  A multiple-graphene-layer (MGL) structure with a stack of GLs and a highly
conducting bottom GL on SiC substrate pumped by optical radiation is considered
as an active region of terahertz (THz) and far infrared (FIR) lasers with
external metal mirrors. The dynamic conductivity of the MGL structure is
calculated as a function of the signal frequency, the number of GLs, and the
optical pumping intensity. The utilization of optically pumped MGL structures
might provide the achievement of lasing with the frequencies of about 1 THz at
room temperature due to a high efficiency.
