Tunable TE/TM mode converter with an orthogonal graphene-based grating structure Yiqing Wang, Wenjie Shi, Qian Li, Yifan Chen, Jicheng Wang and Wei Liu Eur. Phys. J. Spec. Top., 231 4 (2022) 589-595 Published online: 13 January 2022 DOI: 10.1140/epjs/s11734-021-00382-9