Deterministic and efficient source of frequency-polarization hyper-encoded photonic qubits
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The frequency or color of photons is an attractive degree of freedom to encode and distribute quantum information over long distances. However, the generation of frequency-encoded photonic qubits has so far relied on probabilistic nonlinear single-photon sources and inefficient gates. Here, we demonstrate the deterministic generation of photonic qubits hyper-encoded in frequency and polarization based on a semiconductor quantum dot in a cavity. We exploit the double dipole structure of a neutral exciton and demonstrate the generation of any quantum superposition in amplitude and phase, controlled by the polarization of the pump laser pulse. The source generates frequency-polarization single-photon qubits at a rate of 4 MHz corresponding to a generation probability at the first lens of 28 ± 2%, with a photon number purity > 98%. The photons show an indistinguishability > 91% for each dipole and 88 % for a balanced quantum superposition of both. The density matrix of the hyper-encoded photonic state is measured by time-resolved polarization tomography, evidencing a fidelity to the target state of 94 ± 8% and concurrence of 77 ± 2%, here limited by frequency overlap in our device. Our approach brings the advantages of quantum dot sources to the field of quantum information processing based on frequency encoding.
Date Issued
2025-06-25
Date Acceptance
2025-04-13
Citation
Optica Quantum, 2025, 3 (3), pp.289-294
ISSN
2837-6714
Publisher
Optica Publishing Group
Start Page
289
End Page
294
Journal / Book Title
Optica Quantum
Volume
3
Issue
3
Copyright Statement
Journal © 2025 Optica Publishing Group. Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 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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Subjects
Optics
Physical Sciences
Physics
Quantum Science & Technology
Science & Technology
Publication Status
Published
Date Publish Online
2025-06-24