▎ 摘　　要

Recently, terahertz (THz) nonreciprocal and functionality-switchable devices have drawn much attention. Here we report a magnetic-free THz unidirectional perfect absorber as well as a functionality-switchable device between the band-pass filter and perfect absorber based on dielectric-graphene multilayers containing a VO2 defect layer. We provide a theoretical explanation for the nonreciprocal transmission properties. The working frequencies of these devices can be tailored by using graphene layers of different chemical potentials. (C) 2022 Optica Publishing Group