  In this paper, optical properties of Chiral Graphene Nanoribbons both in
longitude and transverse polarization have been studied using density
functional theory calculation. It has been shown that the selection rule which
have been reported before for Armchair and Zigzag Graphene Nanoribbons are no
longer valid due to breaking symmetry on these new categorize of graphene
nanoribbons. However, still the edge states play a critical role in optical
absorption. It have been illustrated that depending on the polarization of
incident beam the absorption peaks are different while it is spread in the same
energy range. It is also suggested that the absorption of light is sensitive to
the chiral vector on the edges and direction of the light polarization. Due to
breaking symmetry in chiral graphene nanoribbons, absorption peak is changed
and it would be around 1000nm, introducing a new potential of graphene
nanoribbons for optoelectronic devices.
