摘要： The synthesized graphene monolayer always has restrictions on its physical properties compared to the theoretical model of such material (e.g. area of single film, presence of defects, influence of substrate), so investigation of new graphene-based materials is required to implementation of real efficient terahertz devices. We report an experimental study showing that the conductivity dispersion spectra of modified graphene films (multilayer and intercalated with ferric chloride) in the range from 0.2 to 1.0 THz can be efficiently controlled using infrared optical pumping. It was found that the value of imaginary part of terahertz conductivity spectra of multilayer and intercalated graphene on dielectric substrates increases in absolute value with the rise of the pumping intensity, while the real part does not undergo significant changes. We employ a disorderly stacked multilayer graphene model which takes into account the attenuation of pumping intensity for theoretical analysis of the external optical pumping influence on the THz conductivity spectra of multi-layered graphene. Also, Drude–Smith model was applied to fit conductivity spectra of both multilayered and intercalated graphene samples. The models show adequate agreement with experimentally observed results.