SKM 2023 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 24: Quantum dots: Optics
HL 24.4: Vortrag
Mittwoch, 29. März 2023, 10:15–10:30, POT 151
Exploring the double pulse excitation scheme for generation of photon number coherent states — Yusuf Karli1, •Daniel Vajner2, Florian Kappe1, Paul Hagen3, Lena Hansen4,5, Saimon Filipe Covre da Silva6, Thomas Bracht7, René Schwarz1, Christian Schimpf6, Vikas Remesh1, Juan Loredo4,5, Armando Rastelli6, Vollrath Martin Axt3, Philip Walther4,5, Doris Reiter7, Tobias Heindel2, and Gregor Weihs1 — 1Institute für Experimentalphysik, Universität Innsbruck, Innsbruck, Austria — 2Institute of Solid State Physics, Technische Universität Berlin, Berlin, Germany — 3Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth, Germany Kepler University Linz, Linz, Austria — 4University of Vienna, Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), Vienna, Austria — 5Christian Doppler Laboratory for Photonic Quantum Computer, Faculty of Physics, University of Vienna, Vienna, Austria — 6Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Linz, Austria — 7Condensed Matter Theory, Department of Physics, TU Dortmund, 44221 Dortmund, Germany
High-purity, high-brightness single photon sources are crucial tools for realizing quantum communication networks relying on high-security protocols based on the quantum key distribution (QKD). The pursuit for efficient single-photon sources has led to semiconductor quantum dots which have recently emerged as high-brightness, on-demand single-photon sources for QKD implementations. An important property concerning the security in single-photon QKD is the so-called photon number coherence (PNC). While most of the existing schemes realize this based on phase randomization, thereby sacrificing photon brightness for it, here we demonstrate a new route toward the tailored generation of various degrees of PNC from a quantum dot. We perform a stimulated two-photon excitation of a quantum dot and demonstrate a two-fold enhancement in the brightness of the generated single photons. Facilitated by the abundant tuning parameters like polarization, time control, and excitation power in this excitation method, we demonstrate a controlled generation of varying degrees of PNC states from the quantum dot. Our results pave the way for the realization of bright and efficient nanoscale sources of highly indistinguishable, tunable PNC photon states for practical QKD devices.