▎ 摘　　要

We study parameters optimization of negative dynamic conductivity in terahertz range of frequencies in optically and electrically pumped graphene structures. Graphene structures consist of single-graphene-layer (SGL) structures and multiple-structure-layer (MGL) structures, The optimization of parameters including quasi-Femi energy, effective temperature, electron-hole momentum relaxation time and the number of graphene layer (GL) etc. were studied systematically. From the simulations we find that the negative dynamic conductivity in optically pumped graphene structures can be largest when effective temperature T = 50K, relaxation time tau =10 ps, quasi-Femi energy epsilon(F) = 55meV and the number of GL K = 120. The negative dynamic conductivity in electrically pumped graphene structures can be largest when T = 50K, tau =10 ps, bias voltage V = 120meV and low gate voltage. Meanwhile, the negative dynamic conductivity can be larger in electrically pumped graphene structures than that in optically pumped graphene structures.