Prospective visible laser active media based on disordered fluorite-type structure crystals Oleg Morozov, Sergey Kuznetsov, Vasiliy Konyushkin, Andrey Nakladov, Alexey Nizamitdinov, Pavel Fedorov and Vadim Semashko EPJ Web Conf., 220 (2019) 03024 Published online: 25 October 2019 DOI: 10.1051/epjconf/201922003024