Significant enhancement of light absorption in undoped graphene using dielectric multilayer system

The interband optical conductivity of undoped graphene gives only 2.3% absorption of light regardless of the light frequency. In this work, we show that by enhancing the electric field on a graphene surface through the interference effect, the light absorption of an undoped monolayer graphene can be much enhanced up to 50%. The monolayer graphene is put at the center of a specially designed multilayer structure of dielectric media. The enhanced absorption can be achieved for any arbitrary frequency by changing the number of layers or the refractive index of the layers. We also show that the absorption of light is used by Joule's heating of graphene which can be applied for local heating by light.