high-rate detection of entangled photons is essential for advancing photonic quantum information processing. Although several experimental demonstrations have been reported, the achievable coincidence rates have so far remained limited. One of the main bottlenecks arises from the dead time of single-photon detectors, which constrains coincidence detection at high photon-pair generation rates. In this work, we employ 16-pixel superconducting nanowire single-photon detectors (SNSPDs) to mitigate the impact of detector dead time. Consequently, we achieve coincidence rates exceeding 3 million counts per second (Mcps) in two-photon interference and CHSH inequality experiments using 5-GHz clocked sequential time-bin entangled photon pair source. To the best of our knowledge, this is the first demonstration of multi-Mcps coincidence detection of entangled photons, paving the way for high-speed entangled-photon-based quantum information processing.