Third-order nonlinear optical properties of CuS/reduced graphene oxide nanocomposites Yu Hao, Lan Yang, Jinze Li, Ruonan Xing and Yuzong Gu Eur. Phys. J. Appl. Phys., 94 2 (2021) 20401 Published online: 28 May 2021 DOI: 10.1051/epjap/2021200278