article published yes Rebecca Aschwanden author Nicolás Claro-Rodríguez author Ruizhe Zhao author Patricia Anna Maria Kallert author 723320009-0007-5230-0223 Tobias Krieger author Quirin Buchinger author Saimon F. Covre da Silva author Sandra Stroj author Michele Rota author Sven Höfling author Tobias Huber-Loyola author Armando Rastelli author Rinaldo Trotta author Lingling Huang author Tim Bartley author 49683 Klaus Jöns author 85353 Thomas Zentgraf author 305250000-0002-8662-1101 15 department 230 department 289 department 623 department TRR 142 - Project Area A project TRR 142; TP A08: Nichtlineare Kopplung von Zwischenschicht-Exzitonen in van der Waals-Heterostrukturen an plasmonische und dielektrische Nanokavitäten project TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen project 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 overcome 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. American Chemical Society (ACS)2026 eng metasurfacebeamsplitterinterferometerquantum networksingle photonsnanophotonics 2330-4022 2330-4022 2603.2509010.1021/acsphotonics.6c00096 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> @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} } 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>. 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). 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> 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>. 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>. 654602026-04-20T04:52:59Z2026-04-20T05:01:00Z