  The dependence of the photocurrent generated in a Pd/graphene/Ti junction
device on the incident photon polarization is studied. Spatially resolved
photocurrent images were obtained as the incident photon polarization is
varied. The photocurrent is maximum when the polarization direction is
perpendicular to the graphene channel direction and minimum when the two
directions are parallel. This polarization dependence can be explained as being
due to the anisotropic electron-photon interaction of Dirac electrons in
graphene.
