Effect of geometry, anisotropy and composition on the third-order optical nonlinearities of multilayer hyperbolic metamaterials -INVITEDDomenico Genchi, Francesca Dodici, Tiziana Cesca and Giovanni MatteiEPJ Web Conf., 287 (2023) 05019DOI: https://doi.org/10.1051/epjconf/202328705019