First hyperpolarizability of cellulose nanocrystals: an experimental and theoretical investigation - Legat, Thibaut; Mairesse, Francois; Dok, Ahmet R.; de Coene, Yovan; Thielemans, Wim; Champagne, Benoit; Van Cleuvenbergen, Stijn (ISSN:2050-750X ; ISSN:2050-7518 ; Journal Of Materials Chemistry B, vol. 13 (3), (1024-1036, 2025)