Summary Data and source code relate to the article "Enhanced Purcell factor for nanoantennas supporting interfering resonances" [1], whose subject are the effects of coupled resonances and quasibound states in the continuum on the Purcell factor in dielectric resonant nanoantennas. The provided scripts reproduce the analysis of interfering resonances in a nanodisk coupled to an enclosed emitter and can be easily adapted for further investigations. Structure The cases refer to different aspect ratios of the nanodisk with (a and b) and without (c and d) substrate. The scans reproduce the data used to find the aspect ratios (a and c) supporting the maximal Purcell enhancement. RPExpand [2] is used for Riesz projection expansions, which quantify the interactions of the resonances. The directories resonance and scattering contain input files for the commercial software JCMsuite, which rigorously solves Maxwell's equations with the finite-element method (FEM). In order to switch to a custom setup, you must adapt these input files. If you want to recalculate all results, make sure that you remove the directories containing resultbags. These are stored in the directory results, e.g., results/case_a/resultbags. Requirements JCMsuite (tested with version: 4.6.3) Matlab (tested with version: R2019b) In order to run the scripts you must replace the corresponding place holders in the files by a path to your installation of JCMsuite. Free trial licenses are available, please refer to the homepage of JCMwave. [1] Rémi Colom, Felix Binkowski, Fridtjof Betz, Yuri Kivshar, Sven Burger, Enhanced Purcell factor for nanoantennas supporting interfering resonances, Physical Review Research 4, 023189 (2022), https://doi.org/10.1103/PhysRevResearch.4.023189 [2] Fridtjof Betz, Felix Binkowski, Sven Burger, RPExpand: Software for Riesz projection expansion of resonance phenomena, SoftwareX 15, 100763 (2021), https://doi.org/10.1016/j.softx.2021.100763

The authors acknowledge funding from the German Research Foundation (DFG, Excellence Cluster MATH+, EXC-2046/1, Project No. 390685689), the Helmholtz Association (Helmholtz Excellence Network SOLARMATH, Project No. ExNet-0042-Phase-2-3), and the German Federal Ministry of Education and Research (BMBF Forschungscampus MODAL, Project No. 05M20ZBM). Also, this project has received funding from the European Metrology Programme for Innovation and Research co-financed by the Participating States and by the European Union's Horizon 2020 research and innovation program (projects 20FUN05 SEQUME and 20FUN02 POLIGHT). Y.K. acknowledges support from the Australian Research Council (Grants No. DP200101168 and No. DP210101292).