Erbium ions (Er3+) used for photon upconversion suffer from a low absorption cross-section and a low brightness. The ability of silicon metasurfaces to provide greatly enhanced electrical near-fields is employed to gain a more than 2400-fold enhanced photon upconversion. With the aid of optical simulations using JCMsuite, the enhancement is attributed to the excitation of metasurface resonances from specific incident angles.
D. Ahiboz, et al. Metasurface-Enhanced Photon Upconversion upon 1550 nm Excitation. Adv. Opt. Mater. 2101285 (2021).