Tuning the dispersion relation of a plasmonic waveguide via graphene contact Yu Zhou, Cheng Wang, Di-Hu Xu, Ren-Hao Fan, Kun Zhang, Ru-Wen Peng, Qing Hu and Mu Wang EPL, 107 3 (2014) 34007 Published online: 31 July 2014 DOI: 10.1209/0295-5075/107/34007