Development of Terahertz-Range Planar Gyrotrons with Transverse Energy Extraction Operating at Cyclotron HarmonicsN.S. Ginzburg, T. Idehara, Yu.V. Zaslavsky, I.V. Zotova, M.Yu. Glyavin, A.S. Sergeev, A.M. Malkin and I.V. ZheleznovEPJ Web Conf., 187 (2018) 01008DOI: https://doi.org/10.1051/epjconf/201818701008