Probing fluctuations in photon emission statistics of spin injected quantum dots with time dependent electronic excitation
Abstract
Electrically spin-injected ensembles of InGaAs/GaAs quantum dots emit circularly polarized single photons, with the emission helicity determined by the spin polarization of the injected electrons. A ferromagnetic CoFeB spin-injection layer with perpendicular magnetic anisotropy, combined with an MgO tunnel barrier, enables spin-polarized electron injection into the quantum-dot active region, resulting in circularly polarized photon emission at zero applied magnetic field. These devices realize direct spin-charge-photon conversion in an electrically driven, microelectronics-compatible quantum light source that operates without an external pump laser. Using an extended Hanbury Brown-Twiss interferometer with four detectors and time-tagged readout, we measure time-resolved photon-number statistics that resolve up to |2⟩ Fock states within a single excitation cycle. While single-photon (n=|1⟩) emission tracks the electrical excitation pulse as expected, the two-photon (n=|2⟩) statistics exhibit pronounced fluctuations at multiple temporal positions within the pulse. These fluctuations vanish upon demagnetization of the spin-injection layer, establishing a direct link between the multi-photon emission dynamics and the spin polarization of the injected carriers. The observations indicate that spin injection controls not only the helicity of the emitted photons but also higher-order temporal correlations of the emission. The behavior is phenomenologically captured by inserting both a variable excitation mechanism and a set of multi-emitter collapse operators within a stochastic wave function evolution. The platform thus opens a route to electrically driven, spin-controlled single and multi-photon Fock-state sources and provides a testbed for spin-conditioned multi-emitter dynamics in solid-state quantum light sources.
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BibTeX
@misc{wijesundara2026probing,
title = {{Probing fluctuations in photon emission statistics of spin injected quantum dots with time dependent electronic excitation}},
author = {Chiran Wijesundara and Vincent Iglesias-Cardinale and Yuan Lu and Herbert Fotso and Bo Xu and Tim Thomay},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40593},
eprint = {2610.40593},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40593},
note = {CC0},
}
RIS
TY - UNPB
TI - Probing fluctuations in photon emission statistics of spin injected quantum dots with time dependent electronic excitation
AU - Chiran Wijesundara
AU - Vincent Iglesias-Cardinale
AU - Yuan Lu
AU - Herbert Fotso
AU - Bo Xu
AU - Tim Thomay
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40593
UR - https://arxiv.org/abs/2610.40593
AB - Electrically spin-injected ensembles of InGaAs/GaAs quantum dots emit circularly polarized single photons, with the emission helicity determined by the spin polarization of the injected electrons. A ferromagnetic CoFeB spin-injection layer with perpendicular magnetic anisotropy, combined with an MgO tunnel barrier, enables spin-polarized electron injection into the quantum-dot active region, resulting in circularly polarized photon emission at zero applied magnetic field. These devices realize direct spin-charge-photon conversion in an electrically driven, microelectronics-compatible quantum light source that operates without an external pump laser. Using an extended Hanbury Brown-Twiss interferometer with four detectors and time-tagged readout, we measure time-resolved photon-number statistics that resolve up to |2⟩ Fock states within a single excitation cycle. While single-photon (n=|1⟩) emission tracks the electrical excitation pulse as expected, the two-photon (n=|2⟩) statistics exhibit pronounced fluctuations at multiple temporal positions within the pulse. These fluctuations vanish upon demagnetization of the spin-injection layer, establishing a direct link between the multi-photon emission dynamics and the spin polarization of the injected carriers. The observations indicate that spin injection controls not only the helicity of the emitted photons but also higher-order temporal correlations of the emission. The behavior is phenomenologically captured by inserting both a variable excitation mechanism and a set of multi-emitter collapse operators within a stochastic wave function evolution. The platform thus opens a route to electrically driven, spin-controlled single and multi-photon Fock-state sources and provides a testbed for spin-conditioned multi-emitter dynamics in solid-state quantum light sources.
ER -