We conduct a theoretical study and numerical simulations of terahertz radiation generation in the medium based on armchair-edge nanoribbons and zigzag nanotubes with metallic conductivity. The multicascade mechanism of radiation generation is considered in the task of terahertz radiation generation. The level of the injection current in nanoparticle arrays has been estimated. The task expands to the similar medium where radiation current is generated with the use of infrared radiation stimulated absorption, for example, radiation of a CO2 laser. Numerical results for the effective dielectric function have been obtained with the use of the effective medium-approximation, the Maxwell-Garnett’s theory and the Maxwell-Garnett model with the Clausius-Mossotti correction (geometrical model arrays).