Gate-tunable nearly total absorption in graphene with resonant metal back reflector Jiang-Tao Liu, Nian-Hua Liu, Li Wang, Xin-Hua Deng and Fu-Hai Su EPL, 104 5 (2013) 57002 Published online: 18 December 2013 DOI: 10.1209/0295-5075/104/57002