InAs(P)/InP QDs as sources of single indistinguishable photons at 1.55 µm

Daniel A. Vajner, Maja Wasiluk, Pawel Holewa, Emilia Ostój-Zięba, Martin von Helversen, Aurimas Sakanas, Alexander Huck, Kresten Yvind, Niels Gregersen, Anna Musial, Marcin Syperek, Elizaveta Semenova, Tobias Heindel

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Epitaxial quantum dots (QDs) exhibit substantial promise as non-classical light sources in quantum technologies. In particular, the generation of single, indistinguishable photons on demand is pivotal for advanced quantum cryptographic key exchange algorithms. This study investigates the quantum optical characteristics of single photons emitted by InAs(P)/InP QDs heterogeneously integrated with silicon. The investigated QDs, grown via metalorganic vapor-phase epitaxy in the Stranski-Krastanow mode, showcase the emission at ~1.55 µm, indispensable for long-haul, low-loss optical transmission through standard silica fibers. The photon extraction efficiency is enhanced to ~10% by employing a metallic mirror beneath the QDs in combination with a top mesa structure [4]. Our study confirms the single-photon emission from the QDs through measurements of the second-order autocorrelation function, revealing 𝑔(2) (0) = 0.005(4) for biexciton under two photon resonant excitation of the biexciton-exciton radiative cascade. To investigate the degree of indistinguishability of emitted photons, we conducted also HongOu-Mandel-type two-photon interference (TPI) experiment. The TPI visibility, quantifying the degree of indistinguishability of emitted photons, is crucial in examining the coherence of carriers within the QD. Exciton-phonon interactions and carrier-carrier scattering significantly contribute to the degradation of coherence within the QDs. Using direct integration of the raw experimental data or fitting to a model, we evaluated the raw (i.e., ‘as measured’) and the post-selected TPI visibility up to 35% and 73%, respectively [6], which represents a
state-of-the-art achievement for InAs/InP QDs emitting at 1.55 µm. The significant progress in the generation of single indistinguishable photons in the telecom C-band offers crucial insights into their potential integration within quantum information technologies.
Original languageEnglish
Publication date2024
Number of pages1
Publication statusPublished - 2024
Event12th International Conference on Quantum Dots - Audimax TUM, Munich, Germany
Duration: 18 Mar 202422 Mar 2024


Conference12th International Conference on Quantum Dots
LocationAudimax TUM
Internet address


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