Seminar by Costantino De Angelis

Flat-optics devices exhibiting a linear local (LL) response are defined by a
position-dependent, linear transfer function, which can be locally tailored by engineering metaatoms arranged within metasurfaces. Spatial dispersion, i.e., nonlocality, is usually regarded as a nonideality in LL flat-optics devices. However, the nonlocal response of metasurfaces has been recently indicated as an effective means to achieve advanced functionalities [2]. Despite the advantages, linear approaches — both local and nonlocal — face limitations related to the restricted numerical aperture and frequency bandwidth. Here
we demonstrate that the combination of nonlinear and nonlocal effects in the same flat-optics device is a powerful strategy to achieve advanced image processing and analog computing functionalities with reduced structural complexity and increased efficiencies in terms of angular and frequency bandwidth [3].
[1] Hail, C.U., Foley, M., Sokhoyan, R. et al., Nat Commun 14, 8476 (2023).
[2] Overvig, A. and Alù, A., Laser Photonics Rev. 16, 2100633 (2022).
[3] de Ceglia, D., Alù, A., Neshev, D. N. and De Angelis, C., Opt. Mater. Express 14, 92 (2024).