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Electrically Tunable Orbital Coupling and Quantum Light Emission from O-Band Quantum Dot Molecules

P. S. Avdienko1,2,*, L. Hanschke2,3, Q. Buchinger4, N. Akhlaq1,2, I. Lubianskii5, E. Weber5, H. Riedl5, M. Kamp4, T. Huber-Loyola4,6,7 et al.

S. Höfling4, A. T. Pfenning4,6, K. Müller2,3, and J. J. Finley1,2,†

  • *Contact author: pavel.avdienko@tum.de
  • †Contact author: jj.finley@tum.de
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PRX Quantum 7, 033070 – Published 30 September, 2026

DOI: https://doi.org/10.1103/xx5b-rlgx

Abstract

We present the observation of electrically tunable quantum coupling of orbital states in individual InAs/InGaAs quantum dot molecules emitting in the telecom O-band (∼1.3  μm). By tuning the static electric field along the growth axis of the quantum dot (QD)-molecule, we observe pronounced anticrossings between excitonic transitions and determine the dependence of the interdot electron tunnel coupling on the interdot separation. As the electric field applied along the growth axis of the QD-molecules increases, positively charged exciton complexes sequentially emerge in the time-integrated emission spectra due to electrons escaping from the system while holes remain trapped. Moreover, for strong pumping, biexciton emission from the O-band molecules is identified. We demonstrate single-photon emission from the InAs/InGaAs QD-molecule emitting around 1.3  μm with a g(2)(0) = 0.017±0.002 and explore the impact of tuning orbital coupling on the second-order correlation function.

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Our manuscript reports the synthesis and direct observation of electrically tunable quantum coupling of orbital states in individual InAs/InGaAs quantum dot molecules emitting in the telecom O-band (∼1.3  μm). By tuning the static electric field along the growth axis of the QD-molecule, we observe anticrossings of neutral and charged excitonic states, determine the dependence on the interdot separation, and correlate with structural data obtained from transmission electron microscopy. The scalability of the synthesis is confirmed via voltage-dependent scanning hyperspectral imaging, statistical information across multiple individual O-band QD-molecules. Moreover, for strong pumping, biexciton emission from the O-band molecules is identified. We demonstrate single-photon emission from the InAs/InGaAs QD-molecule emitting around 1.3  μm with a g(2)(0)=0.017(2) and explore the impact of tuning the orbital coupling on the second-order correlation function.

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PRX Quantum 7, 033070– Published 30 September, 2026
  • Received 24 March 2026
  • Accepted 3 September 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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