Design and investigation of a low-threshold organic laser diode using mixed-order DFB cavities Yara El Droubi, Quentin Gaimard, Jeanne Solard, Mahmoud Chakaroun and Azzedine Boudrioua EPJ Web Conf., 266 (2022) 06005 Published online: 13 October 2022 DOI: 10.1051/epjconf/202226606005