Far-field radiation of bulk, edge and corner eigenmodes from a finite 2D Su-Schrieffer-Heeger plasmonic lattice
Pith reviewed 2026-05-21 21:34 UTC · model grok-4.3
The pith
Antisymmetric modes in finite 2D SSH plasmonic lattices radiate less and show higher Q-factors than symmetric ones.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
By employing a coupled electromagnetic dipole formalism, the contribution of each array mode to the far-field radiation is isolated for bulk, edge and corner out-of-plane eigenmodes in a finite 2D SSH plasmonic nanoparticle array. The breaking of symmetries in multipartite unit cells is exploited to tailor the optical properties and far-field radiation of the resonant modes. Antisymmetric modes are darker and have higher Q-factors than their symmetric counterparts. The out-of-plane nature of the dipolar resonances imposes that all bulk Γ-modes are dark, while corner and edge states need extra in-plane symmetries to cancel the far-field radiation; radiation patterns in turn become more more
What carries the argument
Coupled electromagnetic dipole formalism that isolates the far-field radiation contribution of each array mode.
Load-bearing premise
The coupled electromagnetic dipole formalism accurately captures the far-field radiation and eigenmode isolation for out-of-plane dipolar resonances in the finite array without significant contributions from higher-order multipoles or full retardation effects.
What would settle it
Direct experimental comparison of measured far-field radiation intensity and quality factors between symmetric and antisymmetric modes in fabricated finite 2D SSH plasmonic nanoparticle arrays of different sizes.
read the original abstract
Subwavelength arrays of plasmonic nanoparticles allow us to control the behaviour of light at the nanoscale. Here, we develop an eigenmode analysis, employing a coupled electromagnetic dipole formalism, which permits us to isolate the contribution to the far-field radiation of each array mode. Specifically, we calculate the far-field radiation patterns by bulk, edge and corner out-of-plane eigenmodes in a finite 2D Su-Schrieffer-Heeger (SSH) array of plasmonic nanoparticles with out-of-plane dipolar resonances. The breaking of symmetries in multipartite unit cells is exploited to tailor the optical properties and far-field radiation of the resonant modes. We prove that the antisymmetric modes are darker and have higher Q-factors than their symmetric counterparts. Also, the out-of-plane nature of the dipolar resonances imposes that all bulk $\Gamma$-modes are dark, while corner and edge states need extra in-plane symmetries to cancel the far-field radiation; radiation patterns in turn become more complex and concentrated along the array plane with increasing array size.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript develops an eigenmode analysis employing a coupled electromagnetic dipole formalism to isolate the far-field radiation contributions of bulk, edge, and corner out-of-plane eigenmodes in a finite 2D Su-Schrieffer-Heeger plasmonic nanoparticle array. It exploits symmetry breaking in multipartite unit cells to show that antisymmetric modes are darker and possess higher Q-factors than symmetric counterparts, that all bulk Γ-modes are dark due to the out-of-plane dipolar character, and that corner and edge states require additional in-plane symmetries to suppress radiation; radiation patterns are reported to grow more complex and concentrate in the array plane with increasing size.
Significance. If the symmetry-based conclusions hold under the employed model, the work supplies a transparent, analytically grounded route to predict and engineer darkness and Q-factors in topological plasmonic lattices without parameter fitting. The emphasis on finite-size effects and the explicit separation of mode contributions via the dipole formalism are useful for guiding experimental design of subwavelength directional sources or high-Q resonators.
major comments (1)
- [Coupled electromagnetic dipole formalism (methods section)] The central claims on mode darkness, Q-factor ordering, and radiation cancellation rest on the coupled electromagnetic dipole formalism accurately capturing far-field radiation for out-of-plane resonances. No quantitative estimate of higher-multipole or retardation corrections, nor comparison to full-wave simulations for representative array sizes, is provided; this assumption is load-bearing for the assertion that bulk Γ-modes are dark and that antisymmetric modes are systematically darker.
minor comments (2)
- [Abstract] The abstract asserts that radiation patterns become more complex and in-plane concentrated with array size, but does not report any quantitative metric (e.g., directivity or integrated side-lobe level) to support the qualitative statement.
- [Introduction or model section] Notation for the multipartite unit-cell symmetries and the precise definition of the antisymmetric versus symmetric eigenmodes could be clarified with an explicit table or diagram early in the text to aid readers unfamiliar with the SSH geometry.
Simulated Author's Rebuttal
We thank the referee for their careful reading and constructive feedback on our manuscript. We address the single major comment below and are prepared to revise the work to strengthen the presentation of the coupled-dipole results.
read point-by-point responses
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Referee: [Coupled electromagnetic dipole formalism (methods section)] The central claims on mode darkness, Q-factor ordering, and radiation cancellation rest on the coupled electromagnetic dipole formalism accurately capturing far-field radiation for out-of-plane resonances. No quantitative estimate of higher-multipole or retardation corrections, nor comparison to full-wave simulations for representative array sizes, is provided; this assumption is load-bearing for the assertion that bulk Γ-modes are dark and that antisymmetric modes are systematically darker.
Authors: We agree that the dipole approximation is central to the quantitative claims. The formalism is employed precisely because it permits an exact decomposition of the far-field into individual eigenmode contributions while retaining the symmetries of the finite SSH lattice. For the subwavelength particles and out-of-plane dipolar resonances considered, the leading radiation term is the electric dipole; symmetry-enforced cancellations (antisymmetric pairs, bulk Γ-point out-of-plane cancellation, and additional in-plane ordering for edge/corner states) are therefore expected to survive small higher-multipole or retardation corrections. Nevertheless, we acknowledge that an explicit validation would increase confidence. In the revised manuscript we will add (i) an order-of-magnitude estimate of the relative strength of quadrupole and magnetic-dipole terms based on the particle-radius-to-wavelength ratio and (ii) a direct comparison of far-field patterns and Q-factors for a representative small array (e.g., 4×4) obtained from both the coupled-dipole model and full-wave FDTD simulations, confirming that the darkness ordering and radiation patterns remain consistent within the parameter regime of the study. revision: yes
Circularity Check
No significant circularity; standard coupled-dipole analysis applied to SSH geometry
full rationale
The paper develops an eigenmode analysis using the coupled electromagnetic dipole formalism to isolate far-field contributions from bulk, edge, and corner modes in a finite 2D SSH plasmonic array. Claims that antisymmetric modes are darker with higher Q-factors, that all bulk Γ-modes are dark due to out-of-plane dipoles, and that corner/edge states require additional in-plane symmetries follow directly from symmetry arguments within this standard framework. No steps reduce by construction to fitted inputs, self-definitions, or load-bearing self-citations; the derivation remains self-contained against external benchmarks of the dipole approximation.
Axiom & Free-Parameter Ledger
free parameters (1)
- inter-particle spacing and radius
axioms (1)
- domain assumption Coupled electromagnetic dipole formalism is sufficient to isolate far-field radiation of each eigenmode
Lean theorems connected to this paper
-
IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
We develop an eigenmode analysis, employing a coupled electromagnetic dipole formalism... out-of-plane dipolar resonances... antisymmetric modes are darker and have higher Q-factors... all bulk Γ-modes are dark
-
IndisputableMonolith/Foundation/AlexanderDuality.leanalexander_duality_circle_linking unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
the out-of-plane nature of the dipolar resonances imposes that all bulk Γ-modes are dark
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
-
[1]
V. Giannini, A. I. Fern´ andez-Dom´ ınguez, S. C. Heck, and S. A. Maier, Plasmonic Nanoantennas: Fundamen- tals and Their Use in Controlling the Radiative Pro- perties of Nanoemitters, Chemical Reviews111, 3888 (2011)
work page 2011
-
[2]
K. L. Kelly, E. Coronado, L. L. Zhao, and G. C. Schatz, The Optical Properties of Metal Nanoparticles: The In- fluence of Size, Shape, and Dielectric Environment, The Journal of Physical Chemistry B107, 668 (2003)
work page 2003
-
[3]
P. Genevet, F. Capasso, F. Aieta, M. Khorasanine- jad, and R. Devlin, Recent advances in planar optics: from plasmonic to dielectric metasurfaces, Optica4, 139 (2017). 13
work page 2017
-
[4]
A. I. Kuznetsov, M. L. Brongersma, J. Yao, M. K. Chen, U. Levy, D. P. Tsai, N. I. Zheludev, A. Faraon, A. Ar- babi, N. Yu, D. Chanda, K. B. Crozier, A. V. Kil- dishev, H. Wang, J. K. W. Yang, J. G. Valentine, P. Ge- nevet, J. A. Fan, O. D. Miller, A. Majumdar, J. E. Fr¨ och, D. Brady, F. Heide, A. Veeraraghavan, N. Enghe- ta, A. Al` u, A. Polman, H. A. At...
work page 2024
-
[5]
M. S. Rider, S. J. Palmer, S. R. Pocock, X. Xiao, P. Arro- yo Huidobro, and V. Giannini, A perspective on topologi- cal nanophotonics: Current status and future challenges, Journal of Applied Physics125, 120901 (2019)
work page 2019
-
[6]
M. S. Rider, A. Buendia, D. R. Abujetas, P. A. Huido- bro, J. A. S´ anchez-Gil, and V. Giannini, Advances and Prospects in Topological Nanoparticle Photonics, ACS Photonics9, 1483 (2022)
work page 2022
-
[7]
N. A. Mortensen, S. I. Bozhevolnyi, and A. Al` u, Topolo- gical nanophotonics, Nanophotonics8, 1315 (2019)
work page 2019
-
[8]
F. D. M. Haldane and S. Raghu, Possible Realization of Directional Optical Waveguides in Photonic Crystals with Broken Time-Reversal Symmetry, Physical Review Letters100, 013904 (2008)
work page 2008
-
[9]
Z. Wang, Y. Chong, J. D. Joannopoulos, and M. Soljaˇ ci´ c, Observation of unidirectional backscattering-immune to- pological electromagnetic states, Nature461, 772 (2009)
work page 2009
-
[10]
A. B. Khanikaev, S. Hossein Mousavi, W.-K. Tse, M. Kargarian, A. H. MacDonald, and G. Shvets, Pho- tonic topological insulators, Nature Materials12, 233 (2013)
work page 2013
- [11]
-
[12]
X. Wu, Y. Meng, J. Tian, Y. Huang, H. Xiang, D. Han, and W. Wen, Direct observation of valley-polarized topo- logical edge states in designer surface plasmon crystals, Nature Communications8, 1304 (2017)
work page 2017
- [13]
- [14]
-
[15]
B. Zhen, C. W. Hsu, L. Lu, A. D. Stone, and M. Sol- jaˇ ci´ c, Topological Nature of Optical Bound States in the Continuum, Physical Review Letters113, 257401 (2014)
work page 2014
-
[16]
W. Chen, Y. Chen, and W. Liu, Singularities and Poin- car´ e Indices of Electromagnetic Multipoles, Physical Re- view Letters122, 153907 (2019)
work page 2019
-
[17]
G. Salerno, Perspective: Topological photonics in na- noscaled systems with far-field radiation and polariza- tion singularities, Applied Physics Letters127, 080501 (2025)
work page 2025
-
[18]
M. Honari-Latifpour and L. Yousefi, Topological plasmo- nic edge states in a planar array of metallic nanoparticles, Nanophotonics8, 799 (2019)
work page 2019
- [19]
-
[20]
K. Koshelev, S. Lepeshov, M. Liu, A. Bogdanov, and Y. Kivshar, Asymmetric Metasurfaces with High- Q Re- sonances Governed by Bound States in the Continuum, Physical Review Letters121, 193903 (2018)
work page 2018
- [21]
-
[22]
M. B. De Paz and P. A. Huidobro, Bound states in the continuum in subwavelength emitter arrays, Physical Re- view Research5, 033108 (2023)
work page 2023
-
[23]
J. J. Alvarez-Serrano, J. R. Deop-Ruano, V. Aglieri, A. Toma, and A. Manjavacas, Normal Incidence Exci- tation of Out-of-Plane Lattice Resonances in Bipartite Arrays of Metallic Nanostructures, ACS Photonics11, 301 (2024)
work page 2024
-
[24]
F. J. Garc´ ıa De Abajo,Colloquium: Light scattering by particle and hole arrays, Reviews of Modern Physics79, 1267 (2007)
work page 2007
-
[25]
D. R. Abujetas, J. Olmos-Trigo, J. J. S´ aenz, and J. A. S´ anchez-Gil, Coupled electric and magnetic dipole for- mulation for planar arrays of particles: Resonances and bound states in the continuum for all-dielectric metasur- faces, Physical Review B102, 125411 (2020)
work page 2020
-
[26]
N. Ustimenko, C. Rockstuhl, and A. B. Evlyukhin, Re- sonances in finite-size all-dielectric metasurfaces for light trapping and propagation control, Physical Review B 109, 115436 (2024)
work page 2024
-
[27]
A. Muster, D. R. Abujetas, F. Scheffold, and L. S. Froufe- P´ erez, CoupledElectricMagneticDipoles.jl - Julia modu- les for coupled electric and magnetic dipoles method for light scattering, and optical forces in three dimensions, Computer Physics Communications306, 109361 (2025)
work page 2025
-
[28]
M. Proctor, X. Xiao, R. Craster, S. Maier, V. Giannini, and P. Arroyo Huidobro, Near- and Far-Field Excitation of Topological Plasmonic Metasurfaces, Photonics7, 81 (2020)
work page 2020
- [29]
-
[30]
A. Buendia, Topological Nanophotonics: Symmetry- protected states of arrays of plasmonic nanoparticles — hdl.handle.net (2024)
work page 2024
-
[31]
L. Novotny and B. Hecht,Principles of Nano-Optics, 2nd ed. (Cambridge University Press, 2012)
work page 2012
-
[32]
V. Popescu and A. Zunger, Extracting E versus k effec- tive band structure from supercell calculations on alloys and impurities, Physical Review B85, 085201 (2012)
work page 2012
- [33]
- [34]
-
[35]
A. Buendia, J. A. S´ anchez-Gil, V. Giannini, W. L. Bar- nes, and M. S. Rider, Long-range molecular energy trans- fer mediated by strong coupling to plasmonic topolo- gical edge states, Nanophotonics 10.1515/nanoph-2024- 0077 (2024). 14
-
[36]
W. P. Su, J. R. Schrieffer, and A. J. Heeger, Solitons in Polyacetylene, Physical Review Letters42, 1698 (1979)
work page 1979
- [37]
-
[38]
W. A. Benalcazar and A. Cerjan, Bound states in the continuum of higher-order topological insulators, Physi- cal Review B101, 161116 (2020)
work page 2020
-
[39]
H. Schl¨ omer, Z. Jiang, and S. Haas, Plasmons in two- dimensional topological insulators, Physical Review B 103, 115116 (2021)
work page 2021
-
[40]
J. Wang, Y. Liu, D. Yang, Z. Hu, X. Zhang, S. Xia, D. Song, M. Ren, S. Gao, R. Wang, Z. Chen, and J. Xu, Tunable terahertz topological edge and corner states in designer surface plasmon crystals, Optics Express29, 19531 (2021)
work page 2021
- [41]
-
[42]
S. Liu, W. Gao, Q. Zhang, S. Ma, L. Zhang, C. Liu, Y. J. Xiang, T. J. Cui, and S. Zhang, Topologically Protec- ted Edge State in Two-Dimensional Su–Schrieffer–Heeger Circuit, Research2019, 2019/8609875 (2019)
work page 2019
-
[43]
R. Heilmann, G. Salerno, J. Cuerda, T. K. Hakala, and P. T¨ orm¨ a, Quasi-BIC Mode Lasing in a Quadrumer Plas- monic Lattice, ACS Photonics9, 224 (2022)
work page 2022
-
[44]
A. Buendia, J. A. S´ anchez-Gil, and V. Giannini, Exploi- ting Oriented Field Projectors to Open Topological Gaps in Plasmonic Nanoparticle Arrays, ACS Photonics10, 464 (2023)
work page 2023
- [45]
-
[46]
D. R. Abujetas and J. A. S´ anchez-Gil, Near-Field Excita- tion of Bound States in the Continuum in All-Dielectric Metasurfaces through a Coupled Electric/Magnetic Di- pole Model, Nanomaterials11, 998 (2021)
work page 2021
-
[47]
C. W. Hsu, B. Zhen, A. D. Stone, J. D. Joannopoulos, and M. Soljaˇ ci´ c, Bound states in the continuum, Nature Reviews Materials1, 16048 (2016)
work page 2016
-
[48]
S. S. Kruk, W. Gao, D.-Y. Choi, T. Zentgraf, S. Zhang, and Y. Kivshar, Nonlinear Imaging of Nanoscale Topo- logical Corner States, Nano Letters21, 4592 (2021)
work page 2021
-
[49]
Y. Moritake, M. Ono, and M. Notomi, Far-field optical imaging of topological edge states in zigzag plasmonic chains, Nanophotonics11, 2183 (2022)
work page 2022
-
[50]
F. Bleckmann, Z. Cherpakova, S. Linden, and A. Alberti, Spectral imaging of topological edge states in plasmonic waveguide arrays, Physical Review B96, 045417 (2017)
work page 2017
-
[51]
L. Orsini, H. Herzig Sheinfux, Y. Li, S. Lee, G. M. An- dolina, O. Scarlatella, M. Ceccanti, K. Soundarapandian, E. Janzen, J. H. Edgar, G. Shvets, and F. H. L. Koppens, Deep subwavelength topological edge state in a hyperbo- lic medium, Nature Nanotechnology 10.1038/s41565-024- 01737-8 (2024)
-
[52]
Z. Sadrieva, K. Frizyuk, M. Petrov, Y. Kivshar, and A. Bogdanov, Multipolar origin of bound states in the continuum, Physical Review B100, 115303 (2019)
work page 2019
-
[53]
M. A. Gorlach, X. Ni, D. A. Smirnova, D. Korobkin, D. Zhirihin, A. P. Slobozhanyuk, P. A. Belov, A. Al` u, and A. B. Khanikaev, Far-field probing of leaky topological states in all-dielectric metasurfaces, Nature Communica- tions9, 909 (2018)
work page 2018
- [54]
-
[55]
R. Guo, M. Neˇ cada, T. Hakala, A. V¨ akev¨ ainen, and P. T¨ orm¨ a, Lasing at K Points of a Honeycomb Plasmonic Lattice, Physical Review Letters122, 013901 (2019)
work page 2019
- [56]
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