Controlling the photon number coherence of solid-state quantum light sources for quantum cryptography

Yusuf Karli (Corresponding author), Daniel A. Vajner, Florian Kappe, Paul C.A. Hagen, Lena M. Hansen, René Schwarz, Thomas K. Bracht, Christian Schimpf, Saimon F. Covre da Silva, Philip Walther, Armando Rastelli, Vollrath Martin Axt, Juan C. Loredo, Vikas Remesh, Tobias Heindel, Doris E. Reiter, Gregor Weihs

Publications: Contribution to journalArticlePeer Reviewed

Abstract

Quantum communication networks rely on quantum cryptographic protocols including quantum key distribution (QKD) based on single photons. A critical element regarding the security of QKD protocols is the photon number coherence (PNC), i.e., the phase relation between the vacuum and one-photon Fock state. To obtain single photons with the desired properties for QKD protocols, optimal excitation schemes for quantum emitters need to be selected. As emitters, we consider semiconductor quantum dots, that are known to generate on-demand single photons with high purity and indistinguishability. Exploiting two-photon excitation of a quantum dot combined with a stimulation pulse, we demonstrate the generation of high-quality single photons with a controllable degree of PNC. The main tuning knob is the pulse area giving full control from minimal to maximal PNC, while without the stimulating pulse the PNC is negligible in our setup for all pulse areas. Our approach provides a viable route toward secure communication in quantum networks.
Original languageEnglish
Article number17
Number of pages9
Journalnpj Quantum Information
Volume10
Issue number1
DOIs
Publication statusPublished - 27 Jan 2024

Austrian Fields of Science 2012

  • 103025 Quantum mechanics
  • 103021 Optics

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