On-chip time resolved detection of quantum dot emission using integrated superconducting single photon detectors

TL;DR

This paper demonstrates on-chip detection of quantum dot emission using integrated superconducting nanowire detectors, achieving high efficiency and ultrafast timing, advancing integrated quantum photonic circuits.

Contribution

It introduces an integrated system combining quantum dots, waveguides, and superconducting detectors with high detection efficiency and precise time resolution.

Findings

Evanescent coupling yields two orders of magnitude higher detection efficiency.

Quantum dot exciton lifetime measured at approximately 0.93 ns.

Detection jitter as low as 72 ps demonstrates ultrafast timing capabilities.

Abstract

We report the routing of quantum light emitted by self-assembled InGaAs quantum dots (QDs) into the optical modes of a GaAs ridge waveguide and its efficient detection on-chip via evanescent coupling to NbN superconducting nanowire single photon detectors (SNSPDs). Individual QD light sources embedded within such integrated nano-photonic circuits are highly attractive for the realization of quantum photonic circuits for many applications in photonic information science. Here, we demonstrate that the waveguide coupled SNSPDs primarily detect QD luminescence with scattered photons from the excitation laser being negligible by comparison. The SNSPD detection efficiency from the evanescently coupled waveguide modes is shown to be two orders of magnitude higher when compared with operation under normal incidence illumination. Furthermore, in-situ time resolved measurements show an average exciton lifetime of 0.93 \pm 0.03 ns when recorded with the integrated detector with an ultrafast timing jitter of only 72 \pm 2 ps showing the great potential of this highly integrated quantum optics system.