Roadmap on Nonlocality in Photonic Materials and Metamaterials
Creators: name: Monticone, Francesco
name: Mortensen, N. Asger
name: Fernández-Domínguez, Antonio I.
name: Luo, Yu
name: Zheng, Xuezhi
name: Tserkezis, Christos
name: Khurgin, Jacob B.
name: Shahbazyan, Tigran V.
name: Chaves, André J.
name: Peres, Nuno M. R.
name: Wegner, Gino
name: Busch, Kurt
name: Hu, Huatian
name: Della Sala, Fabio
name: Zhang, Pu
name: Ciracì, Cristian
name: Aizpurua, Javier
name: Babaze, Antton
name: Borisov, Andrei G.
name: Chen, Xue-Wen
name: Christensen, Thomas
name: Yan, Wei
name: Yang, Yi
name: Hohenester, Ulrich
name: Huber, Lorenz
name: Wubs, Martijn
name: De Liberato, Simone
name: Gonçalves, P. A. D.
name: De Abajo, F. Javier García
name: Hess, Ortwin
name: Tarasenko, Illya
name: Cox, Joel D.
name: Jelver, Line
name: Dias, Eduardo J. C.
name: Sánchez, Miguel Sánchez
name: Margetis, Dionisios
name: Gómez-Santos, Guillermo
name: Stauber, Tobias
name: Tretyakov, Sergei
name: Simovski, Constantin
name: Pakniyat, Samaneh
name: Gómez-Díaz, J. Sebastián
name: Bondarev, Igor V.
name: Biehs, Svend-Age
name: Boltasseva, Alexandra
name: Shalaev, Vladimir M.
name: Krasavin, Alexey V.
name: Zayats, Anatoly V.
name: Alù, Andrea
name: Song, Jung-Hwan
name: Brongersma, Mark L.
name: Levy, Uriel
name: Long, Olivia Y.
name: Guo, Cheng
name: Fan, Shanhui
name: Bozhevolnyi, Sergey I.
name: Overvig, Adam
name: Prudêncio, Filipa R.
name: Silveirinha, Mário G.
name: Gangaraj, S. Ali Hassani
name: Argyropoulos, Christos
name: Huidobro, Paloma A.
name: Galiffi, Emanuele
name: Yang, Fan
name: Pendry, John B.
name: Miller, David A. B.
Publisher: name: arXiv
Year: 2025
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Photonic technologies continue to drive the quest for new optical materials with unprecedented responses. A major frontier in this field is the exploration of nonlocal (spatially dispersive) materials, going beyond the local, wavevector-independent assumption traditionally made in optical material modeling. On one end, the growing interest in plasmonic, polaritonic and quantum materials has revealed naturally occurring nonlocalities, emphasizing the need for more accurate models to predict and design their optical responses. This has major implications also for topological, nonreciprocal, and time-varying systems based on these material platforms. Beyond natural materials, artificially structured materials--metamaterials and metasurfaces--can provide even stronger and engineered nonlocal effects, emerging from long-range interactions or multipolar effects. This is a rapidly expanding area in the field of photonic metamaterials, with open frontiers yet to be explored. In the case of metasurfaces, in particular, nonlocality engineering has become a powerful tool for designing strongly wavevector-dependent responses, enabling enhanced wavefront control, spatial compression, multifunctional devices, and wave-based computing. Furthermore, nonlocality and related concepts play a critical role in defining the ultimate limits of what is possible in optics, photonics, and wave physics. This Roadmap aims to survey the most exciting developments in nonlocal photonic materials, highlight new opportunities and open challenges, and chart new pathways that will drive this emerging field forward--toward new scientific discoveries and technological advancements.