Magneto-optical properties of the photon echo: status of research and prospects of application I.I. Popov, A.U. Bahadurov, N.S. Vashurin, E.A. Vinogradov, V.O. Kompanets, S.V. Chekalin and S.E. Putilin EPJ Web Conf., 161 (2017) 01010 Published online: 31 October 2017 DOI: 10.1051/epjconf/201716101010