Cascaded Metasurface Interferometer for Multipath Interference with Classical and Quantum Light
Abstract
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 2x2-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 realize a multimode interferometer composed of two cascaded metasurfaces. We characterize the individual and cascaded metasurfaces 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.
Keywords
Cite
@article{arxiv.2603.25090,
title = {Cascaded Metasurface Interferometer for Multipath Interference with Classical and Quantum Light},
author = {Rebecca Aschwanden and Nicolás Claro-Rodríguez and Ruizhe Zhao and Patricia Kallert and Tobias Krieger and Quirin Buchinger and Saimon F. Covre da Silva and Sandra Stroj and Michele Rota and Sven Höfling and Tobias Huber-Loyola and Armando Rastelli and Rinaldo Trotta and Lingling Huang and Tim Bartley and Klaus D. Jöns and Thomas Zentgraf},
journal= {arXiv preprint arXiv:2603.25090},
year = {2026}
}