Manipulation of negative-index collimation beam using band-gap guidance Fengfu Shen, Ge Zhu, Qing Shi and Zengtao Lv Eur. Phys. J. Appl. Phys., 82 1 (2018) 10401 Published online: 18 July 2018 DOI: 10.1051/epjap/2018170212