Broadband THz quantum cascade laser frequency combs with surface emission and inverse-designed facet reflectorsUrban Senica, Sebastian Gloor, Paolo Micheletti, Mattias Beck, Jérôme Faist and Giacomo ScalariEPJ Web Conf., 287 (2023) 07009DOI: https://doi.org/10.1051/epjconf/202328707009