Quasi-normal mode expansion as a tool for the design of nanophotonic devices Rémi Colom, Felix Binkowski, Fridtjof Betz, Martin Hammerschmidt, Lin Zschiedrich and Sven Burger EPJ Web Conf., 238 (2020) 05008 Published online: 20 August 2020 DOI: 10.1051/epjconf/202023805008