---
_id: '65460'
abstract:
- lang: eng
  text: "Beamsplitters represent fundamental components in both classical and quantum
    optical systems, enabling the distribution of light, as well as the generation
    of interference, superposition, and entanglement. However, optical networks constructed
    from conventional bulk 2 × 2-beamsplitters encounter inherent scalability issues,
    as the number of required beamsplitters scales quadratically with the number of
    optical modes for a fully connected network. Metasurfaces offer a promising route
    to\r\novercome these constraints. By manipulating light at the wavelength scale,
    compact optical components with advanced functionalities can be constructed, which
    address several modes simultaneously. In this work, we design and experimentally
    utilize a metasurface as a multiport beamsplitter. Furthermore, we realized a
    multimode interferometer composed of two cascaded metasurfaces. We characterize
    the individual and cascaded metasurfaces by using classical light, showing controllable
    splitting ratios through tunable phase relations. We then expand the approach
    to quantum light, employing single photons to demonstrate second- and third-order
    photon correlations as well as single photon interference across multiple spatial
    paths. These results establish metasurface-based multiport beamsplitters as a
    scalable and reconfigurable platform bridging classical and quantum photonics. "
article_number: acsphotonics.6c00096
article_type: original
author:
- first_name: Rebecca
  full_name: Aschwanden, Rebecca
  last_name: Aschwanden
- first_name: Nicolás
  full_name: Claro-Rodríguez, Nicolás
  last_name: Claro-Rodríguez
- first_name: Ruizhe
  full_name: Zhao, Ruizhe
  last_name: Zhao
- first_name: Patricia Anna Maria
  full_name: Kallert, Patricia Anna Maria
  id: '72332'
  last_name: Kallert
  orcid: 0009-0007-5230-0223
- first_name: Tobias
  full_name: Krieger, Tobias
  last_name: Krieger
- first_name: Quirin
  full_name: Buchinger, Quirin
  last_name: Buchinger
- first_name: Saimon F.
  full_name: Covre da Silva, Saimon F.
  last_name: Covre da Silva
- first_name: Sandra
  full_name: Stroj, Sandra
  last_name: Stroj
- first_name: Michele
  full_name: Rota, Michele
  last_name: Rota
- first_name: Sven
  full_name: Höfling, Sven
  last_name: Höfling
- first_name: Tobias
  full_name: Huber-Loyola, Tobias
  last_name: Huber-Loyola
- first_name: Armando
  full_name: Rastelli, Armando
  last_name: Rastelli
- first_name: Rinaldo
  full_name: Trotta, Rinaldo
  last_name: Trotta
- first_name: Lingling
  full_name: Huang, Lingling
  last_name: Huang
- first_name: Tim
  full_name: Bartley, Tim
  id: '49683'
  last_name: Bartley
- first_name: Klaus
  full_name: Jöns, Klaus
  id: '85353'
  last_name: Jöns
- first_name: Thomas
  full_name: Zentgraf, Thomas
  id: '30525'
  last_name: Zentgraf
  orcid: 0000-0002-8662-1101
citation:
  ama: Aschwanden R, Claro-Rodríguez N, Zhao R, et al. Cascaded Metasurface Interferometer
    for Multipath Interference with Classical and Quantum Light. <i>ACS Photonics</i>.
    Published online 2026. doi:<a href="https://doi.org/10.1021/acsphotonics.6c00096">10.1021/acsphotonics.6c00096</a>
  apa: Aschwanden, R., Claro-Rodríguez, N., Zhao, R., Kallert, P. A. M., Krieger,
    T., Buchinger, Q., Covre da Silva, S. F., Stroj, S., Rota, M., Höfling, S., Huber-Loyola,
    T., Rastelli, A., Trotta, R., Huang, L., Bartley, T., Jöns, K., &#38; Zentgraf,
    T. (2026). Cascaded Metasurface Interferometer for Multipath Interference with
    Classical and Quantum Light. <i>ACS Photonics</i>, Article acsphotonics.6c00096.
    <a href="https://doi.org/10.1021/acsphotonics.6c00096">https://doi.org/10.1021/acsphotonics.6c00096</a>
  bibtex: '@article{Aschwanden_Claro-Rodríguez_Zhao_Kallert_Krieger_Buchinger_Covre
    da Silva_Stroj_Rota_Höfling_et al._2026, title={Cascaded Metasurface Interferometer
    for Multipath Interference with Classical and Quantum Light}, DOI={<a href="https://doi.org/10.1021/acsphotonics.6c00096">10.1021/acsphotonics.6c00096</a>},
    number={acsphotonics.6c00096}, journal={ACS Photonics}, publisher={American Chemical
    Society (ACS)}, author={Aschwanden, Rebecca and Claro-Rodríguez, Nicolás and Zhao,
    Ruizhe and Kallert, Patricia Anna Maria and Krieger, Tobias and Buchinger, Quirin
    and Covre da Silva, Saimon F. and Stroj, Sandra and Rota, Michele and Höfling,
    Sven and et al.}, year={2026} }'
  chicago: Aschwanden, Rebecca, Nicolás Claro-Rodríguez, Ruizhe Zhao, Patricia Anna
    Maria Kallert, Tobias Krieger, Quirin Buchinger, Saimon F. Covre da Silva, et
    al. “Cascaded Metasurface Interferometer for Multipath Interference with Classical
    and Quantum Light.” <i>ACS Photonics</i>, 2026. <a href="https://doi.org/10.1021/acsphotonics.6c00096">https://doi.org/10.1021/acsphotonics.6c00096</a>.
  ieee: 'R. Aschwanden <i>et al.</i>, “Cascaded Metasurface Interferometer for Multipath
    Interference with Classical and Quantum Light,” <i>ACS Photonics</i>, Art. no.
    acsphotonics.6c00096, 2026, doi: <a href="https://doi.org/10.1021/acsphotonics.6c00096">10.1021/acsphotonics.6c00096</a>.'
  mla: Aschwanden, Rebecca, et al. “Cascaded Metasurface Interferometer for Multipath
    Interference with Classical and Quantum Light.” <i>ACS Photonics</i>, acsphotonics.6c00096,
    American Chemical Society (ACS), 2026, doi:<a href="https://doi.org/10.1021/acsphotonics.6c00096">10.1021/acsphotonics.6c00096</a>.
  short: R. Aschwanden, N. Claro-Rodríguez, R. Zhao, P.A.M. Kallert, T. Krieger, Q.
    Buchinger, S.F. Covre da Silva, S. Stroj, M. Rota, S. Höfling, T. Huber-Loyola,
    A. Rastelli, R. Trotta, L. Huang, T. Bartley, K. Jöns, T. Zentgraf, ACS Photonics
    (2026).
date_created: 2026-04-20T04:52:59Z
date_updated: 2026-04-20T05:01:00Z
department:
- _id: '15'
- _id: '230'
- _id: '289'
- _id: '623'
doi: 10.1021/acsphotonics.6c00096
external_id:
  arxiv:
  - '2603.25090'
keyword:
- metasurface
- beamsplitter
- interferometer
- quantum network
- single photons
- nanophotonics
language:
- iso: eng
main_file_link:
- url: https://pubs.acs.org/doi/10.1021/acsphotonics.6c00096
project:
- _id: '54'
  name: TRR 142 - Project Area A
- _id: '65'
  name: 'TRR 142; TP A08: Nichtlineare Kopplung von Zwischenschicht-Exzitonen in van
    der Waals-Heterostrukturen an plasmonische und dielektrische Nanokavitäten'
- _id: '53'
  name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
    zu funktionellen Strukturen'
publication: ACS Photonics
publication_identifier:
  issn:
  - 2330-4022
  - 2330-4022
publication_status: published
publisher: American Chemical Society (ACS)
quality_controlled: '1'
status: public
title: Cascaded Metasurface Interferometer for Multipath Interference with Classical
  and Quantum Light
type: journal_article
user_id: '30525'
year: '2026'
...
---
_id: '65316'
abstract:
- lang: eng
  text: Metasurfaces are powerful tools for manipulating light using small structures
    on the nanoscale. In most metasurfaces, near-field couplings are treated as being
    unfavorable perturbations. Here, we experimentally investigate a structure consisting
    of sinusoidally modulated silicon waveguides where near-field coupling of local
    resonances leads to negative coupling, i.e., a negative coupling constant. This
    gives rise to wave-vector-dependent eigenstates of elliptical, linear, and circular
    polarizations. In particular, fully circular polarization states are not only
    present at a single point in momentum space (k-space) but also along a line. This
    circular polarization line, as well as a linear polarization line, emanates from
    a polarization degeneracy at the Dirac point. We experimentally validate the existence
    of these eigenstates and demonstrate the energy-, polarization-, and wave vector
    dependence of this metasurface as well as its sensitivity to fabrication tolerances.
    By tuning the incident k-vector, certain polarization-energy eigenstates are strongly
    reflected, allowing for uses in angle-tunable polarization filters and light sources.
author:
- first_name: Helene
  full_name: Wetter, Helene
  last_name: Wetter
- first_name: Jan
  full_name: Wingenbach, Jan
  id: '69187'
  last_name: Wingenbach
- first_name: Falk
  full_name: Rehberg, Falk
  last_name: Rehberg
- first_name: Wenlong
  full_name: Gao, Wenlong
  last_name: Gao
- first_name: Stefan
  full_name: Schumacher, Stefan
  id: '27271'
  last_name: Schumacher
  orcid: 0000-0003-4042-4951
- first_name: Thomas
  full_name: Zentgraf, Thomas
  id: '30525'
  last_name: Zentgraf
  orcid: 0000-0002-8662-1101
citation:
  ama: Wetter H, Wingenbach J, Rehberg F, Gao W, Schumacher S, Zentgraf T. Polarization-
    and Wave-Vector Selective Optical Metasurface with Near-Field Coupling. <i>ACS
    Photonics</i>. 2026;13:2128-2133. doi:<a href="https://doi.org/10.1021/acsphotonics.5c02865">10.1021/acsphotonics.5c02865</a>
  apa: Wetter, H., Wingenbach, J., Rehberg, F., Gao, W., Schumacher, S., &#38; Zentgraf,
    T. (2026). Polarization- and Wave-Vector Selective Optical Metasurface with Near-Field
    Coupling. <i>ACS Photonics</i>, <i>13</i>, 2128–2133. <a href="https://doi.org/10.1021/acsphotonics.5c02865">https://doi.org/10.1021/acsphotonics.5c02865</a>
  bibtex: '@article{Wetter_Wingenbach_Rehberg_Gao_Schumacher_Zentgraf_2026, title={Polarization-
    and Wave-Vector Selective Optical Metasurface with Near-Field Coupling}, volume={13},
    DOI={<a href="https://doi.org/10.1021/acsphotonics.5c02865">10.1021/acsphotonics.5c02865</a>},
    journal={ACS Photonics}, publisher={American Chemical Society (ACS)}, author={Wetter,
    Helene and Wingenbach, Jan and Rehberg, Falk and Gao, Wenlong and Schumacher,
    Stefan and Zentgraf, Thomas}, year={2026}, pages={2128–2133} }'
  chicago: 'Wetter, Helene, Jan Wingenbach, Falk Rehberg, Wenlong Gao, Stefan Schumacher,
    and Thomas Zentgraf. “Polarization- and Wave-Vector Selective Optical Metasurface
    with Near-Field Coupling.” <i>ACS Photonics</i> 13 (2026): 2128–33. <a href="https://doi.org/10.1021/acsphotonics.5c02865">https://doi.org/10.1021/acsphotonics.5c02865</a>.'
  ieee: 'H. Wetter, J. Wingenbach, F. Rehberg, W. Gao, S. Schumacher, and T. Zentgraf,
    “Polarization- and Wave-Vector Selective Optical Metasurface with Near-Field Coupling,”
    <i>ACS Photonics</i>, vol. 13, pp. 2128–2133, 2026, doi: <a href="https://doi.org/10.1021/acsphotonics.5c02865">10.1021/acsphotonics.5c02865</a>.'
  mla: Wetter, Helene, et al. “Polarization- and Wave-Vector Selective Optical Metasurface
    with Near-Field Coupling.” <i>ACS Photonics</i>, vol. 13, American Chemical Society
    (ACS), 2026, pp. 2128–33, doi:<a href="https://doi.org/10.1021/acsphotonics.5c02865">10.1021/acsphotonics.5c02865</a>.
  short: H. Wetter, J. Wingenbach, F. Rehberg, W. Gao, S. Schumacher, T. Zentgraf,
    ACS Photonics 13 (2026) 2128–2133.
date_created: 2026-04-02T07:25:30Z
date_updated: 2026-04-20T05:09:57Z
department:
- _id: '15'
- _id: '230'
- _id: '289'
- _id: '623'
doi: 10.1021/acsphotonics.5c02865
external_id:
  arxiv:
  - '2512.14452'
intvolume: '        13'
keyword:
- metasurface
- waveguides
- Dirac point
- polarization
- negative coupling
language:
- iso: eng
main_file_link:
- url: https://pubs.acs.org/doi/10.1021/acsphotonics.5c02865
page: 2128-2133
publication: ACS Photonics
publication_identifier:
  issn:
  - 2330-4022
  - 2330-4022
publication_status: published
publisher: American Chemical Society (ACS)
quality_controlled: '1'
status: public
title: Polarization- and Wave-Vector Selective Optical Metasurface with Near-Field
  Coupling
type: journal_article
user_id: '30525'
volume: 13
year: '2026'
...