pith. sign in

arxiv: 2512.02798 · v2 · submitted 2025-12-02 · ❄️ cond-mat.mes-hall · quant-ph

Theory of single-photon emission from neutral and charged excitons in a polarization-selective cavity

Luca Vannucci , Niels Gregersen This is my paper

Pith reviewed 2026-05-17 02:15 UTC · model grok-4.3

classification ❄️ cond-mat.mes-hall quant-ph
keywords single-photon sourcesquantum dotsexcitonspolarization-selective cavityPurcell enhancementsemiconductor microcavitiesquantum optics
0
0 comments X

The pith

An asymmetric vertical cavity can direct nearly all photons from a quantum-dot exciton into one desired polarization.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

Standard resonant pumping of quantum-dot excitons for indistinguishable photons loses half the output to the orthogonal polarization. This work models the quantum dynamics of neutral or charged excitons inside a deliberately asymmetric vertical cavity that applies stronger Purcell enhancement to one polarization. The authors locate the drive configuration that best prepares the initial state and show that the collected efficiency in the favored polarization can approach unity. They supply closed-form expressions for the polarized photon yields in terms of the two Purcell-modified emission rates. A reader would care because removing the built-in 50 % loss would make quantum-dot sources far more usable for photonic quantum processors and simulators.

Core claim

The asymmetric cavity that selectively enhances one polarization permits an optimal initialization protocol for both neutral and charged excitons and opens a route to near-unity polarized collection efficiency; the polarized photon numbers are given by simple analytic formulas that depend only on the two Purcell-enhanced spontaneous-emission rates.

What carries the argument

Polarization-selective asymmetric vertical cavity that applies unequal Purcell factors to the two orthogonal emission channels.

If this is right

  • The analytic formulas let designers predict polarized output without solving the full master equation for each new cavity geometry.
  • Both neutral and charged excitons can reach high polarized efficiency once the cavity asymmetry and drive parameters are chosen correctly.
  • The same framework directly quantifies how much the unwanted polarization component shrinks as the Purcell contrast increases.
  • Near-unity polarized efficiency removes the usual 50 % collection loss that has limited vertical-cavity quantum-dot sources.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The approach could be combined with electrical tuning or strain engineering to further suppress residual decoherence channels.
  • The same asymmetry principle might be applied to other cavity geometries, such as micropillars or photonic-crystal defects, to test scalability.
  • Experimental groups could use the derived rate formulas to extract the effective Purcell factors from measured polarization contrasts.

Load-bearing premise

The cavity asymmetry boosts one polarization without adding enough extra decoherence, mode mismatch, or non-radiative decay to keep the overall efficiency well below the predicted near-unity value.

What would settle it

Fabricate the proposed asymmetric cavity around a quantum dot, perform resonant polarized pumping in the identified optimal configuration, and measure the fraction of photons collected in the favored polarization; a result significantly below the analytic near-unity prediction would falsify the claim.

Figures

Figures reproduced from arXiv: 2512.02798 by Luca Vannucci, Niels Gregersen.

Figure 1
Figure 1. Figure 1: FIG. 1. (a) Energy levels of a neutral exciton with eigenstates [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2 [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Number of photons emitted with (a) [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Number of photons emitted in each polarization as a function of the FSS, calculated analytically with Eqs. ( [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. (a) Sketch of the energy levels of a charged exciton with eigenstates [PITH_FULL_IMAGE:figures/full_fig_p007_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. (a) Number of photons emitted with [PITH_FULL_IMAGE:figures/full_fig_p010_6.png] view at source ↗
read the original abstract

Single-photon sources based on neutral or charged excitons in a semiconductor quantum dot are attractive resources for photonic quantum computers and simulators. To obtain indistinguishable photons, the source is pumped on resonance with polarized laser pulses, and the output is collected in orthogonal polarization. However, for sources featuring vertical emission of light, 50% of the emitted photons are unavoidably lost in this way. Here, we theoretically study the quantum dynamics of an exciton embedded in an asymmetric vertical cavity that favors emission in a specific polarization. We identify the configuration for optimal state initialization and demonstrate a path toward near-unity polarized efficiency. We also derive simple analytical formulas for the photon output in each polarization as a function of the Purcell-enhanced emission rates, which shed light on the physical mechanism behind our results.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 3 minor

Summary. The manuscript presents a theoretical quantum-dynamics study of single-photon emission from neutral and charged excitons in a quantum dot embedded in an asymmetric vertical cavity that selectively enhances one polarization via the Purcell effect. The authors derive closed-form analytical expressions for the polarized photon output probabilities as functions of the two orthogonal Purcell-enhanced emission rates, identify an optimal initial-state configuration, and show that the efficiency in the favored polarization can approach unity for sufficiently strong cavity asymmetry.

Significance. If the derivations are correct, the work provides a concrete theoretical route to eliminating the inherent 50% polarization loss in vertically emitting single-photon sources, which is directly relevant to photonic quantum information processing. The analytical formulas constitute a clear strength, offering transparent insight into the physical mechanism without requiring numerical fitting. The treatment of both neutral and charged excitons broadens the scope, and the parameter dependence on the Purcell rates makes the predictions falsifiable and experimentally testable.

minor comments (3)
  1. The abstract and introduction could more explicitly state the range of Purcell-factor ratios over which the near-unity limit is approached, to make the practical requirements clearer.
  2. Figure captions should define all symbols (e.g., the two polarization labels and the initialization angles) so that the plots are self-contained.
  3. A brief comparison of the analytic expressions with the numerical solution of the master equation in a dedicated panel or appendix would strengthen the validation of the closed-form results.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and for the positive evaluation. The referee's summary accurately reflects the scope and main results of our theoretical analysis. We appreciate the recognition of the analytical expressions for polarized photon output probabilities, the identification of the optimal initial-state configuration, and the relevance to eliminating polarization loss in single-photon sources. Since the report recommends minor revision but lists no specific major comments, we have no points to address in detail at this time.

Circularity Check

0 steps flagged

No significant circularity; derivation self-contained

full rationale

The paper models exciton dynamics via standard rate equations in an asymmetric cavity, taking Purcell-enhanced emission rates for orthogonal polarizations as direct inputs derived from cavity geometry. It then derives closed-form analytical expressions for polarized photon output and identifies an optimal initialization configuration that yields near-unity efficiency under those rates. These steps follow directly from the master equation without any self-definition of outputs in terms of inputs, without fitting parameters to target efficiencies, and without load-bearing self-citations or uniqueness theorems. The formulas are explicit functions of the input rates, making the efficiency scaling a straightforward consequence rather than a tautology. No step reduces by construction to its own premises.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The central claim rests on a standard quantum-optical model of the exciton-cavity interaction with polarization-dependent Purcell factors; no new entities are introduced.

free parameters (1)
  • Purcell-enhanced emission rates
    The output formulas are expressed directly in terms of these rates, which encode the cavity asymmetry and must be determined from the specific geometry.
axioms (1)
  • domain assumption The exciton behaves as a two-level system whose emission can be selectively enhanced by cavity asymmetry in one polarization.
    Standard assumption in cavity QED treatments of quantum-dot emitters.

pith-pipeline@v0.9.0 · 5427 in / 1237 out tokens · 72365 ms · 2026-05-17T02:15:57.044164+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

42 extracted references · 42 canonical work pages

  1. [1]

    For example, forθ= π 4 and in the limit ∆FSS ≫Γ H ,Γ V we obtainN H +N V = (ΓH+ΓV )2 4ΓHΓV , which is always>1 except for ΓH = ΓV

    However, for Γ H ̸= ΓV we observe that the sumN V +N H is not normalized to 1. For example, forθ= π 4 and in the limit ∆FSS ≫Γ H ,Γ V we obtainN H +N V = (ΓH+ΓV )2 4ΓHΓV , which is always>1 except for ΓH = ΓV . This is a flaw of the effective Hamiltonian approach and makes it impossible to apply such a simplified model in our work. To understand the origi...

    work page

  2. [2]

    Maring, A

    N. Maring, A. Fyrillas, M. Pont, E. Ivanov, P. Stepanov, N. Margaria, W. Hease, A. Pishchagin, A. Lemaˆ ıtre, I. Sagnes, T. H. Au, S. Boissier, E. Bertasi, A. Baert, M. Valdivia, M. Billard, O. Acar, A. Brieussel, R. Mezher, S. C. Wein, A. Salavrakos, P. Sinnott, D. A. Fioretto, P.-E. Emeriau, N. Belabas, S. Mansfield, P. Senellart, J. Senellart, and N. S...

    work page 2024

  3. [3]

    Aaronson and A

    S. Aaronson and A. Arkhipov, The Computational Complexity of Linear Optics, inProceedings of the Forty-Third Annual ACM Symposium on Theory of Computing, STOC ’11 (Association for Computing Machinery, New York, NY, USA, 2011) p. 333–342

    work page 2011

  4. [4]

    P. G. Kwiat, K. Mattle, H. Weinfurter, A. Zeilinger, A. V. Sergienko, and Y. Shih, New high-intensity source of polarization- entangled photon pairs, Phys. Rev. Lett.75, 4337 (1995)

    work page 1995

  5. [5]

    Joshi, A

    C. Joshi, A. Farsi, S. Clemmen, S. Ramelow, and A. L. Gaeta, Frequency multiplexing for quasi-deterministic heralded single-photon sources, Nat. Commun.9, 847 (2018)

    work page 2018

  6. [6]

    Kaneda and P

    F. Kaneda and P. G. Kwiat, High-efficiency single-photon generation via large-scale active time multiplexing, Sci. Adv.5, eaaw8586 (2019)

    work page 2019

  7. [7]

    Heindel, J.-H

    T. Heindel, J.-H. Kim, N. Gregersen, A. Rastelli, and S. Reitzenstein, Quantum dots for photonic quantum information technology, Adv. Opt. Photon.15, 613 (2023)

    work page 2023

  8. [8]

    B.-Y. Wang, E. V. Denning, U. M. G¨ ur, C.-Y. Lu, and N. Gregersen, Micropillar single-photon source design for simulta- neous near-unity efficiency and indistinguishability, Phys. Rev. B102, 125301 (2020)

    work page 2020

  9. [9]

    Huber, A

    T. Huber, A. Predojevi´ c, D. F¨ oger, G. Solomon, and G. Weihs, Optimal excitation conditions for indistinguishable photons from quantum dots, New J. Phys.17, 123025 (2015)

    work page 2015

  10. [10]

    Somaschi, V

    N. Somaschi, V. Giesz, L. De Santis, J. C. Loredo, M. P. Almeida, G. Hornecker, S. L. Portalupi, T. Grange, C. Ant´ on, J. Demory, C. G´ omez, I. Sagnes, N. D. Lanzillotti-Kimura, A. Lema´ ıtre, A. Auffeves, A. G. White, L. Lanco, and P. Senellart, Near-optimal single-photon sources in the solid state, Nat. Photon.10, 340 (2016)

    work page 2016

  11. [11]

    R. Uppu, F. T. Pedersen, Y. Wang, C. T. Olesen, C. Papon, X. Zhou, L. Midolo, S. Scholz, A. D. Wieck, A. Ludwig, and P. Lodahl, Scalable integrated single-photon source, Sci. Adv.6, eabc8268 (2020)

    work page 2020

  12. [12]

    X. Zhou, P. Lodahl, and L. Midolo, In-plane resonant excitation of quantum dots in a dual-mode photonic-crystal waveguide with highβ-factor, Quantum Sci. Technol.7, 025023 (2022)

    work page 2022

  13. [13]

    Ollivier, I

    H. Ollivier, I. Maillette de Buy Wenniger, S. Thomas, S. C. Wein, A. Harouri, G. Coppola, P. Hilaire, C. Millet, A. Lemaˆ ıtre, I. Sagnes, O. Krebs, L. Lanco, J. C. Loredo, C. Ant´ on, N. Somaschi, and P. Senellart, Reproducibility of high-performance quantum dot single-photon sources, ACS Photonics7, 1050 (2020)

    work page 2020

  14. [14]

    H. Wang, Y. M. He, T. H. Chung, H. Hu, Y. Yu, S. Chen, X. Ding, M. C. Chen, J. Qin, X. Yang, R. Z. Liu, Z. C. Duan, J. P. Li, S. Gerhardt, K. Winkler, J. Jurkat, L. J. Wang, N. Gregersen, Y. H. Huo, Q. Dai, S. Yu, S. H¨ ofling, C. Y. Lu, and J. W. Pan, Towards optimal single-photon sources from polarized microcavities, Nat. Photonics13, 770 (2019)

    work page 2019

  15. [15]

    N. Tomm, A. Javadi, N. O. Antoniadis, D. Najer, M. C. L¨ obl, A. R. Korsch, R. Schott, S. R. Valentin, A. D. Wieck, A. Ludwig, and R. J. Warburton, A bright and fast source of coherent single photons, Nat. Nanotechnol.16, 399–403 (2021)

    work page 2021

  16. [16]

    Ding, Y.-P

    X. Ding, Y.-P. Guo, M.-C. Xu, R.-Z. Liu, G.-Y. Zou, J.-Y. Zhao, Z.-X. Ge, Q.-H. Zhang, H.-L. Liu, L.-J. Wang, M.-C. Chen, H. Wang, Y.-M. He, Y.-H. Huo, C.-Y. Lu, and J.-W. Pan, High-efficiency single-photon source above the loss-tolerant threshold for efficient linear optical quantum computing, Nat. Photon.19, 387 (2025)

    work page 2025

  17. [17]

    U. M. G¨ ur, M. Mattes, S. Arslanagi´ c, and N. Gregersen, Elliptical micropillar cavity design for highly efficient polarized emission of single photons, Appl. Phys. Lett.118, 061101 (2021)

    work page 2021

  18. [18]

    D. R. Kazanov and A. M. Monakhov, Optical Modes in Elliptical Microcavities for Single-Photon Sources, JETP Lett. 117, 422 (2023)

    work page 2023

  19. [19]

    Z. Ge, T. Chung, Y.-M. He, M. Benyoucef, and Y. Huo, Polarized and Bright Telecom C-Band Single-Photon Source from InP-Based Quantum Dots Coupled to Elliptical Bragg Gratings, Nano Lett.24, 1746 (2024)

    work page 2024

  20. [20]

    X. Chen, R. Su, J. Liu, J. Li, and X.-H. Wang, Scalable and highly efficient approach for an on-chip single-photon source, Photon. Res.10, 2066 (2022)

    work page 2066

  21. [21]

    Y. Wang, L. Vannucci, S. Burger, and N. Gregersen, Near-unity efficiency in ridge waveguide-based, on-chip single-photon sources, Mater. Quantum. Technol.2, 045004 (2022)

    work page 2022

  22. [22]

    N. Tomm, A. R. Korsch, A. Javadi, D. Najer, R. Schott, S. R. Valentin, A. D. Wieck, A. Ludwig, and R. J. Warburton, Tuning the Mode Splitting of a Semiconductor Microcavity with Uniaxial Stress, Phys. Rev. Appl.15, 054061 (2021)

    work page 2021

  23. [23]

    Jaynes and F

    E. Jaynes and F. Cummings, Comparison of quantum and semiclassical radiation theories with application to the beam maser, Proceedings of the IEEE51, 89 (1963)

    work page 1963

  24. [24]

    Friedler, C

    I. Friedler, C. Sauvan, J. P. Hugonin, P. Lalanne, J. Claudon, and J. M. G´ erard, Solid-state single photon sources: the nanowire antenna, Opt. Express17, 2095 (2009)

    work page 2095

  25. [25]

    Claudon, J

    J. Claudon, J. Bleuse, N. S. Malik, M. Bazin, P. Jaffrennou, N. Gregersen, C. Sauvan, P. Lalanne, and J.-M. G´ erard, A highly efficient single-photon source based on a quantum dot in a photonic nanowire, Nature Photon.4, 174 (2010)

    work page 2010

  26. [26]

    Cosacchi, F

    M. Cosacchi, F. Ungar, M. Cygorek, A. Vagov, and V. M. Axt, Emission-Frequency Separated High Quality Single-Photon Sources Enabled by Phonons, Phys. Rev. Lett.123, 017403 (2019). 13

    work page 2019

  27. [27]

    Gustin and S

    C. Gustin and S. Hughes, Efficient pulse-excitation techniques for single photon sources from quantum dots in optical cavities, Advanced Quantum Technologies3, 1900073 (2020)

    work page 2020

  28. [28]

    Vannucci and N

    L. Vannucci and N. Gregersen, Highly efficient and indistinguishable single-photon sources via phonon-decoupled two-color excitation, Phys. Rev. B107, 195306 (2023)

    work page 2023

  29. [29]

    Heinisch, N

    N. Heinisch, N. K¨ ocher, D. Bauch, and S. Schumacher, Swing-up dynamics in quantum emitter cavity systems: Near ideal single photons and entangled photon pairs, Phys. Rev. Res.6, L012017 (2024)

    work page 2024

  30. [30]

    Gaignard, M

    M. Gaignard, M. Finazzer, C. Spinnler, G. N. Nguyen, S. Kotal, A. Artioli, Y. Genuist, N. Gregersen, J.-P. Poizat, J.-M. G´ erard, R. J. Warburton, and J. Claudon, Resonance Fluorescence from a Single Quantum Dot in a Nanopost Optical Cavity, ACS Photonics12, 3671 (2025)

    work page 2025

  31. [31]

    M. A. Jacobsen, Y. Wang, L. Vannucci, J. Claudon, J.-M. G´ erard, and N. Gregersen, Performance of the nanopost single- photon source: beyond the single-mode model, Nanoscale15, 6156 (2023)

    work page 2023

  32. [32]

    Piccinini, A

    C. Piccinini, A. Rodek, A. A. Madigawa, A. Garcia, Jr., S. F. Covre da Silva, V. Remesh, L. Vannucci, G. Weihs, A. Rastelli, N. Gregersen, and B. Munkhbat, Exciton and biexciton preparation via coherent swing-up excitation in a GaAs quantum dot embedded in micropillar cavity, (2025), arXiv:2510.21428

    work page arXiv 2025

  33. [33]

    Schwartz, E

    M. Schwartz, E. Schmidt, U. Rengstl, F. Hornung, S. Hepp, S. L. Portalupi, K. llin, M. Jetter, M. Siegel, and P. Michler, Fully On-Chip Single-Photon Hanbury-Brown and Twiss Experiment on a Monolithic Semiconductor–Superconductor Platform, Nano Lett.18, 6892 (2018)

    work page 2018

  34. [34]

    Peniakov, J

    G. Peniakov, J. Michl, M. Helal, R. Joos, M. Jetter, S. L. Portalupi, P. Michler, S. H¨ ofling, and T. Huber-Loyola, Initialization of Neutral and Charged Exciton Spin States in a Telecom-Emitting Quantum Dot, (2025), arXiv:2504.20497

    work page arXiv 2025

  35. [35]

    Wolfram Research, Inc., Mathematica, Version 14.0, Champaign, IL, 2025

    work page 2025

  36. [36]

    Hoehne, P

    T. Hoehne, P. Schnauber, S. Rodt, S. Reitzenstein, and S. Burger, Numerical Investigation of Light Emission from Quantum Dots Embedded into On-Chip, Low-Index-Contrast Optical Waveguides, Phys. Status Solidi B256, 1800437 (2019)

    work page 2019

  37. [37]

    W. Yao, R. Liu, and L. J. Sham, Nanodot-cavity electrodynamics and photon entanglement, Phys. Rev. Lett.92, 217402 (2004)

    work page 2004

  38. [38]

    R.-B. Liu, W. Yao, and L. Sham, Quantum computing by optical control of electron spins, Adv. Phys.,59, 703 (2010)

    work page 2010

  39. [39]

    B.-Y. Wang, T. H¨ ayrynen, L. Vannucci, M. A. Jacobsen, C.-Y. Lu, and N. Gregersen, Suppression of background emission for efficient single-photon generation in micropillar cavities, Applied Physics Letters118, 114003 (2021)

    work page 2021

  40. [40]

    Gin´ es, M

    L. Gin´ es, M. Mocza la-Dusanowska, D. Dlaka, R. Hoˇ s´ ak, J. R. Gonzales-Ureta, J. Lee, M. Jeˇ zek, E. Harbord, R. Oulton, S. H¨ ofling, A. B. Young, C. Schneider, and A. Predojevi´ c, High Extraction Efficiency Source of Photon Pairs Based on a Quantum Dot Embedded in a Broadband Micropillar Cavity, Phys. Rev. Lett.129, 033601 (2022)

    work page 2022

  41. [41]

    Trotta, J

    R. Trotta, J. S. Wildmann, E. Zallo, O. G. Schmidt, and A. Rastelli, Highly entangled photons from hybrid piezoelectric- semiconductor quantum dot devices, Nano Lett.14, 3439 (2014)

    work page 2014

  42. [42]

    Ollivier, P

    H. Ollivier, P. Priya, A. Harouri, I. Sagnes, A. Lemaˆ ıtre, O. Krebs, L. Lanco, N. D. Lanzillotti-Kimura, M. Esmann, and P. Senellart, Three-dimensional electrical control of the excitonic fine structure for a quantum dot in a cavity, Phys. Rev. Lett.129, 057401 (2022)

    work page 2022