Polarization Dependent Optical Responses of Graphene Nanoribbons*

The optical response of an anisotropic system depends on light's polarization direction. In this study, we perform first-principle calculations on polarization dependent optical absorption spectra of graphene nanoribbons at the RPA and GW-BSE level. We observe significant polarization dependent features. We demonstrate the many-body origins of these features. We also discuss the polarization dependent optical responses of other carbon nanostructures, and connect our work to experimental measurements.