Nature Nanotechnology, Published online: 20 January 2026; doi:10.1038/s41565-025-02099-5Optical computing is emerging as a low-power alternative by processing data with light instead of electrons. Advances in metasurfaces, plasmonics, and thin-film lithium niobate enable photonic circuits now being co-integrated with CMOS chips for hybrid, energy-efficient artificial intelligence (AI) computing.