  Optical extinction and absorption enhancement in the infrared range of a
monolayer graphene sheet by patterning split ring resonators (SRRs) is studied.
It is found that the electric mode is stronger in enhancing infrared extinction
and absorption compared to the magnetic mode and other higher-order modes. We
improve the infrared extinction of the SRR graphene sheet by increasing the
graphene area ratio in the SRR unit cell design. With the increase of the
graphene area ratio, the radiation ability of the electric dipolar mode and
dissipation of graphene compete for a maximum infrared absorption of about 50%.
The findings on enhancing infrared extinction and absorption of graphene sheet
by harvesting the electric dipolar mode may have potential applications in
terahertz and infrared detection and modulation for graphene photonics and
optoelectronics.
