Electrons in bilayers graphene (BLG) can exhibits qualitatively new properties than in single layers,such as interlayer drags and correlations.The electronic and transport properties of BLG differ significantly from single layer graphene SLG in many respects,particularly in the terahertz regime.Various models for low energy BLG exist in the literature depending on the coupling terms included,and whether electronic bands beyond the lowest energy subbands are retained.Many interesting results were obtained based on a model that includes only the most dominant of the interlayer coupling terms in BLG,as well as the usual nearest neighbor intralayer term.