Strong enhancement of light absorption and highly directive thermal emission in graphene.

Graphene is a two-dimensional material with exotic electronic, optical and thermal properties. The optical absorption in monolayer graphene is limited by the fine structure constant α. Here we demonstrated the strong enhancement of light absorption and thermal radiation in homogeneous graphene. Numerical simulations show that the light absorbance can be controlled from near zero to 100% by tuning the Fermi energy. Moreover, a set of periodically located absorption peaks is observed at near grazing incidence. Based on this unique property, highly directive comb-like thermal radiation at near-infrared frequencies is demonstrated.