Time-domain surface plasmon polaritons on a graphene sheet

A time-domain analysis is presented of the transient field excited by a vertical electric dipole on a graphene sheet described through a local scalar conductivity model valid in the intraband regime. The analysis is carried out by means of the double-deformation method of Tsang and Kong [J. Math. Phys. 20, 1170 (1979)JMAPAQ0022-248810.1063/1.524169], a modified modal technique which allows for defining a causal surface-plasmon-polariton (SPP) contribution to the total transient field that is also computationally very efficient for a graphene sheet. Numerical results are presented and validated against independent numerical full-wave simulations. The proposed approach provides a viable route to the direct time-domain investigation of the role of SPPs in graphene-based structures employed in ultra-wide-band nanosystems.